FINAL REPORT 

HAYNES GENERATING STATION

CLEAN WATER ACT

SECTION 316(b) IMPINGEMENT 

MORTALITY AND ENTRAINMENT 

CHARACTERIZATION STUDY

Prepared by 

MBC Applied Environmental Sciences 

Tenera Environmental, Inc. 

URS Corporation 

for 

City of Los Angeles Department of Water and Power 

111 N. Hope Street 

Los Angeles, California 90012-2607 

November 30, 2007
Haynes Generating Station 

IM&E Final Report Table of Contents

 i

TABLE OF CONTENTS 

SECTION PAGE

1.0 EXECUTIVE SUMMARY ................................................................................ 1-1

1.1 Entrainment......................................................................................................................1-1

1.2 Source Water....................................................................................................................1-2

1.3 Impingement ....................................................................................................................1-2

1.4 Impact Assessment ..........................................................................................................1-3

2.0 INTRODUCTION............................................................................................ 2-1

2.1 Background and Overview ..............................................................................................2-1

2.1.1 Section 316(b) of the Clean Water Act...............................................................2-2

2.1.2 Development of the Study Plan ..........................................................................2-3

2.1.3 Study Plan Objectives.........................................................................................2-5

2.1.4 Study Plan Approach ..........................................................................................2-6

2.2 Report Organization.........................................................................................................2-7

2.3 Contractors and Responsibilities......................................................................................2-7

3.0 DESCRIPTION OF THE GENERATING STATION AND CHARACTERISTICS 

OF THE SOURCE WATER BODY ................................................................... 3-1

3.1 Description of the Generating Station..............................................................................3-1

3.2 Description of the Cooling Water Intake System ............................................................3-2

3.2.1 System Configuration and Operation..................................................................3-2

3.2.2 Circulating Water Pump Flows...........................................................................3-6

3.3 Environmental Setting .....................................................................................................3-7

3.3.1 Physical Description ...........................................................................................3-7

3.3.1.1 Physical Features ...................................................................................3-7

3.3.1.2 Temperature and Salinity.......................................................................3-9

3.3.1.3 Tides and Currents...............................................................................3-10

3.3.2 Source Water Definition ...................................................................................3-19

3.3.2.1 Study Requirements and Rationale......................................................3-19

3.3.2.2 Methods for Calculating HnGS Source Water.....................................3-19

3.3.3 Biological Resources ........................................................................................3-23

3.3.3.1 Habitat Variation .................................................................................3-23

3.3.3.2 Nursery Grounds..................................................................................3-24

3.3.3.3 Fish Diversity.......................................................................................3-24

3.3.3.4 Shellfish Diversity ...............................................................................3-25

3.3.3.5 Protected Species .................................................................................3-25

4.0 COOLING WATER INTAKE STRUCTURE ENTRAINMENT AND SOURCE 

WATER STUDY............................................................................................. 4-1

4.1 Introduction......................................................................................................................4-1

4.1.1 Discussion of Species to be Analyzed ................................................................4-1

4.1.1.1 Fish ........................................................................................................4-2

4.1.1.2 Shellfish .................................................................................................4-2

4.1.1.3 Protected Species ...................................................................................4-2

4.2 Historical Data .................................................................................................................4-3

4.2.1 Summary of Historical Data ...............................................................................4-3

4.2.2 Relevance to Current Conditions........................................................................4-6

4.2.3 QA/QC Procedures and Data Validation ............................................................4-6
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4.3 Methods ...........................................................................................................................4-7

4.3.1 Field Sampling....................................................................................................4-7

4.3.1.1 Cooling-Water Intake System Entrainment Sampling...........................4-7

4.3.1.2 Source Water Sampling .........................................................................4-7

4.3.2 Laboratory Analysis............................................................................................4-8

4.3.3 QA/QC Procedures & Data Validation.............................................................4-10

4.3.4 Data Analysis....................................................................................................4-10

4.3.4.1 Entrainment Estimates .........................................................................4-10

4.3.4.2 Demographic Approaches....................................................................4-11

4.3.4.3 Empirical Transport Model..................................................................4-15

4.4 Sampling Summary........................................................................................................4-19

4.5 Results............................................................................................................................4-20

4.5.1 Cooling Water Intake Structure Entrainment Summary...................................4-20

4.5.1.1 Fishes ...................................................................................................4-20

4.5.1.2 Shellfishes............................................................................................4-27

4.5.2 Source Water Summary ....................................................................................4-28

4.5.2.1 Fishes ...................................................................................................4-28

4.5.2.2 Shellfishes............................................................................................4-31

4.5.3 Results by Species for Cooling Water Intake Structure Entrainment...............4-32

4.5.3.1 Anchovies (Engraulidae) .....................................................................4-32

4.5.3.2 Silversides (Atherinopsidae)................................................................4-41

4.5.3.3 White croaker (Genyonemus lineatus).................................................4-50

4.5.3.4 Combtooth blennies (Hypsoblennius spp.) ..........................................4-57

4.5.3.5 CIQ Goby complex (Clevelandia, Ilypnus, Quietula) .........................4-67

5.0 IMPINGEMENT STUDY ................................................................................. 5-1

5.1 Introduction......................................................................................................................5-1

5.1.1 Species to be Analyzed.......................................................................................5-1

5.2 Historical Data .................................................................................................................5-1

5.2.1 Summary of Historical Data ...............................................................................5-1

5.2.2 Relevance to Current Conditions........................................................................5-2

5.3 Methods ...........................................................................................................................5-2

5.3.1 Field Sampling....................................................................................................5-3

5.3.2 QA/QC Procedures & Data Validation...............................................................5-4

5.3.3 Data Analysis......................................................................................................5-5

5.4 Sampling Summary..........................................................................................................5-6

5.5 Results..............................................................................................................................5-7

5.5.1 Impingement Results ..........................................................................................5-7

5.5.2 Fish Impingement Results by Species ..............................................................5-20

5.5.2.1 Queenfish (Seriphus politus) ...............................................................5-20

5.5.2.2 Topsmelt (Atherinops affinis) ..............................................................5-26

5.5.2.3 Northern anchovy (Engraulis mordax)................................................5-30

5.5.2.4 Pipefishes (Syngnathidae)....................................................................5-34

5.5.2.5 Shiner perch (Cymatogaster aggregata)..............................................5-39

5.5.2.6 Specklefin midshipman (Porichthys myriaster) ..................................5-44

5.5.2.7 Pacific sardine (Sardinops sagax)........................................................5-48

5.5.2.8 California Skate (Raja inornata) .........................................................5-50

5.5.2.9 Jack Mackerel (Trachurus symmetricus)............................................5-51

5.5.2.10 Vermilion rockfish (Sebastes miniatus)...............................................5-54

5.5.3 Shellfish Impingement by Species....................................................................5-55

5.5.3.1 California two-spot octopus (Octopus bimaculatus/bimaculoides).....5-55
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5.5.3.2 California seahare (Aplysia californica) ..............................................5-59

5.5.3.3 Market squid (Loligo opalescens)........................................................5-63

6.0 IMPACT ASSESSMENT.................................................................................. 6-1

6.1 Impact Assessment Overview: Data and Approach.........................................................6-1

6.1.1 CWIS impacts.....................................................................................................6-2

6.1.2 Review of IM&E Sampling Approach ...............................................................6-2

6.1.3 Approaches for Assessment of CWIS Impacts...................................................6-4

6.1.3.1 Adverse Environmental Impact (AEI) Standard....................................6-5

6.1.4 Relating Measured Impacts to Source Populations ............................................6-6

6.2 Summary of Entrainment and Impingement Results .......................................................6-9

6.2.1 Taxa Composition...............................................................................................6-9

6.2.2 Temporal Occurrence .......................................................................................6-13

6.2.3 Combined Analysis and Modeling Results for Selected Species .....................6-14

6.3 Assessment of Taxa by Habitat Type ............................................................................6-17

6.3.1 Background on Oceanographic Setting and Population Trends .......................6-17

6.3.1.1 Habitat Associations and Fisheries ......................................................6-19

6.3.2 Bay and Harbor Habitats...................................................................................6-20

6.3.3 Rocky Reef and Kelp Bed Habitats ..................................................................6-23

6.3.4 Coastal Pelagic Habitats ...................................................................................6-24

6.3.5 Shelf Habitats....................................................................................................6-29

6.3.6 Deep Pelagic Habitats.......................................................................................6-30

6.4 Conclusions and Discussion ..........................................................................................6-30

6.4.1 IM&E Losses Relative to 1977 USEPA AEI Criteria ......................................6-32

7.0 LITERATURE CITED..................................................................................... 7-1

APPENDICES 

Appendix A. Physical Oceanographic Data 

Appendix B. Field Sampling and Sample Processing Procedures 

Appendix C. Model Parameterization 

Appendix D. Entrainment Data 

Appendix E. Impingement Data 

Appendix F. Master Species Lists 
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IM&E Final Report Table of Contents

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LIST OF TABLES

Table 1.4-1. Summary of entrainment and impingement sampling results and model output for 

common fish and invertebrate species based on actual flows at HnGS in 2006.*.............................1-6

Table 1.4-2. Summary of entrainment and impingement sampling results and model output for 

common fish and invertebrate species based on design flows at HnGS in 2006.*............................1-7

Table 1.4-3. Habitat associations for taxa included in assessment of CWIS effects at the HnGS.............1-8

Table 3.2-1. Daily average cooling water flow volumes by unit at HnGS in 2006. ..................................3-7

Table 3.3-1. Temperature and salinity of surface and bottom waters off Alamitos Bay, 2001–2004. ....3-10

Table 3.3-2. ADCP deployment parameters for current meters in the vicinity of HnGS (Stations 

CM 1 and CM 2)..............................................................................................................................3-13

Table 4.2-1. Summary of larval fish and fish egg densities, and annual entrainment mortality 

estimates for critical taxa for HnGS in 1979−1980 (from IRC 1981). ..............................................4-5

Table 4.2-2. Summary of planktonic invertebrate densities and annual entrainment mortality 

estimates for critical taxa for Haynes Generating Station in 1979−1980 (from IRC 1981). .............4-5

Table 4.4-1. Entrainment/source water surveys and number of samples collected from January 

through December 2006...................................................................................................................4-19

Table 4.5-1. Average concentration of larval fishes and fish eggs in entrainment samples collected 

at HnGS (Station E3) in 2006. .........................................................................................................4-21

Table 4.5-2. Calculated total annual entrainment of larval fishes and fish eggs at HnGS in 2006 

based on actual and design cooling water intake pump flows. ........................................................4-23

Table 4.5-3. Average concentration of target invertebrate larvae in entrainment samples collected at 

HnGS (Station E3) in 2006..............................................................................................................4-27

Table 4.5-4. Calculated total annual entrainment of target shellfish larvae at HnGS in 2006 based 

on actual and design (maximum) cooling water intake pump flows. ..............................................4-27

Table 4.5-5. Average concentration of larval fishes in samples collected at HnGS source water 

stations in and near Alamitos Bay (Stations H2−H4, S1−S3 and O1−O3) in 2006.........................4-28

Table 4.5-6. Average concentration of larval target invertebrates in samples collected at HnGS 

source water stations in and near Alamitos Bay (Stations H2−H4, S1−S3 and O1−O3) in 2006. ..4-31

Table 4.5-7. Annual landings and revenue for northern anchovy in the Los Angeles region based on 

PacFIN data......................................................................................................................................4-35

Table 4.5-8. Stage-specific life history parameters for northern anchovy (Engraulis mordax) 

modified from Butler et al. (1993). Z = instantaneous daily mortality; S = finite survival rate. .....4-38

Table 4.5-9. Survivorship table for adult northern anchovy (Engraulis mordax) from Butler et al. 

(1993) showing spawners (Lx) surviving at the start of age interval and numbers of eggs 

spawned annually (Mx). ..................................................................................................................4-39

Table 4.5-10. Results of FH modeling for anchovy larvae based on entrainment estimates 

calculated using actual and design (maximum) CWIS flows. .........................................................4-39

Table 4.5-11. Results of AEL modeling for northern anchovy larvae based on entrainment estimates 

calculated using actual and design (maximum) CWIS flows. .........................................................4-40

Table 4.5-12. ETM data and results for northern anchovy larvae based on actual and design 

(maximum) cooling water flows and a sampling volume in the nearshore of 140,698,222 m3

.......4-41

Table 4.5-13. Annual landings for jacksmelt and topsmelt in the Southern California region based 

on RecFIN data (values are numbers of fish). .................................................................................4-44

Table 4.5-14. Average concentrations and annual entrainment mortality of silverside taxa at HnGS. ...4-46
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Table 4.5-15. ETM data and results for silverside larvae based on actual and design (maximum) 

cooling water flows sampling volume in the nearshore of 140,698,222 m3

. ...................................4-50

Table 4.5-16. Annual landings and revenue for white croaker in the Los Angeles region based on 

PacFIN data......................................................................................................................................4-52

Table 4.5-17. Results of FH modeling for white croaker eggs based on entrainment estimates 

calculated using actual and design (maximum) CWIS flows. .........................................................4-56

Table 4.5-18. ETM data and results for white croaker larvae based on actual and design (maximum) 

cooling water flows sampling volume in the nearshore of 140,698,222 m3

. ...................................4-57

Table 4.5-19. Survivorship table for adult combtooth blenny from data in Stephens (1969) showing 

spawners (Lx) surviving to the age interval and numbers of eggs spawned annually (Mx)............4-64

Table 4.5-20. Results of FH modeling for combtooth blenny larvae based on entrainment estimates 

calculated using actual and design (maximum) CWIS flows. .........................................................4-65

Table 4.5-21. Results of AEL modeling for combtooth blenny larvae based on entrainment 

estimates calculated using actual and design (maximum) CWIS flows. .........................................4-66

Table 4.5-22. ETM data and results for combtooth blenny larvae based on actual and design 

(maximum) cooling water flows sampling volume in the nearshore of 140,698,222 m3

. ...............4-67

Table 4.5-23. Total lifetime fecundity estimates for three goby species based on a life table in 

Brothers (1975)................................................................................................................................4-74

Table 4.5-24. Results of FH modeling for CIQ goby complex larvae based on entrainment 

estimates calculated using actual and design (maximum) CWIS flows. .........................................4-74

Table 4.5-25. Results of AEL modeling for CIQ goby complex larvae based on entrainment 

estimates calculated using actual and design (maximum) CWIS flows. .........................................4-75

Table 4.5-26. ETM data and results for CIQ goby larvae based on actual and design (maximum) 

cooling water flows sampling volume in the nearshore of 140,698,222 m3

. ...................................4-76

Table 5.4-1. Number of impingement surveys at HnGS in 2006 by unit. .................................................5-6

Table 5.5-1. HnGS fish impingement sampled abundance and biomass during 2006...............................5-8

Table 5.5-2. Annual HnGS fish impingement estimates based on both actual and design 

(maximum) cooling water flows......................................................................................................5-10

Table 5.5-3. HnGS macroinvertebrate impingement sampled abundance and biomass during 2006......5-12

Table 5.5-4. Annual HnGS macroinvertebrate impingement estimates based on both actual and 

design (maximum) cooling water flows. .........................................................................................5-14

Table 5.5-5. Percent of total impingement by unit at HnGS in 2006.......................................................5-15

Table 5.5-6. Annual recreational landings for queenfish in the Los Angeles region based on 

RecFIN data. ....................................................................................................................................5-21

Table 5.5-7 Queenfish life history parameters used in equivalent adult modeling..................................5-25

Table 5.5-8. Northern anchovy life history parameters used in equivalent adult modeling. ...................5-33

Table 5.5-9. Annual landings and revenue for surfperches in the Los Angeles region based on 

PacFIN data......................................................................................................................................5-40

Table 5.5-10. Annual landings and revenue for Pacific sardine in the Los Angeles region based on 

PacFIN data......................................................................................................................................5-49

Table 5.5-11. Pacific sardine life history parameters used in equivalent adult modeling........................5-50

Table 5.5-12. Annual landings and revenue for jack mackerel in the Los Angeles region based on 

PacFIN data......................................................................................................................................5-53

Table 5.5-13. Annual landings and revenue for vermilion rockfish in the Los Angeles region based 

on PacFIN data.................................................................................................................................5-55
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Table 5.5-14. Annual landings and revenue for market squid in the Los Angeles region based on 

PacFIN data......................................................................................................................................5-65

Table 6.1-1. Habitat associations for taxa included in assessment of CWIS effects at the HnGS. 

Primary habitat in bold, upper case and secondary habitat in lower case..........................................6-9

Table 6.2-1. Rank and estimated annual entrainment of most common fish larvae, fish eggs, and 

target shellfishes at HnGS in 2006...................................................................................................6-11

Table 6.2-2. Rank and estimated annual impingement of the most common fish taxa at HnGS in 

2006 by estimated abundance and weight for actual and design normal flows. Heat treatment 

mortality included............................................................................................................................6-12

Table 6.2-3. Rank and estimated annual impingement of the most common invertebrates at HnGS 

in 2006 by estimated abundance and weight for actual and design normal flows. Heat 

treatment mortality included............................................................................................................6-13

Table 6.2-4. Summary of entrainment and impingement sampling results and model output for 

common fish and invertebrate species based on actual flows at HnGS in 2006..............................6-15

Table 6.2-5. Summary of entrainment and impingement sampling results and model output for 

common fish and invertebrate species based on design flows at HnGS in 2006.............................6-16

Table 6.3-1. Percent of larvae entrained (abundance) or adults/juveniles impinged (biomass) 

associated with general habitat types and fisheries..........................................................................6-19

Table 6.4-1. Comparison of larval fish densities and total annual entrainment at HnGS from studies 

in 1978−1979 and studies in 2006. ..................................................................................................6-32

Table 6.4-2. Fish and shellfish species under NMFS federal management or with CDFG special 

status entrained and/or impinged at HnGS in 2006 based on actual flow volumes.........................6-34

Table 6.4-3. Summary of positive time series findings for fish species in detail evaluation with 

respect to oceanographic variables (ENSO, SST, and PDO), fishing effects and the current 

population trends..............................................................................................................................6-35
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LIST OF FIGURES

Figure 3.1-1. Location of the HnGS and AES Alamitos Generating Station (AGS).................................3-1

Figure 3.2-1. Top view of the beginning of the Haynes Generating Station intake adjacent to the 

Long Beach Marina (not to scale)......................................................................................................3-3

Figure 3.2-2. Site plan of the Haynes Generating Station (not to scale)....................................................3-4

Figure 3.2-3. Plan view of Haynes Generating Station screenhouses........................................................3-5

Figure 3.2-4. Daily cooling water flow volumes at the HnGS from January 2006 to February 2007. ......3-6

Figure 3.3-1. Aerial view of Alamitos Bay and San Gabriel River outlet vicinity....................................3-8

Figure 3.3-2. Current patterns in Los Angeles and Long Beach Harbors predicted by a depthaveraged two-dimensional hydrodynamic model developed by the US Army Corps of 

Engineers. ........................................................................................................................................3-12

Figure 3.3-3. Net displacement at current meter stations CM 1 and CM 2 from January 2006 to 

January 2007....................................................................................................................................3-15

Figure 3.3-4. Cumulative current vectors from Station CM 1 in San Pedro Bay from January 2006 

to January 2007................................................................................................................................3-16

Figure 3.3-5. Cumulative current vectors from Station CM 2 in San Pedro Bay from January 2006 

to January 2007................................................................................................................................3-17

Figure 3.3-6. Composite cumulative current vectors from Stations CM 1 (upcoast) and CM 2 

(onshore) in San Pedro Bay from January 2006 to January 2007....................................................3-18

Figure 3.3-7. Source water boundaries and bathymetry defined for ETM modeling effects of HnGS....3-21

Figure 3.3-8. Correspondence of tidal heights estimated at Station CM 1 and at Port of Los Angeles 

Outer Harbor (POLA), August 2006. ..............................................................................................3-22

Figure 3.3-9. Estimates of Alamitos Bay daily tidal inflow and outflow volumes from January to 

December 2006................................................................................................................................3-22

Figure 3.3-10. View of Long Beach Marina and HnGS intake structure below water surface along 

concrete bulkhead. ...........................................................................................................................3-23

Figure 4.2-1. Locations of entrainment, near-field and far-field sampling stations for 1978–79 

316(b) study [figure from IRC (1981)]..............................................................................................4-4

Figure 4.3-1. Location map of HnGS entrainment (E3) and source water sampling stations....................4-9

Figure 4.5-1. Mean concentration (# / 1,000 m3 [264,172 gal] − wide bars) and standard deviation 

(narrow bars) of all larval fishes collected at entrainment Station E3 during 2006.........................4-25

Figure 4.5-2. Mean concentration (# / 1,000 m3 [264,172 gal] − wide bars) and standard deviation 

(narrow bars) of fish eggs collected at entrainment Station E3 during 2006...................................4-25

Figure 4.5-3. Mean concentration (#/1.0 m3 [264 gal]) of all fish larvae at entrainment Station E3 

during night (Cycle 3) and day (Cycle 1) sampling.........................................................................4-26

Figure 4.5-4. Mean concentration (#/1.0 m3 [264 gal]) of all fish eggs at entrainment Station E3 

during night (Cycle 3) and day (Cycle 1) sampling.........................................................................4-26

Figure 4.5-5. Mean concentration (# / 1,000 m3 [264,172 gal] − wide bars) and standard deviation 

(narrow bars) of all larval fishes collected at HnGS source water stations during 2006. ................4-30

Figure 4.5-6. Mean concentration (# / 1.0 m3 [264 gal]) of all larval fishes collected at HnGS source 

water stations during night (Cycle 3) and day (Cycle 1) sampling..................................................4-30

Figure 4.5-7. Mean concentration (# / 1,000 m3 [264,172 gal] − wide bars) and standard deviation 

(narrow bars) of anchovy larvae collected at HnGS entrainment Station E3 during 2006..............4-36

Figure 4.5-8. Mean concentration (# / 1,000 m3 [264,172 gal] − wide bars) and standard deviation 

(narrow bars) of anchovy larvae collected at HnGS source water stations during 2006. ................4-36
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Figure 4.5-9. Mean concentration (#/1.0 m3 [264 gal]) of anchovy larvae at entrainment Station E3 

during night (Cycle 3) and day (Cycle 1) sampling.........................................................................4-37

Figure 4.5-10. Length (mm) frequency distribution for larval anchovy collected at entrainment 

stations in Alamitos Bay. .................................................................................................................4-37

Figure 4.5-11. Silverside fishery and population trends: a) Southern California recreational 

landings, b) King Harbor observational data, and c) Ocean Resource Enhancement Hatchery 

Program (OREHP) gill net monitoring data. Error bars are ± 1 S.E................................................4-45

Figure 4.5-12. Mean concentration (# / 1,000 m3 [264,172 gal] − wide bars) and standard deviation 

(narrow bars) of silverside larvae collected at HnGS entrainment Station E3 during 2006. ...........4-47

Figure 4.5-13. Mean concentration (# / 1,000 m3 [264,172 gal] − wide bars) and standard deviation 

(narrow bars) of silverside larvae collected at HnGS source water stations during 2006. ..............4-47

Figure 4.5-14. Mean concentration (#/1.0 m3 [264 gal]) of silverside larvae at entrainment Station 

E3 during night (Cycle 3) and day (Cycle 1) sampling. ..................................................................4-48

Figure 4.5-15. Length (mm) frequency distribution for larval silversides collected at entrainment 

stations in Alamitos Bay. .................................................................................................................4-48

Figure 4.5-16. Mean concentration (# / 1,000 m3 [264,172 gal] − wide bars) and standard deviation 

(narrow bars) of white croaker larvae collected at HnGS entrainment Station E1 during 2006......4-53

Figure 4.5-17. Mean concentration (# / 1,000 m3 [264,172 gal] − wide bars) and standard deviation 

(narrow bars) of white croaker larvae collected at HnGS source water stations during 2006.........4-54

Figure 4.5-18. Mean concentration (#/1.0 m3 [264 gal]) of white croaker larvae at entrainment 

Station E1 during night (Cycle 3) and day (Cycle 1) sampling. ......................................................4-54

Figure 4.5-19. Length (mm) frequency distribution for larval white croaker collected at entrainment 

Station E1.........................................................................................................................................4-55

Figure 4.5-20. Abundance of combtooth blennies collected per boulder at King Harbor, Redondo 

Beach, California from 1984−2006 (from Pondella, unpubl. data). ................................................4-60

Figure 4.5-21. Mean concentration (# / 1,000 m3 [264,172 gal] − wide bars) and standard deviation 

(narrow bars) of combtooth blenny larvae collected at HnGS entrainment Station E3 during 

2006. ................................................................................................................................................4-62

Figure 4.5-22. Mean concentration (# / 1,000 m3 [264,172 gal] − wide bars) and standard deviation 

(narrow bars) of combtooth blenny larvae collected at HnGS source water stations during 

2006. ................................................................................................................................................4-62

Figure 4.5-23. Mean concentration (#/1.0 m3 [264 gal]) of combtooth blenny larvae at entrainment 

Station E3 during night (Cycle 3) and day (Cycle 1) sampling. ......................................................4-63

Figure 4.5-24. Length (mm) frequency distribution for combtooth blenny larvae collected at 

entrainment stations in Alamitos Bay..............................................................................................4-63

Figure 4.5-25. Mean concentration (# / 1,000 m3 [264,172 gal] − wide bars) and standard deviation 

(narrow bars) of unidentified goby larvae (CIQ gobies) collected at HnGS entrainment Station 

E3 during 2006.................................................................................................................................4-71

Figure 4.5-26. Mean concentration (# / 1,000 m3 [264,172 gal] − wide bars) and standard deviation 

(narrow bars) unidentified goby larvae (CIQ gobies) collected at HnGS source water stations 

during 2006......................................................................................................................................4-71

Figure 4.5-27. Mean concentration (#/1.0 m3 [264 gal]) of unidentified goby larvae at entrainment 

Station E3 during night (Cycle 3) and day (Cycle 1) sampling. ......................................................4-72

Figure 4.5-28. Length (mm) frequency distribution for unidentified goby larvae collected at 

entrainment stations in Alamitos Bay..............................................................................................4-72

Figure 5.5-1. Mean concentration (# / 1,000,000 m3 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of fishes in HnGS normal operation impingement samples during 2006.........5-16
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Figure 5.5-2. Mean biomass (kg / 1,000,000 m3 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of fishes in HnGS normal operation impingement samples during 2006.........5-16

Figure 5.5-3. Mean concentration (# / 1,000,000 m3 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of invertebrates in HnGS normal operation impingement samples during 

2006. ................................................................................................................................................5-17

Figure 5.5-4. Mean biomass (kg / 1,000,000 m3 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of invertebrates in HnGS normal operation impingement samples during 

2006. ................................................................................................................................................5-17

Figure 5.5-5. Mean concentration (# / 1,000,000 m3 [264.172 million gal]) of fishes in normal 

operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling.....................5-18

Figure 5.5-6. Mean biomass (kg / 1,000,000 m3 [264.172 million gal]) of fishes in normal operation 

impingement samples during night (Cycle 3) and day (Cycle 1) sampling.....................................5-18

Figure 5.5-7. Mean concentration (# / 1,000,000 m3 [264.172 million gal]) of invertebrates in 

normal operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling.........5-19

Figure 5.5-8. Mean biomass (kg / 1,000,000 m3 [264.172 million gal]) of invertebrates in normal 

operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling.....................5-19

Figure 5.5-9. Mean concentration (# / 1,000,000 m3 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of queenfish in HnGS normal operation impingement samples during 

2006. ................................................................................................................................................5-23

Figure 5.5-10. Mean biomass (kg / 1,000,000 m3 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of queenfish in HnGS normal operation impingement samples during 

2006. ................................................................................................................................................5-23

Figure 5.5-11. Mean concentration (# / 1,000,000 m3 [264.172 million gal]) of queenfish in normal 

operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling.....................5-24

Figure 5.5-12. Mean biomass (kg / 1,000,000 m3 [264.172 million gal]) of queenfish in normal 

operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling.....................5-24

Figure 5.5-13. Length (mm) frequency distribution for queenfish collected in impingement 

samples.............................................................................................................................................5-25

Figure 5.5-14. Age class distribution of queenfish collected in HnGS impingement samples................5-26

Figure 5.5-15. Mean concentration (# / 1,000,000 m3 [264.172 million gal] – wide bars) and 

standard error (narrow bars) of topsmelt in HnGS normal operation impingement samples 

during 2006......................................................................................................................................5-27

Figure 5.5-16. Mean biomass (kg / 1,000,000 m3 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of topsmelt in HnGS normal operation impingement samples during 2006. ...5-28

Figure 5.5-17. Mean concentration (# / 1,000,000 m3 [264.172 million gal]) of topsmelt in normal 

operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling.....................5-28

Figure 5.5-18. Mean biomass (kg / 1,000,000 m3 [264.172 million gal]) of topsmelt in normal 

operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling.....................5-29

Figure 5.5-19. Length (mm) frequency distribution for topsmelt collected in impingement samples.....5-29

Figure 5.5-20. Mean concentration (# / 1,000,000 m3 [264.172 million gal] – wide bars) and 

standard error (narrow bars) of northern anchovy in HnGS normal operation impingement 

samples during 2006. .......................................................................................................................5-31

Figure 5.5-21. Mean biomass (kg / 1,000,000 m3 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of northern anchovy in HnGS normal operation impingement samples 

during 2006......................................................................................................................................5-31

Figure 5.5-22. Mean concentration (# / 1,000,000 m3 [264.172 million gal]) of northern anchovy in 

normal operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling.........5-32
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IM&E Final Report Table of Contents

 x

Figure 5.5-23. Mean biomass (kg / 1,000,000 m3 [264.172 million gal]) of northern anchovy in 

normal operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling.........5-32

Figure 5.5-24. Length (mm) frequency distribution for northern anchovy collected in impingement 

samples.............................................................................................................................................5-33

Figure 5.5-25. Age class distribution of northern anchovy collected in HnGS impingement 

samples.............................................................................................................................................5-34

Figure 5.5-26. Mean concentration (# / 1,000,000 m3 [264.172 million gal] – wide bars) and 

standard error (narrow bars) of pipefishes in HnGS normal operation impingement samples 

during 2006......................................................................................................................................5-37

Figure 5.5-27. Mean biomass (kg / 1,000,000 m3 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of pipefishes in HnGS normal operation impingement samples during 

2006. ................................................................................................................................................5-37

Figure 5.5-28. Mean concentration (# / 1,000,000 m3 [264.172 million gal]) of pipefishes in normal 

operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling.....................5-38

Figure 5.5-29. Mean concentration (kg / 1,000,000 m3 [264.172 million gal]) of pipefishes in 

normal operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling.........5-38

Figure 5.5-30. Length (mm) frequency distribution for pipefishes collected in impingement 

samples.............................................................................................................................................5-39

Figure 5.5-31. Mean concentration (# / 1,000,000 m3 [264.172 million gal] – wide bars) and 

standard error (narrow bars) of shiner perch in HnGS normal operation impingement samples 

during 2006......................................................................................................................................5-42

Figure 5.5-32. Mean biomass (kg / 1,000,000 m3 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of shiner perch in HnGS normal operation impingement samples during 

2006. ................................................................................................................................................5-42

Figure 5.5-33. Mean concentration (# / 1,000,000 m3 [264.172 million gal]) of shiner perch in 

normal operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling.........5-43

Figure 5.5-34. Mean biomass (kg / 1,000,000 m3 [264.172 million gal]) of shiner perch in normal 

operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling.....................5-43

Figure 5.5-35. Length (mm) frequency distribution for shiner perch collected in normal operation 

impingement samples. .....................................................................................................................5-44

Figure 5.5-36. Mean concentration (# / 1,000,000 m3 [264.172 million gal] – wide bars) and 

standard error (narrow bars) of specklefin midshipman in HnGS normal operation 

impingement samples during 2006. .................................................................................................5-46

Figure 5.5-37. Mean biomass (kg / 1,000,000 m3 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of specklefin midshipman in HnGS normal operation impingement 

samples during 2006. .......................................................................................................................5-46

Figure 5.5-38. Mean concentration (# / 1,000,000 m3 [264.172 million gal]) of specklefin 

midshipman in normal operation impingement samples during night (Cycle 3) and day (Cycle 

1) sampling. .....................................................................................................................................5-47

Figure 5.5-39. Mean biomass (kg / 1,000,000 m3 [264.172 million gal]) of specklefin midshipman 

in normal operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling. ...5-47

Figure 5.5-40. Length (mm) frequency distribution for specklefin midshipman collected in normal 

operation impingement samples. .....................................................................................................5-48

Figure 5.5-41. Mean concentration (# / 1,000,000 m3 [264.172 million gal] – wide bars) and 

standard error (narrow bars) of California two-spot octopus in HnGS normal operation 

impingement samples during 2006. .................................................................................................5-57
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Figure 5.5-42. Mean biomass (kg / 1,000,000 m3 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of California two-spot octopus in HnGS normal operation impingement 

samples during 2006. .......................................................................................................................5-57

Figure 5.5-43. Mean concentration (# / 1,000,000 m3 [264.172 million gal]) of California two-spot 

octopus in normal operation impingement samples during night (Cycle 3) and day (Cycle 1) 

sampling...........................................................................................................................................5-58

Figure 5.5-44. Mean biomass (kg / 1,000,000 m3 [264.172 million gal]) of California two-spot 

octopus in normal operation impingement samples during night (Cycle 3) and day (Cycle 1) 

sampling...........................................................................................................................................5-58

Figure 5.5-45. Length (mm) frequency distribution for California two-spot octopus collected in 

impingement samples. .....................................................................................................................5-59

Figure 5.5-46. Mean concentration (# / 1,000,000 m3 [264.172 million gal] – wide bars) and 

standard error (narrow bars) of California seahare in HnGS normal operation impingement 

samples during 2006. .......................................................................................................................5-61

Figure 5.5-47. Mean biomass (kg / 1,000,000 m3 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of California seahare in HnGS normal operation impingement samples 

during 2006......................................................................................................................................5-62

Figure 5.5-48. Mean concentration (# / 1,000,000 m3 [264.172 million gal]) of California seahare in 

normal operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling.........5-62

Figure 5.5-49. Mean biomass (kg / 1,000,000 m3 [264.172 million gal]) of California seahare in 

normal operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling.........5-63

Figure 5.5-50. Mean concentration (# / 1,000,000 m3 [264.172 million gal] – wide bars) and 

standard error (narrow bars) of market squid in HnGS normal operation impingement samples 

during 2006......................................................................................................................................5-66

Figure 5.5-51. Mean biomass (kg / 1,000,000 m3 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of market squid in HnGS normal operation impingement samples during 

2006. ................................................................................................................................................5-67

Figure 5.5-52. Mean concentration (# / 1,000,000 m3 [264.172 million gal]) of market squid in 

normal operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling.........5-67

Figure 5.5-53. Mean concentration (kg / 1,000,000 m3 [264.172 million gal]) of market squid in 

normal operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling.........5-68

Figure 5.5-54. Frequency distribution of mantle length measurements (mm) for market squid 

collected in impingement samples. ..................................................................................................5-68

Figure 6.1-1. Marine habitat types in California (from Allen and Pondella [2006]). ................................6-8

Figure 6.3-1. Sea surface temperature anomalies for Newport Pier, California. Values are ± the 

long-term average (1925-2006). ......................................................................................................6-18

Figure 6.3-2. Comparison between silverside larval densities at entrainment station (E3) and 

Alamitos Bay stations (H2-H4) during monthly plankton tows in 2006. ........................................6-21

Figure 6.3-3. White croaker fishery and population trends: a) recreational and commercial landings 

for Los Angeles area ports from RecFIN and PacFIN databases; b) Huntington Beach 

Generating Station (HBGS) impingement average annual biomass; and c) NPDES trawl data 

with average number of fish per trawl minute for HBGS and Harbor, Haynes and Alamitos 

Generating Stations, collected off Huntington Beach and inside the Los Angeles-Long Beach 

Harbor breakwaters, respectively.....................................................................................................6-27
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IM&E Final Report Table of Contents

 xii

Figure 6.3-4. Queenfish fishery and population trends: a) recreational landings for Los Angeles 

area ports from RecFIN database; b) HBGS impingement average annual biomass; and c) 

average number of fish per trawl minute for HBGS and Harbor, Haynes and Alamitos 

Generating Stations, collected off Huntington Beach and inside the Los Angeles-Long Beach 

Harbor breakwaters, respectively.....................................................................................................6-28
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IM&E Final Report List of Abbreviations

 xiii

LIST OF ACRONYMS AND ABBREVIATIONS

ADCP acoustic Doppler current profiler 

AEL adult equivalent loss 

BMPs best management practices 

BTA best technology available 

CDFG California Department of Fish and Game 

CDS Comprehensive Demonstration Study 

CEQA California Environmental Quality Act 

cfs cubic feet per second 

CIQ Clevelandia, Ilypnus, Quietula

cm centimeters 

cm/s centimeters per second 

CPFV commercial passenger fishing vessels 

CWA Clean Water Act 

CWIS cooling water intake system 

DML dorsal mantle length 

EAM equivalent adult model 

EFH Essential Fish Habitat 

El. Elevation (relative to mean sea level) 

EPA United States Environmental Protection Agency 

ETM Empirical Transport Model 

FH fecundity hindcasting 

FMP Fishery Management Plan 

ft feet 

ft/s feet per second 

g grams 

gal gallonsGIS Geographic Information System 

gpm gallons per minute 

HnGS Haynes Generating Station 

IM&E Impingement Mortality and Entrainment 

in inches 

kg kilograms 

km kilometers 

LADWP Los Angeles Department of Water and Power 

LARWQCB Los Angeles Regional Water Quality Control Board 

lbs pounds 

m meter 

m3 cubic meters 

mgd million gallons per day 

ml milliliter 

ML mantle length 

MLLW mean lower low water 

mm millimeters 

m/s meter per second 

MSL mean sea level 

MW megawatts 

NL notochord length 

NMFS National Marine Fisheries Service 

NOAA National Oceanic and Atmospheric Administration 
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IM&E Final Report List of Abbreviations

 xiv

NPDES National Pollutant Discharge Elimination System 

PacFIN Pacific Fisheries Information Network 

PE proportional entrainment 

PFMC Pacific Fisheries Management Council 

PIC Proposal for Information Collection 

Pm probability of mortality 

POLA Port of Los Angeles 

PSU practical salinity units 

QA/QC Quality Assurance/Quality Control 

QC quality control 

RecFIN Recreational Fisheries Information Network 

rpm revolutions per minute 

RWQCB California Regional Water Quality Control Board 

SCB Southern California Bight 

SL standard length 

SWRCB State Water Resources Control Board 

TLF total lifetime fecundity 

USFWS U.S. Fish and Wildlife Service 

YOY young-of-the-year 
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IM&E Final Report Executive Summary

1-1 

1.0 EXECUTIVE SUMMARY

This report presents data from in-plant and offshore field surveys performed for the Los Angeles 

Department of Water and Power’s Haynes Generating Station (HnGS) Impingement Mortality and 

Entrainment (IM&E) Characterization Study. This study was designed and performed to comply with 

EPA’s 2004 316(b) Phase II regulations. Originally, results from the study were to be used in determining 

impingement mortality and entrainment from once-through cooling, evaluating potential fish protection 

technologies and operational measures at the facility, scaling potential restoration projects, and/or 

evaluating the cost-benefits in reducing IM&E at the facility. However, in March 2007, the United States 

Environmental Protection Agency (EPA) suspended the Phase II regulations and directed administrators 

to determine compliance with 316(b) on a best professional judgment (BPJ) basis. 

Prior to the Phase II Rule, 316(b) decisions were based on precedents from case law and on EPA’s (1977) 

draft “Guidance for Evaluating the Adverse Impact of Cooling Water Intake Structures on the Aquatic 

Environment: Section 316(b) P.L. 92-500.” As Section 316(b) requires that an intake technology employs 

the ‘best technology available’ (BTA) for minimizing ‘adverse environmental impacts’ (AEI), there are 

two steps in determining compliance: 

1. Whether or not an AEI is caused by the intake and, if so, 

2. What intake structure represents BTA to minimize that impact? 

The usual approach for a 316(b) demonstration would be to only consider the question of BTA if a 

determination has been made that a facility is causing an AEI. The purpose of this report is to assess the 

potential for AEI from the operation of the HnGS cooling water intake system (CWIS). The two primary 

impacts of a once-through power plant CWIS are impingement of juvenile and adult life stages of fishes, 

shellfishes, and other organisms on screens at the openings to the CWIS, and entrainment of smaller 

organisms, usually larval forms of fishes and shellfishes, and other forms of plankton, into the CWIS. The 

information in this report will also be used to assist in the renewal of the National Pollutant Discharge 

Elimination System (NPDES) permit for the HnGS. This report provides a characterization of the fish and 

invertebrate species subject to entrainment and impingement at the HnGS, information on the current 

levels of IM&E at the HnGS, and a discussion on the level of significance of the IM&E losses. 

1.1 ENTRAINMENT

Composition and abundance of ichthyoplankton and shellfish larvae entrained by HnGS were determined 

by sampling in the immediate proximity of the cooling water intake every two weeks from January 2006 

to January 2007. A total of 12,651 entrainable fish larvae from 35 separate taxonomic categories was 

collected during the 26 entrainment surveys. The most abundant larval fish taxon in the samples was 

unidentified gobies, which comprised 51.3% of the total larvae collected, followed by silversides (23.9%) 

and combtooth blennies (20.1%). Densities of fish larvae peaked in late May at an average concentration 

of approximately 17,000 per 1,000 m3

 (264,172 gal), although seasonal peaks in spawning differed among 

the most abundantly entrained larvae. For example, anchovies (mainly northern anchovy), silversides, and 

white croaker had peak spawning periods in spring, while combtooth blennies were mainly summer 

spawners. Gobies spawned year-round, with peaks in both spring and summer, reflecting the multi-
Haynes Generating Station 

IM&E Final Report Executive Summary

1-2 

species composition of the group. In addition to fish larvae, 5,941 fish eggs from 13 taxa were 

enumerated from the surveys. The most abundant taxonomic group of fish eggs in the samples was 

unidentified eggs, which made up 69.4% of the total eggs collected, followed by sand flounder eggs 

(11.4%). Fish eggs peaked in abundance in March−April prior to the peak abundance of fish larvae in 

May, and also had a secondary peak in August. Larvae and eggs were substantially more abundant in 

samples collected at night than those collected during the day in nearly every survey. Total annual 

entrainment was estimated to be 3.65 billion fish larvae and 1.68 billion fish eggs during 2006 using the 

HnGS CWIS actual flows as the basis for calculations. Using the design (maximum capacity) CWIS 

flows, total annual entrainment was estimated to increase to 4.53 billion fish larvae and 2.12 billion fish 

eggs. 

A total of 50 larval target invertebrates representing 9 taxa was collected from the HnGS entrainment 

station during the bi-weekly surveys in 2006. The most abundant target shellfish larvae in the samples 

were shore crab megalops (Grapsidae unid.) followed by kelp crab megalops (Pugettia spp.), which made 

up 28.0% and 24.0%, respectively of the total target invertebrate larvae collected. Total annual 

entrainment was estimated to be 14.9 million target invertebrate larvae based on actual cooling water 

flows. Using the design CWIS flows, total annual entrainment was estimated to increase to 18.5 million 

target invertebrates. 

1.2 SOURCE WATER

To determine composition and abundance of the early life stages of fish and shellfish in the source waters 

of the HnGS, sampling at nine stations in the coastal waters in Alamitos Bay and San Pedro Bay was 

conducted once monthly on the same day that the entrainment station (E3) was sampled. 

A total of 41,319 larval fishes representing 68 taxa was collected from HnGS source water stations during 

12 monthly surveys in 2006. Unidentified gobies (Clevelandia, Ilypnus, Quietula (CIQ) goby complex), 

white croaker, combtooth blennies, and anchovies were the most abundant taxa and comprised over 90% 

of all specimens collected. The greatest concentrations of larval fishes occurred during April 2006 (ca. 

5,800 per m3

 [264 gal]) and the fewest in October 2006 (ca. 600 per m3 [264 gal]). Spawning peaks 

occurred predominantly in spring and summer for the major species groups and were similar to those 

described for the entrainment samples. 

A total of 2,291 larval target invertebrates (developmentally advanced larvae of crabs, spiny lobsters, and 

market squid) representing 20 taxa was collected from HnGS source water stations in and near Alamitos 

Bay during 12 monthly surveys in 2006. Megalops of kelp crabs, pea crabs, shore crabs, spider crabs, and 

unidentified megalops were the most abundant taxa and comprised nearly 90% of all specimens collected. 

1.3 IMPINGEMENT

Weekly impingement surveys were performed during all 52 weeks at the HnGS between January 2006 

and January 2007. Additionally, five marine growth control (heat treatment) surveys were performed in 

2006. 
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IM&E Final Report Executive Summary

1-3 

A total of 6,580 fishes representing at least 53 distinct taxa and weighing 72.5 kg (159.9 lbs) was 

collected during impingement sampling in 2006. Queenfish was the most abundant species, with 3,708 

individuals collected (56% of the total) and an estimated annual impingement based on actual cooling 

water flow of 30,946 individuals weighing 19.5 kg (42.9 lbs). The annual impingement of queenfish 

represented 58% of the total impingement abundance but only 4% of the biomass. The next most 

abundant species in impingement samples were topsmelt, northern anchovy, bay pipefish, unidentified 

pipefishes, shiner perch, and specklefin midshipman (Porichthys myriaster). Combined these taxa 

accounted for 91.2% of the sampled impingement abundance. The estimated annual total impingement 

based on cooling water flow volumes in 2006 was 53,442 individuals weighing 529.8 kg (1,168 lbs). The 

estimated annual impingement based on design flows was 56,613 fishes weighing 556.5 kg (1,227.0 lbs). 

Impingement abundance in 2006 was highest in summer (July–September) and impingement biomass was 

greatest in spring (April–May). Highest impingement was recorded in summer (July and August 2006), 

corresponding to an increase in impingement of juvenile queenfish. The small size of the queenfish 

impinged (most in the 30-mm size class) suggested they were probably spawned in spring since 

individuals usually reach 100 mm by the end of their first year. In general, fish impingement abundance 

was greatest during nighttime, though biomass was greater during the day. 

A total of 2,682 macroinvertebrates representing at least 49 distinct taxa and weighing 37.0 kg (81.6 lbs) 

was collected during impingement sampling in 2006. Of this total, only 12 individuals from seven taxa 

weighing 0.2 kg (0.4 lbs) were impinged during the five marine growth control procedures. Red jellyfish 

was the most abundant species, with 621 individuals collected (23% of the total) and an estimated annual 

impingement of 4,562 individuals weighing 16.6 kg (37 lbs). The next most abundant species in 

impingement samples were the nudibranch Hermissenda crassicornis, tuberculate pear crab, and yellow 

shore crab. Combined these species accounted for 59.1% of the sampled impingement abundance. The 

estimated annual total impingement based on actual cooling water flow volumes in 2006 was 20,346 

individuals weighing 268.8 kg (592.7 lbs). The estimated annual impingement based on design flow was 

21,773 macroinvertebrates weighing 293.8 kg (647.9 lbs). Invertebrate impingement abundance was 

greatest from January through June, with highest abundance recorded in spring (April–May). Invertebrate 

biomass was much more variable throughout the year, with peaks in late-March, late-April, and earlyAugust. 

1.4 IMPACT ASSESSMENT

The data collected from the entrainment, source water, and impingement sampling was used to assess the 

potential for AEI to fish and shellfish populations. The assessment was limited to the taxa that were 

sufficiently abundant to provide reasonable assessment of impacts. The list of species included in the 

assessment were reviewed and approved by the Los Angeles Regional Water Quality Control Board 

(LARWQCB) and other stakeholders. The most abundant taxa had the greatest frequency of occurrence 

among surveys and among stations. Since the most abundant organisms may not necessarily be the 

organisms that experience the greatest effects on the population level, the data were also examined to 

determine if additional taxa should be included in the assessment. For example, this might include 

commercially or recreationally important taxa, taxa with limited habitats, and any threatened or 

endangered fish or shellfish species. The National Marine Fisheries Service requested that all species 
Haynes Generating Station 

IM&E Final Report Executive Summary

1-4 

managed under the Magnuson-Stevens Fishery Conservation and Management Act be included in the 

impingement results. None of these species were included in the entrainment assessment since they were 

scarce in entrainment and source water samples. No species listed as threatened or endangered by the 

state or federal governments were entrained or impinged at the HnGS during the study. 

The assessment was primarily done by calculating impingement and entrainment estimates based on 

CWIS actual and design flow volumes for individual taxa, and then using these results to model the losses 

to adult and larval source populations using two general modeling approaches and three different models. 

One approach uses species life history information in two different demographic models to estimate the 

equivalent number of adults (adult equivalent loss [AEL]) or adult females (fecundity hindcasting [FH]) 

lost due to entrainment or impingement. The other modeling approach was only used with the entrainment 

data. This model (empirical transport model [ETM]) estimates the conditional mortality on a population 

resulting from entrainment. The demographic model estimates from entrainment and impingement were 

added together to evaluate the combined effects of the CWIS. The life history information necessary for 

the modeling was not available for most species so combined assessments were only done for northern 

anchovy. 

The assessment included 13 taxonomic groups or species of fishes and 3 taxonomic groups or species of 

shellfishes (Tables 1.4-1 and 1.4-2). These taxa were categorized into five habitat types that were 

simplified from a more detailed categorization of habitats used by Allen and Pondella (2006) (Table 

1.4-3). Taxa that occur in more than one habitat were included in the habitat group that best reflected the 

primary distribution for the taxa. This approach was used because it focused the assessment on the taxa 

and habitats that were most at risk to CWIS effects. 

Impacts to Southern California Bight (SCB) fish and invertebrate populations caused by the entrainment 

of planktonic larvae through the HnGS CWIS can only be assessed indirectly through modeling. These 

impacts are additive with the direct impingement losses. Three taxa (CIQ goby complex, combtooth 

blennies, and silversides) comprised 95% of all entrained fish larvae. Of the ten most abundant fish 

species entrained at HnGS, only two (white croaker and anchovies) have any direct commercial or 

recreational fishery value. All of the abundantly entrained species can be considered forage species for 

larger predatory fishes, sea birds, or marine mammals. Approximately 45% of the 33 different fish taxa 

entrained belonged to species with some direct fishery value (e.g., anchovies, silversides, croakers, sand 

basses, and California halibut) even though most of those (except silversides, white croaker and 

anchovies) were in very low abundance in the samples and as a result were not assessed for potential 

impacts. 

The ETM procedure estimated the annual probability of mortality due to entrainment (PM). It puts the 

entrainment estimate into context by comparing it with a known source population at risk of entrainment. 

The greatest PM estimate for a target taxon was for the silverside complex with a predicted fractional 

larval loss of 40.9%. The next greatest probabilities of mortality were for CIQ gobies (25.2%) and 

combtooth blennies (13.9%). The distance of shoreline potentially affected by entrainment was directly 

proportional to the estimate of time that the larvae are exposed to entrainment. All three of these species 

had local populations primarily located in the habitats of Alamitos Bay, and most larvae were entrained at 

sizes that indicated they were recently hatched. For example, the relatively high silverside mortality 
Haynes Generating Station 

IM&E Final Report Executive Summary

1-5 

estimate resulted from a single large pulse of larvae entrained in late May, probably from eggs that had 

been deposited on dock structures in the marina adjacent to the HnGS intakes. The modeled species with 

primarily nearshore (non-bay) distributions included white croaker and northern anchovy, and these had 

PM estimates well below 1%. These levels of additional mortality would be considered low, especially 

when the populations of these species extend over a much larger geographic range than the extrapolated 

source water bodies. No invertebrate taxa were modeled for entrainment impacts due to the low 

abundance of the target taxa (e.g., spiny lobsters, Cancer crabs). 

Fish impingement has been routinely measured for decades at several coastal power plants in southern 

California, and these data are reported annually as part of their NPDES receiving water monitoring 

studies. The same core group of fish species continues to be impinged at these power plants, and there is 

no measurable effect on fish populations from the operation of the cooling water systems. For species that 

are harvested commercially, such as northern anchovy, the biomass of fish impinged is orders of 

magnitude less than annual commercial landings. 

Compared to the IM&E study conducted at HnGS in 1978−1979 (IRC 1981), silverside larvae were 

nearly two orders of magnitude more abundant in the recent 2006 entrainment samples while other taxa 

analyzed in both studies were less abundant in 2006. Anchovy and croaker larvae in particular were 

significantly more abundant in the earlier study, due in part to the cooler water climatic regime in the 

SCB that favored populations of these taxa. The most abundant impinged species in 1978−1979 were 

shiner perch (38%), Pacific pompano (14.9%), and white seaperch (12.5%), while in the 2006 samples 

queenfish, topsmelt and northern anchovy were the numerically dominant species accounting for 75% of 

all impinged fishes. The estimated annual fish biomass impingement (normal operations and heat 

treatments) was 1,344 kg (2,964 lbs) in 1978−1979 compared to 529.8 kg (1,168 lbs) in 2006. The 

operations and configuration of the HnGS cooling water system have remained largely unchanged since 

all units went into service with the exception of the replacement of the cooling water pumps at Units 3 & 

4 (now Unit 8). Therefore, changes in impingement and entrainment through time are most likely due to 

natural biological changes and not due to substantial changes in plant operation. 
Haynes Generating Station 

IM&E Final Report 

Table 1.4-1. Summary of entrainment and impingement sampling results and model output for common fish and inverteb

actual flows at HnGS in 2006.* 

Species Common Name 

Est. Annual 

Larval Ent. 

(millions) 

Est. Annual 

Egg Ent. 

(millions) 

ETM

PM (%) 2*FH AEL 

Annual

Imping.

Estimate 

Fishes 

Gobiidae2 gobies 1,828.4 0 25.15 3,932,562L 1,671,266L 7 

Atherinopsidae unid.3 silversides 920.3 11.5 40.95 6,315 

Hypsoblennius spp. combtooth blennies 732.0 0 13.89 836,002L 1,783,945L 32 

Genyonemus lineatus white croaker 75.4 57.8 0.63 64E 861 

Engraulis mordax northern anchovy 22.7 11.1 0.76 8,600C 20,634L 5,7944 

Seriphus politus queenfish 2.5 0 30,946 Syngnathus spp. pipefishes 3.1 − 4,553 

Porichthys myriaster specklefin midshipman − − 620 

Cymatogaster aggregata shiner perch − − 582 Sardinops sagax Pacific sardine 0.3 0 90 

Raja inornata California skate − − 8 

Trachurus symmetricus jack mackerel 0 0 7 Sebastes miniatus vermilion rockfish 0 0 7 Invertebrates Octopus spp. California two-spot octopus − − 337 

Aplysia californica California seahare − − 195 

Loligo opalescens market squid 0.2 − 78 

1standardized impingement adult equivalent mortality 2only cheekspot goby collected in impingement samples 3only topsmelt was collected in abundance in impingement samples 4Engraulis mordax larvae collected from impingement sampling are combined with adults 

*Model estimates indicate whether the number was based on eggs (E), larvae (L), or both combined (C). 
Haynes Generating Station 

IM&E Final Report 

Table 1.4-2. Summary of entrainment and impingement sampling results and model output for common fish and inverteb

design flows at HnGS in 2006.* 

Species Common Name 

Est. Annual 

Larval Ent. 

(millions) 

Est. Annual 

Egg Ent. 

(millions) 

ETM

PM (%) 2*FH AEL 

Annual

Imping.

Estimate 

Fishes Gobiidae2 gobies 2,334.2 0 31.7 5,020,588L 2,133,657L 7 

Atherinopsidae unid.3 silversides 1,062.8 20.8 46.9 6,747 

Hypsoblennius spp. combtooth blennies 915.3 0 17.7 1,045,330L 2,230,628L 32 

Genyonemus lineatus white croaker 96.2 86.5 0.79 96E 877 

Engraulis mordax northern anchovy 27.3 14.0 0.92 10,364C 24,845L 6,5134 

Seriphus politus queenfish 2.9 0 32,389 Syngnathus spp. pipefishes 3.8 − 4,801 

Porichthys myriaster specklefin midshipman − − 632 

Cymatogaster aggregata shiner perch − − 628 

Sardinops sagax Pacific sardine 0.3 0 98 Raja inornata California skate − − 9 

Trachurus symmetricus jack mackerel 0 0 7 

Sebastes miniatus vermilion rockfish 0 0 7 

Invertebrates Octopus spp. California two-spot octopus − − 353 

Aplysia californica California seahare − − 221 

Loligo opalescens market squid 0.3 − 78 

1standardized impingement adult equivalent mortality 2only cheekspot goby collected in impingement samples 3only topsmelt was collected in abundance in impingement samples 4Engraulis mordax larvae collected from impingement sampling are combined with adults 

*Model estimates indicate whether the number was based on eggs (E), larvae (L), or both combined (C). 
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IM&E Final Report Executive Summary

1-8 

Table 1.4-3. Habitat associations for taxa included in assessment of CWIS effects at the HnGS. 

 Fishery Habitats 

Scientific name Common name 

S-Sport, 

C-Comm.

bays, 

harbors

reefs, 

kelp 

beds 

coastal 

pelagic shelf 

Fishes 

Atherinopsidae unid. silversides S, C X x

Cymatogaster aggregata shiner perch S X x 

Engraulidae unid. anchovies C X 

Genyonemus lineatus white croaker S, C x X x 

Gobiidae unid. CIQ goby complex X 

Hypsoblennius spp. combtooth blennies X x

Porichthys myriaster specklefin midshipman X x 

Raja inornata California skate C x X 

Sardinops sagax Pacific sardine C x X 

Sebastes miniatus vermilion rockfish S, C X 

Seriphus politus queenfish S X x

Syngnathidae pipefishes X 

Trachurus symmetricus jack mackerel S, C x X 

Shellfishes/Invertebrates 

Aplysia californica California seahare C x X 

Loligo opalescens market squid S X 

Octopus spp. California two-spot 

octopus C x X 

Primary habitat in bold, upper case and secondary habitat in lower case. Taxa also designated 

as to whether they are targeted by a sport (S) or commercial (C) fishery.
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IM&E Final Report Introduction

2-1 

2.0 INTRODUCTION

The Haynes Generating Station (HnGS) is a fossil-fueled steam electric power generating station that is 

owned and operated by the Los Angeles Department of Water and Power (LADWP). HnGS is located in 

the city of Long Beach on the eastern side of the San Gabriel River flood control channel. The plant uses 

a once through cooling water system for five of its seven generating units with a total maximum permitted 

flow of approximately 1,014 million gallons per day (mgd). These five units withdraw cooling water from 

a common bulkhead intake in Long Beach Marina, Alamitos Bay that is connected to the plant through an 

earthen intake channel that runs 1.5 miles parallel to the east bank of the San Gabriel River to the intake 

screenhouses. The cooling water from the plant is discharged into the lower San Gabriel River flood 

control channel. 

Cooling water intake systems (CWIS) are regulated under §316(b) of the federal Clean Water Act 

(CWA). In July 2004, EPA published new regulations for §316(b) applicable to large existing power 

plants with daily cooling water volumes in excess of 50 mgd. Due to the design, location, and operating 

characteristics of the cooling water system for HnGS, which withdraws a maximum of 967.7 mgd, it was 

subject to these new regulations that required submittal of comprehensive plan for compliance by January 

2008. The new regulations were challenged by a coalition of environmental groups that was heard by the 

Second U.S. Circuit Court of Appeals. The court rendered a decision in January 2007 that remanded 

several key componenets of the regulations back to the EPA. In March 2007, EPA issued a memorandum 

suspending the rule and directing that all permits for Phase II facilities implement 316(b) on a case-bycase basis using “best professional judgement” (BPJ). The language of the memorandum was expanded 

and published in the Federal Register in July 2007 (Volume 72, 130:37107-37109). 

The studies presented in this report were conducted in partial fulfillment of the requirements of the new 

regulations. With the suspension of the Phase II regulations, the results of the studies will be used to 

determine if impingement and entrainment losses pose any significant risk of adverse environmental 

impact (AEI) to the species and life stages of fish and shellfish impinged or entrained. The absence of any 

significant impacts would be a technically sound basis under BPJ for determining that the cooling water 

intake structure represents the best technology available. This would allow any additional requirements 

to further reduce impingement and/or entrainment to be deferred until issues with the Phase II Rule are 

resolved. 

2.1 BACKGROUND AND OVERVIEW

On July 9, 2004, the USEPA published the second phase of new regulations under §316(b) of the CWA. 

The final Phase II regulations went into effect in September 2004, and apply to existing generating 

stations (Phase II facilities) each with a CWIS that withdraw at least 50 mgd from rivers, streams, lakes, 

reservoirs, oceans, estuaries, or other waters of the United States. Pursuant to the Phase II regulations, the 

LADWP submitted the Proposal for Information Collection (PIC) for HnGS to the Los Angeles Regional 

Water Quality Control Board (LARWQCB) in October 2005 (LADWP 2005). The PIC included the study 

plan for the HnGS Impingement Mortality and Entrainment (IM&E) Characterization Study. 
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2.1.1 Section 316(b) of the Clean Water Act 

The suspended Section 316(b) of the CWA required that the location, design, construction, and capacity 

of CWISs reflect the best technology available (BTA) to minimize adverse environmental impacts due to 

the impingement mortality (IM) of aquatic organisms (i.e., fish, shellfish, and other forms of aquatic life) 

on intake structures and the entrainment (E) of eggs and larvae through cooling water systems. The 

suspended 316(b) Phase II regulations established performance standards for CWISs of existing power 

plants that withdraw more than 50 mgd of surface waters and use more than 25% of the withdrawn water 

for cooling purposes. The regulations required all large existing power plants to reduce impingement 

mortality by 80−95% and to reduce entrainment of smaller aquatic organisms drawn through the cooling 

system by 60–90% when compared against a “calculation baseline.” The water body type on which the 

facility is located, the capacity utilization rate, and the magnitude of the design intake flow relative to the 

water body flow determined whether a facility was required to meet the performance standards for only 

impingement or both impingement and entrainment. 

The suspended Phase II regulations provided power plants with five options for meeting the performance 

standards, but unless a facility can show that it can meet the standards using the existing intake design or 

is installing one of the approved EPA technologies for IM&E reduction, it must submit information 

documenting its existing levels of IM&E. These data can come from existing data that may have 

previously been collected at the facility or a similar facility nearby. The data were then required to be 

submitted in an IM&E Characterization Study that was one component of the §316(b) Comprehensive 

Demonstration Study (CDS) required under the suspended Phase II regulations. The impingement 

mortality component of the studies was not required if the through-screen intake velocity was less than or 

equal to 15 centimeters (cm) (0.5 ft) per second. The entrainment characterization component is not 

required if a facility: 

1. Has a capacity utilization rate of less than 15%; 

2. Withdraws cooling water from a lake or reservoir, excluding the Great Lakes; or 

3. Withdraws less than 5% of the mean annual flow of a freshwater river or stream. 

Based on previously collected intake velocity measurements and plant operating characteristics, both the 

IM&E components of the study were required at the HnGS. Previous §316(b) Demonstration studies were 

done at HnGS in 1978−1979 (IRC 1981). Entrainment and field (source water) plankton samples were 

collected biweekly, and impingement samples were collected at varying intervals (daily to weekly) at all 

of the intake screening structures. A summary of the historical IM&E studies is provided in Sections 4.2 

and 5.2 of this report. Due to the time period since the original data were collected, a study plan for new 

IM&E studies was submitted with the PIC to the LARWQCB in October 2005. 

The PIC was submitted prior to the publication of the Second U.S. Circuit Court of Appeals Decision on 

the §316(b) Phase II regulations issued on January 25, 2007. The EPA issued a memorandum to its 

Regional Offices dated March 20, 2007. This memorandum announced that EPA was withdrawing the 

§316(b) Phase II Rule for existing steam electric generating stations in its entirety based on the Court 

decision. The memorandum further directed EPA Regional Offices to implement §316(b) in NPDES 

permits on a “Best Professional Judgment” (BPJ) basis until the issues raised by the Court decision are 
Haynes Generating Station 

IM&E Final Report Introduction

2-3 

resolved. EPA is currently considering several alternatives for responding to the Court decision and it 

may be several years before it is resolved either through further litigation and/or Rulemaking. The 

guidance in this memorandum was published in the Federal Register on July 9, 2007 (Volume 72, 

130:37107-37109). 

The information in this report is being submitted to assist in the evaluation of fish protection technologies 

and operational measures described in the PIC so that when the issues with the suspended Phase II Rule 

are resolved, LADWP will be in a position to move forward in a timely manner to comply with the Rule. 

The information is also important in evaluating the potential for AEI potentially caused by impingement 

and entrainment. In support of this approach to compliance, the assessment of the IM&E study focuses on 

determining if impingement and entrainment losses pose any significant risk of AEI to the species and life 

stages of fish and shellfish impinged or entrained. The AEI assessment in this report is based on previous 

EPA guidance on 316(b) (USEPA 1977) and focuses on evaluating the following: 

• potential impacts that could pose a risk to populations of any impinged or entrained species; 

• impacts to the local commercial or recreational fishery; or 

• any impacts to a protected species. 

For entrained and juvenile species the analysis will provide estimates of adult losses for a representative 

set of commercial and recreational species. For forage species, estimates of the reductions to commercial 

and recreational species will be made due to the reduction in biomass as a result of impingement and 

entrainment. Demonstrating no significant risk of AEI would be a technically sound basis to defer 

requirements for reducing impingement and/or entrainment until issues with the Phase II Rule are 

resolved. The rationale and approach for the AEI assessment in this report and the results and conclusions 

from our analysis are provided in Section 6.0. 

2.1.2 Development of the Study Plan 

The suspended Phase II §316(b) regulations required that the plan for the IM&E Characterization Study 

include sufficient data to develop a scientifically valid estimate of IM&E including all methods and 

quality assurance/quality control (QA/QC) procedures for sampling and data analysis. The sampling and 

data analysis methods must be appropriate for a quantitative survey and include consideration of the 

methods used in other studies performed in the source water body. The sampling plan must also include a 

description of the study area (including the area of influence of the CWIS), and provide for taxonomic 

identifications of the sampled or evaluated biological assemblages (including all life stages of fish and 

shellfish) that are known to be relevant to the development of the plan. 

The regulations also required that the PIC include summaries of any historical studies characterizing 

IM&E, and/or the physical and biological conditions in the vicinity of the CWISs and their relevance to 

the proposed studies. These are required to assist the LARWQCB in reviewing and commenting on the 

IM&E study plan. If the data from previous studies will be used in characterizing the existing levels of 

IM&E then the PIC must demonstrate that the data are representative of current conditions and were 

collected using appropriate QA/QC procedures. 
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2-4 

The HnGS IM&E Characterization Study Plan was developed in 2005 by MBC Applied Environmental 

Sciences and Tenera Environmental. The Study Plan was designed to provide the biological information 

necessary to fulfill all pertinent 316(b) Phase II requirements, and was based on entrainment and 

impingement studies performed in California in recent years for California Energy Commission 

relicensing studies (such as those at the AES Huntington Beach, Duke Morro Bay, Duke Moss Landing, 

and Duke South Bay Power Plants), and 316(b) Demonstrations (such as at the PG&E Diablo Canyon and 

NRG Encina Power Plants). All of these studies were performed with input from technical working 

groups, comprised of representatives from the project applicants, the California Regional Water Quality 

Control Board (RWQCB), California Department of Fish and Game (CDFG), National Marine Fisheries 

Service, U.S. Fish and Wildlife Service (USFWS), and consultants. 

The Study Plan was submitted to the LARWQCB in October 2005. LADWP and its consultants 

subsequently met with the LARWQCB to review the Study Plan and address comments. Pursuant to 

comments during the meeting that were included in a letter from the LARWQCB in April 2006 the 

following changes were made to the Study Plan: 

• Fish eggs will be identified (to the extent practicable) and counted from entrainment samples; and 

• Crab megalopae larvae will be identified (to the extent practicable) and counted from entrainment 

samples. 

The revisions to the study plan only affected sample processing and did not affect the sampling that 

started in January 2006. On January 30, 2007, representatives from the LADWP, URS, MBC, and Tenera 

met with representatives from the LARWQCB, USEPA Region IX, State Water Resources Control Board 

(SWRCB), CDFG, and NMFS to review preliminary data from the HnGS IM&E Characterization Study, 

and determine the fish and shellfish species that would be assessed in the IM&E Report. The USFWS was 

invited to the meeting but did not attend. The meeting was also attended by a representative from Tetra 

Tech, a consultant to the EPA and Regional Board, and representatives from the following environmental 

groups: Heal the Bay and Santa Monica Baykeeper. 

An initial draft of the IM&E results with the species identified at the January meeting was sent to the 

attendees in early May for review. Another meeting with the group was held on May 7, 2007 to finalize 

the list of species that would be included in the assessment presented in this report. 

As a result of these meetings, there was agreement that the impingement sampling would identify, count, 

weigh, and measure all collected fishes, crabs, lobsters, shrimp, squid and octopus. This approach was 

taken to include all of the impingeable ‘shellfish’ that are recreationally or commercially important and a 

large number of other species that are not targeted by a fishery. It was also agreed that the entrainment 

sampling would identify and count all fish eggs and larvae, megalops stage larvae for all species of crabs, 

California spiny lobster phyllosoma larvae, and market squid hatchlings. 

At the January 30 meeting, NMFS requested that all species managed under the Magnuson-Stevens 

Fishery Conservation and Management Act (Magnuson-Stevens Act) be assessed in the HnGS IM&E 

report. Off southern California, these species are listed in the Coastal Pelagics Fishery Management Plan 

(FMP) and the Pacific Groundfish FMP. It was agreed that for entrainment, additional demographic or 

ETM calculations would only be performed on these species if they were collected in sufficient 
Haynes Generating Station 

IM&E Final Report Introduction

2-5 

abundance in entrainment and source water samples, and if sufficient life history information was 

available to permit those calculations. For impingement, it was agreed that only market squid would need 

additional assessment since impingement estimates are calculated for all species, and no additional 

modeling was proposed. 

2.1.3 Study Plan Objectives 

Under the suspended §316(b) regulations, the IM&E Characterization Study must include the following 

elements (for all applicable components): 

1. Taxonomic identifications of all life stages of fish, shellfish, and any species protected under 

federal, state, or tribal law (including threatened or endangered species) that are in the vicinity of 

the CWIS and are susceptible to impingement and entrainment; 

2. A characterization of all life stages of fish, shellfish, and any species protected under federal, 

state, or tribal law (including threatened or endangered species) identified in the taxonomic 

identification noted previously, including a description of the abundance and temporal and spatial 

characteristics in the vicinity of the CWIS, based on sufficient data to characterize the annual, 

seasonal, and diel variations in the IM&E; and 

3. Documentation of current IM&E of all life stages of fish, shellfish, and any protected species 

identified previously and an estimate of IM&E to be used as the calculation baseline. 

The suspended Phase II §316(b) regulations provided the LARWQCB with considerable latitude in 

determining the level of detail necessary in meeting these objectives and stated that “while the taxonomic 

identification in item 1 will need to be fairly comprehensive, the quantitative data required in elements 2 

and 3 may be more focused on species of concern, and/or species for which data are available.” If the 

CDS was based on a given technology, restoration or site-specific standards, the level of detail in terms of 

the quantification of the baseline could be tailored to the compliance alternative selected and did not have 

to address all species and life stages. Logically it could be based on dominant species and/or 

commercially or recreationally important species. 

The data collected from the study will be used in developing a characterization of baseline levels of 

IM&E for HnGS required under the suspended Phase II regulations. The calculation baseline is defined in 

the suspended Phase II §316(b) regulations as follows: 

“Calculation baseline means an estimate of impingement mortality and entrainment that would 

occur at your site assuming that: the cooling water system has been designed as a once-through 

system; the opening of the cooling water intake structure is located at, and the face of the 

standard 3/8-in mesh traveling screen is oriented parallel to, the shoreline near the surface of the 

source waterbody; and the baseline practices, procedures, and structural configuration are those 

that your facility would maintain in the absence of any structural or operational controls, 

including flow or velocity reductions, implemented in whole or in part for the purposes of 

reducing impingement mortality and entrainment. You may also choose to use the current level of 

impingement mortality and entrainment as the calculation baseline. The calculation baseline may 

be estimated using: historical impingement mortality and entrainment data from your facility or 

another facility with comparable design, operational, and environmental conditions; current 

biological data collected in the waterbody in the vicinity of your cooling water intake structure; 
Haynes Generating Station 

IM&E Final Report Introduction

2-6 

or current impingement mortality and entrainment data collected at your facility. You may 

request that the calculation baseline be modified to be based on a location of the opening of the 

cooling water intake structure at a depth other than at or near the surface if you can demonstrate 

to the Director that the other depth would correspond to a higher baseline level of impingement 

mortality and/or entrainment.” 

As presented in the PIC, the HnGS CWIS does not conform to the calculation baseline. Significant 

deviations from the calculation baseline are: 

• The intake system includes a long intake canal rather than screens located at the shoreline; and 

• Units 1 and 2 have fixed panel rather than traveling screens. 

The suspended Phase II regulations allowed facilities to request that the calculation baseline be modified 

due to deviations from the calculation baseline if it could be demonstrated that these deviations provide 

reduced levels of IM&E. After the calculation baseline has been determined, then potential credits from 

the calculation baseline could be requested. A potential credit pertains to flow reductions which occurred 

when the cooling water pumps for Units 3 and 4, rated at 48,000 gpm were replaced in 2005 with four 

smaller pumps, rated at 40,000 gpm, resulting in a 32,000 gpm decrease in flows. With the suspension of 

the Phase II regulations the same arguments regarding deviations from the calculation baseline would 

apply to determining if the current design represents the BTA for minimizing AEI. 

Another objective of the study is to provide data that can be used in meeting different alternatives for 

compliance that might be used by LADWP. One approach that was the subject of the Court Decision was 

the use of restoration to meet the performance standards for IM&E reduction. To this end, source water 

data were collected to estimate the sizes of the populations potentially subject to entrainment. The Court 

decision rejected the use of restoration, but the source water data will still be important in assessing the 

impacts of entrainment at a population level that would otherwise be limited to a few species with 

adequate life history information. The study provides data that could be used to evaluate and estimate the 

economic value of the environmental benefit of meeting the performance standards. While the Court 

decision has limited the use of the data in cost-benefit analysis this aspect is still important in evaluating 

the potential AEI of IM&E and is one of the approaches used in the assessment presented in Section 6.0. 

2.1.4 Study Plan Approach 

The IM&E studies at HnGS were designed to examine losses resulting from both impingement of juvenile 

and adult fish and shellfishes on traveling screens at the intake during normal operations and from 

entrainment of larval fishes and shellfishes into the CWIS. The sampling methodologies and analysis 

techniques were designed to collect the data necessary for compliance with the suspended §316(b) Phase 

II Final Rule and were similar to recent impingement and entrainment studies conducted for the AES 

Huntington Beach Generating Station (MBC and Tenera 2005), the Duke Energy South Bay Power Plant 

(Tenera 2004), and the Cabrillo Power I LLC, Encina Power Station (Tenera 2007). The studies at 

Huntington Beach were performed as part of the California Energy Commission California 

Environmental Quality Act (CEQA) process for permitting power plant modernization projects, while the 

South Bay and Encina projects were for §316(b) compliance. The study plans for these projects were 

subject to review by state and federal resource agency staff and independent scientists from various 

environmental organizations. 
Haynes Generating Station 

IM&E Final Report Introduction

2-7 

Impingement sampling has been conducted at the HnGS since 2000. The impingement sampling methods 

used in this study are similar to the National Pollutant Discharge Elimination System (NPDES) 

monitoring program, but the sampling frequency has been increased to weekly to capture any seasonal 

variation and to collect additional data on diel variation. 

The entrainment sampling was designed to reflect the uncertainties surrounding the use of restoration for 

compliance with the suspended §316(b) regulations. If the use of restoration was not allowed as a result of 

the court decision, the entrainment data would be used in baseline calculations of losses that would be 

required to estimate the commercial and recreational values of adult fish losses in a cost benefit analysis 

of various technology and operational alternatives being considered to comply with required reductions in 

entrainment mortality. Larval fish and shellfish abundances can vary greatly through the year and 

therefore biweekly sampling was used for characterizing entrainment. If the restoration option was upheld 

in the court decision, models of the conditional mortality due to entrainment could be used in designing 

appropriate restoration projects for offsetting entrainment losses. These models were based on 

proportional comparisons of entrainment and source water abundances and were theoretically insensitive 

to seasonal or annual changes in the abundance of entrained species. Therefore, source water sampling 

occurred monthly, which is consistent with the sampling frequency for recently completed studies in 

southern California. 

2.2 REPORT ORGANIZATION

The remainder of this report is organized as follows. Section 3.0 includes a detailed description of the 

HnGS and CWIS. Data on circulating water pump flows from the study period are presented and 

discussed as these are the data used in calculating estimates of impingement mortality and entrainment 

presented in other sections of the report. Section 3.0 also includes a description of the environmental 

setting for the plant including the physical oceanographic data used to support the boundaries of the 

source water potentially affected by the plant’s CWIS. The methods and results for the entrainment and 

source water sampling are presented in Section 4.0 and the methods and results for the impingement 

sampling are presented in Section 5.0. The results from the entrainment and impingement sampling are 

integrated into an overall impact assessment for the HnGS CWIS in Section 6.0. The references used in 

the report are presented in Section 7.0. Appendices include detailed summaries of the entrainment, source 

water and impingement data. 

2.3 CONTRACTORS AND RESPONSIBILITIES

The IM&E Study was designed and performed by EPRI Solutions (Palo Alto, California), MBC Applied 

Environmental Sciences (Costa Mesa, California), and Tenera Environmental (San Luis Obispo, 

California), and URS Corporation (Santa Ana, California). The roles of each of the respective firms were 

as follows: 

• EPRI Solutions

 Input on sampling design 

• MBC Applied Environmental Sciences

 Study design 
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IM&E Final Report Introduction

2-8 

 Field sampling 

 Impingement Mortality data entry and analysis 

 Reporting 

• Tenera Environmental

 Study design 

 Physical oceanographic data collection and analysis 

 Field sampling Quality Assurance/Quality Control (QA/QC) 

 Laboratory processing of entrainment and source water plankton samples 

 Entrainment data entry and analysis 

 Reporting 

• URS Corporation

 Project management 

Each of the two biological contractors (i.e., MBC and Tenera) was responsible for ensuring that all data 

were verified prior to being entered, and that appropriate QA/QC measures were employed during data 

entry and analysis. 
Haynes Generating Station Generating Station and

IM&E Final Report Source Water Descriptions

3-1 

3.0 DESCRIPTION OF THE GENERATING STATION AND 

CHARACTERISTICS OF THE SOURCE WATER BODY

3.1 DESCRIPTION OF THE GENERATING STATION

The HnGS is located on the coast of the Pacific Ocean in the City of Long Beach, California (Figure 

3.1-1). The HnGS uses a once-through cooling water system for five of its generating units. Units 1 and 2 

each have a rated capacity of 222 megawatts electric(MW), Unit 5 is rated at 341 MW, Unit 6 is rated at 

259 MW, and Unit 8, which recently replaced Units 3 and 4, is rated at 235 MW. Units 9 and 10 are gasfired turbines rated at 170 MW each. The total net generating capacity of HnGS is now 1,619 MW. For 

the years 2000 through 2004, the capacity factor of Unit 1 was 30%, Unit 2 had a capacity factor of 34%, 

Unit 5 had a capacity factor of 26%, and Unit 6 had a capacity factor of 17%. Unit 8 went into operation 

in December 2004 and underwent shakedown testing in early 2005. As a result, reliable capacity factor 

data for Unit 8 is not available. The HnGS withdraws 1,497.3 cfs (672,000 gallons per minute [gpm]) of 

cooling water when all units are in operation. 

Figure 3.1-1. Location of the HnGS and AES Alamitos Generating Station (AGS). 
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IM&E Final Report Source Water Descriptions

3-2 

3.2 DESCRIPTION OF THE COOLING WATER INTAKE SYSTEM 

3.2.1 System Configuration and Operation 

Circulating water for the five units is withdrawn from a single CWIS, located in the Long Beach Marina, 

about 2.4 kilometers (km) (1.5 miles) southeast of the facility. The normal depth of the marina at the site 

of the intake openings is 3 meters (m) (10 feet [ft]). There are seven intake openings in the marina’s 

northwest facing bulkhead wall, below the gangways (Figure 3.2-1). Each opening is 2.3 m (7.5 ft) tall 

and 15.2 m (50 ft) wide. The upper edge of each opening is located at elevation (El. [relative to Mean Sea 

Level]) –0.6 m (2 ft), and the lower edge is at El. –2.9 m (9.5 ft). To keep large debris from entering the 

intake bays, 0.9 cm (3/8 inch) by 7.6 cm (3 inches) trash bars centered every 15.2 cm (6 inches) are 

located at the face of each intake bay. The calculated intake velocity at the marina opening is 0.5 meter 

per second (m/s) (1.6 ft). Each of the seven openings leads to a 2.4 m (8 ft) diameter conduit pipe that 

travels 335 m (1,100 ft) under the San Gabriel River into the intake channel. Only six of the intake 

tunnels are used during normal operation. Flow to the seventh pipe is blocked with stop logs to eliminate 

any biofouling. The velocities through the intake conduit pipes are 5.0 ft/s. The calculated velocity of the 

intake channel is 1.0 (3.2 ft) m/s. Intake structure characteristics, formulas, and velocity calculations for 

the HnGS CWIS are provided in Appendix B of the HnGS PIC. 

A manmade, earthen intake channel runs 2.4 km (1.5 miles) along the east bank of the San Gabriel River 

to the screenhouses (Figure 3.2-2). The channel bottom is at El. –5.8 m (19 ft), and its upper banks rise to 

El. 2.4 m (8 ft). The width of the channel bottom is 9.1 m (30 ft), and the distance between the opposing 

banks is 50.3 m (165 ft). The end of the channel runs parallel to the east side of the plant. Along the 

channel, there are six screenhouses. 

The Unit 1 and 2 screenhouses each have two screenbays with an invert El. –2.6 m (15 ft) and a top deck 

El. 2.0 m (6.7 ft) (Figure 3.2-3). Each screenbay is equipped with stationary screens. The screens are 

3.0 m (10 ft) wide, and are made of 0.9 cm (3/8 inch) wire mesh. Circulating water pumps, two per unit, 

are located just downstream of the screens. The vertical, single-stage pumps are rated at 3.0 m3

 (107 ft3) 

per second [48,000 gpm]. 

Units 5 and 6 withdraw water from separate, but identical, screenhouses, each with four traveling water 

screens. Each bay is about 2.7 m (9.0 ft) wide with an invert El. –5.2 m (17 ft) and a top deck El. 2.0 m 

(6.7 ft). The screens are 2.4 m (8.0 ft) wide with standard 0.9 cm (3/8 inch) square mesh and rotate at a 

speed of 1.54 revolutions per minute (rpm). There are two pumps for each unit located downstream of the 

traveling water screens. The vertical, single stage pumps for Units 5 and 6 are rated at 5 cubic meters (m3

) 

(178.2 ft3

) per second (80,000 gpm) each. 

Unit 8 draws water from the two screenhouses formerly used by Units 3 and 4. Each screenhouse has two 

screenbays that are about 3.3 m (11 ft) wide with a bottom elevation of El. –4.9 m (16.0 ft) and a top deck 

at El. 2.0 m (6.7 ft). The bays are equipped with 3.0 m (10.0 ft) wide traveling water screens with 0.9 cm 

(3/8 inch) square mesh. The screens rotate at 1.4 rpm. Downstream of each screen is a circulating water 

pump. Each of these four pumps is rated at 2.5 m3

 (89.1 ft3) per second (40,000 gpm). 

Velocities at the screen bays were calculated to be 0.9 ft/s for Units 1 and 2, 0.3 m/s (0.8 ft/s) for Units 5 

and 6, and 0.2 m/s (0.7 ft/s) for Unit 8 (formerly Units 3 and 4). All velocities were calculated at mean 

lower low water level (MLLW), El. -0.8 m (2.7 ft), and full flow conditions. 
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The screens for Units 5, 6 and 8 are usually washed once every eight hours. High-pressure nozzles 

(2.5 m3

/minute [400 gpm]) spray fish and debris from the screens. The debris travels through a debris 

trough and into a trash bucket at the north end of each structure for disposal. Circulating water is 

discharged through six conduits into three discharge stations. These stations discharge the water into the 

San Gabriel River flood control channel, which runs along the west side of the station. This channel is 

also used as the discharge for the AES Alamitos Generating Station. Downstream of the discharge point, 

the San Gabriel River enters the Pacific Ocean. 

Marine growth control procedures (heat treatments) are performed periodically at some of the units to 

help prevent biofouling. This occurs by creating a semi-closed system in which the cooling water is 

allowed to recirculate through the system at a constantly maintained temperature of 46°C (115°F). In 

addition to marine growth control procedures, chlorine is injected into the system every eight hours at the 

rate of 0.2 kilograms (kg) (0.5 pounds [lbs]) per minute for 20 minutes. 

At Units 1 and 2, backflushing is conducted periodically (usually once per shift) to prevent introduction 

of debris into the condenser systems. During backflushing, one of the two circulating water pumps is shut 

down, and a stoplog is partially inserted into the unit’s discharge conduit. This shunts cooling water, 

forcing it to back up and back out the intake screens. Any debris built up on the screens is subsequently 

discharged into the intake canal. This process typically takes between five and thirty minutes. 

Note that measurements in drawing are in feet and do not include metric conversions. 

Figure 3.2-1. Top view of the beginning of the Haynes Generating Station intake adjacent to the Long 

Beach Marina (not to scale). 
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Figure 3.2-2. Site plan of the Haynes Generating Station (not to scale). 
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Note that measurements in drawing are in feet and do not include metric conversions. 

Figure 3.2-3. Plan view of Haynes Generating Station screenhouses. 

Units 1 & 2

Units 5 & 6

Unit 8
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3.2.2 Circulating Water Pump Flows 

The HnGS CWIS withdraws 2,544 m3 per minute (672,000 gpm) of cooling water from the Long Beach 

Marina when all units are in operation. Daily cooling water flow volumes at the HnGS during 2006 are 

depicted in Figure 3.2-4. Highest flows generally occurred in spring and summer, with facility flow 

greater than 99% of maximum during extended periods in May, July, and September. Lowest flows 

occurred in early July when Units 5 and 6 were not operating, and in mid-November when Units 5 and 8 

were not operating. Daily cooling flow in 2006 averaged about 2,925,868 m3

 per day (773.0 mgd), or 

about 80% of maximum design flow (Maximum = 3,662,669 m3

 per day, or 967.7 mgd). 

Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06 Jan-07 

HnGS Cooling Water Flow

(Percent of Maximum)

0

20

40

60

80

100

Figure 3.2-4. Daily cooling water flow volumes at the HnGS from January 2006 to February 2007. 

Daily average cooling water flow was highest at Units 5 and 6, which have larger cooling water pumps 

than the other units (Table 3.2-1). Flows at Units 1 and 2 were similar to each other, and slightly higher 

than flows at Unit 8 (former Units 3 and 4). 
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Table 3.2-1. Daily average cooling water flow volumes by unit at HnGS in 2006. 

U1 U2 U8 

(formerly U3) 

U8 

(formerly U4) U5 U6 

Daily average 

flow (m3

) 441,824 445,280 405,758 406,436 579,984 646,587 

Daily average 

flow (gallons) 116,730,345 117,643,397 107,201,534 107,380,603 153,232,219 170,828,712 

Percent of 

maximum 84.44 85.10 93.06 93.21 66.51 74.14 

3.3 ENVIRONMENTAL SETTING

The following section describes the physical and biological environments in the vicinity of the HnGS. 

The HnGS withdraws cooling water from Alamitos Bay, which is hydraulically connected to San Pedro 

Bay. Cooling water is discharged into the lower San Gabriel River flood control channel at a point 

adjacent to the generating station. 

3.3.1 Physical Description 

Alamitos Bay is a man-made, small-vessel harbor that was constructed at the mouth of the San Gabriel 

River, beginning mainly in the 1920s. Prior to this time, it was a seasonal estuary with extensive areas of 

tidal marshes and mud flats. Alamitos Bay is relatively shallow with water depths throughout most of the 

bay from 3.6−5.5 m (12−18 ft) MLLW. The bay is exposed to semidiurnal tides with a mean range of 1.1 

m (3.6 ft). Sediments within the bay consist of sand, silt, and clay. Eelgrass (Zostera marina) is present at 

locations near the entrance channel, near the west end of Naples Island, and in the Marine Stadium arm of 

the bay (Valle et al. 1999). 

The lower San Gabriel River empties into San Pedro Bay just downcoast, and adjacent to, the Alamitos 

Bay entrance jetty (Figure 3.3-1). The river originates in the San Gabriel Mountains, and historically 

flowed to the Los Angeles River. In 1867, flooding altered the river’s course, causing it to empty into 

Alamitos Bay. Catastrophic flooding in 1914 prompted flood protection measures on a basin-wide scale. 

During the 1920s, 1930s, and 1940s, several rivers, including the San Gabriel, were substantially dammed 

and channelized to prevent flooding and allow basin recharging. After this, most of the flow in the San 

Gabriel was reduced to the point that significant amounts of fresh water occurred in the lower reaches 

only during periods of rainfall. 

3.3.1.1 Physical Features 

Alamitos Bay has a surface area of approximately 1.2 km2

 (285 acres) (SWRCB et al. 1998). Prominent 

features within Alamitos Bay include Naples Island, which is a marshland constructed of material 

dredged from the bay in 1908 and 1909 (Reish and Winter 1954), and Colorado Lagoon, which is a 

manmade tidal lagoon that receives sea water from an inlet that is connected to the Marine Stadium and 

Alamitos Bay. The Marine Stadium originally consisted of tidal flats and marshlands, and was dredged 

for rowing events for the 1932 U.S. Olympics (Reish and Winter 1954). Marinas within Alamitos Bay 

presently provide slips for approximately 4,000 boats. 
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Los Cerritos Channel

San Gabriel River HnGS

San Pedro Bay

Alamitos Bay

Marine Stadium

Naples 

Island

Colorado Lagoon

Island Chaffee

Intake Canal

Figure 3.3-1. Aerial view of Alamitos Bay and San Gabriel River outlet vicinity.

Los Cerritos Channel is a flood control channel that connects with Alamitos Bay through the Marine 

Stadium. The tidal prism extends from Alamitos Bay to Anaheim Road. The channel was put on the 

USEPA 303(d) list of impaired water bodies by the LARWQCB due to elevated ammonia, sediment 

contamination, and elevated coliform levels (SWRCB et al. 1998). The AES Alamitos Generating Station 

withdraws cooling water from Los Cerritos Channel via two rock-lined canals. The Los Cerritos Wetlands 

are located at the point where Los Cerritos Channel joins Alamitos Bay. The wetlands currently consist of 

about 0.5 km2

 (130 acres) of wetlands, with nearly 3.2 km2 (800 acres) of degraded wetland habitat 

proposed for restoration. Historically the wetlands consisted of about 9.7 km2

 (2,400 acres) and included 

what is now Alamitos Bay. Since much of the site was modified due to former oil development activities, 

most of the land was privately held. In 2006, the California Coastal Conservancy was one of several 

agencies that purchased 0.3 km2

 (66 acres) of the wetlands, and hopes to acquire more. 

Four oil production islands (Islands Grissom, Chaffee, Freeman, and White)—each 0.04−0.05 km2

(10−12 acres) in size—are located just upcoast from the entrance to Alamitos Bay. The islands are 

constructed of large boulders and sand, and the drilling rigs are camouflaged and soundproofed. More 

than 1,200 wells have been drilled on the four islands. Platform Esther, an oil-drilling platform, is located 

approximately 2 km (1.2 miles) southeast from the entrance of Alamitos Bay in approximately 12 m 

(39 ft) of water. Another drilling platform, Belmont Island, was formerly located off the entrance to 

Alamitos Bay in 14 m (46 ft) of water. It was decommissioned and removed between 2000 and 2002. 
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3.3.1.1.1 Climate and Weather 

Southern California lies in a climatic regime defined as Mediterranean, characterized by mild winters and 

warm, dry summers. In Long Beach, coolest temperatures generally occur from December through 

February, with warmest temperatures in August and September (Weather Underground 2007). Average 

temperatures range from 8−28°C (46−83°F) (City of Long Beach 2007). Average annual precipitation in 

the coastal regions ranges between 25−38 cm (10−15 inches), with most precipitation occurring from 

October through April. 

A subtropical high-pressure system offshore the Southern California Bight, defined as the nearshore 

coastal areas from Point Conception south into Baja California, produces a net weak southerly/onshore 

flow in the area (Dailey et al. 1993). Wind speeds are usually moderate, and are on the order of 10 km/hr 

(6 miles/hr). Wind speeds diminish with proximity to the coast, averaging about one-half the speeds 

offshore. Coastal winds in southern California are about one-half those found off central and northern 

California. However, strong winds occasionally accompany the passage of a storm. A diurnal land breeze 

is typical, particularly during summer, when a thermal low forms over the deserts to the east of the Los 

Angeles area. On occasion, a high-pressure area develops over the Great Basin, reversing the surface 

pressure gradient and resulting in strong, dry, gusty offshore winds in the coastal areas. These Santa Ana 

winds are most common in late summer, but can occur any time of year. 

3.3.1.2 Temperature and Salinity 

Waters within Alamitos Bay are primarily marine (30–35 practical salinity units [PSU]) with water 

temperatures ranging from about 13°C (55°F) in winter to 25°C (77°F) in summer (Allen and Horn 1975; 

IRC 1981). The bay has undergone extensive changes in the last 100 years. Originally an estuary and 

wetland system prior to the 1920s, it is now highly developed. 

The temperature and salinity of the waters offshore Alamitos Bay have been measured semiannually or 

annually for many years as part of the HnGS NPDES monitoring program (Table 3.3-1). The monitoring 

program consists of 9 stations in the nearshore waters off Alamitos Bay and the mouth of the San Gabriel 

River flood control channel, from depths of 3.6 to 12.2 m (12 to 40 ft). Three additional stations are 

monitored within the San Gabriel River. From 2000 through 2004, all stations were sampled during both 

ebb and flood tides during five winter surveys and five summer surveys. Salinity is not a required 

monitoring component but results have been measured and reported since 2001. 
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Table 3.3-1. Temperature and salinity of surface and bottom waters off Alamitos Bay, 2001–2004. 

Season Parameter Surface Bottom 

Winter Minimum temperature °C (°F) 14.5 (58.2) 13.5 (56.3) 

 Average temperature °C (°F) 16.7 (62.1) 14.6 (58.3) 

 Maximum temperature °C (°F) 23.5 (74.2) 16.6 (61.9) 

 

Summer Minimum temperature °C (°F) 18.5 (65.3) 13.9 (57.1) 

 Average temperature °C (°F) 21.3 (70.4) 18.1 (64.6) 

 Maximum temperature °C (°F) 27.4 (81.3) 21.8 (71.2) 

 

Winter Minimum salinity (PSU) 28.8 32.4 

 Average salinity (PSU) 32.1 33.2 

 Maximum salinity (PSU) 33.4 33.6 

 

Summer Minimum salinity (PSU) 32.3 33.2 

 Average salinity (PSU) 33.2 33.5 

 Maximum salinity (PSU) 33.6 33.9 

In general, temperatures in the study area are usually several degrees warmer in summer than in winter, 

with bottom waters consistently colder than surface waters. Temperatures throughout the water column in 

the study area are usually warmest in the afternoon due to solar heating, and the formation of a 

thermocline is especially common during summer, though thermoclines may also develop in winter. 

Salinity in the study area is relatively uniform, ranging from 28.8 to 33.9 practical salinity units (PSU), 

typical for nearshore waters of southern California. Salinity is usually slightly higher near bottom than at 

the surface. Lowest salinity typically occurs directly offshore the mouth of the San Gabriel River. 

Additional water quality monitoring was performed at the HnGS intake structure during spring and 

summer (April–June) 2004 (MBC 2004). Water temperatures at the surface and a depth of one meter 

ranged from about 17.9°C (64.2°F) to 21.4°C (70.5°F) during sampling, with little or no difference 

between the two depths. Salinity consistently ranged between 33.2 and 34.2 PSU. 

3.3.1.3 Tides and Currents 

Tides in southern California are classified as mixed, semi-diurnal, with two unequal high tides (high 

water and higher high water) and two unequal low tides (low water and lower low water) each lunar day 

(approximately 24.5 hr). Between 1997 and 2002, water level extremes in Outer Los Angeles Harbor 

ranged from –0.6 m to +2.35 m (-1.97 ft to + 7.71 ft) above MLLW. The tidal prism of Alamitos Bay 

(defined as the body of water contained within the mean tidal range) is approximately 1.96 x 106

 m3

(517.8 million gallons) (IRC 1981). 

3.3.1.3.1 Historical Overview 

Detailed circulation studies were performed within Alamitos Bay and the nearshore areas of San Pedro 

Bay during the original HnGS 316(b) Demonstration (IRC 1981). Waters drawn into the Bay become 

progressively better mixed as they are drawn toward the inner reaches where the cooling water intakes are 

located. This is the opposite of what would normally occur in back bay areas, which normally have the 
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poorest flushing and longest retention times. IRC (1981) determined that cooling water withdrawals from 

Haynes and Alamitos induce a net transport into the bay, with the mean residence time of water estimated 

at about one day. 

At the entrance to Alamitos Bay, currents are bi-directional, with a strong bias toward in-flowing over 

out-flowing currents, and speeds ranging to about 40 centimeters per second (cm/s) (1.4 feet per second 

[ft/s]) (IRC 1981). Current speeds diminish in mid-bay, with most current speeds less than 20 cm/s (0.7 

ft/s). At the HnGS intake structure in Long Beach Marina, surface waters flow away from the intake 

structure approximately one-third of the time; however, mid-depth or below, waters flow directly toward 

the intake approximately 80% of the time. 

Recirculation of discharged cooling water at HnGS (from the San Gabriel River back to the intake 

structure in Alamitos Bay) was estimated to be about 4%. This relatively low value was attributed to 

predominant downcoast currents which transport discharged waters away from Alamitos Bay. It was 

concluded that “...very little of the water entrained into the Haynes Generating Station resided within 

Alamitos Bay more than five days.” Due to the predominant downcoast water movement outside 

Alamitos Bay, the immediate oceanic source waters for Alamitos Bay were determined to lie in the 

northern lees of the Long Beach and Middle Breakwaters (Outer Long Beach Harbor), with minor 

amounts derived from downcoast between Alamitos and Anaheim Bays. Downcoast flow off Alamitos 

Bay averaged about 1.6 cm/s (0.05 ft/s), or about 1.5 km/day (0.9 miles/day) (IRC 1981). 

Circulation patterns in the Ports of Los Angeles and Long Beach, which are part of the greater source 

water area for HnGS, were described in a study of suspended sediment transport in the Harbor region 

(LARCSTF 2005). The ports are protected from incoming waves by the Federal Breakwater, which 

consists of three individual rock jetty structures. In addition to protecting the ports from waves, the 

Federal Breakwater reduces the exchange of the water between the harbor and the rest of San Pedro Bay, 

hence creating unique tidal circulation patterns. 

Maximum flood and ebb current patterns in the Ports of Los Angeles and Long Beach under typical tidal 

conditions are shown in Figure 3.3-2. A depth-averaged two- dimensional hydrodynamic model, RMA2, 

developed by the US Army Corps of Engineers was used to predict the tidal currents shown in the figures. 

The model was calibrated against field data collected by National Oceanic and Atmospheric 

Administration (NOAA) at the Port of Long Beach, as well as against a more sophisticated threedimensional model. On the Long Beach side nearest Alamitos Bay and HnGS, flood currents enter the 

harbor through the Queen’s Gate as well as the opening near the eastern tip of the Federal Breakwall. 

Flood currents passing through Queen’s Gate flow to either side of Pier J. 

During ebb tide the flow in the harbor is drawn from all directions as a potential flow toward the exits. 

Ebb currents leaving the Los Angeles Harbor flow mainly through the Angel’s Gate. On the Long Beach 

side, ebb currents exit either through the Queen’s Gate or the eastern opening passing the tip of the 

Federal Breakwall. Tidal currents within the Ports of Los Angeles and Long Beach are generally very 

small. Typical maximum tidal currents within the harbor are in general less than 0.5 ft/s. Tidal currents 

entering and exiting Angel’s Gate and Queen’s Gate are higher, but are still in general less than 0.8 ft/s. 

Significant offshore flows from flood control channels such as the San Gabriel River can also occur 

during winter storms. 
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Los Angeles/Long Beach Harbors

Flood Tide Current Simulation

Los Angeles/Long Beach Harbors

Ebb Tide Current Simulation

 HnGS

 HnGS

Angel’s Gate

Queen’s Gate

Federal Breakwall

Pier J

Note that the scales used in the figures are in feet and do not include metric conversions. (Figures from Los Angeles CSTF 

[2005]). 

Figure 3.3-2. Current patterns in Los Angeles and Long Beach Harbors predicted by a depthaveraged two-dimensional hydrodynamic model developed by the US Army Corps of Engineers. 
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3.3.1.3.2 2006 ADCP Deployments 

Physical oceanographic data were collected from the source water body to describe current regimes that 

can affect larval transport in the vicinity of the HnGS. Two Nortek Aquadopp® acoustic Doppler current 

profilers (ADCPs) were positioned in separate locations, one (CM1) approximately 2.1 km (1.3 mi) from 

shore off the entrance to Alamitos Bay at a depth of −12.4 m (−40.7 ft) MLLW, and a second unit (CM2) 

approximately 3.2 km (2.0 mi) from shore off the San Gabriel River mouth at a depth of -16.2 m 

(−53.1 ft) MLLW (Figure 3.3-3). Both stations were commissioned on January 10, 2006. Station CM2 

was decommissioned on January 8, 2007 and Station CM1 was decommissioned on January 11, 2007. 

Data were downloaded on May 2, 2006 and August 31, 2006. From May 2−5, 2006 Station CM1 did not 

collect current data due to operational error after the data download. The unit at CM1 had an operating 

frequency of 1 MHz, while the unit at CM2 had an operating frequency of 600 kHz (Table 3.3-2). Both 

units collected data at hourly intervals in a usable range that extended from 0.5 m (1.6 ft) from the ADCP 

to somewhat less than 90% of the distance to the surface. The half-power full beam-width was 2.4 

degrees for both types of units. Other measurement specifications are listed in Table 3.3-2. Water 

temperature and water depth (pressure) were also measured concurrently by the units. Water temperatures 

were calibrated over an approximately four-month period from September 2006 to January 2007 using 

two calibrated Starr-Oddi thermistors. Pressure measurements were adjusted using barometric pressure 

data measured at the Los Angeles International Airport and corrected for sea level. 

Table 3.3-2. ADCP deployment parameters for current meters in the vicinity of HnGS 

(Stations CM 1 and CM 2). 

Unit 

Oper. 

Freq. 

Deploy 

depth 

(m) 

Cells 

(#) 

Cell size 

(m) 

Max. 

range (m)

Cell 

precision 

(cm/s) Ping rate 

Averaging 

Interval 

(s) 

Repetition 

rate (hr) 

CM 1 1 MHZ 12.4 15 1.0 15 0.8 87% 180 1.0 

CM 2 600 kHz 16.2 20 1.0 20 1.4 100% 300 1.0 

Figure 3.3-3 shows the net displacements at the current meter stations from January 2006 to January 2007 

relative to the current meter locations. The net displacement of water at Station CM 1 was to the north and 

to a lesser extent to the east. At Station CM 2 net displacement varied east to west and slightly south. The 

sum of the hourly upcoast components of each current measurement was maximized to estimate a rotation 

of 39o at Station CM 1. This rotation oriented alongshore currents to 321o true. After rotating current 

velocities and averaging over the water column, plots of cumulative current vectors showed that currents 

at the inshore station (CM 1) moved predominantly in an upcoast and onshore direction during 2006 with 

few seasonal reversals (Figure 3.3-4). Small-scale changes in net direction may be attributed to tidally 

induced currents flowing into and out of the Los Angeles-Long Beach Harbor complex. In contrast, 

currents at Station CM 2 located outside of the Long Beach Breakwater and in slightly deeper water than 

the inshore station displayed frequent upcoast-downcoast reversals (Figure 3.3-5). Net downcoast currents 

prevailed in January−April 2006 and in October 2006−January 2007, whereas net upcoast transport 

occurred from May−September 2006 but with frequent reversals during summer months. Over the year 

net transport was downcoast at CM 2. Current vector frequencies, water temperatures and tidal elevation 
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data from the ADCP units are presented in Appendix A as monthly plots for each station. Over the year 

water depths at CM 1 varied from 11.75 m (38.6 ft) to 14.59 m (47.9 ft) with an average of 13.27 m 

(43.6 ft). At CM 2 water depths varied from 15.64 m (51.2 ft) to 18.41 m (60.4 ft) and averaged 17.09 m 

(56.1 ft). 

The extent of source populations of larval organisms was estimated from December 2005 to January 2007 

using a combination of cross-shelf and alongshore components from the two stations, and with 

reproduction of December 2006 and January 2007 data for the data missing in December 2005 and early 

January 2006. A combined plot of data from the two locations using the upcoast-downcoast vector from 

CM 1 and the onshore-offshore vector from CM 2 showed a net upcoast transport direction with a slight 

onshore component (Figure 3.3-6). Estimates of source populations were therefore based on a 

combination of currents measured at the two stations and also subject to the rotations that were used to 

estimate alongshore and onshore water excursions. 
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CM1

-50

0

50

100

150

200

250

300

350

400

450

500

-50 0 50 100 150 200 250

Cumulative East Distance (km)

Cumulative North Distance (km)

CM2

-150

-100

-50

0

50

-50 0 50 100 150

Cumulative East Distance (km)

Cumulative North Distance (km)

Figure 3.3-3. Net displacement at current meter stations CM 1 and CM 2 from January 2006 to 

January 2007. 
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Jan-07

Dec-06

Nov-06

Oct-06

Sep-06

Aug-06

Jul-06

May-06 Jun-06

Apr-06

Mar-06

Feb-06

-50

0

50

100

150

200

250

300

350

400

-50 0 50 100 150 200 250 300 350 400

Cumulative onshore distance (km)

Cumulative upcoast distance (km)

Figure 3.3-4. Cumulative current vectors from Station CM 1 in San Pedro Bay from January 2006 to January 

2007. 
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Feb-06

Mar-06

Apr-06

Jul-06

Jan-07

Dec-06

Nov-06

Oct-06

Sep-06

Aug-06Jun-06

May-06

-160

-140

-120

-100

-80

-60

-40

-20

0

-80 -60 -40 -20 0 20 40 60 80

Cumulative onshore distance (km)

Cumulative upcoast distance (km)

Figure 3.3-5. Cumulative current vectors from Station CM 2 in San Pedro Bay from January 2006 to 

January 2007. 
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Jan-07

Dec-06

Nov-06

Oct-06

Sep-06

Aug-06

Jul-06

Apr-06 May-06 Jun-06

Mar-06

Feb-06

Jan-06

Dec-05

-50

0

50

100

150

200

250

300

350

400

-200 -150 -100 -50 0 50 100 150 200

Cumulative onshore distance (km)

Cumulative upcoast distance (km)

Note: For modeling purposes, data from December 2006 and January 2007 were substituted for the data missing in December 

2005 and early January 2006 

Figure 3.3-6. Composite cumulative current vectors from Stations CM 1 (upcoast) and CM 2 (onshore) in 

San Pedro Bay from January 2006 to January 2007. 
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3.3.2 Source Water Definition 

The source water study area is designed to 1) characterize the larvae of ichthyoplankton and shellfish 

larvae potentially entrained by the HnGS cooling water intake, and 2) be representative of the nearshore 

habitats in the vicinity of the HnGS intake. 

3.3.2.1 Study Requirements and Rationale 

The primary approach for assessing the effects of entrainment by the HnGS requires an estimate of the 

source water population for each species entrained. The spatial extent of the source water population 

subject to entrainment is a function of larval duration and circulation. Information on larval duration is 

estimated from data on the length of the larvae collected from the entrainment samples. The spatial extent 

of the source population for HnGS is complicated since three components of the source water can be 

identified that operate on different time scales relative to the time scale of the period of time that larvae 

are subject to entrainment. The three source water components are: 1) Alamitos Bay where the HnGS 

intake is located, 2) nearshore coastal water that is transported into Alamitos Bay on incoming tides, and 

3) water that is transported out of Alamitos Bay into nearshore coastal waters on outgoing tides. The 

water volume within Alamitos Bay changes with tidal elevation, which also affects the outflow from 

Alamitos Bay into nearshore waters and flow into the bay from the nearshore waters. The volume of the 

source water in the nearshore area, which is potentially subject to entrainment, is affected by currents that 

change seasonally and by weather and sea conditions. The rationale and methods for defining the source 

water for the HnGS are described in the following sections. 

The estimates of the source water population used in assessing the effects of entrainment were based on 

sampling that occurred in Alamitos Bay and nearshore areas outside the bay. The volume of the source 

water within Alamitos Bay is continually changing due to tidal flow. The volume is also affected by flow 

through the Haynes and Alamitos generating stations from the bay and back out to the ocean through the 

San Gabriel River. Oceanographic studies associated with the previous 316(b) study showed that the 

flows from the two plants reduce the residence time of the water in Alamitos Bay to approximately one 

day (IRC 1981). One of the benefits of this increased flow through the bay is improved water quality. The 

IRC studies estimated that the cooling water flows annually supply the bay with 45,000 kg (50 tons) 

additional tons of oxygen relative to the supply provided by natural exchange processes. The sampling 

inside Alamitos Bay provides an estimate of the larval concentrations subject to entrainment. The larval 

concentrations of different species were used with an estimate of the volume of the bay at mean sea level 

(MSL) to calculate the population of larvae potentially subject to entrainment. The same approach was 

used to estimate the larval populations from the nearshore source water stations (S1-S3 and O1-O3 

[Figure 3.3-7]). 

3.3.2.2 Methods for Calculating HnGS Source Water 

Two sources were used in gathering the data necessary for estimating the volume of Alamitos Bay and the 

nearshore source water stations. The inshore and nearshore bathymetry data were from Moffatt & Nichol 

(2004) and from NOAA ENC chart data. Some editing of these data was done to more closely match the 

depths and elevations derived from NOAA navigation data that included coverage for the entire harbor 

and surrounding ENC charts. NOAA used a number of sources in compiling these data including U.S. 

Army Corps of Engineers surveys, drawings, and permits, U.S. Coast Guard Local Notices to Mariner, 
Haynes Generating Station Generating Station and

IM&E Final Report Source Water Descriptions

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National Imagery and Mapping Agency Notices to Mariners, NOAA hydrographic surveys, and the 

largest scale paper chart of an area. Depth data points were identified and selected from the source 

datasets that fell within the water portions of the source water area. This area was identified using a 

coastline Geographic Information System (GIS) layer created from a U.S. Geological Survey topographic 

quad map at 1:24,000 scale and manually edited in ArcGIS to approximate the available NOAA GIS 

coastline themes and latest aerial images from Google Earth (March 2004). MLLW depths were adjusted 

to MSL (shallower by 0.86 m (2.8 ft) per the tide gauge at Station 9410660 Los Angeles, CA). The 

corrected depth data were merged and exported to a new depth point GIS layer relative to MSL. A 20 m 

(65.6 ft) surface grid representing the bathymetry relative to MSL was constructed from this new set of 

combined points resulting in contours at 1 m (3.3 ft) intervals. The resulting bathymetry surface grids 

were then converted into a polygon shapefile, clipped to the coastline, boundary of the source water, and 

used for area and volume calculations. 

The Alamitos Bay source water region consisted of two areas: 1) an inshore area including the Alamitos 

Bay waters inshore, northeast of the coastline, and portions of Colorado Lagoon, and Los Cerritos 

Channel, and 2) the 0.4 km (1.5 mile) long Haynes Intake Canal (Figure 3.3-7). The volume of the intake 

canal was calculated as 330,237 m3

 (87.2 million gal) based on cross-sectional engineering drawings of 

the canal indicating a bottom depth of –5.8 m (19 ft) MSL, bottom width of 9.1 m (30 ft), and distance 

between opposing banks of 50.3 m (165 ft) at an elevation of 2.4 m (8.0 ft) MSL (see Figure 3.2-1). 

The third component of the HnGS source water is outflow from Alamitos Bay. This is used to account for 

larvae from Alamitos Bay that are transported into nearshore areas by ebbing (outflowing) tidal currents 

where they are still subject to entrainment due to subsequent flows back into the bay. This transport 

occurs on a daily basis and was estimated using hourly changes in bathymetric volumes of the bay as a 

function of tidal heights, together with estimated power plant flows of both HnGS and the Alamitos 

Generating Station. The tidal heights in Alamitos Bay were estimated using records of the pressure sensor 

at Station CM 1. Changes in atmospheric pressure were corrected using sea level pressure measurements 

made at the Los Angeles International Airport. Port of Los Angeles (POLA) Outer Harbor tides were used 

for the time period between January 1 and January 10, 2006 before deployment of the current meter. Tidal 

data from Station CM 2 were substituted when CM 1 was not operating between May 2 and May 5, 2006 

and when data were periodically downloaded. Moffatt & Nichol (2004) showed that tidal water levels and 

tide phase at the Marine Stadium part of Alamitos Bay are very similar to those predicted at Los Angeles 

Outer Harbor. As an example, Figure 3.3-8 shows the correspondence between tidal heights estimated at 

Station CM 1 and POLA Outer Harbor for the August 2006 time period. Figure 3.3-9 shows estimates of 

the daily Alamitos Bay outflows from January through December 2006. 

The three components of the source water are used with the estimates of larval entrainment and HnGS 

CWIS flows to calculate impacts on larval fish populations due to entrainment, as described in Section 

4.3.4.3 - Empirical Transport Model. 
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Figure 3.3-7. Source water boundaries and bathymetry defined for ETM modeling effects of HnGS. 
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-1.00

-0.50

0.00

0.50

1.00

1.50

2.00

2.50

08/01/06 08/06/06 08/11/06 08/16/06 08/21/06 08/26/06 08/31/06

Tidal Height (m)

POLA

CM1

Figure 3.3-8. Correspondence of tidal heights estimated at Station CM 1 and at Port of Los Angeles Outer 

Harbor (POLA), August 2006. 

0

2

4

6

8

10

12

J FMAMJ J ASOND

Flow Volume (cubic meters x 10 6

)

Inflow Ouflow

Figure 3.3-9. Estimates of Alamitos Bay daily tidal inflow and outflow volumes from January to 

December 2006. 
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3.3.3 Biological Resources 

The following sections describe the aquatic biological habitats and communities in the vicinity of HnGS, 

including both invertebrate and fish communities. 

3.3.3.1 Habitat Variation 

Subtidal sediments in Alamitos Bay consist primarily of sand and mud, and waters are primarily saline 

(Allen and Horn 1975). Subtidal vegetation (eelgrass [Zostera marina]) is present at locations near the 

entrance channel, near the west end of Naples Island, and in the Marine Stadium arm of the Bay (Valle et 

al. 1999). Depths throughout most of the bay are shallow, ranging from 3.6−5.5 m (12−18 ft). Most of the 

shoreline is developed, and consists of hard intertidal and subtidal substrates, such as concrete bulkheads 

and piers. Long Beach Marina consists of numerous floating docks, including several in the vicinity of the 

HnGS bulkhead intake structure (Figure 3.3-10). The HnGS intake is submerged under the concrete 

walkway at left. 

 

Figure 3.3-10. View of Long Beach Marina and HnGS intake structure below water 

surface along concrete bulkhead. 
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3.3.3.2 Nursery Grounds 

The role as a nursery grounds for juveniles of coastal fish species is probably the most widely recognized 

and accepted function of bays and estuaries in their status as important fish habitats (Allen et al. 2006). 

Valle et al. (1999) sampled the juvenile fishes of Alamitos Bay from 1992 through 1995 with a 1.6-m 

(5.2-ft) beam trawl fitted with 3 millimeters (mm) (0.1 inches) mesh. Of the 46 taxa collected, the most 

abundant were unidentified gobies (Gobiidae), cheekspot goby (Ilypnus gilberti), bay pipefish 

(Syngnathus leptorhynchus), shiner perch (Cymatogaster aggregata), and topsmelt (Atherinops affinis). 

The study concluded that shallow habitats, both vegetated with eelgrass and unvegetated, were especially 

important for juvenile fishes. Juvenile California halibut (Paralichthys californicus) inhabited 

unvegetated areas, while barred sand bass (Paralabrax nebulifer) inhabited eelgrass beds. The habitats 

nearest the bay mouth are particularly important for juveniles of these two species, whereas habitats 

further inside the bay are more important for most other fishes. 

Several features of bays and estuaries may be important to settling species, such as California halibut, 

including warmer water temperatures, decreased turbulence, finer sediments, and different biological 

communities compared with those on the open coast. MBC (1991) determined densities of recently settled 

California halibut in southern California increased with decreasing depth. The semi-protected waters of 

Queensway Bay and Outer Long Beach Harbor, just upcoast from Alamitos Bay, are also important 

habitats for juvenile fishes and invertebrates. Recently transformed cheekspot goby, California tonguefish 

(Symphurus atricaudus), white croaker (Genyonemus lineatus), and queenfish (Seriphus politus) were the 

most abundant juvenile fishes collected in seasonal surveys of Queensway Bay in 1990−1991 and 1994 

(MBC 1994). 

3.3.3.3 Fish Diversity 

Bay and estuarine fish assemblages in California tend to be dominated in abundance by few (usually five 

or less) species and have low diversity even though many other species are typically encountered (Allen 

et al. 2006). A total of 44 fish species were documented from Alamitos Bay by Allen (1976), and 46 taxa 

were collected by Valle et al. (1999) (see Section 3.3.2.2). In the Colorado Lagoon are of the Bay, four 

species comprised 99% of the total abundance: northern anchovy (Engraulis mordax), topsmelt, slough 

anchovy (Anchoa delicatissima), and shiner perch (Allen and Horn 1975). Species diversity and 

abundance at Colorado Lagoon were highest during summer (May–September) and both were highly 

correlated with water temperature, which ranged between 12.8−25.0°C (55−77°F). 

IRC (1981) conducted bimonthly demersal fish surveys near the HnGS intake and just off Alamitos Bay 

in 1978−1979. The number of taxa collected outside the bay (41) was higher than the number from within 

the bay (31), and abundance outside the bay was about twice that from inside Alamitos Bay. Within 

Alamitos Bay, the most abundant species were white croaker, queenfish, and shiner perch, while white 

croaker, queenfish, and northern anchovy were most abundant offshore. 

Long-term demersal fish and invertebrate surveys have been conducted just offshore Alamitos Bay and 

the mouth of the lower San Gabriel River (MBC 2007). At least 66 species of fish have been collected 

since 1972, with an average of about 30 species annually. Abundance has been dominated by northern 

anchovy, white croaker, queenfish, and California tonguefish, which combined account for 90% of the 

long-term trawl catch. In 2006, abundance in summer was about twice that in winter, though species 
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richness was the same between surveys. The warm waters emanating from the mouth of the San Gabriel 

River flood control channel leads to increased productivity and diversity in that area, especially in winter 

when both productivity and diversity would normally decrease (EQA/MBC 1973). 

Between 2001 and 2006, at least 52 fish species were impinged at both the HnGS and the AES Alamitos 

Generating Station (MBC 2007). Queenfish, topsmelt, pipefishes (Syngnathidae), and northern anchovy 

were most abundant at HnGS, while topsmelt, silversides (Atherinopsidae), shiner perch, and Pacific 

staghorn sculpin (Leptocottus armatus) were most abundant at Alamitos. The assemblage impinged at 

HnGS was almost entirely comprised of marine and estuarine species, while freshwater species were 

occasionally impinged at Alamitos due to the proximity of the intakes to Los Cerritos Channel. 

Between April and July 2004, at least 13 larval fish taxa from 11 families were collected from the HnGS 

intake structure, and at least 10 larval fish taxa from nine families were collected from the AES Alamitos 

intake canals (MBC 2004, 2005). At the HnGS intake, combtooth blennies (Hypsoblennius spp.), gobies, 

and silversides accounted for 93% of the larval densities, while gobies and blennies accounted for 97% of 

the density at Alamitos. At HnGS, topsmelt and northern anchovy each represented an additional 2% of 

the total larval density. Combtooth blennies were the dominant taxa during the first half of the study, with 

goby densities increasing substantially from late May to June. Nearly all of the goby and blenny larvae 

were preflexion, indicating they were in the relatively early stage of larval development. Overall, 

nighttime larval densities were significantly higher than daytime densities. Two California spiny lobster 

phyllosoma were also collected during the study. 

3.3.3.4 Shellfish Diversity 

Over 100 demersal macroinvertebrate taxa have been collected just offshore Alamitos Bay since 1978, 

although about 25 species are collected annually (MBC 2007). Blackspotted bay shrimp (Crangon 

nigromaculata), tuberculate pear crab (Pyromaia tuberculata), and spiny sand star (Astropecten armatus) 

are the most abundant species in the area, comprising 84% of the long-term abundance. In 2006, diversity 

and abundance were substantially higher in winter compared to summer. Diver surveys offshore Alamitos 

Bay in the early 1970s identified 116 taxa, with species richness lowest in winter and highest in summer 

(EQA/MBC 1973). The tubiculous polychaete Diopatra splendidissima was the most abundant 

invertebrate recorded during the study. 

In 2006, the most abundant macroinvertebrates impinged at HnGS were: red jellyfish (Polyorchis 

penicillatus), the nudibranch Hermissenda crassicornis, tuberculate pear crab, California aglaja (Navanax 

inermis), and yellow shore crab (Hemigrapsus oregonensis) (MBC 2007). The most abundant species at 

Alamitos were yellow shore crab, moon jelly (Aurelia aurita), Kellet’s whelk (Kelletia kelletii), red 

jellyfish, and tuberculate pear crab. 

3.3.3.5 Protected Species 

Some fish and invertebrate species (abalone) in southern California are protected under CDFG regulations 

although few marine species are listed as either threatened or endangered. Special status fish species that 

could occur in the vicinity of HnGS and that have planktonic larvae potentially at risk of entrainment 

include garibaldi (Hypsypops rubicundus), tidewater goby (Eucyclogobius newberryi), and California 

grunion (Leuresthes tenuis). 
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Garibaldi, designated as the California state marine fish, is a bright orange shallow-water species that is 

relatively common around natural and artificial rock reefs in southern California. Because of its territorial 

behavior it is an easy target for fishers and could be significantly depleted if not protected. Garibaldi 

spawn from March through October, and the female deposits demersal adhesive eggs in a nest that may 

contain up to 190,000 eggs deposited by several females (Fitch and Lavenberg 1975). Larval duration 

ranges from 18−22 days (mean of 20 days) based on daily incremental marks on otoliths in recently 

settled individuals (Wellington and Victor 1989). The larvae are susceptible to entrainment, particularly 

in summer months when spawning is at its peak. 

The tidewater goby is a fish species endemic to California and is listed as federally endangered. The 

tidewater goby is threatened by modification and loss of habitat resulting primarily from coastal 

development. It appears to spend all life stages in lagoons, estuaries, and river mouths (Swift et al. 1989) 

but may enter marine environments when flushed out of these preferred habitats during storm events. 

Adults or larvae may not survive for long periods in the marine environment but larval transport over 

short distances may be a natural mechanism for local dispersal. 

California grunion is a species with special status not because the population is threatened or endangered, 

but because their spring-summer spawning activities on southern California beaches puts them at risk of 

over harvesting, and CDFG actively manages the fishery to ensure sustainability. Spawning occurs only 

three or four nights following each full or new moon, and then only for 1–3 hours immediately after the 

high tide, from late February to early September (Love 1996). The female swims onto the beach, digs tailfirst into the wet sand, and deposits her eggs, which are then fertilized by the male. After the eggs hatch, 

the larvae are carried offshore and can be susceptible to entrainment for approximately 30 days as they 

develop in the plankton. 

Off southern California, the species managed under the Magnuson-Stevens Fishery Conservation and 

Management Act are listed in the Coastal Pelagics Fishery Management Plan (FMP) and the Pacific 

Groundfish FMP. The goals of the management plans include, but are not limited to: the promotion of an 

efficient and profitable fishery, achievement of optimal yield, provision of adequate forage for dependent 

species, prevention of overfishing, and development of long-term research plans (PFMC 1998, 2006). 

There are four fish and one invertebrate species covered under the Coastal Pelagics FMP: northern 

anchovy, Pacific sardine (Sardinops sagax), jack mackerel (Trachurus symmetricus), Pacific (chub) 

mackerel (Scomber japonicus), and market squid (Loligo opalescens). There are 89 fish species covered 

under the Pacific Groundfish FMP, including ratfish (Hydrolagus colliei), finescale codling (Antimora 

microlepis), Pacific rattail (Coryphaenoides acrolepis), three species of sharks, three skates, six species of 

groundfish, 62 species of scorpionfishes and thornyheads, and 12 species of flatfishes. For both the 

Coastal Pelagics and Pacific Groundfish, essential fish habitat (EFH) includes all waters off southern 

California offshore to the Exclusive Economic Zone. 
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4.0 COOLING WATER INTAKE STRUCTURE ENTRAINMENT AND 

SOURCE WATER STUDY 

4.1 INTRODUCTION

The entrainment study incorporates two design elements: 1) CWIS sampling, and 2) source water 

sampling. Sampling at the intake provides estimates of the total numbers of each larval species entrained 

through the CWIS on a biweekly basis depending on pumping capacity. The source water populations of 

fish and shellfish larvae were sampled to estimate proportional entrainment (PE) losses for selected 

species. Abundances of larval fishes and shellfishes vary throughout the year due to changes in 

composition and the oceanographic environment. Because it is desirable from an impact modeling 

standpoint to have a higher resolution of temporal changes in the composition of entrained taxa than 

source water taxa, entrainment sampling was conducted biweekly while source water sampling was 

conducted monthly. The sampling frequency was consistent with other recently completed entrainment 

studies conducted for the AES Huntington Beach Generating Station (MBC and Tenera 2005), the Duke 

Energy South Bay Power Plant (Tenera 2004), and the Cabrillo Power I LLC, Encina Power Station 

(Tenera 2007). 

The entrainment study was designed to specifically address the following questions: 

• What are the species composition and abundance of the larval fishes, fish eggs, crab megalops, 

and spiny lobster larvae entrained by HnGS? 

• What are the local species composition and abundance of the entrainable larval fishes, fish eggs, 

crab megalops, and spiny lobster larvae in Alamitos Bay and adjacent nearshore areas? 

• What are the potential impacts of entrainment losses on these populations due to operation of the 

CWIS? 

The following sections explain the entrainment study methods, quality assurance procedures, and study 

results analyzed on a temporal and spatial basis in relation to power plant operation in 2006. 

4.1.1 Discussion of Species to be Analyzed 

Planktonic organisms in the source water body that are smaller than the CWIS screening system mesh 

(0.9 cm [3/4 in]) are susceptible to entrainment. These include species that complete their entire life cycle 

as planktonic forms (holoplankton) and those with only a portion of their life cycle in the plankton as 

eggs or larvae (meroplankton). This study estimated entrainment effects on meroplanktonic species 

including all fish eggs and larvae, and the advanced larval stages of several invertebrate species including 

all crabs, market squid (Loligo opalescens), and California spiny lobster (Panulirus interruptus). None of 

the holoplanktonic forms (such as copepods) were enumerated because these populations are typically 

widespread over large oceanic areas and the species have short generation times resulting in very low 

potential for population-level impacts. All target taxa in the samples were identified to the lowest 

practical taxonomic level, but some specimens were combined into broader taxonomic groups because the 

morphological characteristics of some species are not distinct at smaller stages, descriptions are lacking 

for some of the larvae (particularly for many of the crab megalops), or specimens were damaged and 
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4-2 

could not be positively identified. Although all target taxa specimens were enumerated in the samples, 

including uncommon species and those with no direct fishery value, detailed impact analysis was only 

applied to a few of the more abundant species or species-groups, in addition to the specific shellfish taxa 

(spiny lobsters, market squid) regardless of abundance. 

4.1.1.1 Fish 

Many of the marine fishes in the vicinity of the CWIS produce free-floating larvae as an early life stage, a 

notable exception being the surfperches which bear well-developed live young. Planktonic larval 

development promotes dispersal of the population but also puts larvae at risk of entrainment. Some 

groups (e.g., croakers, flatfishes, anchovies) broadcast eggs directly into the water column where they 

develop in a free-floating state until hatching into the larval form. In this case both eggs and larvae are 

potentially susceptible to entrainment. For groups that deposit adhesive eggs onto the substrate (e.g., 

gobies, cottids) or brood eggs internally until larvae are extruded (e.g., rockfishes, pipefishes), only the 

larvae and not the eggs are at risk of entrainment. 

4.1.1.2 Shellfish 

“Shellfish” is a general term to describe crabs, shrimps, lobsters, clams, squids and other invertebrates 

that are consumed by humans, and it is used to differentiate this group of fishery species from “finfish” 

which includes bony fishes, sharks and rays. In the present study, crabs, spiny lobster, and market squid 

were selected as representative of the shellfish species at potential risk of entrainment, some of which 

have direct fishery value and others that are primarily important only as forage species for higher trophic 

levels. The inclusion of certain shellfish larvae as target species, and the enumeration of only the later 

stages such as megalops and phyllosomes, was a compromise between attempting to characterize the 

abundance of all planktonic organisms entrained into the CWIS (a nearly impossible task) and only a few 

species with commercial fishery value. In addition, only a few species have complete larval descriptions 

which makes accurate identifications problematical, and impact analyses based on broad taxonomic 

groups subject to a great deal of uncertainty. Nevertheless, by including the megalops stage of all crabs in 

the sample identifications (e.g. hermit crabs, porcelain crabs, shore crabs) there is some measure of the 

relative effects of entrainment on source populations of some of the more abundant but lesser-known 

species that have planktonic larvae. 

4.1.1.3 Protected Species 

Larvae and eggs of some species protected under Federal, State, or Tribal Law (discussed in Section 

3.3.3.5−Protected Species) were enumerated in entrainment samples. Most of these were represented by 

only a few specimens out of the over 12,000 larvae collected during the entrainment sampling. At the 

January 30 meeting, NMFS staff agreed that demographic or ETM calculations would only be done for 

species that were collected in sufficient abundance in entrainment and source water samples, and if 

sufficient life history information was available to permit those calculations. Although calculations of 

these models can be done provided the appropriate life history data exist, the level of uncertainty 

associated with the estimates is very high unless a species is collected in adequate numbers during several 

surveys. Of the taxa on the list only northern anchovy (Engraulis mordax) was in sufficient abundance at 

HnGS to justify a more detailed analysis of potential IM&E impacts. 
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4.2 HISTORICAL DATA

4.2.1 Summary of Historical Data 

The entrainment sampling program at HnGS in 1978–79 (IRC 1981) focused on sampling ‘critical taxa’ 

which provided representative information regarding the effects of the generating station on the marine 

community, based upon criteria described in Federal and State 316(b) Guidelines at the time (USEPA 

1977). These taxa were defined as those that can or do support fisheries, provided significant habitat to 

aquatic communities, or constitute significant trophic links. Within this framework, critical taxa were 

selected using information obtained from literature reviews, prior field experience in the region, and data 

collected during sampling efforts conducted for a preliminary report. The critical taxa list for larval fishes 

was reviewed by the CDFG and submitted to the LARWQCB for approval. 

Zooplankton densities, including fish eggs and larvae, were measured bi-weekly at an entrainment station, 

and two source water stations: a near-field and a far-field station (Figure 4.2-1). Plankton nets were used 

to sample the source water stations and a high volume pump was used to sample in front of the intake 

structure. The far-field station was located in San Pedro Bay and the near-field station in Alamitos Bay. 

The primary entrainment station (E1) was located at the intake structure. Another entrainment station was 

also located at the screens of selected units of the generating station to measure differences in plankton 

concentrations between the entrance and terminus of the 2.4 km (1.5 mile) intake canal, and provide data 

for survival studies of plankton transiting the HnGS cooling water system. 

Table 4.2-1 summarizes the entrainment densities of critical taxa recorded at Station E1 over the 12-

month study. The mean cooling water flow rate at the generating station varied from 1,892,500 −

3,406,500 m3

 per day (500−900 mgd) during the study. Combtooth blennies had the greatest 

concentrations in the entrainment samples with densities averaging 4,000 larvae per 1,000 m3

(264,172 gal). This translated to an annual entrainment mortality of 4.4 billion larvae for combtooth 

blennies. Entrainment estimates for all of the critical taxa combined was 8.46 billion larvae annually. 

Croakers had an annual entrainment estimate of 2.6 billion eggs while northern anchovy egg entrainment 

was estimated at 230 million eggs annually. 

The period of maximum larval abundance for most taxa occurred from December through early July. 

Gobiid larvae, however, were present all year and displayed no pronounced seasonality. Fish eggs were 

enumerated for 3 taxa: northern anchovy, Anchoa spp. (bay anchovies), and the Sciaenid (croaker) species 

complex (Table 4.2-1). The greatest numbers of entrained northern anchovy eggs were in February, with 

another peak in summer months. Anchoa spp. was relatively scarce in samples compared to densities that 

had been recorded in other southern California bays. 
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Figure 4.2-1. Locations of entrainment, near-field and far-field sampling stations for 

1978–79 316(b) study [figure from IRC (1981)]. 
Haynes Generating Station CWIS Entrainment and

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Non-critical fish larvae were identified and enumerated to provide additional information about the 

ichthyoplankton community but these data were not statistically analyzed. Unidentified teleost larvae 

occurred in samples from 84% of the day surveys and 92% of the night surveys. Maximum concentrations 

were observed for the period between mid-December and mid-June and lowest values were observed for 

the summer through mid-winter. Mean concentrations values varied from 0−230 larvae per 1,000 m3

(264,172 gal) for the day surveys and from 0−390 larvae per 1,000 m3

 (264,172 gal) for the night surveys. 

Average concentrations during the night exceeded daytime values for 80% of the surveys. 

Table 4.2-1. Summary of larval fish and fish egg densities, and annual entrainment mortality estimates for 

critical taxa for HnGS in 1979−1980 (from IRC 1981). 

Taxon Common Name 

Mean Day 

Concentration 

(#/1,000m3

) 

Mean Night 

Concentration 

(#/1,000m3

) 

% 

Freq. 

(Day) 

% 

Freq. 

(Night) 

Entrainment 

Estimate 

(# /year) 

Larval Fishes 

Atherinopsidae silversides <10 <10 12 35 1.2 x 107

Engraulidae anchovies 190 930 72 88 5.8 x 108

Gobiidae gobies 2,500 3,450 100 100 3.2 x 109

Hypsoblennius spp. combtooth blennies 4,070 3,910 88 92 4.4 x 109

Genyonemus lineatus white croaker 190 240 52 65 2.1 x 108

Seriphus politus queenfish 50 70 36 42 5.3 x 107

Pleuronichthys guttulatus diamond turbot <10 <10 16 19 4.9 x 106

Fish Eggs 

Engraulis mordax northern anchovy 450 390 48 50 2.3 x 108

Anchoa spp. bay anchovies 10 10 28 23 1.2 x 107

Sciaenid complex croakers 2,120 2,990 80 96 2.6 x 109

Note: A volume of 1,000 m3 is equal to 264,172 gallons. 

Concentrations were also calculated for several ‘critical’ planktonic invertebrate taxa, including four 

species of mysid shrimps, larval rock crab, larval ghost shrimp, and the adults and larvae of one species of 

copepod. Acartia spp. copepodites (larval stage) were the most abundant of the critical taxa and were 

present year-round. These eight taxa accounted for estimated annual losses of 2.24 trillion organisms from 

the HnGS cooling water intake system, assuming 100% through-plant mortality. 

Table 4.2-2. Summary of planktonic invertebrate densities and annual entrainment mortality estimates for 

critical taxa for Haynes Generating Station in 1979−1980 (from IRC 1981). 

Taxon Common Name 

Mean Day 

Concentration 

(#/1,000m3) 

Mean Night 

Concentration 

(#/1,000m3) 

% 

Freq. 

(Day) 

% 

Freq. 

(Night) 

Entrainment 

Estimate 

(# /year) 

Acartia spp. (adult) a copepods 1,104,860 1,369,600 100 100 8.1 x 1011

Acartia spp. (larvae) a copepods 1,880,300 1,903,770 100 100 1.3 x 1012

Cancer spp. (zoeae) rock crabs 590 640 77 77 5.1 x 108

Neotrypaea spp. ghost shrimp 18,360 41,180 100 100 2.7 x 1010

Acanthomysis necropsis mysid shrimp 4,720 21,060 92 96 1.2 x 1010

Neomysis kadiakensis mysid shrimp 90 1,200 36 58 8.4 x 108

Metamysidopsis mysid shrimp 22,420 168,410 96 96 8.6 x 1010

Mysidopsis spp. mysid shrimp 30 320 24 62 1.8 x 108

a densities based on 202 μ net collections from January−September 1979. 

Note: A volume of 1,000 is equal to 264,172 gallons.
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The following conclusions were noted for the plankton entrainment portion of the study (IRC 1981): 

• The seasonal period of highest overall abundance occurred from January through June, with the 

exceptions of Acartia spp. and gobiid larvae, which were abundant throughout the study and 

showed no real seasonal trend. A decline in the abundance of almost all plankton taxa occurred 

from September through December. 

• Diel differences in abundance were significant for several plankton taxa. The ghost shrimp 

Callianassa spp., mysids, sciaenid eggs, Engraulid species complex larvae, and Gobiid species 

complex larvae were significantly more abundant at night than during the day. Upward movement 

of zooplankton and ichthyolarvae through the water column at night can result in an increased 

susceptibility to entrainment. 

• With the exception of Hypsoblennius spp. larvae, larger sized larvae were collected with greater 

frequency at night. Spawning peaks were evidenced by large influxes of small larvae. Surveys 

following spawning peaks generally showed increasingly greater proportions of later stage 

(larger) larvae. 

4.2.2 Relevance to Current Conditions 

The operations and configuration of the HnGS cooling water system have remained largely unchanged 

since all units went into service with the exception of the replacement of the cooling water pumps at 

Units 3 & 4 (now Unit 8). Therefore, changes in entrainment through time are most likely due to natural 

biological changes and not due to substantial changes in cooling water flow. Flow during the 1978–1979 

study averaged about 2,802,487 m3

 per day (740 mgd), or 73% of the design flow (IRC 1981). From 1982 

to 1995, cooling water flow averaged 2,751,695 m3

 per day (727 mgd) (MBC 1997). Flow during the 

2006 study averaged about 2,925,870 m3

 per day (773 mgd), or 80% of current design flow, which is less 

than design flow in the previous study due to the replacement of cooling water pumps at Units 3 & 4. 

Some differences in study methods may affect the comparability of the entrainment data between the 

earlier and present study. One is the use of a pump to collect entrainment samples in the earlier study in 

contrast to the towed plankton net used in the present study. Even though there may be some systematic 

bias in each type of sampling method, the overall relative abundances and seasonality patterns of the 

planktonic larvae were adequately sampled by both methods. The earlier study used a 335μ mesh for the 

first seven surveys (as in the present study), but switched to a finer 202μ mesh in later surveys, mainly to 

provide better estimates of Acartia spp. copepodites densities. 

4.2.3 QA/QC Procedures and Data Validation 

The sampling program during the 1978–1979 study was conducted with the approval of the LARWQCB, 

and detailed procedures and methodologies, as well as QA/QC methods, can be found in Appendices G 

(Biological Field Procedures), H (Laboratory Procedures), and I (Statistical and Analytical Procedures) of 

IRC (1981). 
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4.3 METHODS

4.3.1 Field Sampling 

4.3.1.1 Cooling-Water Intake System Entrainment Sampling 

Composition and abundance of ichthyoplankton and shellfish larvae entrained by HnGS was determined 

by sampling in the immediate proximity of the cooling water intake (Station E3, Figure 4.3-1) every two 

weeks from January through December 2006. During the previous 316(b) demonstration, horizontal 

inflow at the intake structure was measured at all intake depths (-0.6 to –2.9 m [-2 ft to –9.5 ft]), though 

velocities were highest just above bottom (IRC 1981). Therefore, entrainment samples were collected 

using an oblique tow through the water column at two stations along the bulkhead intake. At each station, 

a 0.5 m (1.6 ft) diameter 333 μm (0.013 inches) mesh plankton net was towed by hand from the docks 

(parallel to the bulkhead) approximately 3 m (10 ft) upcurrent from the intake. The net was towed until a 

volume of 15−20 m3 (4,000−5,300 gal) was filtered. The net was equipped with a calibrated General 

Oceanics 2030R flowmeter, allowing the calculation of the amount of water filtered. At the end of each 

tow, the contents of the net were gently rinsed into the cod-end with seawater. Contents were washed 

down from the outside of the net to avoid the introduction of plankton from the wash-down water. 

Samples were then carefully transferred to prelabeled jars with preprinted internal labels and preserved in 

4−10% buffered formalin-seawater. Sampling was conducted four times per 24-hr period--once every six 

hours. 

4.3.1.2 Source Water Sampling 

The configuration of the source water study area was designed to 1) characterize the larvae of 

ichthyoplankton and shellfish potentially entrained by the HnGS cooling water intake, and 2) be 

representative of the nearshore habitats in the vicinity of the HnGS intake. 

Source water was sampled at nine stations located in Alamitos Bay and San Pedro Bay (Figure 4.3-1). All 

stations were sampled using a wheeled bongo plankton net using the same oblique towing method 

described for the entrainment sampling. Sampling was conducted once monthly on the same day that the 

entrainment station was sampled. Samples were also processed using the same procedures described for 

entrainment sampling. During each source water survey, the nine source water stations were sampled four 

times per 24-hr period at 6-hr intervals. This interval allowed adequate time for one vessel and crew to 

conduct all source water and entrainment sampling while also partitioning samples into day-night blocks 

for analysis of diel trends. During each sampling cycle the order in which the stations were sampled was 

varied to avoid introducing a systematic bias into the data. Detailed stepwise procedures are presented in 

Appendix B. 
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4.3.2 Laboratory Analysis 

Samples were returned to the laboratory and transferred from formalin to 70% ethanol after 

approximately 72 hours. Samples were examined under a dissecting microscope and all fish eggs 

(entrainment samples only) and larvae were removed and placed in labeled vials, in addition, the 

following shellfish larvae were also removed: 

• crab megalopa 

• California spiny lobster phyllosoma 

• market squid paralarvae 

The samples from the two nets were preserved in separate 400 milliliters (ml) (13.5 oz) jars and processed 

separately, but the data from the two nets were combined for analysis. If the quantity of material exceeded 

200 ml (6.8 oz), then the sample was split into multiple jars to ensure that the material was properly 

preserved. In some cases the collection of ctenophores, salps, and other larger planktonic organisms 

resulted in samples with large volumes of material, but these could be separated from other plankton with 

little difficulty and were generally not split, depending upon the final volume of the material. 

Specimens were enumerated and identified to the lowest practical taxon. A representative sample of up to 

50 larvae from each species for each survey (100 during the first two surveys) was measured from the 

entrainment samples using a dissecting microscope and image analysis system. If fewer than 50 

individuals from a species were collected during the survey then all of the larvae from the survey were 

measured. Total length was measured to an accuracy of at least 0.1 mm (0.004 inches). 
Haynes Generating Station CWIS Entrainment and

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Figure 4.3-1. Location map of HnGS entrainment (E3) and source water sampling stations. 
Haynes Generating Station CWIS Entrainment and

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4.3.3 QA/QC Procedures & Data Validation 

A quality control (QC) program was implemented for the field and laboratory components of the study. 

Quality control surveys were completed on a quarterly basis to ensure that the field sampling was 

conducted properly. Prior to the start of the study the field survey procedures were reviewed with all 

personnel and all personnel were given printed copies of the procedures. 

A more detailed QC program was applied to all laboratory processing. The first ten samples sorted by an 

individual were resorted by a designated quality control (QC) sorter. A sorter was allowed to miss one 

target organism if the total number of target organisms in the sample was less than 20. For samples with 

20 or more target organisms the sorter was required to maintain a sorting accuracy of 90%. After a sorter 

completed ten consecutive samples with greater than 90% accuracy, the sorter had one of their next ten 

samples randomly selected for a QC check. If the sorter failed to achieve an accuracy level of 90% then 

their next ten samples were resorted by the QC sorter until they met the required level of accuracy. If the 

sorter maintained the required level of accuracy random QC checks resumed at the level of one sample 

checked per ten sorted. 

A similar QC program was conducted for the taxonomists identifying the samples. The first ten samples 

of fish or invertebrates identified by an individual taxonomist were completely re-identified by a 

designated QC taxonomist. A total of at least 50 individual fish or invertebrate larvae from at least five 

taxa must have been present in these first ten samples; if not, additional samples were re-identified until 

this criterion was met. Taxonomists were required to maintain a 95% identification accuracy level in these 

first ten samples. After the taxonomist identified ten consecutive samples with greater than 95% accuracy, 

they had one of their next ten samples checked by a QC taxonomist. If the taxonomist maintained an 

accuracy level of 95% then they continued to have one of each ten samples checked by a QC taxonomist. 

If one of the checked samples fell below the minimum accuracy level then ten more consecutive samples 

were identified by the QC taxonomist until ten consecutive samples met the 95% criterion. Identifications 

were cross-checked against taxonomic voucher collections maintained by MBC and Tenera 

Environmental, and specialists were consulted for problem specimens. Occasionally, outside experts were 

consulted to assist in the identification of the fish eggs. Due to the large overlap in diagnostic 

characteristics of several species of fishes in the egg and early embryo stages, egg identification is highly 

subjective and therefore no QC program was conducted to verify the egg identification. 

4.3.4 Data Analysis 

4.3.4.1 Entrainment Estimates 

Estimates of daily larval entrainment for the sampling period from January 2006 through December 2006 

at HnGS were calculated from data collected at the entrainment station and data on daily cooling water 

flow from the power plant. Estimates of average larval concentration for the day when entrainment 

samples were collected were extrapolated across the days between surveys to calculate total entrainment 

during the days when no samples were collected. The total estimated daily entrainment for the survey 

periods and across the entire year were then summed to obtain estimates of total survey and annual 

entrainment, respectively. The annual entrainment estimates, in conjunction with demographic data 

collected from the fisheries literature, were used in modeling CWIS effects using adult equivalent loss 

(AEL) and fecundity hindcasting (FH). Data for the same target taxa from sampling of the entrained 
Haynes Generating Station CWIS Entrainment and

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larvae and potential source populations of larvae were used to calculate estimates of proportional 

entrainment (PE) that were used to estimate the probability of mortality (PM) due to entrainment using the 

ETM. Each approach (e.g., AEL, FH, and ETM), as appropriate for each target taxon, was used to assess 

effects of power plant losses. The results from the models were used in determining the magnitude of the 

CWIS losses relative to source water data from other sources and evaluating the potential for adverse 

environmental impacts. Parameters of the models used in the analyses are detailed in Appendix C. 

All of the modeling approaches require an estimate of the age of the larvae being entrained. The 

demographic approaches extrapolate estimates from the average age at entrainment, while the ETM 

requires an estimate of the period of time that the larvae are exposed to entrainment. These estimates were 

obtained by measuring a representative number of larvae of each of the target taxa from the entrainment 

samples and using published larval growth rates. Although a large number of larvae may have been 

collected and measured from entrainment samples a random sample of 200 from the total measurements 

was used to calculate the average age at entrainment and total larval duration. The average age at 

entrainment was calculated by dividing the difference between the estimated size at hatching and the 

average size of the larvae from entrainment by a larval growth rate obtained from the literature. The 

period of time that the larvae were exposed to entrainment was calculated by dividing the difference 

between the size at hatching and the size at the 95th percentile by a larval growth rate obtained from the 

literature. The duration of the egg stage was added to this value for species with planktonic eggs. The 

95th percentile value was used to eliminate outliers from the calculations. The size at hatching was 

estimated as follows: 

Hatch Length = Median Length – ((Median Length – 1st Percentile Length)/2). 

This calculated value was used because of the large variation in size among larvae smaller than the 

average length and approximates the value of the 25th percentile used in other studies as the hatch length. 

This calculation assumes that the length frequency distribution is skewed towards smaller sized larvae and 

usually resulted in a value close to the hatch size reported in the literature. 

4.3.4.2 Demographic Approaches 

AEL models evolved from impact assessments that compared power plant losses to commercial fisheries 

harvests and/or estimates of the abundance of adults. In the case of adult fishes impinged by intake 

screens, the comparison was relatively straightforward. To compare the numbers of impinged sub-adults 

and juveniles and entrained larval fishes to adults, it was necessary to convert all these losses to adult 

equivalents. Horst (1975) and Goodyear (1978) provided early examples of the equivalent adult model 

(EAM) to convert numbers of entrained early life stages of fishes to their hypothetical adult equivalency. 

Demographic approaches, exemplified by the EAM, produce an absolute measure of loss beginning with 

simple numerical inventories of entrained or impinged individuals and increasing in complexity when the 

inventory results are extrapolated to estimate numbers of adult fishes or biomass. We used two different 

but related demographic approaches in assessing entrainment effects at HnGS: AEL, which expresses 

effects as absolute losses of numbers of adults, and FH, which estimates the number of adult females at 

the age of maturity whose reproductive output has been eliminated by entrainment of larvae. 
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Age-specific survival and fecundity rates are required for AEL and FH. AEL estimates require 

survivorship estimates from the age at entrainment to adult recruitment; FH requires egg and larval 

survivorship up to the age of entrainment plus estimates of fecundity. Furthermore, to make estimation 

practical, the affected population is assumed to be stable and stationary, and age-specific survival and 

fecundity rates are assumed to be constant over time. Each of these approaches provides estimates of 

adult fish losses, which ideally need to be compared to standing stock estimates of adult fishes. 

Species-specific survivorship information (e.g., age-specific mortality) from egg or larvae to adulthood is 

limited for many of the taxa collected during the study. These rates, when available, were inferred from 

the literature along with estimates of uncertainty. Uncertainty surrounding published demographic 

parameters is seldom known and rarely reported, but the likelihood that it is very large needs to be 

considered when interpreting results from the demographic approaches for estimating entrainment effects. 

For some well-studied species (e.g., northern anchovy), portions of early mortality schedules and 

fecundity have been reported. Because the accuracy of the estimated entrainment effects from AEL and 

FH will depend on the accuracy of age-specific mortality and fecundity estimates, lack of demographic 

information may limit the utility of these approaches. 

The precursor to the AEL and FH calculations is an estimate of total annual larval entrainment. Estimates 

of larval entrainment at HnGS were based on bi-weekly sampling where ET is the estimate of total 

entrainment for the one-year study period and Ei is the entrainment estimate for the individual survey 

periods. Estimates of entrainment for the study period were based on two-stage sampling designs, with 

days within surveys, and cycles (four six-hour collection periods per day) within days. The within-day 

sampling was based on a stratified random sampling scheme with four temporal cycles and two replicates 

per cycle. Estimates of variation for each survey were computed from the four temporal cycles. 

There were usually no estimates of variation available for the life history information used in the models. 

The ratio of the mean to standard deviation (coefficient of variation) was assumed to be 50% for all life 

history parameters used in the models. 

Fecundity Hindcasting (FH)

The FH approach compares larval entrainment losses with adult fecundity to estimate the amount of adult 

female reproductive output eliminated by entrainment, hindcasting the numbers of adult females at the 

age of maturity (age at which 50% of the females are mature) effectively removed from the 

reproductively active population. The accuracy of these estimates of effects, as with those of the AEL

above, is dependent upon accurate estimates of age-specific mortality from the egg and early larval stages 

to entrainment and accurate estimates of the total lifetime female fecundity. If it can be assumed that the 

adult population has been stable at some current level of exploitation and that the male: female ratio is 

constant and 50:50, then fecundity and mortality are integrated into an estimate of the loss of adults at the 

age of maturity by converting entrained larvae back into females (e.g., hindcasting) and multiplying by 

two. 
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A potential advantage of FH is that survivorship need only be estimated for a relatively short period of the 

larval stage (e.g., egg to larval entrainment). The method requires age-specific mortality rates and 

fecundities to estimate entrainment effects and some knowledge of the abundance of adults to assess the 

fractional losses these effects represent. This method assumes that the loss of the reproductive potential of 

a single female at the age of maturity is equivalent to the loss of two adult fish at the age of maturity, 

assuming a 50:50 male: female ratio. 

In the FH approach, the total larval entrainment for a species, ET, was projected backward from the 

average age at entrainment to estimate the number of females at the age of maturity that would produce 

over their lifetime the numbers of larvae seen in the entrainment samples. The estimated number of 

breeding females at the age of maturity, FH, whose fecundity is equal to the total loss of entrained larvae 

was calculated as follows: 

1

T

n

j

j

E FH

TLF S =

=

g∏

(1) 

Where: 

ET = total entrainment estimate; 

Sj = survival rate from eggs to entrained larvae of the j

th stage; 

TLF = average total lifetime fecundity for females, equivalent to the average number of eggs 

spawned per female over their reproductive years. 

The two key input parameters in Equation 1 are total lifetime fecundity TLF and survival rates Sj from 

spawning to the average age at entrainment. The average age at entrainment was estimated from lengths 

of a representative sample of larvae measured from the entrainment samples. Descriptions of these 

parameters may not be available for many species and are a possible limitation of the method. TLF was 

estimated in these studies using survivorship and fecundity tables that account for changes in fecundity 

with age. The fecundity data used in calculating TLF is described below for each taxon. 

Adult Equivalent Loss (AEL)

The AEL approach uses estimates of the abundance of the entrained or impinged organisms to project the 

loss of equivalent numbers of adults based on mortality schedules and age-at-recruitment. The primary 

advantage of this approach is that it translates power plant-induced early life-stage mortality into numbers 

of adult fishes, which is the life-stage most dealt with by resource managers. This latter advantage may be 

offset by the need to gather age-specific mortality rates to predict adult losses and the need for 

information on the adult population of interest for estimating population-level effects (i.e., fractional 

losses). 
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Starting with the number of age class j larvae entrained Ej, it is conceptually easy to convert these 

numbers to an equivalent number of adults lost AEL at some specified age class from the formula: 

1

n

j j

j

AEL E S == ∑ (2) 

Where: 

n = number of age classes from the average age at entrainment to adult recruitment; 

Ej = estimated number of larvae lost in age class j; and 

Sj = survival probability for the jth class to adulthood (Goodyear 1978). 

Age-specific survival rates from the average age at entrainment to the age at first maturity must be 

included in this assessment method. The age at first maturity, when 50% of the females are mature, was 

used in the AEL extrapolations so the FH and AEL models are extrapolated to the same age and can be 

compared using the equivalency that 2FH≈AEL. We used a modified form of Equation 2 where the total 

entrainment was used having an average age a: 

n

T j

j a

AEL E S == ∏ (3) 

Where: 

ET = annual estimate of larvae lost in all age classes. 

The average age at entrainment was estimated from lengths of a representative sample of larvae as 

described above. For some commercial species, natural survival rates are known after the fish recruit into 

the commercial fishery. For the earlier years of development, this information is not well known for 

commercial species and may not exist for some non-commercial species. 

Equivalent Adult Model (EAM)

For the HnGS impact assessment, annual impingement totals were converted to numbers of equivalent 

adults for several species. Similar to demographic modeling performed with entrainment estimates, 

conversion of impingement totals was limited to species with sufficient life history information. 

Conversion of numbers of juveniles/adults collected in impingement sampling to numbers of equivalent 

adults has not been performed in recent impingement studies in California. However, the methods 

described below are similar to those used by EPA in developing the Phase I and Phase II 316(b) 

regulations. 

Species-specific von Bertalanffy growth parameters, annual (daily) total instantaneous mortality (Z), and 

female length at 50% maturity were collected from available age and growth studies, both published and 

unpublished, and online databases (such as FishBase [www.fishbase.org] and the CDFG web life history 

database [www.dfg.ca.gov/mrd/lifehistories/index.html]). For each individual fish the age was estimated 

using the von Bertalanffy growth model with the appropriate parameters ( 0 L kt , , ∞ ). 

( ) ( ) 0 1 kt t LL e t

− − = − ∞
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Annual (daily) age was calculated as 

0

ln 1 Lt

L

t t k ∞

⎛ ⎞ ⎜ ⎟ −

⎝ ⎠ = + − . 

An interval of time Δt was calculated using the difference between the estimated age of impingement t

and the age at 50% maturity L50% : 

50% ln 1 ln 1 L Lt

L L

t

k

∞ ∞

⎛ ⎞⎛ ⎞ ⎜ ⎟⎜ ⎟ − −−

⎝ ⎠⎝ ⎠ Δ = −

Instantaneous mortality (Z) for each species was taken from these same age and growth studies (see 

species-specific analysis for citation), where available, or calculated based on published daily mortality 

rates. Total annual instantaneous survival was calculated as S = e-Z. The species-specific age at 50% 

female maturity was derived using the von Bertalanffy equation using the reported size at 50% maturity. 

Equivalent adult abundances of the species-specific age at 50% maturity were calculated using a 

modification of the Equivalent Adult Model (EAM; USEPA 2002): 

( ) 50%

1

est

N t t

i

AE S −

=

= ∑ 

where: 

AE = number of target age equivalents killed 

N = number of individuals impinged 

S = total annual instantaneous survival 

t50% = age at female 50% maturity 

test = estimated age of impinged fish 

Equivalent adults were summed across all surveys. Equivalent adults of those individuals collected during 

normal operations were subjected to flow adjustment calculations to estimate the annual normal operation 

impingement. No adjustments were made to individuals collected during heat treatments. 

4.3.4.3 Empirical Transport Model 

As an alternative to the demographic models described above, the ETM was proposed by the USFWS to 

estimate mortality rates resulting from circulating water withdrawals by power plants (Boreman et al. 

1978, and subsequently in Boreman et al. 1981). The ETM model provides an estimate of incremental 

mortality (a conditional estimate in absence of other mortality, Ricker 1975) caused by HnGS on local 

Los Angeles Harbor complex larval populations by using empirical data (plankton samples) rather than 

relying solely on hydrodynamic and demographic calculations. Consequently, ETM requires an additional 

level of field sampling to characterize the abundance and composition of source water larval populations. 

The fractional loss to the source water population represented by entrainment is provided by estimates of 

proportional entrainment (PE) for each survey that can then be expanded to predict regional effects on 

appropriate adult populations using ETM, as described below. ETM estimates were calculated using actual 

and design (maximum capacity) cooling water flows and a sampling volume in the nearshore of 

140,698,222 m3

 (37.2 billion gal). 
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Variations of this model have been discussed in MacCall et al. (1983) and have been used to assess 

impacts at a southern California power plant (Parker and DeMartini 1989). The ETM has also been used 

to assess impacts at the Salem Nuclear Generating Station in Delaware Bay, New Jersey (PSE&G 1993) 

as well as other power stations along the East Coast. Empirical transport modeling permits the estimation 

of conditional mortality due to entrainment while accounting for the spatial and temporal variability in 

distribution and vulnerability of each life stage to power plant withdrawals. The modeling approach 

described below uses a PE approach that is similar to the method described by MacCall et al. (1983) and 

used by Parker and DeMartini (1989) in their final report to the California Coastal Commission (Murdoch 

et al. 1989a) for the San Onofre Nuclear Generating Station. 

The general equation to estimate PE for a day on which entrainment was sampled is: 

Ei

i

Si

N PE

N = (4) 

Where: 

 estimated average number of larvae entrained during the day in survey i, calculated as

 (estimated density of larvae in the water entrained that day) (average daily cooling flow 

 vo

NEi =

×

lume during the survey period),

 estimated number of larvae in the source water that day in survey i (estimated density 

 of larvae in the souce water that day) (source water volume).

NSi =

×

The PEi value represents the effects of a number of processes operating over a day and is estimated for 

each survey. Since actual cooling water flow was used in calculating entrainment estimates, the PEi 

estimate was calculated using the average daily cooling water flow over each entrainment survey period, 

an approximate period of two weeks. 

The values used in calculating PE are population estimates based on the respective larval concentrations 

and volumes of both the cooling water system flow and source water areas. The abundance of larvae at 

risk in various regions of the source water, R, summed over k stations during the i

th survey can be directly 

expressed as follows: 

1

ρ == ⋅ ∑

n

R S i R Rik k k

N V (5) 

where SRk V is the static volume of the source water in region R at station k, and ρ Rik denotes an estimate 

of the average larval concentration in the source water in region R for station k during survey i. 

Three source water components were identified for HnGS: 1) Alamitos Bay where the HnGS intake is 

located, 2) nearshore coastal water that is transported into Alamitos Bay on incoming tides, and 3) water 

that is transported out of Alamitos Bay into nearshore coastal waters on outgoing tides. Each of these 

source water components operates on the time scale of the period of time that larvae are subject to 

entrainment. Because the spatial scales of the components vary, the conditional mortality due to 
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entrainment, PE, could not be expressed simply as in Equation 3. The calculation of PE for the three 

source water components is incorporated into the ETM calculation for estimating the total annual 

proportional mortality due to entrainment, PM as follows: 

1

1 1

( )

i

i i

i i

i

q

N

E

M i

i NS NSOut

AB ABOut

S

N

P f N N

NN q P • =

⎛ ⎞ ⎡ ⎤ ⎜ ⎟ ⎢ ⎥

=− − − + +

⎝ ⎠ ⎣ ⎦

∑ (6) 

where: 

fi = estimated fraction of total source water larval population present during the i

th survey; 

q = number of days the larvae are exposed to entrainment; 

Ei N = the estimated number of larvae entrained during the i

th survey; 

NSi N = the estimated number of larvae in the nearshore sampled during the i

th survey; 

Si P = the ratio of the length of the sampled nearshore area sampled during the i

th survey to the 

total current displacement over the period of q days that the larvae could be exposed to 

entrainment; 

NSOuti N = an adjustment for the outflow from Alamitos Bay calculated using the average 

concentration from the nearshore sampling during the i th survey and the outflow 

volume; 

ABi N = the estimated number of larvae in Alamitos Bay during the i th survey; and 

ABOuti N = an adjustment for the outflow from Alamitos Bay calculated using the average 

concentration from Alamitos Bay sampling during the i th survey and the outflow 

volume. 

The sizes of NNS, NAB, and NE were calculated as the product of larval concentration and volume as in 

Equation 5. The estimate, NNS, for the nearshore sampling area for each i

th survey used in the ETM

calculations included six areas (Figure 4.3-1) with component densities and volumes. The sampled 

nearshore area, NNS, for each i

th survey represents a proportion of the total nearshore source water 

potentially affected by entrainment over the number of days, q, that the larvae are exposed to entrainment. 

The proportion of the sampled nearshore area to the total source water, PS, was estimated for each i

th

survey using current displacement measured using current meters deployed offshore from Alamitos Bay 

(Figure 4.3-1). The incorporation of PS into the ETM model is typically defined by the ratio of the area or 

volume of the study grid to a larger area or volume containing the population of inference (Parker and 

DeMartini 1989). However, if an estimate of the larval (or adult) population in the larger area is available, 

then PS can also be computed using an estimate of the proportion of the larval or adult population in the 

study area. If the distribution in the larger area is assumed to be uniform or the same as the nearshore 

sampling area, then the value of PS for the proportion of the population will be the same as the proportion 

computed using area or volume. The current displacement measured over q days was used to estimate the 
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4-18 

distance alongshore or offshore that larvae could have been transported into the nearshore areas around 

Alamitos Bay where they would be subject to entrainment. The ratio of the alongshore distance of the 

nearshore sampling area to the alongshore current displacement, PS, measured using data from the current 

meter at Station CM1 was used to adjust the nearshore population estimate, NNS, for the size of the total 

source water population for taxa that are primarily distributed in nearshore areas and embayments such as 

gobies and blennies. The data from the current meter at CM1 included both alongshore and onshoreoffshore component vectors, but its location inside the Los Angeles-Long Beach Harbor breakwaters 

primarily provided data on alongshore movement in, and out of, the harbor complex. 

The estimate of PS, the proportion of the sampled source water population to the total source population, 

was adjusted for taxa with more offshore distributions using data from the current meter at Station CM2 

which was located outside of the harbor breakwaters. Data from this station provided more accurate data 

on onshore currents that could transport larvae from offshore into nearshore areas where they could be 

subject to entrainment. Unlike the data from Station CM1 that included upcoast and downcoast 

displacement, only onshore displacement was used in calculating the offshore distance for the source 

population. Rather than extrapolating the entire coastal length of the potential source water population 

offshore a much more conservative approach was used that based the estimate of PS on the ratio of the 

width of the nearshore sampling area to the offshore displacement indicated by the current meter data. 

To establish independent survey estimates, it was assumed that during each survey a new and distinct 

cohort of larvae was subject to entrainment. Each of the surveys was weighted by fi and estimated as the 

proportion of the total annual source water population present during each ith survey period. For each 

study period, the sum of the proportions equals one: 

1

1

and 1.

n

S

i i n

i

Si

i

N f f

N =

=

= ∑ =

∑

The estimate of the population-wide probability of entrainment (PE) is the central feature of the ETM

approach (Boreman et al. 1981, MacCall et al. 1983). If a population is stable and stationary, then PM also 

estimates the effects on the fully-recruited adult age classes when uncompensated natural mortality from 

larva to adult is assumed. 

Assumptions associated with the estimation of PM include the following: 

• The samples at each survey period represent a new and independent cohort of larvae. 

• The estimates of larval abundance for each survey represent a proportion of total annual larval 

production during that survey. 

• The conditional probability of entrainment PEi is constant within survey periods. 

• Lengths and applied growth rates of larvae accurately estimate larval duration. 

The variance calculations associated with PM only include the error directly associated with the sampling 

in the PEi and was calculated using the average coefficient of variation (CV), the ratio of the standard 

deviation to the mean, from the estimates of PEi as follows: 
Haynes Generating Station CWIS Entrainment and

IM&E Final Report Source Water Study

4-19 

 Var P CV P ( ) ( /100) M = PE M . 

This estimate does not include the error associated with the estimates of PS, the larval duration, and 

source water, entrainment, and outflow volumes. It also does not account for the variance across the days 

within a survey period. The sources of variation included in the estimate represent the sampling error and 

natural variation of the entrainment and source water populations. 

4.4 SAMPLING SUMMARY

Twenty-six surveys were completed at the entrainment station between January 11 and December 18, 

2006 (Table 4.4-1). Sampling efforts alternated between surveys where only entrainment samples were 

collected and surveys where both entrainment and source water samples were collected. Totals of 208 

entrainment samples and 863 source water samples were processed for data analysis. 

Table 4.4-1. Entrainment/source water surveys and number of samples collected from 

January through December 2006. 

Entrainment Samples Source Water Samples

Survey 

Number Date 

Number 

Collected 

Number 

Processed 

Number 

Collected 

Number 

Processed 

ABEA01 1/5/06 8 8 − −

ABEA02 1/17/06 8 8 72 72 

ABEA03 1/31/06 8 8 − −

ABEA04 2/14/06 8 8 72 72 

ABEA05 2/27/06 8 8 

ABEA06 3/13/06 8 8 72 71 a

ABEA07 3/26/06 8 8 − −

ABEA08 4/10/06 8 8 72 72 

ABEA09 4/24/06 8 8 − −

ABEA10 5/8/06 8 8 72 72 

ABEA11 5/22/06 8 8 − −

ABEA12 6/5/06 8 8 72 72 

ABEA13 6/19/06 8 8 − −

ABEA14 7/05/06 8 8 72 72 

ABEA15 7/17/06 8 8 − −

ABEA16 7/31/06 8 8 − −

ABEA17 8/14/06 8 8 72 72 

ABEA18 8/28/06 8 8 

ABEA19 9/11/06 8 8 72 72 

ABEA20 9/25/06 8 8 − −

ABEA21 10/09/06 8 8 72 72 

ABEA22 10/23/06 8 8 − −

ABEA23 11/06/06 8 8 72 72 

ABEA24 11/20/06 8 8 − −

ABEA25 12/04/06 8 8 72 72 

ABEA26 12/18/06 8 8 − −

 208 208 864 863 

a One sample from Station O2 was not preserved properly and was voided.
Haynes Generating Station CWIS Entrainment and

IM&E Final Report Source Water Study

4-20 

4.5 RESULTS

4.5.1 Cooling Water Intake Structure Entrainment Summary 

4.5.1.1 Fishes 

A total of 12,651 entrainable fish larvae from 35 separate taxonomic categories was collected from 

Station E3 during the 26 entrainment surveys (Table 4.5-1). The most abundant larval fish taxon in the 

samples was unidentified gobies, which comprised 51.3% of the total larvae collected, followed by 

silversides (23.9%) and combtooth blennies (20.1%). Densities of fish larvae peaked in late May at an 

average concentration of approximately 17,000 per 1,000 m3

 (264,172 gal) (Figure 4.5-1). In addition, 

5,941 fish eggs from 13 taxa were enumerated in the 208 entrainment samples. The most abundant 

taxonomic group of fish eggs in the samples was unidentified eggs, which made up 69.4% of the total 

eggs collected, followed by sand flounder eggs (11.4%). Fish eggs peaked in abundance in March−April 

prior to the peak abundance of fish larvae in May, and also had a secondary peak in August (Figure 4.5-

2). Larvae and eggs were substantially more abundant in samples collected at night than those collected 

during the day in nearly every survey (Figure 4.5-3 and 4.5-4). Damaged larval fishes that could not be 

positively identified comprised 0.2% of the total catch. Total annual entrainment was estimated to be 3.65 

billion fish larvae and 1.68 billion fish eggs during 2006 using the HnGS CWIS actual flows as the basis 

for calculations (Table 4.5-2). Using the design (maximum capacity) CWIS flows, total annual 

entrainment increases to 4.53 billion fish larvae and 2.12 billion fish eggs. Commercially and 

recreationally important taxa comprised 2.6% of the total larvae collected. 
Haynes Generating Station CWIS Entrainment and

IM&E Final Report Source Water Study

4-21 

Table 4.5-1. Average concentration of larval fishes and fish eggs in entrainment samples 

collected at HnGS (Station E3) in 2006. 

Taxon Common Name 

Avg. Conc. 

(per 1,000 m3) 

Total 

Count 

Percentage 

of Total 

Cumulative 

Percentage 

Larval Fish 

Gobiidae unid. gobies 1,667.51 6,354 51.31 51.31 

Atherinopsidae unid. silversides 778.19 3,263 23.94 75.25 

Hypsoblennius spp. combtooth blennies 651.69 2,444 20.05 95.31 

Genyonemus lineatus white croaker 67.68 267 2.08 97.39 

Engraulidae unid. anchovies 19.54 76 0.60 97.99 

Labrisomidae unid. labrisomid blennies 14.11 52 0.43 98.42 

Gobiesocidae unid. clingfishes 8.33 32 0.26 98.68 

unidentified fish, damaged unid. damaged fish 8.04 30 0.25 98.93 

Sciaenidae unid. croakers 6.54 25 0.20 99.13 

Gibbonsia spp. clinid kelpfishes 3.86 14 0.12 99.25 

Syngnathus spp. pipefishes 2.57 10 0.08 99.33 

Pleuronichthys guttulatus diamond turbot 2.33 9 0.07 99.40 

larvae, unidentified yolksac unidentified yolksac larvae 2.18 8 0.07 99.46 

Seriphus politus queenfish 2.10 8 0.06 99.53 

Acanthogobius flavimanus yellowfin goby 2.05 8 0.06 99.59 

Gillichthys mirabilis longjaw mudsucker 1.83 7 0.06 99.65 

Typhlogobius californiensis blind goby 1.78 7 0.05 99.70 

larval/post-larval fish unid. larval fishes 1.32 5 0.04 99.74 

Paralichthys californicus California halibut 1.09 4 0.03 99.78 

Leptocottus armatus Pacific staghorn sculpin 1.07 4 0.03 99.81 

Hypsypops rubicundus garibaldi 1.01 4 0.03 99.84 

Citharichthys spp. sanddabs 0.74 3 0.02 99.86 

Rhinogobiops nicholsii blackeye goby 0.59 2 0.02 99.88 

Cheilotrema saturnum black croaker 0.53 2 0.02 99.90 

Umbrina roncador yellowfin croaker 0.52 2 0.02 99.91 

Pleuronectidae unid. righteye flounders 0.30 1 0.01 99.92 

Haemulidae unid. grunts 0.28 1 0.01 99.93 

Xenistius californiensis salema 0.28 1 0.01 99.94 

Paralabrax spp. sand bass 0.28 1 0.01 99.95 

Chaenopsidae unid. tube blennies 0.25 1 0.01 99.96 

Roncador stearnsii spotfin croaker 0.25 1 0.01 99.97 

Stenobrachius leucopsarus northern lampfish 0.24 1 0.01 99.97 

Parophrys vetulus English sole 0.23 1 0.01 99.98 

Sardinops sagax Pacific sardine 0.23 1 0.01 99.99 

Clupeiformes unid. herrings and anchovies 0.22 1 0.01 99.99 

Merluccius productus Pacific hake 0.22 1 0.01 100.00 

3,249.97 12,651 

Note: A volume of 1,000 m3 is equal to 264,172 gallons.

 (table continued) 
Haynes Generating Station CWIS Entrainment and

IM&E Final Report Source Water Study

4-22 

Table 4.5-1 (continued). Abundance of fish larvae and fish eggs sampled at HnGS Entrainment Station E3 

from January through December 2006 

Taxon Common Name 

Avg. Conc. 

(per 1,000 m3) 

Total 

Count 

Percentage 

of Total 

Cumulative 

Percentage 

Fish Eggs 

fish eggs unid. unidentified fish eggs 1,054.48 4,159 69.44 69.44 

Paralichthyidae unid. sand flounder eggs 172.37 669 11.35 80.79 

Sciaenidae / Paralich / Labr SPL fish eggs 78.33 288 5.16 85.95 

Genyonemus lineatus white croaker eggs 63.01 239 4.15 90.10 

Citharichthys spp. sanddab eggs 57.94 229 3.82 93.92 

Sciaenidae unid. croaker eggs 36.68 140 2.42 96.33 

Pleuronichthys spp. turbot eggs 25.54 96 1.68 98.01 

Atherinopsidae unid. silverside eggs 10.49 43 0.69 98.70 

Engraulidae unid. anchovy eggs 10.03 41 0.66 99.36 

Paralichthys californicus California halibut eggs 4.44 17 0.29 99.66 

Atherinops affinis topsmelt eggs 3.90 15 0.26 99.91 

Blenniidae blenny eggs 0.79 3 0.05 99.96 

Labridae unid. wrasse eggs 0.54 2 0.04 100.00 

 1,518.53 5,941 

Note: A volume of 1,000 m3 is equal to 264,172 gallons.
Haynes Generating Station CWIS Entrainment and

IM&E Final Report Source Water Study

4-23 

Table 4.5-2. Calculated total annual entrainment of larval fishes and fish eggs at HnGS in 2006 based on 

actual and design cooling water intake pump flows. 

Taxon Common Name 

Annual 

Entrainment 

(Actual Flows) 

Annual 

Entrainment 

(Design Flows) 

Larval Fish 

Gobiidae unid. gobies 1,828,364,516 2,334,220,376 

Atherinopsidae unid. silversides 920,323,104 1,062,818,072 

Hypsoblennius spp. combtooth blennies 732,022,349 915,313,887 

Genyonemus lineatus white croaker 75,425,299 96,188,344 

Engraulidae unid. anchovies 22,673,541 27,301,289 

Labrisomidae unid. labrisomid blennies 15,068,186 19,493,190 

Gobiesocidae unid. clingfishes 9,088,713 11,712,226 

unidentified fish, damaged unidentified damaged fish 8,705,487 11,578,027 

Sciaenidae unid. croakers 7,187,066 9,313,532 

Gibbonsia spp. clinid kelpfishes 3,583,074 5,590,130 

Syngnathus spp. pipefishes 3,111,275 3,765,987 

Pleuronichthys guttulatus diamond turbot 2,664,083 3,409,219 

Seriphus politus queenfish 2,490,643 2,937,768 

larvae, unidentified yolksac unidentified yolksac larvae 2,415,796 3,051,218 

Acanthogobius flavimanus yellowfin goby 2,024,413 2,715,310 

Gillichthys mirabilis longjaw mudsucker 1,977,286 2,550,861 

Typhlogobius californiensis blind goby 1,961,918 2,453,304 

larval/post-larval fish unid. larval fishes 1,184,545 1,620,620 

Paralichthys californicus California halibut 1,153,745 1,520,648 

Hypsypops rubicundus garibaldi 985,374 1,381,248 

Leptocottus armatus Pacific staghorn sculpin 876,157 1,491,536 

Citharichthys spp. sanddabs 821,712 1,026,911 

Rhinogobiops nicholsii blackeye goby 703,083 823,133 

Cheilotrema saturnum black croaker 626,312 764,490 

Umbrina roncador yellowfin croaker 506,822 721,836 

Pleuronectidae unid. righteye flounders 385,901 414,783 

Haemulidae unid. grunts 375,837 396,576 

Xenistius californiensis salema 375,837 396,576 

Paralabrax spp. sand bass 359,420 388,533 

Roncador stearnsii spotfin croaker 332,942 351,314 

Stenobrachius leucopsarus northern lampfish 268,400 332,364 

Parophrys vetulus English sole 260,975 323,169 

Sardinops sagax Pacific sardine 255,242 319,095 

Clupeiformes unid. herrings and anchovies 243,832 301,941 

Merluccius productus Pacific hake 243,832 301,941 

Chaenopsidae unid. tube blennies 161,673 354,629 

3,649,208,392 4,527,644,084 

Note: A volume of 1,000 m3 is equal to 264,172 gallons.

 (table continued) 
Haynes Generating Station CWIS Entrainment and

IM&E Final Report Source Water Study

4-24 

Table 4.5-2 (continued). Calculated total annual entrainment of larval fishes and fish eggs at HnGS in 

2006 based on actual and design cooling water intake pump flows. 

Taxon Common Name 

Annual 

Entrainment 

(Actual Flows) 

Annual 

Entrainment 

(Design Flows) 

Fish Eggs 

fish eggs unid. unidentified fish eggs 1,191,101,773 1,474,924,676 

Paralichthyidae unid.) sand flounder eggs 183,531,130 236,704,432 

Sciaenidae / Paralichthyidae / Labridae SPL fish eggs 90,493,059 109,555,973 

Citharichthys spp. sanddab eggs 63,124,903 80,387,665 

Genyonemus lineatus white croaker eggs 57,836,910 86,480,192 

Sciaenidae unid. croaker eggs 40,580,902 51,237,429 

Pleuronichthys spp. turbot eggs 28,681,415 36,053,832 

Atherinopsidae unid. silverside eggs 11,560,935 14,653,846 

Engraulidae unid. anchovy eggs 11,128,912 14,029,527 

Atherinops affinis topsmelt eggs 4,427,698 5,441,190 

Paralichthys californicus California halibut eggs 3,894,210 6,151,903 

Labridae unid. wrasse eggs 733,860 950,979 

Blenniidae blenny eggs 500,220 1,097,230 

1,687,595,926 2,117,668,875 

Note: A volume of 1,000 m3 is equal to 264,172 gallons.
Haynes Generating Station CWIS Entrainment and

IM&E Final Report Source Water Study

4-25 

Concentration (#/1000 cubic meters)

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

50000

Survey

01-Jan

2006

01-Mar

2006 01-May2006

01-Jul

2006 01-Sep2006

01-Nov

2006

01-Jan

2007

Figure 4.5-1. Mean concentration (# / 1,000 m3 [264,172 gal] − wide bars) and standard 

deviation (narrow bars) of all larval fishes collected at entrainment Station E3 during 

2006. 

Concentration (#/1000 cubic meters)

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

Survey

01-Jan

2006

01-Mar

2006 01-May2006

01-Jul

2006 01-Sep2006

01-Nov

2006

01-Jan

2007

Figure 4.5-2. Mean concentration (# / 1,000 m3 [264,172 gal] − wide bars) and standard 

deviation (narrow bars) of fish eggs collected at entrainment Station E3 during 2006. 
Haynes Generating Station CWIS Entrainment and

IM&E Final Report Source Water Study

4-26 

Date

12/18/06

12/04/06

11/20/06

11/06/06

10/23/06

10/09/06

09/25/06

09/11/06

08/28/06

08/14/06

07/31/06

07/17/06

07/05/06

06/19/06

06/05/06

05/22/06

05/08/06

04/24/06

04/10/06

03/26/06

03/13/06

02/27/06

02/14/06

01/31/06

01/17/06

01/05/06

Nighttime Daytime Mean Concentration/cubic meter

-60.0 -50.0 -40.0 -30.0 -20.0 -10.0 0.00 10.00 20.00 30.00 40.00 50.00 60.00

Note: Negative nighttime values are a plotting artifact 

Figure 4.5-3. Mean concentration (#/1.0 m3 [264 gal]) of all fish larvae at entrainment 

Station E3 during night (Cycle 3) and day (Cycle 1) sampling. 

Date

12/18/06

12/04/06

11/20/06

11/06/06

10/23/06

10/09/06

09/25/06

09/11/06

08/28/06

08/14/06

07/31/06

07/17/06

07/05/06

06/19/06

06/05/06

05/22/06

05/08/06

04/24/06

04/10/06

03/26/06

03/13/06

02/27/06

02/14/06

01/31/06

01/17/06

01/05/06

Nighttime Daytime Mean Concentration/cubic meter

-12.0 -10.0 -8.00 -6.00 -4.00 -2.00 0.00 2.00 4.00 6.00 8.00 10.00 12.00

Note: Negative nighttime values are a plotting artifact 

Figure 4.5-4. Mean concentration (#/1.0 m3 [264 gal]) of all fish eggs at entrainment 

Station E3 during night (Cycle 3) and day (Cycle 1) sampling. 
Haynes Generating Station CWIS Entrainment and

IM&E Final Report Source Water Study

4-27 

4.5.1.2 Shellfishes 

A total of 50 larval target invertebrates representing 9 taxa was collected from the HnGS entrainment 

station (E3) during 26 bi-weekly surveys in 2006 (Table 4.5-3 and Appendix D). The most abundant 

target shellfish larvae in the samples were shore crab megalops (Grapsidae unid.) followed by kelp crab 

megalops (Pugettia spp.), which made up 27.4% and 25.0%, respectively of the total target invertebrate 

larvae collected. Unidentified crab and unidentified brachyura megalops included species for which there 

were no descriptions as well as specimens that had some type of damage that prevented identification to a 

lower taxonomic category. There was no seasonality apparent in the abundance of the larvae although 

Grapsidae was present from April through December. The only target species larvae with commercial 

fishery value was market squid, which had only a single entrained larva. Total annual entrainment was 

estimated to be 14.8 million target invertebrate larvae using the actual cooling water flows (Table 4.5-4). 

Using the design (maximum capacity) CWIS flows, total annual entrainment increases to 18.5 million 

target invertebrates. 

Table 4.5-3. Average concentration of target invertebrate larvae in entrainment samples collected at 

HnGS (Station E3) in 2006. 

Taxon Common Name 

Avg. Conc.

(per 1,000 m3

)

Total 

Count 

Percentage 

of Total

Cumulative 

Percentage

Grapsidae unid. (megalops) shore crab megalops 3.59 14 27.36 27.36 

Pugettia spp. (megalops) kelp crabs megalops 3.28 12 25.00 52.36 

Pinnixa spp. (megalops) pea crabs megalops 1.84 7 14.02 66.39 

unidentified crab (megalops) unid. crab megalops 1.76 7 13.41 79.80 

Brachyura unid. (megalops) unid. crab megalops 1.33 5 10.14 89.94 

Loxorhynchus spp. spider crabs 0.57 2 4.34 94.28 

Paguridae unid. (megalops) hermit crab megalops 0.30 1 2.29 96.57 

Majidae unid. (megalops) spider crab megalops 0.24 1 1.83 98.40 

Loligo opalescens market squid 0.21 1 1.60 100.00 

 13.12 50 

Note: A volume of 1,000 m3 is equal to 264,172 gallons.

Table 4.5-4. Calculated total annual entrainment of target shellfish larvae at HnGS in 2006 based on 

actual and design (maximum) cooling water intake pump flows. 

Taxon Common Name 

Annual 

Entrainment 

(Actual Flow) 

Annual 

Entrainment 

(Design Flow) 

Grapsidae unid. (megalops) shore crab megalops 4,264,792 5,217,248 

Pugettia spp. (megalops) Kelp crabs megalops 3,629,771 4,586,866 

Pinnixa spp. (megalops) pea crabs megalops 2,031,387 2,574,200 

unidentified crab (megalops) unidentified crab megalops 1,949,343 2,464,009 

Brachyura unid. (megalops) unidentified crab megalops 1,549,133 1,826,174 

Loxorhynchus spp. spider crabs 565,680 790,366 

Paguridae unid. (megalops) hermit crab megalops 325,547 412,641 

Majidae unid. (megalops) spider crab megalops 307,149 334,557 

Loligo opalescens market squid 231,898 289,912 

14,854,700 18,495,973
Haynes Generating Station CWIS Entrainment and

IM&E Final Report Source Water Study

4-28 

4.5.2 Source Water Summary 

4.5.2.1 Fishes 

A total of 41,319 larval fishes representing 68 taxa was collected from HnGS source water stations in and 

near Alamitos Bay (Stations H2−H4, S1−S3 and O1−O3) during 12 monthly surveys in 2006 (Table 4.5-5 

and Appendix D). Unidentified gobies (Clevelandia, Ilypnus, Quietula (CIQ) goby complex), white 

croaker, combtooth blennies, and anchovies were the most abundant taxa and comprised over 90% of all 

specimens collected. Damaged fishes that could not be positively identified comprised 1.0% of the total 

catch. The greatest concentrations of larval fishes occurred during April 2006 (ca. 5,800 per m3

 [264 gal]) 

and the fewest in October 2006 (ca. 600 per m3 [264 gal]) (Figure 4.5.5). Larvae were more abundant in 

samples collected at night than those collected during the day in nearly every survey (Figure 4.5-6). 

Table 4.5-5. Average concentration of larval fishes in samples collected at HnGS source water stations in 

and near Alamitos Bay (Stations H2−H4, S1−S3 and O1−O3) in 2006. 

Taxon Common Name 

Avg. Conc. 

(per 1,000 m3

) Total Count

Percentage of 

Total 

Cumulative 

Percentage 

Larval Fish 

Gobiidae unid. Gobies 1,071.51 19,916 47.36 47.36 

Genyonemus lineatus white croaker 450.11 7,865 19.89 67.25 

Hypsoblennius spp. Combtooth blennies 369.87 6,861 16.35 83.60 

Engraulidae unid. Anchovies 168.79 3,015 7.46 91.06 

larvae, unidentified yolksac unidentified yolksac larvae 39.85 698 1.76 92.82 

Sciaenidae unid. Croakers 30.70 563 1.36 94.18 

unidentified fish, damaged unidentified damaged fish 22.09 407 0.98 95.15 

Atherinopsidae unid. Silversides 17.84 331 0.79 95.94 

Paralichthys californicus California halibut 10.28 188 0.45 96.39 

Acanthogobius flavimanus yellowfin goby 9.43 165 0.42 96.81 

Gobiesocidae unid. Clingfishes 8.66 163 0.38 97.19 

Seriphus politus queenfish 7.60 137 0.34 97.53 

Labrisomidae unid. Labrisomid blennies 7.22 135 0.32 97.85 

Pleuronichthys guttulatus diamond turbot 5.54 96 0.24 98.09 

Hypsypops rubicundus garibaldi 4.71 90 0.21 98.30 

Gillichthys mirabilis longjaw mudsucker 4.05 79 0.18 98.48 

Paralabrax spp. Sand bass 3.45 56 0.15 98.63 

Typhlogobius californiensis blind goby 3.24 56 0.14 98.78 

Pleuronichthys verticalis hornyhead turbot 2.21 37 0.10 98.87 

Syngnathus spp. Pipefishes 1.83 34 0.08 98.96 

Citharichthys spp. Sanddabs 1.83 33 0.08 99.04 

Parophrys vetulus English sole 1.83 34 0.08 99.12 

Gibbonsia spp. Clinid kelpfishes 1.80 32 0.08 99.20 

Lepidogobius lepidus bay goby 1.73 33 0.08 99.27 

Pleuronichthys ritteri spotted turbot 1.56 27 0.07 99.34 

Leptocottus armatus Pacific staghorn sculpin 1.51 30 0.07 99.41 

Stenobrachius leucopsarus northern lampfish 1.22 20 0.05 99.46 

Cheilotrema saturnum black croaker 1.22 22 0.05 99.52 

Pleuronichthys spp. Turbots 1.19 22 0.05 99.57 

(table continued)
Haynes Generating Station CWIS Entrainment and

IM&E Final Report Source Water Study

4-29 

Table 4.5-5 (continued). Average concentration of larval fishes in samples collected at HnGS source 

water stations in and near Alamitos Bay (Stations H2−H4, S1−S3 and O1−O3) in 2006. 

Taxon Common Name 

Avg. Conc. 

(per 1,000 m3) Total Count

Percentage of 

Total 

Cumulative 

Percentage 

Larval Fish 

Roncador stearnsii spotfin croaker 0.83 16 0.04 99.61 

Merluccius productus Pacific hake 0.81 14 0.04 99.64 

larval/post-larval fish unid. larval fishes 0.79 13 0.03 99.68 

Clinocottus spp. sculpins 0.67 11 0.03 99.71 

Sebastes spp. rockfishes 0.64 13 0.03 99.73 

Pleuronectidae unid. righteye flounders 0.55 10 0.02 99.76 

Heterostichus rostratus giant kelpfish 0.42 8 0.02 99.78 

Menticirrhus undulatus California corbina 0.36 7 0.02 99.79 

Ruscarius creaseri roughcheek sculpin 0.36 6 0.02 99.81 

Peprilus simillimus Pacific butterfish 0.34 6 0.01 99.82 

Symphurus atricaudus California tonguefish 0.30 5 0.01 99.84 

Pleuronectiformes unid. flatfishes 0.28 5 0.01 99.85 

Oxyjulis californica senorita 0.27 5 0.01 99.86 

Triphoturus mexicanus Mexican lampfish 0.24 4 0.01 99.87 

Oxylebius pictus painted greenling 0.22 4 0.01 99.88 

Blennioidei unid. blennies 0.20 3 0.01 99.89 

Paralichthyidae unid. sand flounders 0.19 4 0.01 99.90 

Ophidiidae unid. cusk-eels 0.18 3 0.01 99.91 

Umbrina roncador yellowfin croaker 0.18 3 0.01 99.91 

Scorpaenidae unid. scorpionfishes 0.17 3 0.01 99.92 

Ophidion scrippsae basketweave cusk-eel 0.17 3 0.01 99.93 

Rhinogobiops nicholsii blackeye goby 0.17 3 0.01 99.94 

Sphyraena argentea Pacific barracuda 0.17 3 0.01 99.95 

Semicossyphus pulcher California sheephead 0.13 2 0.01 99.95 

Girella nigricans opaleye 0.12 2 0.01 99.96 

Sardinops sagax Pacific sardine 0.12 2 0.01 99.96 

Chaenopsidae unid. tube blennies 0.10 2 <0.01 99.97 

Zaniolepis spp. combfishes 0.09 2 <0.01 99.97 

Cottidae unid. sculpins 0.09 2 <0.01 99.97 

Icelinus spp. sculpins 0.07 1 <0.01 99.98 

Halichoeres semicinctus rock wrasse 0.07 1 <0.01 99.98 

Pomacentridae unid. damselfishes 0.07 1 <0.01 99.98 

Bathylagidae unid. blacksmelt 0.06 1 <0.01 99.99 

Neoclinus spp. fringeheads 0.06 1 <0.01 99.99 

Myctophidae unid. lanternfishes 0.06 1 <0.01 99.99 

Haemulidae unid. grunts 0.05 1 <0.01 99.99 

Artedius spp. sculpins 0.05 1 <0.01 99.99 

Hexagrammidae unid. greenlings 0.05 1 <0.01 99.99 

Scorpaenichthys marmoratus cabezon 0.04 1 <0.01 100.00 

 2,262.63 41,319 

Note: A volume of 1,000 m3 is equal to 264,172 gallons.
Haynes Generating Station CWIS Entrainment and

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Concentration (#/1000 cubic meters)

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

Survey

01-Jan

2006

01-Mar

2006 01-May2006

01-Jul

2006 01-Sep2006

01-Nov

2006

01-Jan

2007

Figure 4.5-5. Mean concentration (# / 1,000 m3 [264,172 gal] − wide bars) and standard deviation 

(narrow bars) of all larval fishes collected at HnGS source water stations during 2006. 

Date

12/04/06

11/06/06

10/09/06

09/11/06

08/14/06

07/05/06

06/05/06

05/08/06

04/10/06

03/13/06

02/14/06

01/17/06

Nighttime Daytime Mean Concentration/cubic meter

-12.0 -10.0 -8.00 -6.00 -4.00 -2.00 0.00 2.00 4.00 6.00 8.00 10.00 12.00

Note: Negative nighttime values are a plotting artifact 

Figure 4.5-6. Mean concentration (# / 1.0 m3 [264 gal]) of all larval fishes collected at HnGS source 

water stations during night (Cycle 3) and day (Cycle 1) sampling. 
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4.5.2.2 Shellfishes 

A total of 2,291 larval target invertebrates (developmentally advanced larvae of crabs, spiny lobsters, and 

market squid) representing 20 taxa (combined species designations) was collected from HnGS source 

water stations in and near Alamitos Bay (Stations H2−H4, S1−S3 and O1−O3) during 12 monthly surveys 

in 2006 (Table 4.5-6 and Appendix D). Megalops of kelp crabs, pea crabs, shore crabs, spider crabs, and 

unidentified megalops were the most abundant taxa and comprised nearly 90% of all specimens collected. 

Data presented in Appendix D includes abundances for the uncombined species designations by survey. 

Table 4.5-6. Average concentration of larval target invertebrates in samples collected at HnGS source 

water stations in and near Alamitos Bay (Stations H2−H4, S1−S3 and O1−O3) in 2006. 

Taxon Common Name 

Avg. Conc. 

(per 1,000 m3

) Total Count

Percentage of 

Total 

Cumulative 

Percentage

Pugettia spp. kelp crabs megalops 69.73 1,253 55.33 55.33 

Pinnixa spp. pea crabs megalops 16.27 309 12.91 68.24 

Grapsidae unid. shore crab megalops 11.40 208 9.04 77.28 

unidentified crab unidentified crab megalops 8.01 144 6.35 83.63 

Majidae unid. spider crab megalops 4.50 80 3.57 87.21 

Brachyura unid. unidentified crab megalops 3.43 65 2.72 89.92 

Paguridae unid. hermit crab megalops 2.90 51 2.30 92.23 

Pinnotheres spp. pea crab megalops 2.39 45 1.90 94.13 

Cancer spp. cancer crabs megalops 1.80 32 1.43 95.56 

Petrolisthes spp. porcelain crab megalops 1.15 20 0.92 96.47 

Porcellanidae unid. (megalops) porcelain crab megalops 1.15 22 0.91 97.38 

Lophopanopeus spp. (megalops) black-clawed crab megalops 1.07 22 0.85 98.23 

Pachycheles spp. porcelain crabs megalops 1.04 18 0.83 99.06 

Diogenidae left-handed hermit crabs 0.36 7 0.29 99.34 

Pachycheles rudis thickclaw porcelain crab 0.36 7 0.29 99.63 

Panulirus interruptus

(phyllosome stage) California spiny lobster (larval) 0.17 3 0.13 99.76 

Loligo opalescens market squid 0.12 2 0.10 99.86 

Pachygrapsus crassipes striped shore crab megalops 0.07 1 0.06 99.92 

Hippoidea mole crab megalops 0.07 1 0.05 99.97 

Panulirus interruptus

(puerulus stage) California spiny lobster (larval) 0.04 1 0.03 100.00 

 126.03 2,291 

Note: A volume of 1,000 m3 is equal to 264,172 gallons.
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4.5.3 Results by Species for Cooling Water Intake Structure Entrainment 

The following five fish taxa were selected for detailed evaluation of entrainment effects based on their 

abundance in entrainment samples. Together they comprised over 98% of the larvae entrained at HnGS in 

2006 (Table 4.5-1). In taxonomic order these are: 

• anchovies (Engraulis mordax and Engraulidae) + eggs 

• silversides (Atherinopsidae) 

• white croaker (Genyonemus lineatus) 

• combtooth blennies (Hypsoblennius spp.) 

• unidentified gobies (Gobiidae) 

4.5.3.1 Anchovies (Engraulidae) 

Three species of anchovy (Family Engraulidae) 

inhabit nearshore areas of southern California: 

northern anchovy (Engraulis mordax), deepbody 

anchovy (Anchoa compressa) and slough anchovy 

(Anchoa delicatissima). This analysis of 

entrainment effects on anchovies will concentrate 

on life history aspects of the northern anchovy 

because all of the Engraulid larvae collected that 

were large enough to be positively identified were 

northern anchovies. Ninety-six percent of the 

specimens identified in the entrainment samples as 

Engraulidae were northern anchovy. The remainder 

were very small specimens still in their recently-hatched yolk-sac stage and some that were damaged to 

an extent that they could not be positively identified to the species level. 

Northern anchovy ranges from Cabo San Lucas, Baja California to Queen Charlotte Island, British 

Columbia (Miller and Lea 1972), and the Gulf of California (Hammann and Cisneros-Mata 1989). They 

are most common from Magdalena Bay, Baja California to San Francisco Bay within 157 km (98 mi) of 

shore (Hart 1973; MBC 1987). Three genetically distinct subpopulations are recognized for northern 

anchovy; (1) Northern subpopulation, from northern California to British Columbia; (2) Central 

subpopulation, from central California to northern Baja California; and (3) Southern subpopulation, off 

southern Baja California (Emmett et al. 1991). 

4.5.3.1.1 Life History and Ecology 

The reported depth range of northern anchovy is from the surface to depths of 310 m (1,017 ft) (Davies 

and Bradley 1972). Juveniles are generally more common inshore and in estuaries. Eggs are elliptical and 

occur from the surface to depths of about 50 m (164 ft), while larvae are found from the surface to about 

75 m (246 m) in epipelagic and nearshore waters (Garrison and Miller 1982). Northern anchovy larvae 

feed on dinoflagellates, rotifers, and copepods (MBC 1987). 

Mark Conlin 
Haynes Generating Station CWIS Entrainment and

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Northern anchovies spawn throughout the year off southern California, with peak spawning between 

February and May (Brewer 1978) although this may vary annually and also geographically. Most 

spawning takes place within 100 km (62 mi) of shore (MBC 1987). On average, female anchovies off Los 

Angeles spawn every 7−10 days during peak spawning periods, approximately 20 times per year (Hunter 

and Macewicz 1980; MBC 1987). Most spawning occurs at night and is completed by dawn (Hunter and 

Macewicz 1980). Anchovies are all sexually mature by age two, and the fraction of the population that is 

sexually mature at one year of age can range from 47 to 100% depending on the water temperature during 

development (Bergen and Jacobsen 2001). Love (1996) reported that they release 2,700−16,000 eggs per 

batch, with an annual fecundity of up to 130,000 eggs per year in southern California. Parrish et al. (1986) 

and Butler et al. (1993) stated that the total annual fecundity for one-year old females was 20,000−30,000 

eggs, while a five-year old could release up to 320,000 eggs per year. 

Northern anchovy eggs hatch in two to four days, undergo a larval phase lasting approximately 70 days, 

and transform into the juvenile stage at about 35−40 mm (Hart 1973; MBC 1987; Moser 1996). Larvae 

begin schooling at 11−12 mm (0.4−0.5 inches) SL (Hunter and Coyne 1982). Northern anchovy reach 

102 mm (4 inches) on average in their first year, and 119 mm (4.7 inches) in their second (Sakagawa and 

Kimura 1976). Larval survival is strongly influenced by the availability and density of phytoplankton 

(Emmett et al. 1991). Strong upwelling may transport some larvae out of the Southern California Bight 

(Power 1986), however, it may also benefit juveniles and adults by increasing certain food resources. 

Growth in length is most rapid during the first four months, and growth in weight is most rapid during the 

first year (Hunter and Macewicz 1980; PFMC 1983). They mature at 78−140 mm (3.1−5.5 inches) in 

length, in their first or second year (Frey 1971; Hunter and Macewicz 1980). Maximum recorded size is 

about 230 mm (9.1 inches) and 60 g (2.1 oz) (Fitch and Lavenberg 1971; Eschmeyer and Herald 1983). 

Maximum age is about seven years (Hart 1973), though most live less than four years (Fitch and 

Lavenberg 1971). 

Northern anchovy is very important in the trophic ecology of marine food webs. They are random 

planktonic feeders, filtering plankton as they swim (Fitch and Lavenberg 1971). Juveniles and adults feed 

mainly at night on zooplankton, including planktonic crustaceans and fish larvae (Fitch and Lavenberg 

1971; Hart 1973; Allen and DeMartini 1983). Numerous fish and marine mammal species feed on 

northern anchovy. Elegant tern and California brown pelican reproduction is strongly correlated with the 

annual abundance of this species (Emmett et al. 1991). Juveniles and adults avoid temperatures above 

25°C (Brewer 1974). 

4.5.3.1.2 Population Trends and Fishery 

Northern anchovy (Engraulis mordax) are one of four coastal pelagic species managed by the Pacific 

Fisheries Management Council (PFMC)⎯the other species include Pacific sardine, Pacific mackerel, and 

jack mackerel. Northern anchovy in the northeastern Pacific is divided into three subpopulations, or 

stocks: northern, central, and southern. Since 1978 the PFMC has managed northern anchovy from the 

central and northern subpopulations. The central subpopulation includes landings from San Francisco to 

Punta Baja, Baja California. 
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Three separate commercial fisheries target northern anchovy in California and Mexico waters: 1) the 

reduction fishery, 2) the live bait fishery, and a 3) non-reduction fishery (Bergen and Jacobson 2001). In 

the reduction fishery anchovies are converted to meal, oil, and protein supplements while the nonreduction fishery includes fish that are processed for human consumption, for animal food, or frozen for 

use as fishing bait. 

Northern anchovy populations began to increase following the collapse of the Pacific sardine (Sardinops 

sagax) fishery in 1952. Landings remained fairly low throughout the 1950s but increased rapidly in the 

mid 1960s when reduction of anchovy without associated canning was permitted (Bergen and Jacobson 

2001). The demand for this fishery was highly linked to the production and price of fish meal worldwide 

(Mason 2004). A drastic decline of 40% in fish meal prices worldwide during the early 1980s (Durand 

1998) and the decline in anchovy abundance nearly ended anchovy reduction by 1983. 

Estimates of the central subpopulation averaged about 359,000 tons from 1963 through 1972, increased to 

over 1.7 million tons in 1974, and then declined to 359,000 tons in 1978 (Bergen and Jacobsen 2001). 

Anchovy biomass in 1994 was estimated at 432,000 tons. The stock is thought to be stable, and the size of 

the anchovy resource is largely dependent on natural influences such as ocean temperatures related to a 

cold regime in the Pacific Decadal Oscillation (Chavez et al. 2003). 

In the Los Angeles-Long Beach Harbor complex, northern anchovy was one of the most abundant 

species, along with topsmelt (Atherinopsis affinis), in purse seine and beach seine sampling in the early 

1980s (Allen et al. 2006). Seasonally the greatest population abundances typically occur in summer and 

early fall as a result of large numbers of young-of-the-year. The earlier 316(b) study of the HnGS in 

1978−1979 (IRC 1981) measured mean density values of engraulid species complex larvae that were 

lowest from July through September and greatest from January through June. Survey means for the nearfield varied from 0 to 880 larvae per 1,000 m3

 (264,172 gal) for day surveys and from 0 to 4,250 larvae 

per 1,000 m3

 (264,172 gal) for night surveys. During the period of peak abundance for January−June, the 

average survey density was 13,650 per 1,000 m3 (264,172 gal). These densities are over fifty times greater 

than the highest 2006 densities recorded in April (see Section 4.5.3.1.3−Sampling Results). 

The California commercial fishery for northern anchovy varies substantially by region and year. There 

have not been any landings of northern anchovy recorded from San Diego County since 1996 when 

318,000 lbs were landed (PacFIN 2007). In 2004 there were 325,000 lbs landed in the Los Angeles area 

as compared to 6.07 million lbs. in the Santa Barbara area, and 8.58 million lbs. in the Monterey area for 

a total value of $750,000. Annual landings in the Los Angeles region since 2000 have varied from a high 

of 8.6 million lbs in 2001 to a low of 0.3 million lbs in 2004, with an average of 3 million lbs annually 

(Table 4.5-7). 
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Table 4.5-7. Annual landings and revenue for northern anchovy in the Los Angeles region based on 

PacFIN data. 

Year Landed Weight (kg) Landed Weight (lbs) Revenue 

2000 1,279,437 2,820,677 $145,579 

2001 3,656,509 8,061,223 $319,628 

2002 1,205,307 2,657,247 $100,716 

2003 327,468 721,944 $37,750 

2004 147,003 324,087 $35,699 

2005 1,979,989 4,365,130 $185,579 

2006 865,971 1,909,139 $75,104 

4.5.3.1.3 Sampling Results 

Engraulid larvae (predominantly northern anchovy) were the fifth most abundant taxon at the entrainment 

station with a mean concentration of 20 per 1,000 m3

 (264,172 gal) over all surveys while engraulid eggs 

had an average concentration of 10 per 1,000 m3

 (264,172 gal) (Table 4.5-1). Almost all larvae occurred 

in April−May (Figure 4.5-7). During periods of maximum abundance in early April 2006 anchovies were 

present in the entrainment samples at average concentrations of 255 per 1,000 m3 (264,172 gal). They 

were absent from samples in almost all other months except September and November. Monthly source 

water concentrations followed a similar seasonal pattern with maximum concentrations exceeding 1,000 

per 1,000 m3

 (264,172 gal) in April 2006 (Figure 4.5-8). There was no consistent trend in abundance 

between daytime and nighttime samples (Figure 4.5-9). The length frequency distribution of measured 

northern anchovy larvae showed a bi-modal distribution with the predominant peak consisting of 

recently-hatched larvae, ranging from 3-5 mm notochord length (NL), and a smaller peak in the range of 

10−14 mm (Figure 4.5-10), reflecting growth of the initial strong cohort from the early April spawning 

event (Figure 4.5-7). The lengths of the larvae from the entrainment station samples ranged from 2.3−28.7 

mm with a mean of 5.3 mm NL. 
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Concentration (#/1000 cubic meters)

0

40

80

120

160

200

240

280

320

360

400

Survey

01-Jan

2006

01-Mar

2006 01-May2006

01-Jul

2006 01-Sep2006

01-Nov

2006

01-Jan

2007

Figure 4.5-7. Mean concentration (# / 1,000 m3 [264,172 gal] − wide bars) and standard 

deviation (narrow bars) of anchovy larvae collected at HnGS entrainment Station E3 during 

2006. 

Concentration (#/1000 cubic meters)

0

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

2400

Survey

01-Jan

2006

01-Mar

2006 01-May2006

01-Jul

2006 01-Sep2006

01-Nov

2006

01-Jan

2007

Figure 4.5-8. Mean concentration (# / 1,000 m3 [264,172 gal] − wide bars) and standard 

deviation (narrow bars) of anchovy larvae collected at HnGS source water stations during 2006. 
Haynes Generating Station CWIS Entrainment and

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Date

12/18/06

12/04/06

11/20/06

11/06/06

10/23/06

10/09/06

09/25/06

09/11/06

08/28/06

08/14/06

07/31/06

07/17/06

07/05/06

06/19/06

06/05/06

05/22/06

05/08/06

04/24/06

04/10/06

03/26/06

03/13/06

02/27/06

02/14/06

01/31/06

01/17/06

01/05/06

Nighttime Daytime Mean Concentration/cubic meter

-0.30 -0.25 -0.20 -0.15 -0.10 -0.05 -0.00 0.05 0.10 0.15 0.20 0.25 0.30

Figure 4.5-9. Mean concentration (#/1.0 m3

 [264 gal]) of anchovy larvae at entrainment 

Station E3 during night (Cycle 3) and day (Cycle 1) sampling. 

N = 186

Percent

0

10

20

30

40

50

60

70

80

90

100

Midpoint for

Length Category (mm)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Figure 4.5-10. Length (mm) frequency distribution for larval anchovy collected 

at entrainment stations in Alamitos Bay. 
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4.5.3.1.4 Modeling Results 

The following section presents the results for demographic and empirical transport modeling of 

entrainment effects on Engraulidae (northern anchovy) larvae. Total annual entrainment at HnGS was 

estimated at 22,673,541 (standard error of 1,037,682) larvae and 11,128,912 (standard error of 846,961) 

eggs using measured cooling water flows during 2006 (Table 4.5-2). If the CWIS pumps were run at the 

design (maximum capacity) flows, annual entrainment estimates increased to 27,301,289 larvae (standard 

error of 1,252,501) and 14,029,527 eggs (standard error 1,092,083; Table 4.5-2). 

Fecundity Hindcasting (FH)

The entrainment estimate for northern anchovy for the 2006 sampling period was used to estimate the 

number of breeding females at the age of maturity needed to produce the estimated number of larvae 

entrained. Butler et al. (1993) modeled annual fecundity and egg and larval survivorship for northern 

anchovy. Their “best” estimate can be derived by fitting the range of mortality estimates from field 

collections to the assumption of a stable and stationary population age structure. Instantaneous daily 

mortality estimates from Butler et al. (1993) were converted, over their average stage durations, to finite 

survivorship rates for each developmental stage (Table 4.5-8). Fish at the mean age of entrainment 

include yolk sac, early stage and late stage larvae. Therefore, survival estimates for all three stages were 

combined to obtain a finite survival value of 0.002 up to the mean age at entrainment (5.0 days). This was 

calculated by dividing a larval growth rate of 0.41 mm/day (0.02 inches/day) into the difference between 

the mean length (5.29 mm [0.21 inches]) and the calculated hatch length of 3.28 mm [0.13 inches]). 

Table 4.5-8. Stage-specific life history parameters for northern anchovy (Engraulis mordax) modified 

from Butler et al. (1993). Z = instantaneous daily mortality; S = finite survival rate. 

Stage Zbest

Stage 

duration

(days) 

Age 

(days) Sbest CVbest

Egg 0.231 2.9 0.512 0.142 

Yolk-sac larva 0.366 3.6 6.5 0.093 0.240 

Early larva 0.286 12 18.5 0.032 0.071 

Late larva 0.0719 45 63.5 0.039 0.427 

Early juvenile 0.0141 62 125.5 0.417 0.239 

Late Juvenile 0.0044 80 205.5 0.703 0.033 

Pre-recruit 0.0031 287 492.5 0.411 0.088 

Clark and Phillips (1952) reported age at sexual maturity as 1–2 years. Similarly, Leet et al. (2001) 

reported that 47% to 100% of one-year olds may be mature in a given year while all are mature by two 

years. For modeling purposes we used a mid-value of 1.5 years. For longevity, Hart (1973) reported a 

value of seven years, but Leet et al. (2001) stated that northern anchovy in the fished population rarely 

exceed four years of age. The survivorship values in Table 4.5-9 were used to estimate an average annual 

fecundity of 163,090 eggs produced over a seven-year period using the data presented in Butler et al. 

(1993). 
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Table 4.5-9. Survivorship table for adult northern anchovy (Engraulis mordax) from Butler et al. (1993) 

showing spawners (Lx) surviving at the start of age interval and numbers of eggs spawned annually (Mx). 

Age (years) Lx Mx LxMx 

1 1,000 22,500 22,500,000 

2 468 93,500 43,800,000 

3 216 195,000 42,000,000 

4 102 280,000 28,600,000 

5 48 328,000 15,700,000 

6 22 328,000 7,210,000 

7 10 328,000 3,280,000 

TLF = 163,090 

The total lifetime fecundity (TLF) was calculated as the sum of LxMx 

divided by 1,000.

The estimated number of reproductive age adult female northern anchovies whose lifetime reproductive 

output was entrained through the HnGS CWIS for 2006 was 4,300 based on the actual cooling water 

flows during the period (Table 4.5-10). Using the design flows, an estimated 5,182 eggs and larvae were 

entrained during the period. The sensitivity analysis, based on the 90% confidence intervals, shows that 

the variation in estimates of entrainment had much less of an effect on the variation of the FH estimate 

than the life history parameters used in the model. 

Table 4.5-10. Results of FH modeling for anchovy larvae based on entrainment estimates calculated using 

actual and design (maximum) CWIS flows. 

Parameter Estimate Std. Error 

FH

Lower 

Estimate 

FH

Upper 

Estimate 

FH

Range 

Actual Flows 

Eggs 

FH Estimate 92 65 29 296 268 

Total Entrainment 11,128,912 846,961 80 103 23 

Larvae 

FH Estimate 4,208 3,649 1,010 17,522 16,512 

Total Entrainment 22,673,541 1,037,682 3,891 4,524 634 

Design Flows 

Eggs 

FH Estimate 116 82 36 373 337 

Total Entrainment 14,029,527 1,092,083 101 131 30 

Larvae 

FH Estimate 5,066 4,394 1,217 21,099 19,882 

Total Entrainment 27,301,289 1,252,501 4,684 5,449 765 

The upper and lower estimates are based on a 90% confidence interval of the mean. FH estimates were also 

calculated using the upper and lower confidence estimates from the entrainment estimates. 
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Adult Equivalent Loss (AEL)

The parameters required for formulation of AEL estimates include larval survival from entrainment to 

settlement and survival from settlement to the age of maturity. Instantaneous daily mortality estimates 

from Butler et al. (1993) were converted, over their average stage durations, to finite survivorship rates 

for each developmental stage (Table 4.5-10). The early larval stage survival was adjusted to the mean age 

at entrainment (5.0 days) and used to calculate a finite survival through age 63.5 days of 0.174 using the 

daily survival rates for late stage larvae. The other finite survival rates from Butler et al. (1993) were used 

to estimate the number of adults of age one year, the age of first maturity when 50% of the females are 

sexually mature. The equivalent number of adult northern calculated from the number of larvae entrained 

through the HnGS CWIS for 2006 was 20,684 based on actual flows during the period (Table 4.5-11). 

Using the design flows, the equivalent number of adults entrained during the period was projected as 

24,845 larvae. 

Table 4.5-11. Results of AEL modeling for northern anchovy larvae based on entrainment estimates 

calculated using actual and design (maximum) CWIS flows. 

Parameter Estimate Std. Error 

AEL

Lower 

Estimate 

AEL

Upper 

Estimate 

AEL

Range 

Actual Flows 

AEL Estimate 20,634 23,886 3,073 138,548 135,475 

Total Entrainment 22,673,541 1,037,682 19,081 22,187 3,107 

Design Flows 

AEL Estimate 24,845 28,762 3,700 166,827 163,127 

Total Entrainment 27,301,289 1,252,501 22,970 26,720 3,750 

The upper and lower estimates are based on a 90% confidence interval of the mean. AEL estimates were also 

calculated using the upper and lower confidence estimates from the entrainment estimates. 

Empirical Transport Model (ETM)

A larval growth rate of 0.41 mm/day (0.02 inches/day) for northern anchovies was estimated from Methot 

and Kramer (1979) and used with the difference in the lengths of the calculated hatch length (3.28 mm 

[0.13 inches]) and 95th percentile value (11.19 mm [0.47 inches]) for the measurements to estimate that 

the larvae were exposed to entrainment for a period of approximately 19.5 days. The average duration of 

the planktonic egg stage, 2.9 days, was added to the period for the larvae to estimate a total period of 

exposure of 22.5 days. 

The monthly estimates of proportional entrainment (PE) for northern anchovies for 2006 ranged from 0 to 

0.0005 using the actual flows and ranged from 0 to 0.0007 based on the design flows, and were only 

collected during five of the paired entrainment-source water surveys (Table 4.5-12). The largest estimate 

was calculated for the November survey, but the results also show that anchovy larvae were collected 

during almost all of the source water surveys with the largest proportion was present during the April 

survey (fi = 0.551 or 55.1%). The values in the table were used to calculate a PM estimate of 0.0076 with a 

standard error of 0.0031 based on the actual flows during the sampling period and an estimate of 0.0092 

(standard error of 0.0037) based on the design flows Estimates were calculated using the alongshore 

extrapolated estimate of the total source population. The average alongshore displacement over the period 

of exposure was 27.02 km (16.8 mi) and the average onshore transport was 24.43 km (15.2 mi). 
Haynes Generating Station CWIS Entrainment and

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Table 4.5-12. ETM data and results for northern anchovy larvae based on actual and design (maximum) 

cooling water flows and a sampling volume in the nearshore of 140,698,222 m3

. 

 Actual Flows Design Flows 

Survey 

Date 

PE

Estimate 

PE

Std. Err. 

PE

Estimate 

PE

Std. Err. fi

17-Jan-06 0 0 0 0 0 

14-Feb-06 0 0 0 0 0 

13-Mar-06 0 0 0 0 0.01710 

10-Apr-06 0.00037 0.00152 0.00047 0.00192 0.55074 

8-May-06 0.00039 0.00197 0.00042 0.00214 0.31753 

5-Jun-06 0.00010 0.00151 0.00014 0.00201 0.04618 

5-Jul-06 0 0 0 0 0.01338 

14-Aug-06 0 0 0 0 0.00036 

11-Sep-06 0.00016 0.00374 0.00017 0.00404 0.02109 

9-Oct-06 0 0 0 0 0.00261 

6-Nov-06 0.00050 0.00789 0.00070 0.01103 0.00889 

4-Dec-06 0 0 0 0 0.02212 

PM 0.0076 0.0031 0.0092 0.0037 −

4.5.3.2 Silversides (Atherinopsidae) 

Three species of silversides (family Atherinopsidae) 

occur in California ocean waters and in the vicinity of 

HnGS: topsmelt (Atherinops affinis), jacksmelt 

(Atherinopsis californiensis), and the California 

grunion (Leuresthes tenuis). Topsmelt are found from 

Vancouver Island British Columbia, to the Gulf of 

California, (Miller and Lea 1972), with a disjunct 

distribution in the northern gulf (Robertson and Allen 

2002). Jacksmelt are found in estuaries and coastal 

marine environments from Yaquina Bay, Oregon to 

the Gulf of California (Eschmeyer and Herald 1983; 

Robertson and Allen 2002). California grunion are 

found from San Francisco to Magdalena Bay, Baja California (Miller and Lea 1972) but are most 

abundant from Point Conception southward (Love 1996). 

4.5.3.2.1 Life History and Ecology 

These schooling fishes are very common in estuaries, kelp beds, and along sandy beaches. Although 

mostly observed on the surface, topsmelt have been seen to depths of 9 m (30 ft) (Love 1996). Jacksmelt 

have been observed at depths of 29 m (95 ft). Grunion are usually seen from just behind the surf line to 

depths of about 18 m (60 ft). 

Jamie Siler 
Haynes Generating Station CWIS Entrainment and

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In a five-year study of fishes in San Diego Bay, topsmelt ranked second in abundance and fifth in 

biomass, comprising about 23% of the individuals and 9% of the total weight (Allen 1999). Topsmelt 

were captured in all samples with peak abundances generally occurring in April due to heavy recruitment 

of young-of-the-year (YOY). Topsmelt occurred in a wide size range over the study and were represented 

by four age classes. Typically, YOY and juvenile topsmelt primarily occupied the intertidal zone while 

adult fish also occupied nearshore and midwater channel sub-habitats. 

Adult topsmelt mature within 2−3 years to an approximate length of 10−15 cm (4−6 inches) and can 

reach a length of 37 cm (14.5 inches). They have a life expectancy of up to eight years (Love 1996). 

Jacksmelt is the largest member of the three species of the silverside that occur in California with adults 

reaching a maximum length of 44 cm (17 inches) (Miller and Lea 1972). The fish reach maturity after two 

years at a size range of 18−20 cm (7.0−7.8 inches) SL, and can live to a maximum age of nine or ten 

years (Clark 1929). Grunion reach 19 cm (7.5 inches) in length, with a life span of up to four years. They 

mature at one year old at a length of approximately 12−13 cm (5 inches). 

The spawning activity of topsmelt corresponds to changes in water temperature (Middaugh et al. 1990). 

In Newport Bay, topsmelt spawn from February to June peaking in May and June (Love 1996). Females 

deposit the eggs on marine plants and other floating objects where fertilization occurs (Love 1996). 

Fecundity is a function of female body size with individuals in the 11−12 cm (4.3−4.7 inches) range 

spawning approximately 200 eggs per season, and fish 16 cm (6.3 inches) or greater spawning 1,000 eggs 

per season (Fronk 1969). The spawning season for jacksmelt is from October through March (Clark 

1929), with peak activity from January through March (Allen et al. 1983). Individuals may spawn 

multiple times during the reproductive season and reproductive females have eggs of various sizes and 

maturities present in the ovary (Clark 1929). Fecundity has not been well documented but is possibly over 

2,000 eggs per female (Emmett et al. 1991). Females lay eggs on marine plants and other floating objects 

where fertilization by males occurs (Love 1996). Hatch length for topsmelt ranges from 4.3−5.4 mm 

(0.17−0.21 inches), and 6−9 mm (0.24−0.35 inches) for jacksmelt (Moser 1996). Larval growth rate 

averages approximately 0.37 mm/day (0.01 inches/day) for both species based on data from Middaugh et 

al. (1990). Plankton sampling conducted during the earlier 316(b) study (IRC 1981) found that nearly all 

silverside larvae were collected in surface samples indicating a strong behavioral tendency for these 

larvae to actively maintain their position in surface strata, possibly through a phototatic response. 

Summary of silverside distribution and life history attributes. 

Range: 

• Topsmelt-Vancouver Island, British Columbia, to southern Baja California and the upper Gulf of California 

• Jacksmelt-Yaquina Bay, Oregon through Gulf of California 

• Grunion-San Francisco to southern Baja California 

Life History: 

• Size up to 19 cm (7.5 inches) (grunion); 37 cm (14.5 inches) (topsmelt); 44cm (17 inches) (jacksmelt) 

• Age at maturity from 2−3 years all species 

• Life span to 4 years (grunion); 8 years (topsmelt); 10 years (jacksmelt) 

• Spawn from February to June (topsmelt); October to March (jacksmelt); February to September (grunion) with 

fecundity ranging from 1,000 (topsmelt)–3,000 (grunion) eggs 

Habitat: Bays, estuaries, nearshore surface waters to depths of 9-29 m (30-95 ft). 

Fishery: Incidental commercial and limited recreational take on hook and line or with nets.
Haynes Generating Station CWIS Entrainment and

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The spawning activity of grunion is quite different from the other silversides. Spawning occurs only three 

or four nights following each full or new moon, and then only for 1–3 hours immediately after the high 

tide, from late February to early September (peaking late March to early June) (Love 1996). The female 

swims onto the beach and digs into the wet sand, burying herself up to her pectoral fins or above. The 

male or males curve around her with vents touching her body, and when the female lays her eggs beneath 

the sand, males emit sperm, which flows down her body and fertilizes the eggs (Love 1996). Females 

spawn four to eight times per season at about 15-day intervals, producing 1,000–3,000 eggs. Hatch length 

for grunion ranges from 6.5−7.0 mm (0.25−0.27 inches) (Moser 1996). 

4.5.3.2.2 Population Trends and Fishery 

Bays, estuaries, and soft bottom sediments in the surf zone are the primary habitats where silversides 

(jacksmelt, topsmelt, and grunion) are typically most abundant within southern California (Allen et al. 

2006; Allen and Pondella 2006). Topsmelt numbers are much greater in bays compared to semi-protected 

or exposed coastlines (Allen and Herbinson 1991), whereas jacksmelt form larger and denser schools than 

topsmelt in nearshore areas (Gregory 2001a). Differential habitat use within bays and estuaries indicate 

that topsmelt occupy much of the water column both along the shoreline and main channels (Allen et al. 

2002; Valle et al. 1999). 

Topsmelt were the most common fish collected in a study of Anaheim Bay, just south of Alamitos Bay 

(Klingbeil et al. 1975). In a series of trawls conducted in Alamitos Bay from 1992-1995, topsmelt wre the 

fifth most dominant species (Valle et al. 1999). They were present year round in both areas and likely 

used the habitat as spawning grounds. Potential population trends of silversides can be examined from 

areas outside of the Alamitos Bay area to evaluate variability over time. There were no consistent trends 

for the recreational catch in southern California from 1980-2006 (Figure 4.5-11a). A time series analysis 

of silversides was conducted at King Harbor in Redondo Beach by the Vantuna Research Group. From 

1974-2006, two trends emerge. First, the density of silversides was generally higher prior to the regime 

shift associated with the PDO (Figure 4.5-11b). Secondly, the density of silversides declined from the 

early 1970’s to the early 1990s, then remained fairly constant through 2006. Overall, the density of 

silversides declined significantly from 1974-2006. In the OREHP time series (Figure 4.5-11c), catch per 

sampling period from 1995-2006 varied around an average of 10.7 fish/station in Santa Monica Bay and 

15.3 fish/station in the rest of the Southern California Bight. The difference between the two time series 

were high catches of jacksmelt in the April samples at Seal Beach in 1995, 1999, 2001. Jacksmelt move 

into this area in the spring to lay their eggs. Overall, since the mid 1990s silversides have been increasing 

in catch throughout the southern California bight including Santa Monica Bay. 

A limited fishery exists for silversides in which they are marketed fresh for human consumption or for 

bait (Gregory 2001a). The commercial fishery for silversides has been conducted with a variety of gears 

including gillnets, lampara nets, and round haul nets. Historically, set-lines were used in San Francisco 

Bay for jacksmelt, and during the 1920s beach nets were used at Newport Beach (Gregory 2001a). 

Commercial catches of jacksmelt have varied sharply over the past 80 years fluctuating from more than 

900,000 kg (2,000,000 lbs) in 1945 to 1,150 kg (2,500 lbs) in 1998 and 1999. Silversides, in general, are 

an incidental fishery and the large fluctuations in the catch records reflect demand rather than relative 

abundances. 
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Grunion are primarily harvested by recreational fishers by hand when these fish spawn on wet sandy 

beaches during spring and summer. They are also taken incidentally in bait nets and other round haul nets 

in limited quantities and are used as live bait, although no commercial landings have been reported 

(Gregory 2001b). In the 1920s, the recreational fishery was showing signs of depletion, and a regulation 

was passed in 1927 establishing a closed season of three months, April through June. The fishery 

improved, and in 1947, the closure was shortened to April through May. 

Both topsmelt and jacksmelt make up a significant portion of the catch from piers and along shores. 

Jacksmelt shore landings declined by over 75% in the 1990s compared to the 1980s (Jarvis et al. 2004) 

Recent catch estimates of jacksmelt by recreational anglers in southern California from 2000 to 2006 

ranged from 29,000 to 152,000 fish, with an average of 67,900 fish caught annually (Table 4.5-13). Sport 

fishery catch estimates for topsmelt in southern California from 2000 to 2006 ranged from 90,000 to 

181,000 fish, with an average of 135,900 fish caught annually. A total of 28 kg (62 lbs) of jacksmelt with 

a revenue of $35 were landed in the Los Angeles-Long Beach area in 2006, while 4.5 kg (10 lbs) of 

topsmelt with a revenue of $50 were landed according to specific CDFG catch block data from the area. 

Table 4.5-13. Annual landings for jacksmelt and 

topsmelt in the Southern California region based on 

RecFIN data (values are numbers of fish). 

Year Jacksmelt Topsmelt 

2000 124,000 30,000 

2001 128,000 41,000 

2002 90,000 152,000 

2003 115,000 29,000 

2004 173,000 87,000 

2005 140,000 70,000 

2006 181,000 66,000 
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a) recreational catch

Year

1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006

Recreational Catch

(1000s of Fish)

0

5 0

100

150

200

250

300

350

400

Topsm elt

Jacksm elt

Atherinopsidae

b) King Harbor

Year

1974 1978 1982 1986 1990 1994 1998 2002 2006

Mean # fish per transect

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

c) OREHP

Year

1996 1998 2000 2002 2004 2006

Mean catch per station

0

20

40

60

80

100

Santa Monica Bay 

Bight 

Figure 4.5-11. Silverside fishery and population trends: a) Southern California recreational 

landings, b) King Harbor observational data, and c) Ocean Resource Enhancement Hatchery 

Program (OREHP) gill net monitoring data. Error bars are ± 1 S.E. 
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4.5.3.2.3 Sampling Results 

Silverside larvae were the second most abundant taxon at the entrainment station with a mean 

concentration of 778 per 1,000 m3

 (264,172 gal) over all surveys while silverside eggs had an average 

concentration of 14 per 1,000 m3

 (264,172 gal) (Table 4.5-1 and Table 4.5-14). Nearly 70% of the 

silverside larvae in the entrainment samples could not be positively identified to the species level, but of 

those that could be positively identified, jacksmelt was the most abundant followed by California grunion, 

and topsmelt. The larvae occurred sporadically in December−May (Figure 4.5-12), but during periods of 

maximum abundance in late May 2006 silversides were present in the entrainment samples at very dense 

average concentrations approaching of 12,000 per 1,000 m3 (264,172 gal). They were absent or very low 

in abundance in samples from July through November. Monthly source water concentrations followed a 

similar seasonal pattern (Figure 4.5-13) but were much lower (ca. average of 20−80 per 1,000 m3 

[264,172 gal]) during spring than the entrainment concentrations. They tended to be much more abundant 

in nighttime samples than daytime samples (Figure 4.5-14). The length frequency distribution of 

measured silverside larvae showed a unimodal distribution with most larvae in the range of 8−10 mm 

(0.3−0.4 inches) (Figure 4.5-15). The lengths of the larvae from the entrainment station samples ranged 

from 2.5−24.4 mm (0.1−1.0 inches) with a mean of 9.5 mm (0.4 inches) NL. 

Table 4.5-14. Average concentrations and annual entrainment mortality of silverside taxa at HnGS. 

Taxon Common Name 

Avg. Conc. 

(per 1,000 m3)

Total 

Count % of Total

Annual 

Entrainment 

(Actual Flows) 

Annual 

Entrainment

(Design Flows)

Larval Fishes 

Atherinopsidae unid. unid. silversides 539.22 2,308 69.29 684,325,416 763,444,182 

Atherinopsis californiensis jacksmelt 135.77 523 17.45 112,462,389 157,508,063 

Leuresthes tenuis California grunion 71.60 306 9.20 90,595,407 100,018,997 

Atherinops affinis topsmelt 31.60 126 4.06 32,939,893 41,846,831 

778.19 3,263 920,323,105 1,062,818,073 

Fish Eggs 

Atherinopsidae unid. (eggs) silverside eggs 10.49 43 72.90 11,560,935 14,653,846 

Atherinops affinis (eggs) topsmelt eggs 3.90 15 27.10 4,427,698 4,441,190 

 14.39 58 15,988,633 19,095,036
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Concentration (#/1000 cubic meters)

0

4000

8000

12000

16000

20000

24000

28000

32000

36000

40000

Survey

01-Jan

2006

01-Mar

2006 01-May2006

01-Jul

2006 01-Sep2006

01-Nov

2006

01-Jan

2007

Figure 4.5-12. Mean concentration (# / 1,000 m3

 [264,172 gal] − wide bars) and standard 

deviation (narrow bars) of silverside larvae collected at HnGS entrainment Station E3 during 

2006. 

Concentration (#/1000 cubic meters)

0

25

50

75

100

125

150

175

200

225

250

275

300

Survey

01-Jan

2006

01-Mar

2006 01-May2006

01-Jul

2006 01-Sep2006

01-Nov

2006

01-Jan

2007

Figure 4.5-13. Mean concentration (# / 1,000 m3

 [264,172 gal] − wide bars) and standard 

deviation (narrow bars) of silverside larvae collected at HnGS source water stations during 

2006. 
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Date

12/18/06

12/04/06

11/20/06

11/06/06

10/23/06

10/09/06

09/25/06

09/11/06

08/28/06

08/14/06

07/31/06

07/17/06

07/05/06

06/19/06

06/05/06

05/22/06

05/08/06

04/24/06

04/10/06

03/26/06

03/13/06

02/27/06

02/14/06

01/31/06

01/17/06

01/05/06

Nighttime Daytime Mean Concentration/cubic meter

-48.0 -40.0 -32.0 -24.0 -16.0 -8.00 0.00 8.00 16.00 24.00 32.00 40.00 48.00

Figure 4.5-14. Mean concentration (#/1.0 m3

 [264 gal]) of silverside larvae at 

entrainment Station E3 during night (Cycle 3) and day (Cycle 1) sampling. 

N = 1181

Percent

0

10

20

30

40

50

Midpoint for

Length Category (mm)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Figure 4.5-15. Length (mm) frequency distribution for larval silversides collected 

at entrainment stations in Alamitos Bay. 
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4.5.3.2.4 Modeling Results 

The following section presents the results for empirical transport modeling of entrainment effects on 

Atherinopsidae complex (silverside) eggs and larvae. Although there was information on the early life 

history for California grunion, there was very little species-specific information available for the other 

two species, topsmelt and jacksmelt, that were collected in greater abundances during the study. 

Therefore, circulating water system effects were estimated using only the ETM and neither of the 

demographic models. Total annual entrainment at HnGS was estimated at 11,560,935 silverside eggs (all 

species combined) (standard error of 3,111,232) and 920,323,104 silverside larvae (all species combined) 

(standard error of 132,981,650) using measured cooling water flows during 2006 (Table 4.5-2). Using the 

design flows, total annual entrainment increased to 14,653,846 silverside eggs (standard error of 

3,916,405) and 1,062,818,073 silverside larvae (standard error of 143,372,928). 

Empirical Transport Model (ETM)

A larval growth rate of 0.44 mm/day (0.02 inches/day) for silversides was estimated from laboratory 

studies by Middaugh et al. (1990) and used with the difference between the calculated hatch length (6.7 

mm [0.26 inches]) and the length of the 95th percentile of the measurements (14.2 mm [0.56 inches]) to 

estimate that the larvae were exposed to entrainment for a period of approximately 17.1 days. 

The monthly estimates of PE for silversides for 2006 ranged from 0 to 0.31110 based on the actual flows 

and ranged from 0 to 0.42120 using the design flows (Table 4.5-15). The largest estimate was calculated 

for the August survey, but the largest proportion of the source population was present during the April 

survey (fi = 0.322 or 32.2%). The values in the table were used to calculate a PM estimate of 0.4095 with a 

standard error of 0.4014 using the actual CWIS flows during the sampling period and an estimate of 

0.4685 with a standard error of 0.4571 using the design flows. Estimates were calculated using the 

alongshore extrapolated estimate of the total source population. The average alongshore displacement 

over the period of exposure was 22.88 km (14.2 mi). 
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Table 4.5-15. ETM data and results for silverside larvae based on actual and design (maximum) cooling 

water flows sampling volume in the nearshore of 140,698,222 m3

. 

 Actual Flows Design Flows 

Survey 

Date 

PE

Estimate 

PE

Std. Err. 

PE

Estimate 

PE

Std. Err. fi

17-Jan-06 0.05777 0.15792 0.09294 0.25386 0.01928 

14-Feb-06 0.11282 0.51574 0.15576 0.70934 0.12048 

13-Mar-06 0.02327 0.07671 0.02882 0.09455 0.05413 

10-Apr-06 0.01664 0.04369 0.02122 0.05516 0.32212 

8-May-06 0.19478 0.54355 0.21216 0.59176 0.11606 

5-Jun-06 0.01330 0.08372 0.01784 0.11193 0.25485 

5-Jul-06 0 0 0 0 0.03498 

14-Aug-06 0.31110 2.00357 0.42120 2.70245 0.00182 

11-Sep-06 0 0 0 0 0 

9-Oct-06 0.01501 0.05541 0.01756 0.06462 0.01508 

6-Nov-06 0.01525 0.06643 0.02130 0.09281 0.00990 

4-Dec-06 0.02945 0.08058 0.04477 0.12248 0.05131 

PM 0.4095 0.4014 0.4685 0.4571 −

4.5.3.3 White croaker (Genyonemus lineatus) 

White croaker (Genyonemus lineatus) range from 

Magdalena Bay, Baja California, north to 

Vancouver Island, British Columbia (Miller and 

Lea 1972). They are one of eight species of 

croakers (Family Sciaenidae) found off California. 

The other croakers include: white seabass 

(Atractoscion nobilis), black croaker (Cheilotrema 

saturnum), queenfish (Seriphus politus), California 

corbina (Menticirrhus undulatus), spotfin croaker 

(Roncador stearnsii), yellowfin croaker (Umbrina 

roncador), and shortfin corvina (Cynoscion parvipinnis). 

4.5.3.3.1 Life History and Ecology 

The reported depth range of white croaker is from near the surface to depths of 238 m (781 ft) (Love et al. 

2005); however, in southern California, Allen (1982) found white croaker over soft bottoms between 10 

and 130 m (33 and 427 ft), and it was collected most frequently at 10 m (33 ft). It is nocturnally active, 

and is considered a benthic searcher that feeds on a wide variety of benthic invertebrate prey. Adults feed 

on polychaetes and crustaceans, while juveniles feed during the day in midwater on zooplankton (Allen 

1982). 

White croakers are oviparous broadcast spawners. They mature between about 130 and 190 mm (5 and 

7.5 inches) TL, between their first to fourth year; approximately 50% spawn at age one year (Love 1996). 

About one-half of males mature by 140 mm (5.5 inches) TL, and one-half of females by 150 mm (5.9 

Illustration from NOAA
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inches) TL, and all fish are mature by 190 mm (7.5 inches) TL in their third to fourth year (Love et al. 

1984). Off Long Beach, white croaker spawn primarily from November through August, with peak 

spawning from January through March (Love et al. 1984). However, some spawning can occur yearround. Batch fecundities ranged from about 800 eggs in a 155 mm (6.1 inches) female to about 37,200 

eggs in a 260 mm (10.2 inches) female, with spawning taking place as often as every five days (Love et 

al. 1984). In their first and second years, females spawn for three months for a total of about 18 times per 

season. Older fish spawn for about four months and about 24 times per season (Love et al. 1984). Some 

older fish may spawn for seven months. The nearshore waters from Redondo Beach (Santa Monica Bay) 

to Laguna Beach are considered an important spawning center for this species (Love et al. 1984). A 

smaller spawning center occurs off Ventura. 

Newly hatched white croaker larvae are 1−2 mm (0.04−0.08 inches) SL and not well developed (Watson 

1982). Larvae are principally located within 4 km 2.5 miles) from shore, and as they develop tend to 

move shoreward and into the epibenthos (Schlotterbeck and Connally 1982). A larval growth rate was 

derived from data on five species of Sciaenidae (croakers) that were raised in the laboratory by Southwest 

Fisheries Science Center staff (Moser 1996). These were the black croaker (Cheilotrema saturnum), 

corbina (Menticirrhus undulatus), spotfin croaker (Roncador stearnsii), queenfish (Seriphus politus), and 

yellowfin croaker (Umbrina roncador). Hatch lengths and larval length at various numbers of days after 

birth presented in Moser (1996) were used to calculate an average daily growth rate of 0.25 mm/day (0.01 

inches/day) from hatching through the flexion stage for these species of Sciaenidae. Although the species 

did not include white croaker this estimate was used for both white croaker since the species that were 

measured all have larvae that are nearly indistinguishable at small sizes (Moser 1996). Maximum reported 

size is 414 mm (16.3 inches) (Miller and Lea 1972), with a life span of 12−15 years (Frey 1971; Love et 

al. 1984). White croakers grow at a fairly constant rate throughout their lives, though females increase in 

size more rapidly than males from age one (Moore 2001). No mortality estimates are available for any of 

the life stages of this species. 

White croaker are primarily nocturnal benthic feeders, though juveniles may feed in the water column 

during the day (Allen 1982). Important prey items include polychaetes, amphipods, shrimps, and 

chaetognaths (Allen 1982). In Outer Los Angeles Harbor, Ware (1979) found that important prey items 

included polychaetes, benthic crustaceans, free-living nematodes, and zooplankton. Younger individuals 

feed on holoplankonic crustaceans and polychaete larvae. White croaker may move offshore into deeper 

water during winter months (Allen and DeMartini 1983); however, this pattern is apparent only south of 

Redondo Beach (Herbinson et al. 2001). 

4.5.3.3.2 Population Trends and Fishery 

White croaker is an important constituent of commercial and recreational fisheries in California. Prior to 

1980, most commercial catches of white croaker were taken by otter trawl, round haul net (lampara), gill 

net, and hook and line in southern California, but after 1980 most commercial catches were taken 

primarily by trawl, and hook and line (Love et al. 1984). Also, since then, the majority of the commercial 

fishery shifted to central California near Monterey mainly due to the increased demand for this species 

from the developing fishery by Southeast Asian refugees (Moore and Wild 2001). Most of the 

recreational catch still occurs in southern California from piers, breakwaters, and private and sport boats. 
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Before 1980, state-wide white croaker landings averaged 311,000 kg (685,000 lbs) annually, exceeding 

450,000 kg (1 million lbs) for several years (Moore and Wild 2001). High landings in 1952 probably 

occurred due to the collapse of the Pacific sardine fishery. Since 1991, landings averaged 209,000 kg 

(461,000 lbs) and steadily declined to an all-time low of 65,000 kg (142,500 lbs) in 1998. Landings by 

recreational fishermen aboard commercial passenger fishing vessels (CPFVs) averaged about 12,000 fish 

per year from 1990 to 1998, with most of the catch coming from southern California. 

Annual relative abundance of white croaker in impingement samples at southern California power plants 

showed decreases during the strong El Niño events of 1982-83, 1986-87, and 1997-98 as compared with 

non- El Niño years (Herbinson et al. 2001). Additionally, the relative abundance of local populations have 

been influenced by contamination from PCBs and other chlorinated hydrocarbons within bays and has 

lead to early ovulation, lower batch fecundities, and lower fertilization rates when compared to noncontaminated areas (Cross and Hose 1988). 

The earlier 316(b) study of the HnGS in 1978−1979 (IRC 1981) measured mean density values of white 

croaker larvae and found that the greatest densities occurred from mid-December to May, with maximum 

values from mid-February through mid-March. From late fall through early winter, and late spring 

through late fall, very low numbers of larvae were collected or they were not present. Mean density 

values varied from 0 to 2,060 larvae per 1,000 m3

 (264,172 gal) for the day surveys and from 0 to 2,310 

larvae per 1,000 m3

 (264,172 gal) for the night surveys. These densities are over thirty times greater than 

the densities measured during the 2006 sampling period in the present study. A statistical comparison of 

mean density values for the winter-spring period of peak abundance in 1978−1979 indicated that the 

numbers of larvae collected on day and night surveys were not significantly different. 

Annual commercial landings in the Los Angeles region since 2000 have varied from a high of 40,000 kg 

(88,200 lbs) in 2000 to a low of 6,800 kg (15,000 lbs) in 2006, with an average of 19,700 kg (43,400 lbs) 

and average net worth of $29,385 annually (Table 4.5-16). Sport fishery catch estimates of white croaker 

in the southern California region from 2000 to 2006 ranged from 64,000 to 253,000 fish, with an average 

of 189,400 fish caught annually (RecFIN 2007). In the Los Angeles-Long Beach area in 2006, 13,680 kg 

(30,166 lbs) were landed for a revenue of $26,630 according to specific CDFG catch block data from the 

area. 

Table 4.5-16. Annual landings and revenue for white croaker 

in the Los Angeles region based on PacFIN data. 

Year Landed Weight 

(kg) 

Landed Weight 

(lbs) Revenue 

2000 40,025 88,240 $50,688 

2001 23,387 51,560 $36,086 

2002 25,880 57,056 $41,816 

2003 21,772 48,000 $33,837 

2004 8,894 19,608 $14,653 

2005 11,182 24,652 $17,531 

2006 6,809 15,011 $11,079 
Haynes Generating Station CWIS Entrainment and

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4.5.3.3.3 Sampling Results 

White croaker larvae was the fourth most abundant taxon at the entrainment station with a mean 

concentration of 68 per 1,000 m3

 (264,172 gal) over all surveys (Table 4.5-1). They were most abundant 

in spring, absent in summer and fall, and began appearing again in December 2006 (Figure 4.5-16). 

During periods of maximum abundance in March 2006 white croaker was present in the entrainment 

samples at average concentrations of 531 per 1,000 m3

 (264,172 gal). Source water abundances followed 

the same seasonal pattern, but the peak average concentration in March was over four times greater than 

the entrainment samples (Figure 4.5-17). There was no consistent relationship in entrainment abundance 

between daytime and nighttime samples for white croaker larvae (Figure 4.5-18). With a sample size of 

233 measured white croaker larvae, the length frequency plot for larvae showed a strongly unimodal 

curve with most of sampled larvae in the 1.5−2.5 mm (0.06−0.10 inches) size classes and a rapid decline 

in frequency of occurrence at larger size classes to 9.5 mm (0.37 inches) (Figure 4.5-19). The mean length 

of specimens from the entrainment station samples was 2.6 mm NL (0.01 inches) for white croaker. Concentration (#/1000 cubic meters)

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Survey

01-Jan

2006

01-Mar

2006 01-May2006

01-Jul

2006 01-Sep2006

01-Nov

2006

01-Jan

2007

Figure 4.5-16. Mean concentration (# / 1,000 m3

 [264,172 gal] − wide bars) and standard deviation 

(narrow bars) of white croaker larvae collected at HnGS entrainment Station E1 during 2006. 
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Concentration (#/1000 cubic meters)

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

6000

Survey

01-Jan

2006

01-Mar

2006 01-May2006

01-Jul

2006 01-Sep2006

01-Nov

2006

01-Jan

2007

Figure 4.5-17. Mean concentration (# / 1,000 m3

 [264,172 gal] − wide bars) and standard deviation 

(narrow bars) of white croaker larvae collected at HnGS source water stations during 2006. 

Date

12/18/06

12/04/06

11/20/06

11/06/06

10/23/06

10/09/06

09/25/06

09/11/06

08/28/06

08/14/06

07/31/06

07/17/06

07/05/06

06/19/06

06/05/06

05/22/06

05/08/06

04/24/06

04/10/06

03/26/06

03/13/06

02/27/06

02/14/06

01/31/06

01/17/06

01/05/06

Nighttime Daytime Mean Concentration/cubic meter

-0.60 -0.50 -0.40 -0.30 -0.20 -0.10 -0.00 0.10 0.20 0.30 0.40 0.50 0.60

Figure 4.5-18. Mean concentration (#/1.0 m3

 [264 gal]) of white croaker larvae at 

entrainment Station E1 during night (Cycle 3) and day (Cycle 1) sampling. 
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N = 252

Percent

0

10

20

30

40

50

Midpoint for

Length Category (mm)

1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0

Figure 4.5-19. Length (mm) frequency distribution for larval white croaker 

collected at entrainment Station E1. 

4.5.3.3.4 Modeling Results 

The following section presents the results for empirical transport modeling of entrainment effects on 

white croaker larvae. No age-specific estimates of survival for larval and later stages of development were 

available from the literature for white croaker, therefore no estimates of FH or AEL were calculated, but 

enough information was available to estimate FH based on numbers of eggs entrained. Total annual 

entrainment at HnGS was estimated at 57,836,910 white croaker eggs (standard error of 2,103,521) and 

75,425,299 white croaker larvae (standard error of 4,341,458) using measured cooling water flows during 

2006 (Table 4.5-2). Using the design flows, total annual entrainment increased to 86,480,192 eggs 

(standard error of 3,219,014) and 96,188,344 larvae (standard error of 5,330,046). 

Fecundity Hindcasting (FH)

The annual entrainment estimate for white croaker eggs was used to calculate the number of females of 

average age and fecundity that would produce in their lifetime the number of eggs entrained. An estimate 

of egg survival of 0.781 was based on an egg stage duration of 2.17 days and an average age at 

entrainment of 0.97 days. A total lifetime fecundity of 2,294,250 eggs per female was calculated based on 

an average number of eggs per batch of 19,000, an average number of 21 batches per year, and a average 

age in the population of 5.75 years. Life history information presented in Love et al. (1984) is 

summarized in Section 4.5.3.4.1 Life History and Ecology. 
Haynes Generating Station CWIS Entrainment and

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The estimated numbers of reproductive age adult female white croakers whose lifetime reproductive 

output was entrained through the HnGS CWIS for the 2006 period was 32 using the cooling water flows 

and 48 using the design flow volumes (Table 4.5-17). The results of the sensitivity analysis show that the 

greatest uncertainty associated with the estimate is related to the life history parameters in the model and 

not the entrainment estimate. 

Table 4.5-17. Results of FH modeling for white croaker eggs based on entrainment estimates 

calculated using actual and design (maximum) CWIS flows. 

Parameter Estimate Std. Error 

FH

Lower 

Estimate 

FH

Upper 

Estimate 

FH

Range 

Actual Flows 

FH Estimate 32 23 10 103 93 

Total Entrainment 57,836,910 2,103,521 30 34 4 

Design Flows 

FH Estimate 48 34 15 155 140 

Total Entrainment 86,480,192 3,219,014 45 51 6 

The upper and lower estimates are based on a 90% confidence interval of the mean. FH estimates were also 

calculated using the upper and lower confidence estimates from the entrainment estimates. 

Empirical Transport Model (ETM)

A larval growth rate of 0.25 mm/day (0.01 inches/day) derived from data on five species of Sciaenidae 

(croakers) that were raised in the laboratory by Southwest Fisheries Science Center staff (Moser 1996) 

was used with the calculated hatch length (1.6 mm [0.06 inches]) and the length at the 95th percentile (6.2 

mm [0.24 inches]) to estimate that white croaker were exposed to entrainment for a period of 

approximately 18.7 days. The duration of the planktonic egg stage, 2.2 days, was added to the period for 

the larvae to estimate a total exposure duration of 20.8 days. 

The monthly estimates of PE for white croaker for 2006 ranged from 0 to 0.00169 using actual cooling 

water flows and from 0 to 0.00184 using the design flows (Table 4.5-18). Estimates were only collected 

during four of the paired entrainment-source water surveys. White croaker larvae are more common in 

nearshore waters and were collected in all but two of source water surveys with the largest proportion of 

the source population present during the March survey (fi = 0.409 or 40.9%). The values in the table were 

used to calculate a PM estimate of 0.0063 with a standard error of 0.0033 using the actual flows during the 

sampling period and an estimate of 0.0079 with a standard error of 0.004 using the design flows. 

Estimates were calculated using the alongshore extrapolated estimate of the total source population. The 

average alongshore displacement over the period of exposure was 26.19 km (16.3 mi) and the average 

onshore transport was 23.66 km (14.7 mi). 
Haynes Generating Station CWIS Entrainment and

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Table 4.5-18. ETM data and results for white croaker larvae based on actual and 

design (maximum) cooling water flows sampling volume in the nearshore of 

140,698,222 m3

.

 Actual Flows Design Flows 

Survey 

Date 

PE

Estimate 

PE

Std. Err. 

PE

Estimate 

PE

Std. Err. fi

17-Jan-06 0 0 0 0 0.01795 

14-Feb-06 0 0 0 0 0.00068 

13-Mar-06 0.00041 0.00243 0.00051 0.00299 0.40907 

10-Apr-06 0.00011 0.00041 0.00014 0.00052 0.35228 

8-May-06 0.00169 0.01399 0.00184 0.01523 0.03572 

5-Jun-06 0 0 0 0 0.00718 

5-Jul-06 0 0 0 0 0 

14-Aug-06 0 0 0 0 0 

11-Sep-06 0 0 0 0 0.00118 

9-Oct-06 0 0 0 0 0.01249 

6-Nov-06 0 0 0 0 0.03490 

4-Dec-06 0.00029 0.00149 0.00044 0.00226 0.12856 

PM 0.0063 0.0033 0.0079 0.0040 −

4.5.3.4 Combtooth blennies (Hypsoblennius spp.) 

Combtooth blennies comprise a large group of 

subtropical and tropical fishes that inhabit inshore 

rocky habitats throughout much of the world. The 

family Blenniidae, the combtooth blennies, 

contains about 345 species in 53 genera (Nelson 

1994; Moser 1996). They derive their common 

name from the arrangement of closely spaced teeth 

in their jaws. Three species of the genus 

Hypsoblennius occur in the vicinity of HnGS: bay 

blenny (H. gentilis), rockpool blenny (H. gilberti), 

and mussel blenny (H. jenkinsi). These species cooccur throughout much of their range although 

they occupy different habitats. The bay blenny is found along both coasts of Baja California and up the 

California coast to as far north as Monterey Bay, (Miller and Lea 1972; Robertson and Allen 2002). The 

rockpool blenny occurs from Magdalena Bay, Baja California to Point Conception, California (Miller and 

Lea 1972; Stephens et al. 1970). The range of the mussel blenny extends from Morro Bay to Magdalena 

Bay, Baja California and in the northern Gulf of California (Love et al. 2005). 

Gerald Allen 
Haynes Generating Station CWIS Entrainment and

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4.5.3.4.1 Life History and Ecology 

Combtooth blennies are all relatively small fishes that typically grow to a total length of less than 200 mm 

(7.9 inches) (Moser 1996). Most have blunt heads that are topped with some arrangement of cirri (Moyle 

and Cech 1988; Moser 1996). Their bodies are generally elongate and without scales. Dorsal fins are 

often continuous and contain more soft rays than spines (Moyle and Cech 1988). Coloration in the group 

is quite variable, even among individuals of the same species (Stephens et al. 1970). 

The three species of Hypsoblennius found in California waters are morphologically similar as early larvae 

(Moser 1996; Ninos 1984). For this reason most Hypsoblennius identified in the HnGS 316(b) plankton 

collections were identified as Hypsoblennius spp. Certain morphological features (e.g., preopercular 

spines) develop at larger sizes and allow taxonomists to identify some larvae to the species level. 

Blennies inhabit a variety of hard substrates in the intertidal and shallow subtidal zones of tropical and 

subtropical marine habitats throughout the world. They may occur to depths of 24 m (80 ft) but are more 

frequently found in water depths of less than 5 m (15 ft) (Love 1996). Combtooth blennies are common in 

rocky tidepools, reefs, breakwaters, and on pier pilings. They are also frequently observed on encrusted 

buoys and boat hulls. 

The California blennies have different habitat preferences. The mussel blenny is only found subtidally 

and inhabits mussel beds, the empty drill cavities of boring clams, barnacle tests, or in crevices among the 

vermiform snail tubes Serpulorbis spp. (Stephens 1969; Stephens et al. 1970). They generally remain 

within one meter of their chosen refuge (Stephens et al. 1970). The bay blenny is usually found subtidally 

but appears to have more general habitat requirements and may inhabit a variety of intertidal and subtidal 

areas (Stephens et al. 1970). They are commonly found in mussel beds and on encrusted floats, buoys, 

docks, and even fouled boat hulls (Stephens 1969; Stephens et al. 1970). Bay blennies are also typically 

found in bays as the common name implies and are tolerant of estuarine conditions (Stephens et al. 1970). 

They are among the first resident fish species to colonize new or disturbed marine habitats such as new 

breakwaters or mooring floats after the substrate is first colonized by attached invertebrates (Stephens et 

al. 1970; Moyle and Cech 1988). Rockpool blennies are mainly found along shallow rocky shorelines, 

along breakwaters, and in shallow kelp forests along the outer coast. 

Summary of combtooth blenny distribution and life history attributes. 

Range: 

• Bay blenny—Monterey Bay to Gulf of California. 

• Mussel blenny—Morro Bay to Magdalena Bay Baja California and the northern Gulf of California 

• Rockpool blenny—Morro Bay to Magdalena Bay Baja California 

Life History: 

• Size: bay blenny to 14.7 cm (5.8 inches) TL, mussel blenny to 13 cm (5.1 inches), rockpool blenny to 17 cm (6.8 

inches) 

• Age at maturity: all species ≈0.5 years 

• Life span: bay blenny ≈7 years, mussel blenny <6 years, rockpool blenny >8 years 

• Fecundity: bay blenny 500–1,500 eggs, mussel blenny 200–2,000 eggs, rockpool blenny 700-1,700 eggs 

Habitat: 

• Bay blenny—soft bottom in bays and estuaries, associated with submerged aquatic vegetation and mussels on 

mooring buoys; to 24 m (80 ft) 

• Mussel blenny—empty worm tubes and barnacle tests on pilings, mussel beds, crevices in shallow rock reefs; to 21 

m (70 ft) 

• Rockpool blenny—under rocks, in crevices on shallow rock reefs; to 18 m (60 ft) 

Fishery: None 
Haynes Generating Station CWIS Entrainment and

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Female blennies mature quickly and reproduce within the first year, reaching peak reproductive potential 

in the third year (Stephens 1969). The spawning season typically begins in the spring and may extend into 

September (Stephens et al. 1970). Blennies are oviparous and lay demersal eggs that are attached to the 

nest substrate by adhesive pads or filaments (Moser 1996). Males tend the nest and developing eggs. 

Females spawn 3–4 times over a period of several weeks (Stephens et al. 1970). Males guard the nest 

aggressively and will often chase the female away, however, several females may occasionally spawn 

with a single male. The number of eggs a female produces varies proportionately with size (Stephens et 

al. 1970). The mussel blenny spawns approximately 500 eggs in the first reproductive year and up to 

1,500 eggs by the third year (Stephens et al. 1970). Total lifetime fecundity may be up to 7,700 eggs 

(Stephens 1969). 

Larvae are pelagic and average approximately 2.7 mm (0.11 inches) in length two days after hatching 

(Stephens et al. 1970). The planktonic phase for Hypsoblennius spp. larvae may last for 3 months 

(Stephens et al. 1970; Love 1996). Captured larvae released by divers have been observed to use surface 

water movement and near-surface currents to aid swimming (Ninos 1984). After release the swimming 

larvae orient to floating algae, bubbles on the surface, or the bottoms of boats or buoys. The size at 

settlement ranges from 12–14 mm (0.5–0.6 inches). After the first year mussel and bay blenny averaged 

40 mm and 45 mm (1.6 in and 1.8 inches) total length, respectively (Stephens et al. 1970). Bay blenny 

grow to a slightly larger size and live longer than mussel blenny, reaching a size of 15 cm (5.9 inches) and 

living for 6–7 years (Stephens 1969; Stephens et al. 1970; Miller and Lea 1972). Mussel blennies grow to 

13 cm (5.1 inches) and have a life span of 3–6 years (Stephens et al. 1970; Miller and Lea 1972). Male 

and female growth rates are similar. 

Juvenile and adult combtooth blennies are omnivores and eat both algae and a variety of invertebrates, 

including limpets, urchins, and bryozoa (Stephens 1969; Love 1996). They are preyed on by spotted sand 

bass, kelp bass, giant kelpfish, and cabezon (Stephens et al. 1970). 

4.5.3.4.2 Population Trends and Fishery 

Combtooth blennies were common in the eelgrass habitat sampled within Alamitos Bay in a series of 

trawls conducted from 1992-1995. The Bay blenny was more common in the outer part of the bay (Valle 

et al. 1999). Stephens and Pondella (2002) measured annual larval densities at King Harbor in Redondo 

Beach from 1974−1997 and found an overall decline in combtooth blennies from highest densities in the 

mid 1970s to lowest densities in the mid 1990s. Part of the decline was attributed to a period of warmer 

water temperatures throughout the region beginning in the late 1970s, but other localized disturbances to 

nesting habitat from storm damage, breakwater renovation, and channel dredging may have had an effect 

on larval production. 

Long-term data on abundances of combtooth blennies from King Harbor in Redondo Beach were 

collected from surveys of quarry rock boulders from 1984−2006 (Pondella unpubl. data). An average of 

1.62 blennies was collected per boulder each year. At the beginning of the study, they were found in the 

highest densities (9.57 individuals/boulder) and then declined until 1995 when the density recorded was 

0.143/boulder (Figure 4.5-20). Since 1995, the density increased to 1.57 individuals/boulder in 2005. 

Annual average densities of combtooth blennies in King Harbor were correlated with average annual sea 

surface temperatures. This is shown in the decline in densities following major El Niño periods in 1983, 
Haynes Generating Station CWIS Entrainment and

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1987, 1992–1993, and 1997. The period of warm seawater temperatures resulted in declines in combtooth 

blenny larvae in King Harbor in the 1990s (Stephens and Pondella 2002). The correlation between adult 

density and sea surface temperature suggests that the abundance of this short-lived species was dependent 

on successful recruitment in response to optimal oceanographic conditions. 

Year

198419861988199019921994199619982000200220042006

Number of Fish

per Boulder

0

2

4

6

8

10

12

Figure 4.5-20. Abundance of combtooth blennies collected per boulder at King Harbor, Redondo Beach, 

California from 1984−2006 (from Pondella, unpubl. data). 

The earlier 316(b) study of the HnGS in 1978−1979 (IRC 1981) measured mean density values of 

Hypsoblennius species complex larvae that were lowest from mid-January through the end of March and 

relatively high for the remainder of the year. Survey means for the near-field varied from 0 to 20,493 

larvae per 1,000 m3

 (264,172 gal) (average 2,725 per 1,000 m3 [264,172 gal]) and from 1 to 1,800 larvae 

per 1,000 m3

 (264,172 gal) (average 120 per 1,000 m3 [264,172 gal]) for the far-field. These near-field 

densities were approximately four times greater than the 2006 densities measured at the entrainment 

station while the far field station densities were about one-third of the 2006 source water densities. 

There is no fishery for combtooth blennies and therefore no records on adult population trends based on 

landings data. 

4.5.3.4.3 Sampling Results 

Combtooth blenny was the third most abundant taxon at the entrainment station with a mean 

concentration of 652 larvae per 1,000 m3

 (264,172 gal) over all surveys (Table 4.5-1). They were most 

abundant in summer, peaking in June, with a smaller peak in early fall (Figure 4.5-21). They were largely 

absent from winter samples. During periods of maximum abundance in early June 2006 combtooth 

blennies were present in the entrainment samples at average concentrations of 3,000 per 1,000 (264,172 
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gal). Source water abundances followed the same seasonal pattern, but the peak average concentration in 

June was approximately 1,200 per 1,000 m3

 (264,172 gal) (Figure 4.5-22). There were substantially more 

larvae in the nighttime samples than daytime samples (Figure 4.5-23). The length frequency range for 

larvae was small with almost all measured specimens within the 2.0−3.0 mm (0.08−0.12 inches) size 

classes (Figure 4.5-24). The mean length of specimens from the entrainment station samples was 2.38 mm 

(0.09 inches) NL with a size range from 1.7 mm to 11.1 mm (0.07 to 0.44 inches). 
Haynes Generating Station CWIS Entrainment and

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Concentration (#/1000 cubic meters)

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

Survey

01-Jan

2006

01-Mar

2006 01-May2006

01-Jul

2006 01-Sep2006

01-Nov

2006

01-Jan

2007

Figure 4.5-21. Mean concentration (# / 1,000 m3 [264,172 gal] − wide bars) and standard deviation 

(narrow bars) of combtooth blenny larvae collected at HnGS entrainment Station E3 during 2006. Concentration (#/1000 cubic meters)

0

400

800

1200

1600

2000

2400

2800

3200

3600

4000

4400

4800

Survey

01-Jan

2006

01-Mar

2006 01-May2006

01-Jul

2006 01-Sep2006

01-Nov

2006

01-Jan

2007

Figure 4.5-22. Mean concentration (# / 1,000 m3 [264,172 gal] − wide bars) and standard deviation 

(narrow bars) of combtooth blenny larvae collected at HnGS source water stations during 2006. 
Haynes Generating Station CWIS Entrainment and

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Date

12/18/06

12/04/06

11/20/06

11/06/06

10/23/06

10/09/06

09/25/06

09/11/06

08/28/06

08/14/06

07/31/06

07/17/06

07/05/06

06/19/06

06/05/06

05/22/06

05/08/06

04/24/06

04/10/06

03/26/06

03/13/06

02/27/06

02/14/06

01/31/06

01/17/06

01/05/06

Nighttime Daytime Mean Concentration/cubic meter

-12.0 -10.0 -8.00 -6.00 -4.00 -2.00 0.00 2.00 4.00 6.00 8.00 10.00 12.00

Figure 4.5-23. Mean concentration (#/1.0 m3

 [264 gal]) of combtooth blenny larvae at 

entrainment Station E3 during night (Cycle 3) and day (Cycle 1) sampling. 

N = 1638

Percent

0

10

20

30

40

50

60

70

80

90

100

Midpoint for

Length Category (mm)

1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0

Figure 4.5-24. Length (mm) frequency distribution for combtooth blenny larvae collected 

at entrainment stations in Alamitos Bay. 
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4.5.3.4.4 Modeling Results 

The following section presents the results for demographic and empirical transport modeling of CWIS 

effects on combtooth blennies. There was very little species-specific life history information available for 

combtooth blennies. Larval survival was estimated using data from Stephens (1969) and Stevens and 

Moser (1982), and there was enough other information on reproduction to calculate both FH and AEL

estimates. Total annual entrainment of combtooth blenny larvae at HnGS was estimated at 732,022,349 

(standard error of 25,578,857) using actual cooling water flows during 2006 (Table 4.5-2). Using the 

design flows, total annual entrainment increased to 915,313,887 larvae (standard error of 31,887,073). 

Fecundity Hindcasting (FH)

The annual entrainment estimate for combtooth blenny larvae was used to estimate the number of females 

at the age of maturity needed to produce this number of larvae over their lifetimes. No estimates of egg 

survival for combtooth blenny were available, but because egg masses are attached to the substrate and 

guarded by the male (Stephens et al. 1970), egg survival is probably high and was conservatively assumed 

to be 100%. The mean length from a random sample of 200 combtooth blenny larvae was 2.4 mm (0.09 

inches). A larval growth rate of 0.20 mm/day (0.008 inches/day) was derived from data in Stevens and 

Moser (1982). The mean length of 2.4 mm (0.09 inches) from 200 randomly selected lengths from the 

almost 1500 larvae measured and calculated hatch length of 2.1 mm (0.08 inches) were used with the 

growth rate to estimate that the mean age at entrainment was 1.5 days. A daily survival rate of 0.89 

computed from data in Stephens (1969) was used to calculate survival to the average age at entrainment 

as 0.891.5 = 0.84. A quadratic equation was used to estimate adult survival S at age in days x using 

Figure 17 in Stephens (1969): 

8 2 4 Sx x 8.528 10 3.918 10 0.4602 − − =× −×+ (5) 

An adult survivorship table (Table 4.5-19) was constructed using the survival equation based on Stephens 

(1969) and information about eggs from Stephens (1969; Table 3) on H. gentilis, H. gilberti and H. 

jenkinsi to estimate a lifetime fecundity of 2,094 eggs. 

Table 4.5-19. Survivorship table for adult combtooth blenny from data in Stephens (1969) showing 

spawners (Lx) surviving to the age interval and numbers of eggs spawned annually (Mx). 

Age (year) Lx Mx LxMx 

0.5 1,000 367 366,667 

1.5 693 633 438,624 

2.5 443 1,067 472,794 

3.5 252 1,533 386,465 

4.5 119 2,000 237,915 

5.5 44 2,500 109,973 

6.5 27 3,000 81,415 

TLF = 2,094 

The total lifetime fecundity was calculated as the sum of LxMx divided by 

1,000. 
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The estimated numbers of reproductive age adult female combtooth blennies whose lifetime reproductive 

output was entrained through the HnGS CWIS during 2006 was 418,001 based on entrainment estimates 

calculated using actual cooling water flows during the period (Table 4.5-20). Using the design flows, the 

number increases to 522,665 reproductive age adults lost during the 2006 sampling period. The range of 

estimates based on the 90% confidence intervals shows that the variation in the estimate of entrainment 

abundance had much less of an effect on the variation of the FH estimate than the life history parameters 

used in the model. 

Table 4.5-20. Results of FH modeling for combtooth blenny larvae based on entrainment estimates 

calculated using actual and design (maximum) CWIS flows. 

Parameter Estimate Std. Error 

FH

Lower 

Estimate 

FH

Upper 

Estimate 

FH

Range 

Actual Flows 

FH Estimate 418,001 362,294 100,455 1,739,330 1,638,875 

Total Entrainment 732,022,349 25,578,857 393,974 442,028 48,054 

Design Flows 

FH Estimate 522,665 453,007 125,609 2,174,827 2,049,218 

Total Entrainment 915,313,887 31,887,073 492,712 552,617 59,905 

The upper and lower estimates are based on a 90% confidence interval of the mean. FH estimates were also 

calculated using the upper and lower confidence estimates from the entrainment estimates. 

Adult Equivalent Loss (AEL)

The parameters required for formulation of AEL include larval survival from entrainment to settlement 

and survival from settlement to the average age of reproduction for a mature female. Larval survival from 

entrainment through settlement at 50 days was estimated as 0.89(50-1.5) = 0.004 using the same daily 

survival rate used in formulating FH. Juvenile and adult survival was calculated from observed age group 

abundances in Stephens (1969). Daily survival through the average female age of 2.7 years for the three 

species was estimated as 0.99 and was used to calculate a finite survival of 0.79. 

The equivalent number of adult combtooth blennies calculated from the number of larvae entrained 

through the HnGS CWIS for the 2006 sampling period was 1,783,945 based on actual cooling water 

flows and 2,230,628 based on the design flows (Table 4.5-21). The results of the sensitivity analysis show 

that the model estimate was much more sensitive to the error associated with the life history estimates 

than the entrainment estimates used in the model. 
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Table 4.5-21. Results of AEL modeling for combtooth blenny larvae based on entrainment estimates 

calculated using actual and design (maximum) CWIS flows. 

Parameter Estimate Std. Error 

AEL

Lower 

Estimate 

AEL

Upper 

Estimate 

AEL

Range 

Actual Flows 

AEL Estimate 1,783,945 2,185,766 237,711 13,387,911 13,150,200 

Total Entrainment 732,022,349 25,578,857 1,681,402 1,886,487 205,085 

Design Flows 

AEL Estimate 2,230,628 2,733,055 297,234 16,740,036 16,442,802 

Total Entrainment 915,313,887 31,887,073 2,102,796 2,358,459 255,663 

The upper and lower estimates are based on a 90% confidence interval of the mean. AEL estimates were 

also calculated using the upper and lower confidence estimates from the entrainment estimates. 

Empirical Transport Model (ETM)

A sample of 200 lengths from the measured larvae were used to calculate the difference between the 

estimated hatch length and the 95th percentile (3.0 mm [0.12 inches]) of the measurements and a growth 

rate of 0.20 mm/day (0.008 inches/day) to estimate that blennies were exposed to entrainment for a period 

of approximately 4.4 days. 

The monthly estimates of PE for combtooth blennies for the 2006 period varied among surveys and 

ranged from 0.00740 to 0.08288 based on the actual cooling water flows and from 0.01329 to 0.01586 

using the design flow volumes during the period. Combtooth blennies were collected during all of the 

paired entrainment-source water surveys (Table 4.5-22). The largest estimate was calculated for the 

October survey, but the largest proportion of the source population was present during the June survey (fi

= 0.309 or 30.9%). The values in the table were used to calculate a PM estimate of 0.1389 with a standard 

error of 0.0761 using the actual flows in 2006 and an estimate of 0.1770 with a standard error of 0.0965 

using the design flows. Estimates were calculated using the alongshore extrapolated estimate of the total 

source population. The average alongshore displacement over the period of exposure was 9.61 km (6.0 

mi). 
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Table 4.5-22. ETM data and results for combtooth blenny larvae based on actual and design (maximum) 

cooling water flows sampling volume in the nearshore of 140,698,222 m3

. 

 Actual Flows Design Flows 

Survey 

Date 

PE

Estimate 

PE

Std. Err. 

PE

Estimate 

PE

Std. Err. fi

17-Jan-06 0.04470 0.04000 0.07191 0.06429 0.00428 

14-Feb-06 0.05030 0.04437 0.06944 0.06085 0.01889 

13-Mar-06 0.07279 0.02515 0.09014 0.03113 0.01756 

10-Apr-06 0.05091 0.02259 0.06490 0.02859 0.05672 

8-May-06 0.04379 0.03225 0.04770 0.03509 0.14543 

5-Jun-06 0.03961 0.04184 0.05312 0.05583 0.30923 

5-Jul-06 0.00740 0.01774 0.01329 0.03164 0.22852 

14-Aug-06 0.03993 0.01983 0.05407 0.02671 0.11707 

11-Sep-06 0.01467 0.02764 0.01586 0.02985 0.06371 

9-Oct-06 0.08288 0.07396 0.09699 0.08610 0.01882 

6-Nov-06 0.05102 0.02336 0.07129 0.03263 0.00974 

4-Dec-06 0.04841 0.07499 0.07358 0.11397 0.01004 

PM 0.1389 0.0761 0.1770 0.0965 −

4.5.3.5 CIQ Goby complex (Clevelandia, Ilypnus, Quietula) 

Gobies are small, demersal fishes that are found worldwide 

in shallow tropical to temperate marine environments. 

Many members of the family are euryhaline and are able to 

tolerate very low salinities and even freshwater. The family 

Gobiidae contains approximately 1,875 species in 212 

genera (Nelson 1994, Moser 1996). Twenty-one goby 

species from 16 genera occur from the northern California 

border to south of Baja California (Moser 1996). In 

addition to the three species comprising the CIQ complex (arrow goby Clevelandia ios [pictured above], 

cheekspot goby Ilypnus gilberti, and shadow goby Quietula y-cauda), there are at least six other common 

species in southern California: blackeye goby (Rhinogobiops nicholsii), yellowfin goby (Acanthogobius 

flavimanus), longjaw mudsucker (Gillichthys mirabilis), blind goby (Typhlogobius californiensis), bay 

goby (Lepidogobius lepidus), and bluebanded goby (Lythrypnus dalli). 

Myomere counts, gut proportions, and pigmentation characteristics can be used to identify most fish 

larvae to the species level. However, the arrow, cheekspot, and shadow gobies cannot be differentiated 

with complete confidence at most larval stages (Moser 1996). Therefore, larval gobies collected during 

entrainment sampling that could not be identified to the species level were grouped into the ‘CIQ’ goby 

complex (for Clevelandia, Ilypnus and Quietula), or the family level ‘Gobiidae’ if specimens were 

damaged but could still be recognized as gobiids. Some larger larval specimens with well-preserved 

pigmentation patterns could be identified to the species level (W. Watson, Southwest Fisheries Science 

Center, pers. comm.) but those that were speciated in this study were subsequently combined into the CIQ 

complex for analysis. The following section presents an overview of the family and life history 

characteristics of each of the three species. 

G

reg Goldsmith, USFWS 
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4.5.3.5.1 Life History and Ecology 

All three species have overlapping ranges in southern California and occupy similar habitats. Arrow goby 

is the most abundant of the three species in bays and estuaries from Tomales Bay to San Diego Bay, 

including Elkhorn Slough (Cailliet et al. 1977), Anaheim Bay (MacDonald 1975) and Newport Bay 

(Allen 1982). Arrow and cheekspot gobies were reported as abundant from the Cabrillo Beach area in 

outer Los Angeles Harbor based on beach seine sampling (Allen et al. 1983). The life history of the arrow 

goby was reviewed by Emmett et al. (1991) and the comparative ecology and behavior of all three species 

were studied by Brothers (1975) in Mission Bay 

Arrow goby have the most northerly range of the three species, occurring from Vancouver Island, British 

Columbia to southern Baja California (Eschmeyer and Herald 1983). The reported northern range limits 

of both shadow goby Quietula y-cauda and cheekspot goby Ilypnus gilberti are in central California with 

sub-tropical southern ranges that extend well into the Gulf of California (Robertson and Allen 2002). 

Their physiological tolerances reflect their geographic distributions with arrow goby less tolerant of 

warmer temperatures compared to cheekspot goby. When exposed to temperatures of 32.1°C (89.8°F) for 

three days in a laboratory experiment, no arrow gobies survived but 95% of cheekspot goby did survive 

(Brothers 1975). The species inhabits burrows of ghost shrimps (Neotrypaea spp.) and other burrowing 

invertebrates such as the fat innkeeper worm (Urechis caupo), and gobies exposed to warm temperatures 

on mudflats can seek refuge in their burrows where temperatures can be several degrees cooler than 

surface temperatures. 

Summary of CIQ goby distribution and life history attributes. 

Range: Vancouver Island, British Columbia to Gulf of California 

Life History: 

• Size up to 57 mm (2.1 inches) (arrow goby); 64 mm (2.5 inches) (cheekspot goby); 70 mm (2.75 inches) (shadow 

goby) 

• Age at maturity from 0.7−1.5 years 

• Life span ranges from <3 years (arrow goby) to 5 years (shadow goby) 

• Spawns year-round in bays and estuaries; demersal, adhesive eggs with fecundity from 225−1,400 eggs per female 

and multiple spawning of 2−5 times per year 

• Juveniles from 14.0−29.0 mm are < 1 year old 

Habitat: Mud and sand substrates of bays and estuaries; commensally in burrows of shrimps and other invertebrates. 

Fishery: None. 

The reproductive biology is similar among the three species in the CIQ complex. Arrow goby typically 

mature sooner than the other two species, attaining 50% maturity in the population after approximately 8 

months as compared to 16−18 months for cheekspot and shadow gobies (Brothers 1975). Mature females 

for all three of these species are oviparous and produce demersal eggs that are elliptical in shape, 

adhesive, and attached to a nest substratum at one end (Matarese et al. 1989; Moser 1996). Hatched larvae 

are planktonic with the duration of the planktonic stage estimated at 60 days for populations in Mission 

Bay (Brothers 1975). Arrow goby mature more quickly and spawn a greater number of eggs at a younger 

age than either the cheekspot or shadow gobies. As with most fishes fecundity is dependent on age and 

size of the female. Fecundity of gobies in Mission Bay ranged from 225−750 eggs per batch for arrow 

gobies, 225−1,030 eggs for cheekspot, and 340−1,400 for shadow, for a mean value of 615 per batch for 

the CIQ complex. Mature females for the CIQ complex deposit 2−5 batches of eggs per year. 
Haynes Generating Station CWIS Entrainment and

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CIQ complex larvae hatch at a size of 2−3 mm (0.08−0.11 inches) (Moser 1996). Data from Brothers 

(1975) were used to estimate an average growth rate of 0.16 mm/day (0.006 inches) for the approximately 

60-day period from hatching to settlement. Brothers (1975) estimated a 60-day larval mortality of 98.3% 

for arrow goby larvae, 98.6% for cheekspot, and 99.2% for shadow. These values were used to estimate 

average daily survival at 0.93 for the three species. Once the larvae transform at a size of approximately 

10−15 mm (0.4−0.6 inches) SL, depending on the species (Moser 1996), the juveniles settle into the 

benthic environment. For the Mission Bay populations mortality following settlement was 99% per year 

for arrow goby, 66−74% for cheekspot goby, and 62−69% for shadow goby. Few arrow gobies exceeded 

3 years of age based on otolith records, whereas cheekspot and shadow gobies commonly lived for 4 

years (Brothers 1975). Gobies eat a variety of larval, juvenile, and adult crustaceans, mollusks, and 

insects. Many will also eat small fishes, fish eggs, and fish larvae. 

4.5.3.5.2 Population Trends and Fishery 

The earlier 316(b) study of the HnGS in 1978−1979 (IRC 1981) found that gobiid larvae were 

comparatively abundant throughout the year except during a late August survey. The range of mean 

density values was 2 to 20,640 larvae per 1,000 m3

 (264,172 gal) for the day surveys and 7 to 24,890 

larvae per 1,000 m3

 (264,172 gal) for the night surveys. These were substantially greater than the average 

densities of 1,661 larvae per 1,000 m3

 (264,172 gal) measured during the present study in 2006 indicating 

a long-term decline in population abundances over time. 

Gobiidae juveniles and adults, primarily cheekspot goby, were the most common species group collected 

in a series of trawls conducted in Alamitos Bay from 1992-1995, comprising about 55% of the total 

number of species collected (Valle et al. 1999). There are no published multi-year studies of postsettlement goby populations in the Los Angeles-Long Beach Harbor complex area, but in a 5-year study 

of fishes in San Diego Bay from 1994−1999, approximately 75% of the estimated 4.5 million (standing 

stock) gobies were juveniles (Allen et al. 2002). Seasonal peaks in population abundance generally 

occurred in summer and fall and were associated with settlement of young-of-the-year although high 

abundances were also recorded in January and April of some years. Population abundances vary among 

years and may be correlated to the severity of winter rainfall events and urban runoff that may impact the 

water quality of seasonal estuaries in southern California. There is no fishery for these goby species 

because of their small size. 

4.5.3.5.3 Sampling Results 

CIQ complex goby larvae were the most abundant taxon at the entrainment station with a mean 

concentration of 1,668 per 1,000 m3

 (264,172 gal) over all surveys (Table 4.5-1). They were present 

during all surveys but tended to be most abundant in June and August (Figure 4.5-25). During periods of 

maximum abundance in early August 2006 CIQ complex gobies were present in the entrainment samples 

at average concentrations exceeding 4,000 per 1,000 m3 (264,172 gal). Gobies were also present at the 

source water stations during all months of the year with a peak average concentration in August 2006 of 

over 2,000 larvae per 1,000 m3

 (264,172 gal) (Figure 4.5-26). The larvae were significantly more 

abundant in nighttime samples during almost all surveys (Figure 4.5-27). The length-frequency 

distribution for a representative sample of CIQ goby larvae showed that the majority of the sampled 

larvae were recently hatched based on the reported hatch size of 2–3 mm (0.08−0.11 inches) (Moser 
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1996). The size classes of most larvae were in the 2.0−5.0 mm (0.08−0.20 inches) range with a very small 

proportion greater than 6.0 mm (0.24 inches) (Figure 4.5-28). The mean length of 1,741 specimens from 

the entrainment station samples was 3.4 mm (0.13 inches) NL with a size range from 1.8 mm to 21.3 mm 

(0.07 to 0.84 inches). 
Haynes Generating Station CWIS Entrainment and

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Concentration (#/1000 cubic meters)

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

Survey

01-Jan

2006

01-Mar

2006 01-May2006

01-Jul

2006 01-Sep2006

01-Nov

2006

01-Jan

2007

Figure 4.5-25. Mean concentration (# / 1,000 m3 [264,172 gal] − wide bars) and standard 

deviation (narrow bars) of unidentified goby larvae (CIQ gobies) collected at HnGS 

entrainment Station E3 during 2006. 

Concentration (#/1000 cubic meters)

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

Survey

01-Jan

2006

01-Mar

2006 01-May2006

01-Jul

2006 01-Sep2006

01-Nov

2006

01-Jan

2007

Figure 4.5-26. Mean concentration (# / 1,000 m3 [264,172 gal] − wide bars) and standard 

deviation (narrow bars) unidentified goby larvae (CIQ gobies) collected at HnGS source 

water stations during 2006. 
Haynes Generating Station CWIS Entrainment and

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Date

12/18/06

12/04/06

11/20/06

11/06/06

10/23/06

10/09/06

09/25/06

09/11/06

08/28/06

08/14/06

07/31/06

07/17/06

07/05/06

06/19/06

06/05/06

05/22/06

05/08/06

04/24/06

04/10/06

03/26/06

03/13/06

02/27/06

02/14/06

01/31/06

01/17/06

01/05/06

Nighttime Daytime Mean Concentration/cubic meter

-18.0 -15.0 -12.0 -9.00 -6.00 -3.00 0.00 3.00 6.00 9.00 12.00 15.00 18.00

Figure 4.5-27. Mean concentration (#/1.0 m3 [264 gal]) of unidentified goby larvae at 

entrainment Station E3 during night (Cycle 3) and day (Cycle 1) sampling. 

N = 1741

Percent

0

10

20

30

40

50

60

70

80

90

100

Midpoint for

Length Category (mm)

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Figure 4.5-28. Length (mm) frequency distribution for unidentified goby larvae 

collected at entrainment stations in Alamitos Bay. 
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4.5.3.5.4 Modeling Results 

The following section presents the results for demographic and empirical transport modeling of CWIS 

entrainment effects on CIQ goby populations. A comprehensive comparative study of the three goby 

species in the CIQ complex by Brothers (1975) provided the necessary life history information for both 

the FH and AEL demographic models. Total annual entrainment of CIQ goby larvae at HnGS was 

estimated to be 1,828,364,516 (standard error of 71,589,462) using actual measured cooling water flows 

during 2006 (Table 4.5-2). Using the design flows, total annual entrainment increased to 2,334,220,376 

larvae (standard error of 87,312,721). 

Fecundity Hindcasting (FH)

The annual entrainment estimate for CIQ gobies was used to estimate the number of females at the age of 

maturity needed to produce the number of larvae entrained during their lifetime. No estimates of egg 

survival for gobies were available, but because gobies deposit demersal egg masses (Wang 1986) and 

exhibit parental care, usually provided by the adult male, egg survival is generally high and was 

conservatively assumed to be 100%. Estimates of larval survival for the three species from Brothers 

(1975) were used to compute an average daily survival of 0.93. A larval growth rate of 0.16 mm/day 

(0.006 inches/day) was estimated from transformation lengths reported by Brothers (1975) for the three 

species and an estimated transformation age of 60 days. The mean length (3.3 mm [0.16 inches]) and the 

calculated hatch length of 2.4 mm (0.09 inches) from a random sample of 200 of the measured larvae 

were used with the calculated growth rate to estimate that the mean age at entrainment was 5.7 days. 

Survival to the average age at entrainment was then estimated as 0.935.7 = 0.66. A survivorship table was 

constructed using data from Brothers (1975) and was used to estimate a total lifetime fecundity of 1,400 

eggs (Table 4.5-23). The age when at 50% of the female population was reproductive averaged 1.67 

years. 

The estimated numbers of reproductive age adult female gobies whose lifetime reproductive output was 

entrained through the HnGS circulating water system for the 2006 period ranged was 1,966,281 using the 

actual cooling water intake flows during the period and 2,510,294 using the design flows (Table 4.5-24). 

The sensitivity analysis shows that the greatest uncertainty associated with the estimate is related to the 

life history parameters in the model and not the entrainment estimate. 
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Table 4.5-23. Total lifetime fecundity estimates for three goby species 

 based on a life table in Brothers (1975). 

Species Age N 

% 

Mature Fecundity Spawns 

No. 

Eggs 

Eggs per 

Spawner TLF 

Clevelandia ios 0 500 0 

 1 100 81 450 1.5 54,675 547 

 2 4 100 700 2.0 5,600 56 603 

Ilypnus gilberti 0 500 0 

 1 80 10 260 0 0 

 2 51 71 480 1.5 26,071 511 

 3 14 99 720 3.0 29,938 587 

 4 2 100 900 3.0 5,400 106 1,204 

Quietula y-cauda 0 500 0 

 1 74 23 410 0 0 

 2 50 87 620 1.5 4,0455 809 

 3 26 99 840 2.5 54,054 1081 

 4 7 100 1,200 3.0 25,200 504 2,394 

 Mean 1,400 

Table 4.5-24. Results of FH modeling for CIQ goby complex larvae based on entrainment estimates 

calculated using actual and design (maximum) CWIS flows. 

Parameter Estimate Std. Error 

FH

Lower 

Estimate 

FH

Upper 

Estimate 

FH

Range 

Actual Flows 

FH Estimate 1,966,281 1,704,589 472,403 8,184,245 7,711,842 

Total Entrainment 1,828,364,516 71,589,462 1,839,633 2,092,929 253,296 

Design Flows 

FH Estimate 2,510,294 2,176,006 603,180 10,447,263 9,844,083 

Total Entrainment 2,334,220,376 87,312,721 2,355,831 2,664,758 308,927 

The upper and lower estimates are based on a 90% confidence interval of the mean. FH estimates were also 

calculated using the upper and lower confidence estimates from the entrainment estimates. 

Adult Equivalent Loss (AEL)

The parameters required for formulation of AEL estimates include larval survival from entrainment to 

settlement, and survival from settlement to the average age of reproduction for a mature female. Larval 

survival from entrainment through settlement was estimated as 0.9360-5.3 = 0.02 using the same daily 

survival rate used in formulating FH. Brothers (1975) estimated that mortality in the first year following 

settlement was 99% for arrow, 66–74% for cheekspot, and 62–69% for shadow goby. These estimates 

were used to calculate a daily survival of 0.995 that was used to estimate a finite survival of 0.21 for the 

first year following settlement. Daily survival through the average female age of 2.21 years from life table 

data for the three species was estimated as 0.994 and was used to calculate a finite survival over the 

period of 0.21. The equivalent number of adult CIQ gobies calculated from the number of larvae 

entrained through the HnGS circulating water system for the 2006 sampling period was 1,671,266 based 

using actual CWIS flows (Table 4.5-25). Using the design flows, the equivalent number of adult CIQ 

gobies increased to 2,133,657 lost due to entrainment in 2006. 
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Table 4.5-25. Results of AEL modeling for CIQ goby complex larvae based on entrainment estimates 

calculated using actual and design (maximum) CWIS flows. 

Parameter Estimate Std. Error 

AEL

Lower 

Estimate 

AEL

Upper 

Estimate 

AEL

Range 

Actual Flows 

AEL Estimate 1,671,266 1,877,936 263,200 10,612,193 10,348,993 

Total Entrainment 1,828,364,516 71,589,462 1,563,620 1,778,912 215,292 

Design Flows 

AEL Estimate 2,133,657 2,397,380 336,053 13,546,953 13,210,901 

Total Entrainment 2,334,220,376 87,312,721 2,002,368 2,264,945 262,577 

The upper and lower estimates are based on a 90% confidence interval of the mean. AEL estimates were also 

calculated using the upper and lower confidence estimates from the entrainment estimates. 

Empirical Transport Model (ETM)

The larval duration used to calculate the ETM estimates for CIQ gobies was based on the lengths of 

entrained larvae. The difference between the lengths of the 95th percentile (5.9 mm [0.23 inches]) and the 

calculated hatch length of 2.4 mm (0.09 inches) was used with a growth rate of 0.16 mm/day 

(0.006 inches/day) to estimate that CIQ goby larvae were vulnerable to entrainment for a period of 

21.8 days. 

CIQ gobies larvae were present in the entrainment and source water samples throughout the year. The 

monthly estimates of PE for the 2006 period ranged from 0.00737 to 0.03408 using the actual cooling 

water intake flows (Table 4.5-26). Using the design flows, the PE estimates ranged from 0.00940 to 

0.03988 during the sampling period. The largest estimates occurred during the October survey with the 

largest proportion of the source population occurring earlier in the year during the April survey (fi = 

0.208 or 20.8%). The values in the table were used to calculate a PM estimate of 0.2515 with a standard 

error of 0.1672 using the actual flow volumes and an estimate of 0.3174 with a standard error of 0.2098 

using the design flow volumes during the period. Estimates were calculated using the alongshore 

extrapolated estimate of the total source population. The average alongshore displacement over the period 

of exposure was 26.88 km (16.7 mi). 
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Table 4.5-26. ETM data and results for CIQ goby larvae based on actual and design (maximum) cooling 

water flows sampling volume in the nearshore of 140,698,222 m3

. 

 Actual Flows Design Flows 

Survey 

Date 

PE

Estimate 

PE

Std. Err. 

PE

Estimate 

PE

Std. Err. fi

17-Jan-06 0.01090 0.02217 0.01753 0.03567 0.03595 

14-Feb-06 0.01293 0.05291 0.01786 0.07275 0.05762 

13-Mar-06 0.00852 0.01168 0.01055 0.01441 0.09862 

10-Apr-06 0.00737 0.01941 0.00940 0.02443 0.20807 

8-May-06 0.02030 0.08267 0.02211 0.08993 0.06801 

5-Jun-06 0.01892 0.07526 0.02537 0.10030 0.12369 

5-Jul-06 0.00841 0.06306 0.01510 0.11236 0.07901 

14-Aug-06 0.02287 0.06195 0.03097 0.08362 0.14845 

11-Sep-06 0.01774 0.11196 0.01918 0.12094 0.04008 

9-Oct-06 0.03408 0.07485 0.03988 0.08722 0.02234 

6-Nov-06 0.00751 0.01308 0.01049 0.01827 0.04867 

4-Dec-06 0.00754 0.01869 0.01146 0.02840 0.06948 

PM 0.2515 0.1672 0.3174 0.2098 −
Haynes Generating Station 

IM&E Final Report Impingement Study

5-1 

5.0 IMPINGEMENT STUDY

5.1 INTRODUCTION

The purpose of the impingement study is to determine the extent of potential impacts from the operation 

of the cooling water system of the HnGS on fishes and selected invertebrates. Impingement occurs when 

organisms larger than the traveling/slide screen mesh size (9.5 mm or 3/8 inch) become trapped against 

the screens, either because they are too fatigued to swim against the intake flows at the screens or they are 

dead. 

There are two facets to the impingement study: normal operation sampling and marine growth control (or 

heat treatment) sampling. Samples collected during normal operations were used to characterize fish loss 

from the day-to-day operation of the generating station. Normal operations samples were collected over a 

24-hr period to determine the daily loss from operation of the cooling water system. Samples were also 

collected during marine growth control procedures, when waters within the CWIS were heated and fishes 

and invertebrates without the ability to avoid those temperatures succumbed. A total of five marine 

growth control procedures were carried out in 2006 to control biofouling within the CWIS. Combined, 

normal operation and heat treatment samples were used to estimate the annual loss of juvenile and adult 

fishes and shellfishes due to operation of the CWIS. 

5.1.1 Species to be Analyzed 

Several types of organisms are susceptible to impingement by the generating station. All fishes and 

macroinvertebrates were processed (identified, enumerated, and where appropriate, measured) in 

impingement samples. However, assessment of impingement effects was limited to the most abundant 

fish taxa that together comprised 90% of all juveniles and adults collected in impingement samples at the 

generating station. Assessment of impingement effects on invertebrates was limited to those that were 

considered commercially or recreationally important, and were collected in sufficient numbers to warrant 

analysis. 

5.2 HISTORICAL DATA

5.2.1 Summary of Historical Data 

During 1978-1979, a total of 17,637 fish representing 73 taxa and weighing 782 kg (1,725 lbs) was 

impinged during the impingement sampling program at Haynes (IRC 1981). The fish were impinged 

during 191 individual 24-hour impingement samples. No impingement sampling was conducted during 

heat treatments due to the intake configuration and the negligible effects on impingement. Mean daily 

impingement (based on both abundance and biomass) was highest throughout the year at Unit 6. In 

descending order of annual impingement abundance and biomass were Units 6, 5, 1, 2, 4, and 3, 

respectively. However, Unit 3 was off-line most of the year. The mean cooling water flow rate at the 

generating station varied from 1,892,500−3,406,500 m3

 per day (500−900 mgd) during the study. The 

estimated annual impingement based on extrapolations of impingement rates was 30,290 fish weighing 

1,344 kg (2,964 lbs). 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-2 

During the year-long study, abundance and biomass peaked in December 1978, February, June, and 

September 1979. The most abundant species were shiner perch, Pacific pompano (Peprilus simillimus), 

and white seaperch (Phanerodon furcatus), which combined accounted for 65% of the total impingement 

abundance. Shiner perch was the most abundant species overall, accounting for 38% of the impingement 

abundance. 

During the last five years of impingement monitoring at HnGS (2001–2005), a total of 54 marine growth 

control (heat treatment) impingement surveys was performed. During these surveys, a total of 522 fish 

weighing 7.8 kg (17 lbs) was impinged. The most abundant fish species impinged were queenfish, 

deepbody anchovy (Anchoa compressa), and California grunion (Leuresthes tenuis), which combined 

accounted for 79% of impingement abundance. A total of 275 macroinvertebrates weighing 7.0 kg (16 

lbs) was also impinged. The most abundant invertebrates impinged were spiny cup-and-saucer 

(Crucibulum spinosum), tuberculate pear crab, and California two-spot octopus (Octopus bimaculatus 

/bimaculoides), which together comprised 68% of the impingement abundance. 

5.2.2 Relevance to Current Conditions 

The operations and configuration of the HnGS cooling water system have remained largely unchanged 

since all units went into service with the exception of the replacement of the cooling water pumps at Units 

3 & 4 (now Unit 8). Therefore, changes in impingement through time are most likely due to natural 

biological changes and not due to substantial changes in cooling water flow. Flow during the 1978–1979 

study averaged about 2,802,487 m3

 per day (740 mgd), or 73% of design flows (IRC 1981). From 1982 to 

1995, cooling water flow averaged 2,751,695 m3

 per day (727 mgd) (MBC 1997). Flow during the 2006 

study averaged about 2,925,870 m3

 per day (773 mgd), or 80% of current design flow, which is less than 

design flow in the previous study due to the replacement of cooling water pumps at Units 3 & 4. 

The sampling program during the 1978–1979 study was conducted with the approval of the LARWQCB, 

and detailed procedures and methodologies, as well as QA/QC methods, can be found in Appendices G 

(Biological Field Procedures), H (Laboratory Procedures), and I (Statistical and Analytical Procedures) of 

IRC (1981). 

5.3 METHODS

The following sections provide information on the impingement sample collection and data analysis 

methods. The impingement sampling program was designed to provide the necessary information for the 

impingement mortality characterization and development of the calculation baseline. The impingement 

sampling provided current estimates of the taxonomic composition, abundance, biomass, seasonality, and 

diel periodicity of organisms impinged at HnGS. The sampling program also documented the size, sex, 

and physical condition of fish and shellfish impinged. The abundance and biomass of organisms impinged 

was used to calculate impingement rates (e.g., the number of organisms impinged per 106

 m3

[264.172 million gal] cooling water flowing into the CWIS). 

The HnGS consists of six separate screen and pump chambers: one each for Units 1, 2, 5, and 6, and two 

screen and pump chambers for Unit 8 (former chambers for Units 3 and 4). These chambers consist of bar 

racks, traveling or slide screens, and the circulating water pumps. Seawater drawn into each unit first 

passes through the bar racks, followed by the traveling or slide screens, and is then pumped to the 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-3 

condensers. All material that was impinged on the traveling/slide screens during the surveys was 

subsequently rinsed from the screens by a high-pressure wash system into a collection basket. A more 

complete description of the cooling water system is presented in Section 3.2. 

5.3.1 Field Sampling 

Impingement sampling at HnGS was conducted over a 24-hour period one day per week from January 4 

to December 27, 2006. Surveys were performed at all units within HnGS that had circulating water pumps 

operating at the beginning of each survey. Before each sampling effort, the traveling/slide screens were 

rotated and washed clean of all impinged debris and organisms. The sluiceways and collection baskets 

were also cleaned before the start of each sampling effort. The operating status of the circulating water 

pumps was recorded on an hourly basis during the study year. At Units 3–6, each 24-hour sampling 

period was divided into four 6-hour cycles. Initiation of sample collection occurred as follows: Cycle 1 

(approx. 0700-1300 hr), Cycle 2 (approx. 1300-1900 hr), Cycle 3 (approx. 1900-0100 hr), and Cycle 4 

(approx. 0100-0700 hr). During this time, the traveling screens were stationary for a period of 

approximately 5.75 hours and then they were rotated and washed for 15 minutes. At the Units 1 and 2 

slide screens, sampling occurred only once per 24-hr period. At all units, the rinse period allowed the 

entire screen to be rinsed of all material impinged since the last screen wash cycle. The impinged material 

was rinsed from the screens into the collection baskets associated with each set of screens. The collection 

baskets were fitted with plastic liners of 6.4 mm (1/4 inches) mesh. 

On some occasions, the screen wash systems were operated (automatically or manually) prior to end of 

each cycle. The material that was rinsed on these occasions was combined with the material collected at 

the end of each cycle. All debris and organisms rinsed from each unit was processed separately from other 

units. During backflushing operations (described in Section 3.2), the slide/traveling screens were always 

rinsed prior to these procedures so impinged organisms could be processed. 

All fishes and macroinvertebrates collected at the end of each cycle were removed from any other 

impinged debris, identified, enumerated, and weighed. Depending on the number of individuals of a given 

species present in the sample, one of two specific procedures is used, as described below. Each of these 

procedures involves the following measurements and observations: 

• The appropriate linear measurement for individual fish and shellfish was determined and 

recorded. These measurements were recorded to the nearest 1 mm (0.04 inch). The following 

standard linear measurements were used for the animal groups indicated: 

 Fishes - Total body length for sharks and rays and standard lengths for bony fishes. 

 Crabs - Maximum carapace width. 

 Shrimps & Lobsters - Carapace length, measured from the anterior margin of carapace 

between the eyes to the posterior margin of the carapace. 

 Octopus - Maximum “tentacle” spread, measured from the tip of one tentacle to the tip of the 

opposite tentacle. 

 Squid – Dorsal mantle length, measured from the edge of the mantle to the posterior end of 

the body. 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-4 

• The wet body weight of individual fish and shellfish was determined after shaking loose water 

from the body. Total weight of all individuals combined was determined in the same manner. All 

weights were recorded to the nearest 1 g (0.035 ounce). 

• Determination of sex was made for fishes where such determination could be made by external 

morphology (such as surfperches, sharks, and rays). 

• The qualitative body condition of individual fish and shellfish was determined and recorded, 

using codes for decomposition and physical damage. 

• Shellfishes and other macroinvertebrates were identified to species and their presence recorded, 

but they were not measured. 

• The amount and type of debris (e.g., Mytilus shell fragments, wood fragments, etc.) and any 

unusual operating conditions in the screen well system were noted by writing specific comments 

in the “Notes” section of the data sheet. Information on weather was also recorded during each 

collection. 

The following specific procedures were used for processing fishes and shellfishes when the number of 

individuals per species in the sample or subsample was less than 30: 

• For each individual of a given species, the linear measurement, weight, and body condition codes 

was determined and recorded. 

The following specific subsampling procedures were used for fishes and shellfishes when the number of 

individuals per species was greater than 30: 

• The linear measurement, individual weight, and body condition codes for a subsample of 30 

individuals was recorded individually on the data sheet. The individuals selected for measurement 

were selected after spreading out all of the individuals in a sorting container, making sure that 

they were well mixed and not segregated into size groups. Individuals with missing heads or other 

major body parts were not measured. 

• The linear measurements of up to 200 individuals of each taxon were recorded. 

• The total number and total weight of all the remaining individuals combined was determined and 

recorded separately. 

Impingement sampling was also conducted during marine growth control operations. Prior to the start of 

marine growth control surveys, traveling/slide screens were rotated and rinsed. At the end of the marine 

growth control procedure, normal pump operation was resumed and the traveling/slide screens rinsed to 

collect any impinged debris and organisms. Processing of the samples was performed using the same 

procedures for normal operation impingement sampling. 

5.3.2 QA/QC Procedures & Data Validation 

During the NPDES impingement surveys (2000–2005), sampling was done in accordance with 

specifications set forth by the LARWQCB in the NPDES permit for the plant. Specimens of uncertain 

identity were crosschecked against taxonomic voucher collections maintained by MBC, as well as 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-5 

available taxonomic literature. Occasionally, outside experts were consulted to assist in the identification 

of species whose identification was difficult. Scales used to measure biomass (spring and electronic) were 

calibrated every three months. 

A quarterly QA/QC program was implemented for the current study to verify compliance with the field 

sampling procedures. Random cycles were chosen for QA/QC re-sorting to verify that all the collected 

organisms were removed from the impinged material. QC surveys were conducted on the following dates: 

February 8-9, April 12, August 2, and October 10-11. If the count of any of individual taxon made during 

the QA/QC survey varied by more than 5% (or one individual if the total number of individuals was less 

than 20) from the count recorded by the observer, then the next three sampling cycles for that observer 

were checked. The survey procedures were reviewed with all personnel prior to the start of the study and 

all personnel were given printed copies of the procedures. 

The following measures were employed to ensure accuracy of all data entered into computer databases 

and spreadsheets: 

• Upon returning from the field, all field data sheets were checked by the Project Manager for 

completeness and any obvious errors; 

• Data were entered into pre-formatted spreadsheets; 

• After data were entered, copies of the spreadsheets were checked against the field data sheets; 

• In the prior studies, data were submitted annually to the LARWQCB, USEPA Region IX, and the 

CDFG. 

5.3.3 Data Analysis 

A log with hourly observations of each of the circulating water pumps for the entire study period was 

obtained from the LADWP. Impingement rates were calculated using the circulating water flow during 

each of the cycles of each 24-hour survey. The total time for each cycle was multiplied by the known flow 

rate of each of the circulating water pumps in operation during each cycle. In a few surveys, 

traveling/slide screens or the screen wash systems were not operational. In those instances, the cooling 

water flow for the pump associated with those screens was not added to the total, since impinged 

organisms could not be collected from that screen. 

The estimated daily impingement rate was then used to calculate weekly and annual impingement. The 

days between the impingement collections were assigned to a weekly survey period by setting the 

collection day as the median day within the period and designating the days before and after the collection 

date to the closest sampling day to create a weekly survey period for each unit. The total calculated flow 

for each survey period was multiplied by the taxon-specific impingement rates for both abundance and 

biomass. The estimated impingement rate for each survey period was summed to determine the annual 

normal operation impingement estimates for each taxon for each unit. These were added to impingement 

totals from marine growth control procedures to estimate total annual impingement. Annual impingement 

estimates are presented in this report based on both (1) actual flow using flow volumes obtained from 

LADWP, and (2) design flow volume based on the maximum permitted cooling water intake flow at the 

HnGS (3,837,499 m3

 per day, or 1,013.760 mgd). 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-6 

During impingement sampling, all fishes and invertebrates that were retained on the traveling screens 

were rinsed from the screens, flowed along a water-filled sluiceway, and were deposited into the 

impingement collection baskets for processing. Data are presented for all impinged taxa, but a subset of 

species was selected for more detailed analysis. This included fish that comprised the top 90% or more of 

the total abundance in impingement samples, and commercially or recreationally important invertebrates 

that were also impinged in sufficient numbers to warrant analysis. This methodology was approved by the 

LARWQCB, SWRCB, USEPA Region IX, NMFS, and CDFG during our January 30, 2006 meeting. 

To put the impingement results in context, losses were compared (1) known population estimates where 

available, (2) commercial fishing landings for those species harvested commercially, and (3) sport fishing 

landings for those species targeted by recreational anglers. Commercial landing data were derived from 

three potential sources: (1) the Pacific Fishery Information Network (PacFIN), which summarized all 

commercial landings in the Los Angeles Area for the last seven years, (2) California Department of Fish 

and Game landing reports originating from Los Angeles area ports from 2005, and (3) California 

Department of Fish and Game catch block data from Long Beach area catch blocks in 2006. The five 

catch blocks included in this analysis included: 718, 719, 738, 739, and 740. Sport fishing landings were 

derived from the Recreational Fishery Information Network (RecFIN), which included all marine areas in 

southern California. 

5.4 SAMPLING SUMMARY

The following sections summarize results from the 2006 impingement weekly sampling at HnGS. The 

study was designed to provide information necessary to characterize annual, seasonal, and diel variations 

in impingement mortality as required by the §316(b) Phase II regulations. Annual variation was 

characterized by comparison to previous impingement studies. Seasonal variation was characterized by 

analysis of impingement rates during the yearlong study, and diel variation was characterized by analysis 

of daytime (Cycle 1) and nighttime (Cycle 3) impingement collections during 2006. 

Normal operation impingement surveys were performed during all 52 weeks of 2006 at HnGS between 

January 4 and December 28, 2006, consisting of 252 surveys from the six screening facilities. 

Additionally, five marine growth control (heat treatment) surveys were performed in 2006. The number of 

surveys by unit is presented in Table 5.4-1. Mechanical malfunctions precluded sample collection at Unit 

1 twice, at Unit 2 three times, at Unit 8 area formerly Unit 3 twice, at Unit 8 area formerly Unit 4 four 

times, and at Unit 6 twice. The remaining surveys with no samples collected represent periods when the 

circulating water pumps for each respective unit were not operational. 

Table 5.4-1. Number of impingement surveys at HnGS in 2006 by unit. 

Survey Type Unit 1 Unit 2 

Unit 8 

(formerly 

U3) 

Unit 8 

(formerly

U4) 

Unit 5 Unit 6 

Normal Operation 45 42 48 45 35 37 

Marine Growth Control 1 3 - - 1 - 

 46 45 48 45 36 37 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-7 

5.5 RESULTS

5.5.1 Impingement Results 

A total of 6,580 fishes representing at least 53 distinct taxa and weighing 72.5 kg (159.9 lbs) was 

collected during impingement sampling in 2006 (Table 5.5-1 and Appendix E). Of this total, only 33 

individuals from at least seven taxa weighing 0.3 kg (0.8 lbs) were impinged during the five marine 

growth control procedures. The estimated annual total impingement based on cooling water flow volumes 

in 2006 was 53,442 individuals weighing 529.8 kg (1,168 lbs) (Table 5.5-2). The estimated annual 

impingement based on design flow was 56,613 fishes weighing 556.5 kg (1,227.0 lbs). Queenfish was the 

most abundant species, with 3,708 individuals collected (56% of the total) and an estimated annual 

impingement based on actual cooling water flow of 30,946 individuals weighing 19.5 kg (42.9 lbs). The 

annual impingement of queenfish represented 58% of the total impingement abundance but only 4% of 

the biomass. The next most abundant species in impingement samples were topsmelt, northern anchovy, 

bay pipefish, unidentified pipefishes, shiner perch, and specklefin midshipman (Porichthys myriaster). 

Combined these taxa accounted for 91.2% of the sampled impingement abundance. A list of the species 

collected during the study are presented in Appendix F. 

A total of 2,682 macroinvertebrates representing at least 49 distinct taxa and weighing 37.0 kg (81.6 lbs) 

was collected during impingement sampling in 2006 (Table 5.5-3 and Appendix E). Of this total, only 12 

individuals from seven taxa weighing 0.2 kg (0.4 lbs) were impinged during the five marine growth 

control procedures. The estimated annual total impingement based on actual cooling water flow volumes 

in 2006 was 20,346 individuals weighing 268.8 kg (592.7 lbs) (Table 5.5-4). The estimated annual 

impingement based on design flow was 21,773 macroinvertebrates weighing 293.8 kg (647.9 lbs). Red 

jellyfish was the most abundant species, with 621 individuals collected (23% of the total) and an 

estimated annual impingement of 4,562 individuals weighing 16.6 kg (37 lbs). The next most abundant 

species in impingement samples were the nudibranch Hermissenda crassicornis, tuberculate pear crab, 

and yellow shore crab. Combined these species accounted for 59.1% of the sampled impingement 

abundance. 
Haynes Generating Station 

IM&E Final Report Impingement Study

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Table 5.5-1. HnGS fish impingement sampled abundance and biomass during 2006. 

 

Sampled 

Normal 

Operation 

Sampled 

Heat 

Treatment 

Total Sampled Percent of 

Total 

Taxon Common Name No. Wt. 

(kg) No. Wt. (kg) No. Wt. (kg) No. Wt. (kg) 

Seriphus politus queenfish 3,699 2.463 9 0.010 3,708 2.473 56.35 3.41

Atherinops affinis topsmelt 780 3.976 8 0.044 788 4.020 11.98 5.54

Engraulis mordax northern anchovy 422 0.731 10 0.018 432 0.749 6.57 1.03

Syngnathus leptorhynchus bay pipefish 408 0.495 1 0.001 409 0.496 6.22 0.68

Engraulis mordax larvae northern anchovy larvae 314 0.03 - - 314 0.030 4.77 0.04

Syngnathus spp. pipefish, unid. 184 0.25 2 0.002 186 0.252 2.83 0.35

Cymatogaster aggregate shiner perch 83 1.779 - - 83 1.779 1.26 2.45

Porichthys myriaster specklefin midshipman 78 21.261 - - 78 21.261 1.19 29.32

Genyonemus lineatus white croaker 72 0.668 - - 72 0.668 1.09 0.92

Leptocottus armatus Pacific staghorn sculpin 67 1.272 - - 67 1.272 1.02 1.75

Heterostichus rostratus giant kelpfish 59 0.644 - - 59 0.644 0.90 0.89

Anchoa delicatissima slough anchovy 59 0.152 - - 59 0.152 0.90 0.21

Urobatis halleri round stingray 53 13.732 - - 53 13.732 0.81 18.94

Leuresthes tenuis California grunion 51 0.077 - - 51 0.077 0.78 0.11

Pleuronichthys guttulatus diamond turbot 18 1.345 - - 18 1.345 0.27 1.85

Pleuronichthys ritteri spotted turbot 16 0.168 - - 16 0.168 0.24 0.23

Gibbonsia elegans spotted kelpfish 15 0.144 1 0.020 16 0.164 0.24 0.23

Myliobatis californica bat ray 13 3.44 1 0.248 14 3.688 0.21 5.09

Sardinops sagax Pacific sardine 12 0.082 - - 12 0.082 0.18 0.11

Atherinopsis californiensis jacksmelt 11 1.635 - - 11 1.635 0.17 2.25

Gibbonsia metzi striped kelpfish 10 0.11 - - 10 0.110 0.15 0.15

Gillichthys mirabilis longjaw mudsucker 10 0.014 - - 10 0.014 0.15 0.02

Xenistius californiensis salema 10 0.013 - - 10 0.013 0.15 0.02

Phanerodon furcatus white seaperch 9 0.083 - - 9 0.083 0.14 0.11

Atherinopsidae silverside, unid. 9 0.055 - - 9 0.055 0.14 0.08

Embiotoca jacksoni black perch 8 0.246 - - 8 0.246 0.12 0.34

Fundulus parvipinnis California killifish 8 0.018 - - 8 0.018 0.12 0.02

Gobiesox rhessodon California clingfish 7 0.009 - - 7 0.009 0.11 0.01

Porichthys notatus plainfin midshipman 6 0.565 - - 6 0.565 0.09 0.78

Symphurus atricaudus California tonguefish 5 0.072 - - 5 0.072 0.08 0.10

Hyperprosopon argenteum walleye surfperch 5 0.023 - - 5 0.023 0.08 0.03

Cheilotrema saturnum black croaker 5 0.009 - - 5 0.009 0.08 0.01

Sphyraena argentea Pacific barracuda 4 0.012 - - 4 0.012 0.06 0.02

Hypsoblennius gilberti rockpool blenny 3 0.041 - - 3 0.041 0.05 0.06

Anisotremus davidsonii sargo 3 0.007 - - 3 0.007 0.05 0.01

Syngnathus californiensis kelp pipefish 3 0.003 - - 3 0.003 0.05 0.00

Porichthys spp. midshipman, unid. 2 0.955 - - 2 0.955 0.03 1.32

Umbrina roncador yellowfin croaker 2 0.671 - - 2 0.671 0.03 0.93

Anchoa compressa deepbody anchovy 1 0.008 1 0.002 2 0.010 0.03 0.01

Odontopyxis trispinosa pygmy poacher 2 0.006 - - 2 0.006 0.03 0.01

Anchoa spp. deepbody/slough anchovy 2 0.005 - - 2 0.005 0.03 0.01

Torpedo californica Pacific electric ray 1 13.700 - - 1 13.700 0.02 18.89

Rhinobatos productus shovelnose guitarfish 1 0.700 - - 1 0.700 0.02 0.97

(table continued) 
Haynes Generating Station 

IM&E Final Report Impingement Study

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Table 5.5-1 (continued). HnGS fish impingement sampled abundance and biomass during 2006.

 Normal 

Operation 

Heat 

Treatment 

Combined 

Impingement 

Percent of 

Total 

Taxon Common Name No. Wt. 

(kg) No. Wt. (kg) No. Wt. (kg) No. Wt. (kg) 

Raja inornata California skate 1 0.133 - - 1 0.133 0.02 0.18

Ophidion scrippsae basketweave cusk-eel 1 0.107 - - 1 0.107 0.02 0.15

Trachurus symmetricus jack mackerel 1 0.067 - - 1 0.067 0.02 0.09

Mustelus californicus grey smoothhound 1 0.047 - - 1 0.047 0.02 0.06

Pleuronichthys verticalis hornyhead turbot 1 0.045 - - 1 0.045 0.02 0.06

Peprilus simillimus Pacific pompano 1 0.037 - - 1 0.037 0.02 0.05

Ophichthus zophochir yellow snake eel 1 0.03 - - 1 0.030 0.02 0.04

Citharichthys stigmaeus speckled sanddab 1 0.01 - - 1 0.010 0.02 0.01

Paraclinus integripinnis reef finspot 1 0.005 - - 1 0.005 0.02 0.01

Hypsoblennius jenkinsi mussel blenny 1 0.004 - - 1 0.004 0.02 0.01

Paralichthys californicus California halibut 1 0.003 - - 1 0.003 0.02 0.00

Synodus lucioceps California lizardfish 1 0.003 - - 1 0.003 0.02 0.00

Cottidae sculpin, unid. 1 0.003 - - 1 0.003 0.02 0.00

Sebastes miniatus vermilion rockfish 1 0.002 - - 1 0.002 0.02 0.00

Ilypnus gilberti cheekspot goby 1 0.001 - - 1 0.001 0.02 0.00

Gobiesocidae clingfish, unid. 1 0.001 - - 1 0.001 0.02 0.00

Clinidae kelp blenny, unid. 1 0.001 - - 1 0.001 0.02 0.00

Totals 6,547 72.168 33 0.345 6,580 72.513 100.00 100.00

No. of Taxa 60 8 60 
Haynes Generating Station 

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Table 5.5-2. Annual HnGS fish impingement estimates based on both actual and design 

(maximum) cooling water flows. 

 Estimated Annual Impingement 

Total Sampled Actual Flow Design Flow 

Taxon Common Name No. Wt. 

(kg) No. Wt. (kg) No. Wt. (kg) 

Seriphus politus queenfish 3,708 2.473 30,946 19.465 32,389 20.358

Atherinops affinis topsmelt 788 4.020 6,315 29.436 6,747 32.398

Engraulis mordax northern anchovy 432 0.749 3,443 6.033 3,923 7.084

Syngnathus leptorhynchus bay pipefish 409 0.496 3,157 3.846 3,286 3.957

Engraulis mordax larvae northern anchovy larvae 314 0.030 2,351 0.212 2,590 0.222

Syngnathus spp. pipefish, unid. 186 0.252 1,373 1.828 1,490 1.986

Genyonemus lineatus white croaker 72 0.668 861 5.783 877 7.478

Porichthys myriaster specklefin midshipman 78 21.261 620 157.234 632 161.765

Cymatogaster aggregata shiner perch 83 1.779 582 12.025 628 13.332

Heterostichus rostratus giant kelpfish 59 0.644 462 5.000 517 5.763

Anchoa delicatissima slough anchovy 59 0.152 482 1.137 503 1.195

Leptocottus armatus Pacific staghorn sculpin 67 1.272 475 9.108 489 9.505

Urobatis halleri round stingray 53 13.732 381 98.052 427 105.662

Leuresthes tenuis California grunion 51 0.077 382 0.580 396 0.599

Pleuronichthys guttulatus diamond turbot 18 1.345 126 9.626 128 9.639

Pleuronichthys ritteri spotted turbot 16 0.168 115 1.137 119 1.209

Gibbonsia elegans spotted kelpfish 16 0.164 100 0.975 110 1.097

Sardinops sagax Pacific sardine 12 0.082 90 0.606 98 0.656

Myliobatis californica bat ray 14 3.688 92 24.635 92 24.655

Gillichthys mirabilis longjaw mudsucker 10 0.014 73 0.105 90 0.130

Atherinopsis californiensis jacksmelt 11 1.635 77 11.533 89 13.804

Xenistius californiensis salema 10 0.013 87 0.108 87 0.110

Atherinopsidae silverside, unid. 9 0.055 64 0.375 75 0.391

Embiotoca jacksoni black perch 8 0.246 71 2.017 74 2.046

Phanerodon furcatus white seaperch 9 0.083 63 0.589 71 0.624

Gibbonsia metzi striped kelpfish 10 0.110 66 0.728 67 0.738

Fundulus parvipinnis California killifish 8 0.018 56 0.125 64 0.146

Gobiesox rhessodon California clingfish 7 0.009 54 0.069 55 0.071

Porichthys notatus plainfin midshipman 6 0.565 44 3.722 50 4.170

Symphurus atricaudus California tonguefish 5 0.072 42 0.607 43 0.627

Sphyraena argentea Pacific barracuda 4 0.012 37 0.114 40 0.117

Hyperprosopon argenteum walleye surfperch 5 0.023 40 0.175 40 0.176

Cheilotrema saturnum black croaker 5 0.009 35 0.063 35 0.063

Porichthys spp. midshipman, unid. 2 0.955 24 11.294 27 13.012

Syngnathus californiensis kelp pipefish 3 0.003 23 0.023 25 0.025

Hypsoblennius gilberti rockpool blenny 3 0.041 25 0.318 25 0.318

Anisotremus davidsonii sargo 3 0.007 22 0.050 24 0.052

Anchoa spp. deepbody/slough anchovy 2 0.005 17 0.043 17 0.043

Odontopyxis trispinosa pygmy poacher 2 0.006 14 0.041 14 0.043

Umbrina roncador yellowfin croaker 2 0.671 14 4.750 14 4.750

Raja inornata California skate 1 0.133 8 1.111 9 1.239

Peprilus simillimus Pacific pompano 1 0.037 7 0.271 9 0.328

Cottidae sculpin, unid. 1 0.003 7 0.022 9 0.026

(table continued) 
Haynes Generating Station 

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Table 5.5-2 (continued). HnGS fish impingement sampled abundance and biomass during 2006.

 Estimated Annual Impingement 

Total Sampled Actual Flow Design Flow 

Taxon Common Name No. Wt. 

(kg) No. Wt. (kg) No. Wt. (kg) 

Anchoa compressa deepbody anchovy 2 0.010 8 0.057 8 0.057

Ophidion scrippsae basketweave cusk-eel 1 0.107 7 0.743 7 0.752

Paralichthys californicus California halibut 1 0.003 7 0.022 7 0.022

Ilypnus gilberti cheekspot goby 1 0.001 7 0.007 7 0.007

Gobiesocidae clingfish, unid. 1 0.001 7 0.007 7 0.007

Mustelus californicus gray smoothhound 1 0.047 7 0.336 7 0.336

Pleuronichthys verticalis hornyhead turbot 1 0.045 7 0.321 7 0.322

Trachurus symmetricus jack mackerel 1 0.067 7 0.477 7 0.477

Clinidae kelp blenny, unid. 1 0.001 7 0.007 7 0.007

Hypsoblennius jenkinsi mussel blenny 1 0.004 7 0.028 7 0.028

Torpedo californica Pacific electric ray 1 13.700 7 97.594 7 97.594

Paraclinus integripinnis reef finspot 1 0.005 7 0.033 7 0.033

Rhinobatos productus shovelnose guitarfish 1 0.700 7 4.910 7 4.917

Citharichthys stigmaeus speckled sanddab 1 0.010 7 0.070 7 0.071

Sebastes miniatus vermilion rockfish 1 0.002 7 0.014 7 0.014

Ophichthus zophochir yellow snake eel 1 0.030 7 0.211 7 0.212

Synodus lucioceps California lizardfish 1 0.003 6 0.019 6 0.019

Totals 6,580 72.513 53,442 529.827 56,613 556.484
Haynes Generating Station 

IM&E Final Report Impingement Study

5-12 

Table 5.5-3. HnGS macroinvertebrate impingement sampled abundance and biomass during 2006. 

 

Sampled 

Normal 

Operation 

Sampled 

Heat 

Treatment 

Total Sampled Percent of 

Total 

Taxon Common Name No. Wt. 

(kg) No. Wt. (kg) No. Wt. (kg) No. Wt. (kg) 

Polyorchis penicillatus red jellyfish 621 2.274 - - 621 2.274 23.15 6.15

Hermissenda crassicornis hermissenda 392 0.175 1 0.001 393 0.176 14.65 0.48

Pyromaia tuberculata tuberculate pear crab 295 0.225 - - 295 0.225 11.00 0.61

Hemigrapsus oregonensis yellow shore crab 275 0.248 1 0.001 276 0.249 10.29 0.67

Navanax inermis California aglaja 234 4.565 2 0.074 236 4.639 8.80 12.54

Aurelia aurita moon jelly 158 8.006 - - 158 8.006 5.89 21.64

Portunus xantusii Xantus swimming crab 90 1.244 - - 90 1.244 3.36 3.36

Leptopecten spp. scallop, unid. 83 0.145 4 0.002 87 0.147 3.24 0.40

Heptacarpus palpator intertidal coastal shrimp 67 0.043 1 0.001 68 0.044 2.54 0.12

Phyllaplysia taylori zebra leafslug 54 0.047 - - 54 0.047 2.01 0.13

O. bimaculatus/bimaculoides Calif. two-spot octopus 44 6.728 2 0.075 46 6.803 1.72 18.39

Crangon nigromaculata blackspotted bay shrimp 38 0.041 - - 38 0.041 1.42 0.11

Bulla gouldiana California bubble 34 0.501 - - 34 0.501 1.27 1.35

Polycera atra orange-spike polycera 33 0.019 - - 33 0.019 1.23 0.05

Flabellina trilineata threeline aeolis 30 0.014 - - 30 0.014 1.12 0.04

Diaulula sandiegensis ring-spotted dorid 29 0.270 - - 29 0.270 1.08 0.73

Aplysia californica California seahare 28 11.511 - - 28 11.511 1.04 31.11

Flabellina iodinea Spanish shawl 26 0.069 - - 26 0.069 0.97 0.19

Neotrypaea gigas giant ghost shrimp 15 0.070 - - 15 0.070 0.56 0.19

Pachygrapsus crassipes striped shore crab 10 0.188 1 0.007 11 0.195 0.41 0.53

Loligo opalescens California market squid 11 0.193 - - 11 0.193 0.41 0.52

Protothaca staminea Pacific littleneck 10 0.031 - - 10 0.031 0.37 0.08

Cnidaria sea jelly, unid. 8 0.046 - - 8 0.046 0.30 0.12

Polycera hedgpethi Hedpeth's polycera 8 0.008 - - 8 0.008 0.30 0.02

Hemigrapsus nudus purple shore crab 8 0.008 - - 8 0.008 0.30 0.02

Pugettia producta northern kelp crab 7 0.035 - - 7 0.035 0.26 0.09

Dendronotus frondosus leafy dendronotid 7 0.005 - - 7 0.005 0.26 0.01

Haminoea virescens green glassy bubble 6 0.014 - - 6 0.014 0.22 0.04

Gastropoda gastropod, unid. 4 0.006 - - 4 0.006 0.15 0.02

Haminoea spp. glassy bubble, unid. 4 0.004 - - 4 0.004 0.15 0.01

Dendronotus subramosus stubby dendronotus 4 0.003 - - 4 0.003 0.15 0.01

Hemigrapsus spp. shore crab, unid. 3 0.004 - - 3 0.004 0.11 0.01

Nudibranchia nudibranch, unid. 3 0.003 - - 3 0.003 0.11 0.01

Octopus spp. octopus, unid. 3 0.002 - - 3 0.002 0.11 0.01

Dendronotus iris giant-frond-aeolis 2 0.010 - - 2 0.010 0.07 0.03

Kelletia kelletii Kellet's whelk 2 0.006 - - 2 0.006 0.07 0.02

Chrysaora colorata purple-striped jellyfish 2 0.005 - - 2 0.005 0.07 0.01

Ceratostoma nuttalli Nuttall's thornmouth 2 0.004 - - 2 0.004 0.07 0.01

Triopha maculata spotted triopha 2 0.002 - - 2 0.002 0.07 0.01

Crepidula onyx onyx slippersnail 2 0.001 - - 2 0.001 0.07 0.00

Molpadia intermedia unnamed sea cucumber 1 0.024 - - 1 0.024 0.04 0.06

Strongylocentrotus purpuratus purple sea urchin 1 0.021 - - 1 0.021 0.04 0.06

Philine auriformis New Zealand snail 1 0.002 - - 1 0.002 0.04 0.01

(table continued) 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-13 

Table 5.5-3 (continued). HnGS macroinvertebrate impingement sampled abundance 

and biomass during 2006.

 Normal 

Operation 

Heat 

Treatment 

Combined 

Impingement 

Percent of 

Total 

Taxon Common Name No. Wt. 

(kg) No. Wt. (kg) No. Wt. (kg) No. Wt. (kg) 

Polyorchis haplus jellyfish 1 0.002 - - 1 0.002 0.04 0.01

Pisaster spp. sea star, unid. 1 0.002 - - 1 0.002 0.04 0.01

Cancer anthonyi yellow crab 1 0.002 - - 1 0.002 0.04 0.01

Neotrypaea californiensis bay ghost shrimp 1 0.001 - - 1 0.001 0.04 0.00

Acanthodoris rhodoceras black-tipped spiny doris 1 0.001 - - 1 0.001 0.04 0.00

Heptacarpus paludicola California coastal shrimp 1 0.001 - - 1 0.001 0.04 0.00

Berthella californica California sidegill slug 1 0.001 - - 1 0.001 0.04 0.00

Argopecten ventricosus Pacific calico scallop 1 0.001 - - 1 0.001 0.04 0.00

Lysmata californica red rock shrimp 1 0.001 - - 1 0.001 0.04 0.00

Aplysia spp. seahare, unid. 1 0.001 - - 1 0.001 0.04 0.00

Aeolidia papillosa shag-rug aeolis 1 0.001 - - 1 0.001 0.04 0.00

Dirona picta spotted dirona 1 0.001 - - 1 0.001 0.04 0.00

Dendrodoris fulva yellow prorostome 1 0.001 - - 1 0.001 0.04 0.00

Totals 2,670 36.836 12 0.161 2,682 36.997 100.00 100.00

No. of Taxa 56 7 56 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-14 

Table 5.5-4. Annual HnGS macroinvertebrate impingement estimates based on both actual 

and design (maximum) cooling water flows. 

 Estimated Annual Impingement 

Total Sampled Actual Flow Design Flow 

Taxon Common Name No. Wt. 

(kg) No. Wt. (kg) No. Wt. (kg) 

Polyorchis penicillatus red jellyfish 621 2.274 4,562 16.553 4,850 17.427

Hermissenda crassicornis hermissenda 393 0.176 2,900 1.313 3,020 1.391

Pyromaia tuberculata tuberculate pear crab 295 0.225 2,560 1.903 2,794 2.073

Hemigrapsus oregonensis yellow shore crab 276 0.249 2,272 1.988 2,482 2.184

Navanax inermis California aglaja 236 4.639 1,697 32.292 1,878 35.915

Aurelia aurita moon jelly 158 8.006 1,102 57.375 1,165 59.599

Portunus xantusii Xantus swimming crab 90 1.244 691 9.263 712 9.556

Leptopecten spp. scallop, unid. 87 0.147 624 1.057 683 1.118

Heptacarpus palpator intertidal coastal shrimp 68 0.044 506 0.333 536 0.355

Phyllaplysia taylori zebra leafslug 54 0.047 446 0.387 484 0.425

O. bimaculatus/bimaculoides Calif. two-spot octopus 46 6.803 337 54.777 353 57.877

Crangon nigromaculata blackspotted bay shrimp 38 0.041 290 0.308 310 0.326

Diaulula sandiegensis ring-spotted dorid 29 0.270 275 2.493 308 2.800

Bulla gouldiana California bubble 34 0.501 237 3.515 241 3.585

Polycera atra orange-spike polycera 33 0.019 227 0.133 233 0.137

Flabellina trilineata threeline aeolis 30 0.014 212 0.102 222 0.106

Aplysia californica California seahare 28 11.511 195 79.414 221 93.128

Flabellina iodinea Spanish shawl 26 0.069 184 0.490 185 0.491

Neotrypaea gigas giant ghost shrimp 15 0.070 107 0.495 111 0.522

Hemigrapsus nudus purple shore crab 8 0.008 83 0.063 88 0.064

Cnidaria sea jelly, unid. 8 0.046 69 0.371 80 0.434

Loligo opalescens California market squid 11 0.193 78 1.366 78 1.368

Pachygrapsus crassipes striped shore crab 11 0.195 71 1.309 74 1.352

Protothaca staminea Pacific littleneck 10 0.031 68 0.211 70 0.219

Polycera hedgpethi Hedpeth's polycera 8 0.008 59 0.059 63 0.063

Pugettia producta northern kelp crab 7 0.035 55 0.291 58 0.311

Dendronotus frondosus leafy dendronotid 7 0.005 48 0.035 50 0.036

Haminoea virescens green glassy bubble 6 0.014 44 0.105 48 0.111

Gastropoda gastropod, unid. 4 0.006 27 0.041 29 0.044

Haminoea spp. glassy bubble, unid. 4 0.004 28 0.028 28 0.028

Dendronotus subramosus stubby dendronotus 4 0.003 27 0.021 27 0.021

Hemigrapsus spp. shore crab, unid. 3 0.004 24 0.033 25 0.034

Nudibranchia nudibranch, unid. 3 0.003 21 0.021 21 0.021

Octopus spp. octopus, unid. 3 0.002 20 0.014 21 0.014

Triopha maculata spotted triopha 2 0.002 14 0.014 17 0.017

Kelletia kelletii Kellet's whelk 2 0.006 14 0.043 16 0.049

Chrysaora colorata purple-striped jellyfish 2 0.005 14 0.033 15 0.039

Dendronotus iris giant-frond-aeolis 2 0.010 14 0.066 14 0.068

Ceratostoma nuttalli Nuttall's thornmouth 2 0.004 14 0.028 14 0.028

Dendrodoris fulva yellow prorostome 1 0.001 6 0.006 14 0.014

Crepidula onyx onyx slippersnail 2 0.001 13 0.007 13 0.007

Argopecten ventricosus Pacific calico scallop 1 0.001 9 0.009 12 0.012

Pisaster spp. sea star, unid. 1 0.002 7 0.014 12 0.024

(table continued) 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-15 

Table 5.5-4 (continued). HnGS macroinvertebrate impingement sampled abundance 

and biomass during 2006.

 Estimated Annual Impingement 

Total Sampled Actual Flow Design Flow 

Taxon Common Name No. Wt. 

(kg) No. Wt. (kg) No. Wt. (kg) 

Heptacarpus paludicola California coastal shrimp 1 0.001 10 0.010 10 0.010

Philine auriformis New Zealand snail 1 0.002 8 0.015 9 0.018

Acanthodoris rhodoceras black-tipped spiny doris 1 0.001 8 0.008 8 0.008

Polyorchis haplus jellyfish 1 0.002 7 0.014 8 0.017

Neotrypaea californiensis bay ghost shrimp 1 0.001 7 0.007 7 0.007

Berthella californica California sidegill slug 1 0.001 6 0.006 7 0.007

Strongylocentrotus purpuratus purple sea urchin 1 0.021 7 0.149 7 0.150

Lysmata californica red rock shrimp 1 0.001 7 0.007 7 0.007

Aplysia spp. seahare unid 1 0.001 7 0.007 7 0.007

Aeolidia papillosa shag-rug aeolis 1 0.001 7 0.007 7 0.007

Dirona picta spotted dirona 1 0.001 7 0.007 7 0.007

Molpadia intermedia unnamed sea cucumber 1 0.024 7 0.173 7 0.174

Cancer anthonyi yellow crab 1 0.002 7 0.014 7 0.014

Totals 2,682 36.997 20,346 268.803 21,773 293.826

Fish impingement was generally greatest at Units 1 and 6, which accounted for 77% of abundance and 

84% of biomass (Table 5.5-5). Abundance was greater at Unit 1 than at Unit 6, but biomass was highest at 

Unit 6. Invertebrate abundance was highest at Units 1 & 6, though biomass was highest at Units 5 & 6. 

Table 5.5-5. Percent of total impingement by unit at HnGS in 2006. 

Type Unit 1 Unit 2 

Unit 8 

(formerly

U3) 

Unit 8 

(formerly

U4) 

Unit 5 Unit 6 

Fish abundance 42.5 14.0 0.9 1.1 7.0 34.6 

Fish biomass 10.6 2.9 1.9 2.2 9.2 73.2 

Invertebrate abundance 27.3 10.4 5.4 4.5 19.3 33.1 

Invertebrate biomass 19.8 11.9 6.2 2.8 29.6 29.7 

Impingement abundance in 2006 was highest in summer (July–September), which corresponded with an 

increase in queenfish impingement (Figures 5.5-1 and 5.5-2). Impingement biomass was greatest in 

spring (April–May). Invertebrate impingement abundance was greatest from January through June, with 

highest abundance recorded in spring (April–May) (Figures 5.5-3 and 5.5-4). Invertebrate biomass was 

much more variable throughout the year, with peaks in late-March, late-April, and early-August. 

In general, fish impingement abundance was greatest during nighttime, though biomass was greater 

during the day (Figures 5.5-5 and 5.5-6). However, there were exceptions to this, including daytime 

surveys in April with higher abundance, and nighttime surveys during several months with greater 

biomass. The same general trend was observed in invertebrate impingement (Figures 5.5-7 and 5.5-8). 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-16 

Survey Date

Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06 Jan-07 

Impingement Density (#/1,000,000 cubic meters)

0

20

40

60

80

100

120

140

160

Figure 5.5-1. Mean concentration (# / 1,000,000 m3

 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of fishes in HnGS normal operation impingement samples during 2006. 

Survey Date

Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06 Jan-07 

Impingement Density (kg/1,000,000 cubic meters) 0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

Figure 5.5-2. Mean biomass (kg / 1,000,000 m3

 [264.172 million gal] – wide bars) and standard error 

(narrow bars) of fishes in HnGS normal operation impingement samples during 2006. 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-17 

Survey Date

Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06 Jan-07 

Impingement Density (#/1,000,000 cubic meters)

0

20

40

60

80

100

Figure 5.5-3. Mean concentration (# / 1,000,000 m3

 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of invertebrates in HnGS normal operation impingement samples during 2006. 

Survey Date

Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06 Jan-07 

Impingement Density (kg/1,000,000 cubic meters) 0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

Figure 5.5-4. Mean biomass (kg / 1,000,000 m3

 [264.172 million gal] – wide bars) and standard error 

(narrow bars) of invertebrates in HnGS normal operation impingement samples during 2006. 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-18 

Impingement Density (#/1,000,000 cubic meters)

-2400 -2000 -1600 -1200 -800 -400 0 400 800 1200 1600 2000 2400

Survey Date

1/1/2006 

2/1/2006 

3/1/2006 

4/1/2006 

5/1/2006 

6/1/2006 

7/1/2006 

8/1/2006 

9/1/2006 

10/1/2006 

11/1/2006 

12/1/2006 

1/1/2007 

Nighttime Daytime

Note: Negative nighttime values are a plotting artifact 

Figure 5.5-5. Mean concentration (# / 1,000,000 m3 [264.172 million gal]) of fishes in normal operation 

impingement samples during night (Cycle 3) and day (Cycle 1) sampling. 

Impingement Density (kg/1,000,000 cubic meters)

-45 -40 -35 -30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45

Survey Date

1/1/2006 

2/1/2006 

3/1/2006 

4/1/2006 

5/1/2006 

6/1/2006 

7/1/2006 

8/1/2006 

9/1/2006 

10/1/2006 

11/1/2006 

12/1/2006 

1/1/2007 

Nighttime Daytime

Note: Negative nighttime values are a plotting artifact 

Figure 5.5-6. Mean biomass (kg / 1,000,000 m3 [264.172 million gal]) of fishes in normal operation 

impingement samples during night (Cycle 3) and day (Cycle 1) sampling. 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-19 

Impingement Density (#/1,000,000 cubic meters)

-600 -500 -400 -300 -200 -100 0 100 200 300 400 500 600

Survey Date

1/1/2006 

2/1/2006 

3/1/2006 

4/1/2006 

5/1/2006 

6/1/2006 

7/1/2006 

8/1/2006 

9/1/2006 

10/1/2006 

11/1/2006 

12/1/2006 

1/1/2007 

Nighttime Daytime

Note: Negative nighttime values are a plotting artifact 

Figure 5.5-7. Mean concentration (# / 1,000,000 m3 [264.172 million gal]) of invertebrates in normal 

operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling. 

Impingement Density (kg/1,000,000 cubic meters)

-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10

Survey Date

1/1/2006 

2/1/2006 

3/1/2006 

4/1/2006 

5/1/2006 

6/1/2006 

7/1/2006 

8/1/2006 

9/1/2006 

10/1/2006 

11/1/2006 

12/1/2006 

1/1/2007 

Nighttime Daytime

Note: Negative nighttime values are a plotting artifact 

Figure 5.5-8. Mean biomass (kg / 1,000,000 m3 [264.172 million gal]) of invertebrates in normal 

operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling. 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-20 

5.5.2 Fish Impingement Results by Species 

Six fish taxa were impinged in sufficient numbers to warrant further analysis. These taxa were: queenfish 

(55% of sampled abundance), topsmelt (12%), northern anchovy (juvenile and adults – 7%, larval 

individuals – 6%), pipefishes (bay pipefish – 6%, and unidentified pipefish – 3%), shiner perch (1%), and 

specklefin midshipman (1%). Combined, these taxa comprised 91% of the fishes in impingement 

samples. The juvenile/adult northern anchovy and impinged larval anchovies were combined for analysis, 

as were all impinged pipefishes. Four additional fish species were analyzed in further detail due to their 

inclusion in the Coastal Pelagic Fishery Management Plan (Pacific sardine [12 individuals collected] and 

jack mackerel [one individual]) and the Pacific Groundfish Fishery Management Plan (California skate 

and vermilion rockfish [one individual each]). 

5.5.2.1 Queenfish (Seriphus politus) 

Queenfish (Seriphus politus Ayres 1860) range 

from west of Uncle Sam Bank, Baja California, 

north to Yaquina Bay, Oregon (Miller and Lea 

1972). Queenfish are common in southern 

California, but rare north of Monterey. They are 

one of eight species of croaker or ‘drums’ (Family 

Sciaenidae) found off California. The other 

croakers include: white seabass (Atractoscion 

nobilis), black croaker (Cheilotrema saturnum), 

white croaker, California corbina (Menticirrhus 

undulatus), spotfin croaker (Roncador stearnsii), 

yellowfin croaker (Umbrina roncador), and shortfin corvina (Cynoscion parvipinnis). Shortfin corvina 

was common off the California coast as far north as San Pedro in the late 1800s (Jordan and Evermann 

1896), but has not been common off the California coast since the 1930s (Miller and Lea 1972). It 

presently occurs as far north as Carlsbad, CA (Tenera 2007). 

5.5.2.1.1 Life History and Ecology 

The reported depth range of queenfish is from the surface to depths of about 37 m (120 ft) (Miller and Lea 

1972); however, in southern California, Allen (1982) found queenfish over soft bottoms between 10 and 

70 m (33 and 230 ft), with highest abundance occurring at 10 m. During the day, queenfish hover in 

dense, somewhat inactive schools close to shore, but disperse to feed in midwater after sunset (Hobson 

and Chess 1976). It is active throughout the night, and feeds several meters off the seafloor in small 

schools or as lone individuals. 

Queenfish is a summer spawner. Goldberg (1976) found queenfish to enter spawning condition in April 

and spawn into August, while DeMartini and Fountain (1981) recorded spawning in queenfish between 

March and August. Spawning is asynchronous among females, but there are monthly peaks in intensity 

during the waxing (first quarter) of the moon (DeMartini and Fountain 1981). They also stated that 

mature queenfish spawn every 7.4 days on average, regardless of size. Duration of the spawning season is 

a function of female body size, ranging from three months (April–June) in recruit spawners to six months 

(March–August) in repeat spawners (>13.5 cm standard length [SL], or 5.3 inches). Based on the 

spawning frequency and number of months of spawning, these two groups of spawners can produce about 

12 and 24 batches of eggs during their respective spawning seasons (DeMartini and Fountain 1981). 

Milton Love
Haynes Generating Station 

IM&E Final Report Impingement Study

5-21 

Goldberg (1976) found no sexually mature females less than 14.8 cm SL (5.8 inches) in Santa Monica 

Bay. This differs from the findings of DeMartini and Fountain (1981) off San Onofre. They found 

females sexually mature at 10.0–10.5 cm SL (3.9–4.1 inches) at slightly greater than age-1. Batch 

fecundities in queenfish off San Onofre ranged from 5,000 eggs in a 10.5 cm (4.1 inches) female to about 

90,000 eggs in a 25 cm (9.8 inches) fish. The average-sized female in that study (14 cm [5.5 inches], 42 g 

[0.09 lbs]) had a potential batch fecundity of 12,000–13,000 eggs. Parker and DeMartini (1989) estimated 

the average batch fecundity to be 12,700 for queenfish collected over a five-year period. Based on a 

female spawning frequency of 7.4 days, a 10.5 cm (4.1 inches) female that spawns for three months 

(April–June) can produce about 60,000 eggs/year, while a 25 cm (9.8 inches) female that spawns for six 

months (March through August) can produce nearly 2.3 million eggs/year (DeMartini and Fountain 

1981). 

Queenfish mature at 10.5 to 12.7 cm (4.1 to 5.0 inches) (DeMartini and Fountain 1981, Love 1996), 

during their first spring or second summer. Maximum reported size is 30.5 cm (12 inches) (Miller and 

Lea 1972). Immature individuals grow at a rate of about 2.5 mm/day (0.1 inches/day), while early adults 

grow about 1.8 mm/day (0.07 inches/day) (Murdoch et al. 1989b). Mortality estimates are unavailable for 

this species. Queenfish feed mainly on crustaceans, including amphipods, copepods, and mysids, along 

with polychaetes and fishes (Hobson and Chess 1976; Hobson et al. 1981; Feder et al. 1974). 

5.5.2.1.2 Population Trends and Fishery 

Queenfish was the most abundant sciaenid impinged at five generating stations in southern California 

from 1977 to 1998, and accounted for over 60% of the total fishes impinged (Herbinson et al. 2001). 

Annual abundance fluctuated from year to year, with notable declines during the strong El Niño events of 

1982-83, 1986-87, and 1997-98. However, abundance remained relatively high throughout the over 20-

year study period. There were no reported commercial landings of queenfish in the commercial CDFG or 

PacFIN records (CDFG 2006, 2007; PacFIN 2007). Annual recreational landings (RecFIN 2007) have 

averaged about 270,000 fish per year since 2000, with a notable increase in 2002 (Table 5.5-6). During 

1978-79, a total of 513 queenfish were impinged at HnGS, equivalent to about 1.5 queenfish per day (IRC 

1981). Abundance was highest in November and December. From 2001 through 2005, annual queenfish 

impingement ranged from 0.1 to 13.6 queenfish per survey, and averaged about 5 fish per survey (MBC 

2006). 

Table 5.5-6. Annual recreational landings for queenfish 

in the Los Angeles region based on RecFIN data. 

Year Total Landed 

2000 83,000

2001 66,000 

2002 942,000 

2003 235,000 

2004 213,000 

2005 201,000 

2006 147,000 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-22 

5.5.2.1.3 Sampling Results 

Queenfish was the most abundant fish species impinged (based on actual cooling water flows) with an 

estimated 30,946 individuals, or 58% of the annual total, weighing 19.47 kg (42.92 lbs) (Table 5.5-2). 

Normal operation impingement represented all but nine impinged individuals, which were recorded 

during marine growth control procedures. Specifically, all queenfish impinged during marine growth 

control were recorded during August 21, 2006 at Unit 5 (9 individuals) and an additional three individuals 

during the August 22, 2006, procedure at Unit 2. Highest normal operation impingement was recorded at 

Unit 1, which accounted for 44% of the total abundance, followed by Unit 6 (35%), Unit 2 (16%), Unit 5 

(4%) and Unit 8 (formerly Unit 3) and Unit 8 (formerly Unit 4) (less than 1% each). Biomass was highest 

at Unit 1 with 49% of the total, followed by Unit 6 (32%), Unit 2 (12%), Unit 5 (6%), Unit 8 (formerly 

Unit 4) (1%), and Unit 8 (formerly Unit 3) (less than 1%). 

Queenfish impingement density peaked in late-July through early-August (Figure 5.5-9). Few queenfish 

were impinged during the first six months of the year, and after August occurrences were low and 

variable. Biomass followed a pattern similar to abundance, although the sporadic instances during the first 

six months were more pronounced compared to abundance, principally due to the impingement of larger 

individuals (Figure 5.5-10). 

Substantial diel periodicity was observed in the impingement of queenfish (Figures 5.5-11 and 5.5-12). 

Insufficient numbers of fish were impinged during the first six months to warrant any comparisons, but 

the second half of the year saw substantial increases during both diel periods. Daylight impingement 

reached a peak of nearly 100 individuals per 1,000,000 m3

 (264.172 million gal), which was less than the 

four highest peaks observed during nighttime surveys, one of which exceeded 1,750 individuals per 

1,000,000 m3 (264.172 million gal). A similar pattern was observed in the diel comparisons of biomass. 

Very little biomass was impinged during the night over the first six months of the year, after which 

impingement increased markedly. Over the second half of the year, daylight impinged biomass never 

exceeded 0.1 kg (0.22 lbs) per 1,000,000 m3

 (264.172 million gal), while five surveys during the night 

recorded impingement rates greater than 0.1 kg (0.22 lbs) per 1,000,000 m3

 (264.172 million gal), with 

density during one survey at nearly 0.7 kg (1.5 lbs) per 1,000,000 m3

 (264.172 million gal). 

Length frequency analysis of 2,359 measured individuals indicates a mean standard length of 35 mm 

(1.4 inches) (Figure 5.5-13). The distribution of length classes confirmed this with greater than 50% of all 

individuals represented in the 30 mm (1.2 inches) size class, followed by the 40 mm and 50 mm (1.6 in 

and 2.0 inches) size classes. The majority of these measured individuals were young of the year, with 

queenfish reaching age one at approximately 100 mm SL (3.9 inches) (MBC and VRG unpubl. data1

). Of 

the 1,538 individuals that were evaluated for condition factor, 99% were dead and the remaining 1% was 

mutilated, with no individuals collected alive. 

 

1

 MBC Applied Environmental Sciences and Vantuna Research Group. Analysis of the age and growth of juvenile 

and adult queenfish (Seriphus politus) from southern California. Project in progress. 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-23 

Survey Date

Impingement Density (#/1,000,000 cubic meters)

Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06 Jan-07 

0

50

100

150

200

250

300

350

Figure 5.5-9. Mean concentration (# / 1,000,000 m3

 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of queenfish in HnGS normal operation impingement samples during 2006. 

Survey Date

Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06 Jan-07 

Impingement Density (kg/1,000,000 cubic meters)

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

Figure 5.5-10. Mean biomass (kg / 1,000,000 m3

 [264.172 million gal] – wide bars) and standard error 

(narrow bars) of queenfish in HnGS normal operation impingement samples during 2006. 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-24 

Impingement Density (#/1,000,000 cubic meters)

-1800-1750-650-600-550-500-450-400-350-300-250-200-150-100 -50 0 50 100

Survey Date

1/1/2006 

2/1/2006 

3/1/2006 

4/1/2006 

5/1/2006 

6/1/2006 

7/1/2006 

8/1/2006 

9/1/2006 

10/1/2006 

11/1/2006 

12/1/2006 

1/1/2007 

Nighttime Daytime

Note: Negative nighttime values are a plotting artifact 

Figure 5.5-11. Mean concentration (# / 1,000,000 m3 [264.172 million gal]) of queenfish in normal 

operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling. 

Impingement Density (kg/1,000,000 cubic meters)

-0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

Survey Date

1/1/2006 

2/1/2006 

3/1/2006 

4/1/2006 

5/1/2006 

6/1/2006 

7/1/2006 

8/1/2006 

9/1/2006 

10/1/2006 

11/1/2006 

12/1/2006 

1/1/2007 

Nighttime Daytime

Note: Negative nighttime values are a plotting artifact 

Figure 5.5-12. Mean biomass (kg / 1,000,000 m3 [264.172 million gal]) of queenfish in normal 

operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling. 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-25 

Length category (mm SL)

10 20 30 40 50 60 70 80 90 100 110 120 130

Percent

0

10

20

30

40

50

60

N = 2,359

Mean = 35

Figure 5.5-13. Length (mm) frequency distribution for queenfish collected in 

impingement samples. 

5.5.2.1.4 Modeling Results 

Queenfish life history parameters are presented in Table 5.5-7. Unpublished research by MBC and the 

Occidental College Vantuna Research Group (VRG) provided all of the applicable adult life history 

parameters that indicate the age at 50% maturity is 1.76642 years. Age class frequency analysis indicated 

the majority of individuals collected were less than 0.6 years old (Figure 5.5-14). A total of 13,971 adult 

equivalents were taken over the year based on actual cooling water flow. Of these four were directly 

attributable to heat treatments while an estimated 13,967 were impinged during normal operation of the 

cooling water system calculated using actual flow rates. Recalculating the actual flow estimates to plant 

design (maximum) flow equated to a total loss of 14,595 adult equivalents. 

Table 5.5-7 Queenfish life history parameters used in equivalent adult modeling. 

 von Bertalanffy growth parameters* 

Total Adult 

Mortality (Z) 

Surviva

l (S) Linf k t0 

Age at 50% 

Maturity 

Length at 

50% 

Maturity 

0.3512 0.703843 176 mm TL 0.302 -1.234 1.76642 105 mm TL 

*Data from MBC and VRG unpublished data 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-26 

Age Class (year)

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.72.3 2.4 2.5

Percent

0

5

10

15

20

25

N = 2539

Figure 5.5-14. Age class distribution of queenfish collected in HnGS impingement samples. 

5.5.2.2 Topsmelt (Atherinops affinis) 

Information on the life history, ecology, population 

trends, and fishery of silversides (Atherinopsidae) is 

summarized in Section 4.4.3.2. The section includes 

information on topsmelt, which was one of three 

species of silversides entrained as larvae at HnGS. 

There were no commercial landings of topsmelt in the 

Los Angeles area in 2005 (CDFG 2006); however, 

there were 4.5 kg (10 lbs) landed in Long Beach area 

catch blocks during 2006 at an estimated value of $50 

(CDFG 2007). During 1978-79, a total of 821 

topsmelt were impinged at HnGS, equivalent to about 

2.5 topsmelt per day (IRC 1981). Abundance was 

highest in May and June. From 2001 through 2005, annual topsmelt impingement ranged from 0 to 0.5 

topsmelt per survey, and averaged about 0.2 fish per survey (MBC 2006). 

5.5.2.2.1 Sampling Results 

Topsmelt was the second most abundant fish species impinged (based on actual cooling water flows) with 

an estimated 6,315 individuals, or 12% of the annual total, weighing 29.44 kg (64.91 lbs) (Table 5.5-2). 

Normal operation impingement represented all but eight impinged individuals, which were recorded 

during marine growth control procedures. Three topsmelt weighing 0.02 kg (0.05 lbs) were impinged 

Jamie Siler 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-27 

during the marine growth control procedure at Unit 5 on August 21, 2006, and five more topsmelt 

weighing 0.02 kg (0.04 lbs) were impinged during the procedure at Unit 2 on November 14, 2006. 

Highest normal operation impingement was recorded at Unit 6, which accounted for 39% of the total 

abundance, followed by Unit 1 (38%), Unit 5 (11% each), Unit 2 (10%), Unit 8 (formerly Unit 3) (2%), 

and Unit 8 (formerly Unit 4) (1%). Biomass was highest at Unit 6 with 62% of the total, followed by Unit 

5 (12%), Unit 1 (11%), Unit 2 (8%), Unit 8 (formerly Unit 4) (5%), and Unit 8 (formerly Unit 3) (1%). 

Topsmelt were impinged throughout the year, though peak impingement densities were recorded from 

July through September (Figure 5.5-15). However, highest impingement biomass occurred in April 

(Figure 5.5-16). Substantial diel periodicity was observed in the impingement of topsmelt (Figures 5.5-17 

and 5.5-18). During the first six months of 2006, impingement was relatively low, and daytime 

impingement was generally higher than nighttime impingement. However, during the second half of 

2006, there were alternating periodicities, but highest biomass was recorded during nighttime surveys. 

Length frequency analysis of 572 measured individuals indicated a mean standard length of 75 mm 

(3 inches). There was a wide distribution of size classes, although most of the measured fishes were 

between the 50 mm and 80 mm (2.0 and 3.1 inches) size classes (Figure 5.5-19). Considering topsmelt 

mature at two years and 100 mm (3.9 inches) or greater (Love 1996), most of the individuals impinged 

were in their first year. Of the 506 individuals that were evaluated for condition factor, 98% were dead 

and the remaining 2% were mutilated, with no individuals collected alive. 

Survey Date

Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06 Jan-07 

Impingement Density (#/1,000,000 cubic meters)

0

20

40

60

80

Figure 5.5-15. Mean concentration (# / 1,000,000 m3

 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of topsmelt in HnGS normal operation impingement samples during 2006. 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-28 

Survey Date

Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06 Jan-07 

Impingement Density (kg/1,000,000 cubic meters) 0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

0.20

Figure 5.5-16. Mean biomass (kg / 1,000,000 m3

 [264.172 million gal] – wide bars) and standard error 

(narrow bars) of topsmelt in HnGS normal operation impingement samples during 2006. 

Impingement Density (#/1,000,000 cubic meters)

-160 -120 -80 -40 0 40 80 120 160

Survey Date

1/1/2006 

2/1/2006 

3/1/2006 

4/1/2006 

5/1/2006 

6/1/2006 

7/1/2006 

8/1/2006 

9/1/2006 

10/1/2006 

11/1/2006 

12/1/2006 

1/1/2007 

Nighttime Daytime

Note: Negative nighttime values are a plotting artifact 

Figure 5.5-17. Mean concentration (# / 1,000,000 m3 [264.172 million gal]) of topsmelt in normal 

operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-29 

Impingement Density (kg/1,000,000 cubic meters)

-1.50 -1.25 -1.00 -0.75 -0.50 -0.25 0.00 0.25 0.50 0.75 1.00 1.25 1.50

Survey Date

1/1/2006 

2/1/2006 

3/1/2006 

4/1/2006 

5/1/2006 

6/1/2006 

7/1/2006 

8/1/2006 

9/1/2006 

10/1/2006 

11/1/2006 

12/1/2006 

1/1/2007 

Nighttime Daytime

Note: Negative nighttime values are a plotting artifact 

Figure 5.5-18. Mean biomass (kg / 1,000,000 m3 [264.172 million gal]) of topsmelt in normal operation 

impingement samples during night (Cycle 3) and day (Cycle 1) sampling. 

Length category (mm SL)

20 40 60 80 100 120 140 160 180 200 220

Percent

0

5

10

15

20

25

30

N = 572

Mean = 75

Figure 5.5-19. Length (mm) frequency distribution for topsmelt collected in impingement samples. 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-30 

5.5.2.3 Northern anchovy (Engraulis mordax) 

Information on the life history, ecology, population 

trends, and fishery of northern anchovy is 

summarized in Section 4.4.3.1. 

Commercial landings of northern anchovy in the 

Los Angeles area in 2005 totaled 1,992,064 kg 

(4,392,501 lbs) at a value of $191,664 (CDFG 

2006). Commercial landings in Long Beach area 

catch blocks in 2006 totaled 392,446 kg 

(865,180 lbs) at an estimated value of 40,732 

(CDFG 2007). During 1978-79, a total of 99 

northern anchovy were impinged at HnGS, 

equivalent to about 0.3 anchovies per day (IRC 

1981). Abundance was highest in May and June. From 2001 through 2005, annual impingement of 

northern anchovy ranged from 0.1 to 1.3 fish per survey, and averaged about 0.4 fish per survey (MBC 

2006). 

5.5.2.3.1 Sampling Results 

Northern anchovy was the third most abundant fish species impinged (based on actual cooling water 

flows) with an estimated 3,443 individuals, or 6% of the annual total, weighing 6.0 kg (13.3 lbs) (Table 

5.5-2). Normal operation impingement represented all but 10 impinged individuals, which were recorded 

during marine growth control procedures. Additionally, an estimated 2,351 anchovy larvae were 

estimated to be impinged in 2006. Four northern anchovy weighing 0.01 kg (0.02 lbs) were impinged 

during a marine growth control on August 21, 2006 procedure at Unit 5, and an additional six individuals 

weighing 0.01 kg (0.02 lbs) were impinged during the August 22, 2006 procedure at Unit 2. Highest 

normal operation impingement was recorded at Unit 1, which accounted for 37% of the total abundance, 

followed by Unit 6 (27%), Unit 5 (21%), Unit 2 (11%), Unit 8 (formerly Unit 4) (2%), and Unit 8 

(formerly Unit 3) (1%). Impinged biomass was highest at Unit 6 with 38% of the total, followed by Unit 1 

(36%), Unit 5 (19percent), Unit 2 (4%), Unit 8 (formerly Unit 4) (2%), and Unit 8 (formerly Unit 3) (1%). 

Northern anchovy were impinged throughout the year, though peak impingement densities were recorded 

in July and August (Figure 5.5-20). Impingement biomass followed a similar pattern to abundance 

(Figure 5.5-21). During periods of highest abundance, impingement abundance and biomass were usually 

higher during nighttime (Figures 5.5-22 and 5.5-23). 

Length frequency analysis of 266 measured individuals indicated a mean standard length of 60 mm 

(2.4 inches). There was a wide distribution of size classes, although most of the measured fishes were 

between the 60 and 80 mm (2.4 and 3.1 inches) size classes (Figure 5.5-24), indicating most were in their 

first year. Of the 285 individuals that were evaluated for condition factor, 90% were dead and the 

remaining 10% were mutilated. 

Mark Conlin 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-31 

Survey Date

Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06 Jan-07 

Impingement Density (#/1,000,000 cubic meters)

0

5

10

15

20

25

30

Figure 5.5-20. Mean concentration (# / 1,000,000 m3

 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of northern anchovy in HnGS normal operation impingement samples during 

2006. 

Survey Date

Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06 Jan-07 

Impingement Density (kg/1,000,000 cubic meters) 0.00

0.02

0.04

0.06

0.08

Figure 5.5-21. Mean biomass (kg / 1,000,000 m3

 [264.172 million gal] – wide bars) and standard error 

(narrow bars) of northern anchovy in HnGS normal operation impingement samples during 2006. 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-32 

Impingement Density (#/1,000,000 cubic meters)

-180-160-140-120-100 -80 -60 -40 -20 0 20 40 60 80 100 120 140 160 180

Survey Date

1/1/2006 

2/1/2006 

3/1/2006 

4/1/2006 

5/1/2006 

6/1/2006 

7/1/2006 

8/1/2006 

9/1/2006 

10/1/2006 

11/1/2006 

12/1/2006 

1/1/2007 

Nighttime Daytime

Note: Negative nighttime values are a plotting artifact 

Figure 5.5-22. Mean concentration (# / 1,000,000 m3 [264.172 million gal]) of northern anchovy in 

normal operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling. 

Impingement Density (kg/1,000,000 cubic meters)

-0.5 -0.4 -0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4 0.5

Survey Date

1/1/2006 

2/1/2006 

3/1/2006 

4/1/2006 

5/1/2006 

6/1/2006 

7/1/2006 

8/1/2006 

9/1/2006 

10/1/2006 

11/1/2006 

12/1/2006 

1/1/2007 

Nighttime Daytime

Note: Negative nighttime values are a plotting artifact 

Figure 5.5-23. Mean biomass (kg / 1,000,000 m3 [264.172 million gal]) of northern anchovy in normal 

operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling. 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-33 

Length category (mm SL)

10 20 30 40 50 60 70 80 90 100 110

Percent

0

5

10

15

20

25

30

N = 266

Mean = 60

Figure 5.5-24. Length (mm) frequency distribution for northern anchovy 

collected in impingement samples. 

5.5.2.3.2 Modeling Results 

Northern anchovy life history parameters are presented in Table 5.5-8. von Bertalanffy parameters were 

derived from data presented for San Pedro Channel, California in Parrish et al. (1986). Annual survival 

estimates were calculated based on daily mortality rates (0.997902) summarized in Butler et al. (1993). 

Age and size at 50% maturity, 0.986614 years and 96 mm SL, respectively, were taken from Hunter and 

Macewicz (1980). The 266 northern anchovies measured over the year exhibited a bimodal age class 

distribution with one peak at approximately 0.2 years of age and a larger peak at approximately 0.5 years 

of age (Figure 5.5-25). Over the survey year approximately 1,840 adult equivalent northern anchovies 

were taken during the actual operation of the cooling water system. Of these, 1,834 individuals were 

impinged during normal operation of the cooling water system with an additional six individuals taken 

during heat treatments. Recalculation of these values based on design (maximum) flow volume of the 

cooling water system amounted to 2,117 individuals. 

Table 5.5-8. Northern anchovy life history parameters used in equivalent adult modeling. 

 von Bertalanffy growth parameters** 

Adult Annual 

Instantaneous 

Mortality (Z)* 

Surviva

l (S) Linf K t0 

Age at 50% 

Maturity*** 

Length at 

50% 

Maturity*** 

0.997902 0.464636 135.7 mm SL 0.784 -0.58 0.987 96 mm SL 

*Calculated from Butler et al. (1993) 

** Calculated from Parrish et al. (1985) 

*** Hunter and Macewicz (1980) 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-34 

Age Class (year)

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3

Percent

0

1

2

3

4

5

6

7

N = 266

Figure 5.5-25. Age class distribution of northern anchovy collected in 

HnGS impingement samples. 

5.5.2.4 Pipefishes (Syngnathidae) 

Three species of pipefish commonly occur 

throughout the nearshore waters of southern 

California, including; kelp pipefish (Syngnathus 

californiensis), bay pipefish (S. leptorhynchus), and 

barcheek pipefish (S. exilis) (Love et al. 2005). As a 

group, these three species generally range from at 

least central Baja California, Mexico to northern 

California, with varying depth ranges (Love et al. 

2005). All species have an upper depth limit 

reaching the surface extending to depths of 5 m 

(16 ft) for bay pipefish, 10 m (33 ft) for barcheek 

pipefish, and 15 m (49 ft) for kelp pipefish (Love et al. 2005). Ecologically, the three species exhibit two 

distinct habitat affinities. Allen and Pondella (2006) included bay pipefish in their southern nearshore and 

bay/estuary species group, while both kelp and barcheek pipefish were included in the nearshore algal bed 

and soft bottom species group. Kelp pipefish have been the most commonly observed of the three species 

in impingement sampling throughout the Los Angeles and Orange County areas, while bay pipefish has 

been largely limited to inshore embayments (MBC unpubl. data). Barcheek pipefish has been very 

uncommon in impingement sampling throughout the Los Angeles and Orange County areas. Two 

additional pipefish species, barred pipefish (Syngnathus auliscus) and snubnose pipefish (Cosmocampus 

arctus), have been reported to occur within southern California, but neither has been observed in 

impingement samples in Los Angeles or Orange Counties with any regularity (MBC unpubl. data). 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-35 

5.5.2.4.1 Life History and Ecology 

Each pipefish species occupies a somewhat distinct habitat. Kelp pipefish have been most commonly 

associated with anchored or drifting algae, often exhibiting cryptic coloration matching the surrounding 

material (Fitch and Lavenberg 1975). Additionally, kelp pipefish have been observed more frequently 

during open coast surveys than each of the remaining species (MBC unpubl. data). 

Eschmeyer and Herald (1983) noted bay pipefish to commonly inhabit eelgrass beds within bays, harbors, 

and estuaries within southern California. Two recent studies of the fish communities of bays within 

southern California reported bay pipefish in abundances far exceeding that of kelp pipefish (Valle et al. 

1999, Allen et al. 2002). In surveys of Alamitos Bay, California, Valle et al. (1999) reported bay pipefish 

as the third most abundant species collected, occurring in 49% of all sampling events, while kelp pipefish 

was absent from the surveys. In a similar study in San Diego Bay, California, Allen et al. (2002) recorded 

bay pipefish as the tenth most abundant species, accounting for 0.69% of the total abundance, while kelp 

pipefish represented 0.01% of the total abundance. 

The last of the three common species, barcheek pipefish, prefers similar habitat types as kelp pipefish, 

namely drift algae (Eschmeyer and Herald 1983; Allen and Pondella 2006). In surveys of Alamitos Bay, 

California, no barcheek pipefish were collected (Valle et al. 1999), while in San Diego Bay, California, 

they were collected in lower abundance than kelp pipefish (Allen et al. 2002). 

Pipefish as a group have been reported to exhibit unique reproductive activities. Fitch and Lavenberg 

(1975) suggest that fertilization of the eggs occurs as the female transfers the eggs to a brood pouch 

located on the male’s abdomen, after which the male provides all parental care and broods the eggs until 

hatching. The authors further report that “pregnant” male kelp pipefish have been observed from 

September to December in southern California. Similar patterns have been observed in the remaining 

pipefish species (Coleman 1999). Little information has been reported in the primary literature regarding 

age and growth of southern California pipefish. Surveys of online databases (www.fishbase.org) indicate 

bay pipefish reach a maximum age of two years. No further information was available on the remaining 

species. 

5.5.2.4.2 Population Trends and Fishery 

No commercial or recreational fishery currently exists for these three species of pipefish, outside of the 

occasional take for the aquarium trade. Other related species, such as seahorses (Hippocampus spp.), 

receive much greater attention for the aquarium trade. Trends in abundance have not been derived for 

pipefishes, due to the lack of either fishery dependent or independent data. During 1978-79, a total of 73 

pipefishes were impinged at HnGS, equivalent to about 0.2 fish per day (IRC 1981). Of these pipefishes, 

45 were bay pipefish, 11 were kelp pipefish, 1 was a barred pipefish, and 16 were unidentified. 

Abundance was highest from May through July. From 2001 through 2005, annual pipefish impingement 

ranged from 0 to 0.4 pipefish per survey, and averaged about 0.2 fish per survey (MBC 2006). 

5.5.2.4.3 Sampling Results 

Bay pipefish was the fourth most abundant fish species impinged (based on actual cooling water flows) 

with an estimated 3,157 individuals, or 6% of the annual total, weighing 3.85 kg (8.48 lbs) (Table 5.5-2). 

An additional 1,373 unidentified pipefishes weighing 1.83 kg (4.03 lbs), and 23 kelp pipefish weighing 

0.02 kg (0.05 lbs), were also impinged. Normal operation impingement represented all but three impinged 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-36 

individuals. One bay pipefish weighing <0.01 kg (<0.01 lbs) was impinged during the May 10, 2006 

marine growth control procedure at Unit 2, and two unidentified pipefishes weighing <0.01 kg (<0.01 lbs) 

were impinged during the March 7, 2006 procedure at Unit 1. Highest normal operation impingement of 

pipefishes was recorded at Unit 6, which accounted for 44% of the total abundance, followed by Unit 1 

(33%), Unit 2 (14%), and Unit 5 (7%), and Units 8 (formerly Unit 3) and 8 (formerly Unit 4) (1% each). 

Biomass was highest at Unit 6 with 52% of the total, followed by Unit 1 (21%), Unit 5 (13%), Unit 2 

(12%), and Units 8 (formerly Unit 3) and 8 (formerly Unit 4) (1% each). 

Pipefishes were impinged throughout the year, though peak impingement densities were recorded in 

spring and summer (April–July), corresponding to results from IRC (1981) (Figure 5.5-26). Impingement 

biomass followed a similar pattern to abundance, with peak periods in May, June, and August (Figure 

5.5-27). During periods of highest abundance, impingement abundance and biomass were usually higher 

during nighttime (Figures 5.5-28 and 5.5-29). 

Length frequency analysis of 484 measured individuals indicated a mean standard length of 160 mm (6.3 

inches). There was a wide distribution of size classes, although most of the measured fishes were between 

the 120 and 190 mm (4.7 and 7.5 inches) size classes (Figure 5.5-30). Fifty-one percent were males, 48% 

were females, and sex could not be determined on the remaining 1%. Of the 484 individuals that were 

evaluated for condition factor, 24% were alive, 74% were dead, and the remaining 2% were mutilated. 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-37 

Survey Date

Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06 Jan-07 

Impingement Density (#/1,000,000 cubic meters)

0

2

4

6

8

10

12

14

16

Figure 5.5-26. Mean concentration (# / 1,000,000 m3

 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of pipefishes in HnGS normal operation impingement samples during 2006. 

Survey Date

Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06 Jan-07 

Impingement Density(kg/1,000,000 cubic meters)

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

Figure 5.5-27. Mean biomass (kg / 1,000,000 m3

 [264.172 million gal] – wide bars) and standard error 

(narrow bars) of pipefishes in HnGS normal operation impingement samples during 2006. 
Haynes Generating Station 

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Impingement Density (#/1,000,000 cubic meters)

-140 -120 -100 -80 -60 -40 -20 0 20 40 60 80 100 120 140

Survey Date

1/1/2006 

2/1/2006 

3/1/2006 

4/1/2006 

5/1/2006 

6/1/2006 

7/1/2006 

8/1/2006 

9/1/2006 

10/1/2006 

11/1/2006 

12/1/2006 

1/1/2007 

Nighttime Daytime

Note: Negative nighttime values are a plotting artifact 

Figure 5.5-28. Mean concentration (# / 1,000,000 m3 [264.172 million gal]) of pipefishes in normal 

operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling. 

Impingement Density (kg/1,000,000 cubic meters)

-0.24 -0.18 -0.12 -0.06 0.00 0.06 0.12 0.18 0.24

Survey Date

1/1/2006 

2/1/2006 

3/1/2006 

4/1/2006 

5/1/2006 

6/1/2006 

7/1/2006 

8/1/2006 

9/1/2006 

10/1/2006 

11/1/2006 

12/1/2006 

1/1/2007 

Nighttime Daytime

Note: Negative nighttime values are a plotting artifact 

Figure 5.5-29. Mean concentration (kg / 1,000,000 m3 [264.172 million gal]) of pipefishes in normal 

operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling. 
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Length category (mm SL)

40 60 80 100 120 140 160 180 200 220 240 260 280 300 320

Percent

0

2

4

6

8

10

12

14

N = 484

Mean = 160

Figure 5.5-30. Length (mm) frequency distribution for pipefishes collected in 

impingement samples. 

5.5.2.5 Shiner perch (Cymatogaster aggregata) 

Shiner perch ranges from San Quintin Bay, Baja 

California, to Port Wrangell, Alaska (Miller and Lea 

1972). There are 19 species of Pacific nearshore 

surfperches (Family Embiotocidae) that occur off 

southern California (Miller and Lea 1972). Most 

inhabit nearshore waters, bays, and estuaries, though 

some are found further offshore. 

5.5.2.5.1 Life History and Ecology 

Shiner perch occurs primarily in shallow-water 

marine, bay, and estuarine habitats (Emmett et al. 1991), and is demersal on sandy and muddy bottoms. 

On the southern California shelf, shiner perch are found at depths to 90 m (198 ft), and Allen (1982) 

reported most occur at about 70 m (154 ft). It has been reported to depths of 146 m (322 ft) (Miller and 

Lea 1972). Juveniles and adults occur in oligohaline to eurohaline waters, and even occasionally in fresh 

water. This species forms schools or aggregations during the day (Fitch and Lavenberg 1975), but solitary 

individuals are found on the bottom at night. Important prey items for this species off southern California 

include calanoid copepods and chaetognaths (Allen 1982). It is a predominantly diurnal visual plankton 

picker, but larger individuals may engage in nocturnal epibenthic searching (Allen 1982). Shiner perch, 

along with white croaker, formed Allen’s (1982) “nearshore schoolers” recurrent group; the two species 

occur commonly off southern California even though shiner perch is considered a cold-temperate, outershelf species, while white croaker is a temperate, inner-shelf species. 
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Eggs of the shiner perch are fertilized internally, and females give birth to live young. Mating occurs 

primarily in the spring and summer in California (Bane and Robinson 1970). The reproductive capacity of 

this species is directly related to female size; smaller females produce as few as 5 young, while larger 

females can produce over 20 young (Wilson and Millemann 1969). Shiner perch have no larval stage. At 

birth, fully developed young are about 34 to 78 mm (1.3 to 3.1 inches) in length (Wilson and Millemann 

1969; Hart 1973). Shiner perch live for about eight years and reach about 180 mm (7.1 inches) in length 

(Miller and Lea 1972; Hart 1973). 

5.5.2.5.2 Population Trends and Fishery 

This species is not commercially important, but some shiner perch are landed for bait and human 

consumption (Emmett et al. 1991). Shiner perch are fished recreationally, especially from piers and in 

bays and estuaries. Total statewide recreational landings of “surfperches” were 489,000 fish in 1999, with 

most of the catch in central and northern California (Fritzche and Collier 2001). Commercial landings in 

the Los Angeles area have fluctuated between about 136 and 1,361 kg (300 and 3,000 lbs) per year since 

2000 (Table 5.5-9). In 2005, “surfperch” landings in the Los Angeles area totaled 21 kg (47 lbs) at a value 

of $86 (CDFG 2006). Commercial landings of “surfperches” reported from catch blocks in the Long 

Beach area totaled 75 kg (165 lbs) in 2006, at an estimated value of $660 (CDFG 2007). Numbers of 

shiner perch in southern California waters declined after the mid-1970s, and this is likely related to 

warming ocean temperature, decreased zooplankton biomass, and reduced upwelling (Stull and Tang 

1996; Beck and Herbinson 2003; Allen et al. 2003). During 1978-79, a total of 6,672 shiner perch were 

impinged at HnGS, equivalent to about 20 shiner perch per day (IRC 1981). It was the most abundant 

species during the yearlong study, and abundance was highest in May and June. From 2001 through 2005, 

annual shiner perch impingement ranged from 0 to 0.4 shiner perch per survey, and averaged about 0.2 

fish per survey (MBC 2006). 

Table 5.5-9. Annual landings and revenue for surfperches in the Los Angeles region 

based on PacFIN data. 

 Landed Weight 

Year kilograms pounds Revenue 

2000 1,278 2,817 $3,085 

2001 239 526 $1,315 

2002 972 2,143 $6,455 

2003 414 913 $1,743 

2004 164 362 $689 

2005 161 354 $403 

2006 497 1,095 $2,624 

5.5.2.5.3 Sampling Results 

Shiner perch was the fifth most abundant fish taxa impinged (based on actual cooling water flow 

volumes) with an estimated 582 individuals, or 1% of the annual total, weighing 12.03 kg (26.91 lbs) 

(Table 5.5-2). All individuals were impinged during normal operations. Highest normal operation 

impingement was recorded at Unit 1, which accounted for 26% of the total abundance, followed by Unit 6 
Haynes Generating Station 

IM&E Final Report Impingement Study

5-41 

(24%), Unit 8 (formerly Unit 4) (17%), Unit 5 (13%), Unit 2 (11%), and Unit 8 (formerly Unit 3) (9%). 

Impinged biomass was highest at Units 8 (formerly Unit 4) and 6, each with 26% of the total, followed by 

Unit 2 (15%), Unit 8 (formerly Unit 3) (13%), Unit 5 (12%), and Unit 1 (9%). 

Shiner perch were absent from impingement collections from January through March, and there was a 

strong peak in impingement in early July (Figures 5.5-31 and 5.5-32), similar to the finding from 1978–79 

(IRC 1981), when shiner perch was most abundant in June. During periods of highest abundance, 

impingement abundance and biomass were usually higher during nighttime (Figures 5.5-33 and 5.5-34). 

Length frequency analysis of 69 measured individuals indicated a mean standard length of 95 mm 

(3.7 inches). Size distribution was bimodal, with peaks at the 60−120 mm (2.4−4.7 inches) size classes 

(Figure 5.5-35). Of the 70 individuals that were evaluated for condition factor, 96% were dead, 3% were 

mutilated and the remaining 1% was alive. Fifty-one percent of the individuals analyzed were females, 

30% were males, and the remaining 19% were juveniles. 
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Survey Date

Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06 Jan-07 

Impingement Density (#/1,000,000 cubic meters)

0

2

4

6

8

10

12

14

Figure 5.5-31. Mean concentration (# / 1,000,000 m3

 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of shiner perch in HnGS normal operation impingement samples during 2006. 

Survey Date

Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06 Jan-07 

Impingement Density (kg/1,000,000 cubic meters) 0.0

0.1

0.2

0.3

0.4

0.5

0.6

Figure 5.5-32. Mean biomass (kg / 1,000,000 m3

 [264.172 million gal] – wide bars) and standard error 

(narrow bars) of shiner perch in HnGS normal operation impingement samples during 2006. 
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Impingement Density (#/1,000,000 cubic meters)

-60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60

Survey Date

1/1/2006 

2/1/2006 

3/1/2006 

4/1/2006 

5/1/2006 

6/1/2006 

7/1/2006 

8/1/2006 

9/1/2006 

10/1/2006 

11/1/2006 

12/1/2006 

1/1/2007 

Nighttime Daytime

Note: Negative nighttime values are a plotting artifact 

Figure 5.5-33. Mean concentration (# / 1,000,000 m3 [264.172 million gal]) of shiner perch in normal 

operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling. 

Impingement Density (kg/1,000,000 cubic meters)

-2.1 -1.8 -1.5 -1.2 -0.9 -0.6 -0.3 0.0 0.3 0.6 0.9 1.2 1.5 1.8 2.1

Survey Date

1/1/2006 

2/1/2006 

3/1/2006 

4/1/2006 

5/1/2006 

6/1/2006 

7/1/2006 

8/1/2006 

9/1/2006 

10/1/2006 

11/1/2006 

12/1/2006 

1/1/2007 

Nighttime Daytime

Note: Negative nighttime values are a plotting artifact 

Figure 5.5-34. Mean biomass (kg / 1,000,000 m3 [264.172 million gal]) of shiner perch in normal 

operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling. 
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Length category (mm SL)

30 40 50 60 70 80 90 100 110 120 130

Percent

0

5

10

15

20

25

N = 69

Mean = 95

Figure 5.5-35. Length (mm) frequency distribution for shiner perch collected in 

normal operation impingement samples. 

5.5.2.6 Specklefin midshipman (Porichthys myriaster) 

The specklefin midshipman, Porichthys myriaster, 

is one of two species of midshipman found off the 

California coast (the other being plainfin 

midshipman [Porichthys notatus]). Specklefin 

midshipman is most commonly found in muddy 

and sandy areas ranging from Point Conception, 

California, to Magdalena Bay, Baja California 

(Hubbs et al. 1939; Fitch and Lavenberg 1975). 

Specklefin midshipman belongs to the family Batrachoididae, which is in the order Batrachoidiformes. 

Fish in this order are usually broad-headed, big-mouthed, benthic dwellers of tropical and temperate 

waters (Bond 1996). 

5.5.2.6.1 Life History and Ecology 

The common habitat of the specklefin midshipman is typically found to be muddy and sandy bays, and 

along the open shore with depths reaching 126 m (413 ft). Although the range of the specklefin 

midshipman and the plainfin midshipman overlap, the specklefin prefers to live in shallower waters than 

the plainfin (Hubbs et al. 1939). 

The specklefin midshipman’s primary habitat is muddy and sandy bottoms; however, during April to June 

they will move to rocky areas for spawning. Females will attach their eggs, 200-400, to the underside of 

rocks and remain with the eggs for a day or two along with the male to guard the eggs. The male will stay 

with the eggs for the month or more it takes them to hatch. During this time the male does not feed, and 

can become emaciated and diseased. Many males may succumb to the stress and die before or after the 

eggs hatch (Fitch and Lavenberg 1975). 
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There is not much documentation on the growth rate of the specklefin midshipman, but it is estimated 

they can grow to 508 mm (20 inches) in length (Allen 1982). Males will grow much larger than females. 

There is no information on their maximum age, but a 457 mm (18 inches) male weighing about 0.9 kg 

(2 lbs) was eight years old (Fitch and Lavenberg 1975). 

Midshipmen in general are non-selective carnivores and scavengers. Crustaceans, octopus, squid, and 

small fish make up the majority of their diet. Giant seabass, sea lions, and porpoises are some of the fauna 

that have been known to feed on midshipmen. During daylight hours when in muddy areas they bury 

themselves and emerge to feed at night (Fitch and Lavenberg 1975). At night they use photophores to 

display light for use in courtship (Bond 1996). They are most active at night and have been known to 

make humming and grunting sounds (Eschmeyer and Herald 1983). 

5.5.2.6.2 Population Trends and Fishery 

There is currently no market for midshipmen. Anglers catch midshipmen incidentally while targeting 

other bottom species. No specklefin midshipman landings were reported in the commercial fishing 

databases queried (CDFG 2006, 2007). During 1978-79, a total of 126 specklefin midshipman was 

impinged at HnGS, equivalent to less than one individual per survey (IRC 1981). It was impinged 

throughout the year, with seasonal peaks in June and November-December. From 2001 through 2005, 

annual impingement of specklefin impingement ranged from 0 to 6 individuals per year (MBC 2006). 

5.5.2.6.3 Sampling Results 

Specklefin midshipman was the eighth most abundant species impinged (based on actual cooling water 

flow volumes) with an estimated 620 individuals, or 1.2% of the annual total, weighing 157.2 kg 

(346.7 lbs) (Table 5.5-2). All impingement was attributed to normal operation of the cooling water 

system, with no individuals recorded during marine growth controls. Normal operation impingement at 

Unit 6 contributed the greatest proportion of the annual total with 59% of all individuals, followed by 

Unit 1 (21%), Unit 5 (12%), Unit 2 (5%), Unit 8 (formerly Unit 3) (2%), and Unit 8 (formerly Unit 4) 

(1%). Impingement biomass was greatest at Unit 6, which contributed 71% to total annual biomass, 

followed by Unit 1 (12%), Unit 5 (11%), Units 8 (formerly Unit 3) and 8 (formerly Unit 4) (3% each), 

and Unit 2 (less than 1%). 

Specklefin midshipman was impinged throughout the year with no definitive seasonality, although there 

were seasonal peaks in both spring (April and May) and fall (October and November) (Figure 5.5-36). 

Biomass exhibited a slightly different pattern with highest values recorded during April and June than 

during the remainder of the year (Figure 5.5-37). This was due to larger individuals impinged during this 

period in comparison to the rest of the year. During periods of peak impingement, higher abundance and 

biomass was generally observed during daylight hours (Figures 5.5-38 and 5.5-39). 

Length frequency analysis of 72 measured individuals indicated a mean standard length of 227 mm SL 

(8.9 inches) (Figure 5.5-40). There was a wide distribution of size classes, although there were peaks in 

two distinct size classes, 50 to 60 mm (2.0 to 2.4 inches) and 290 mm SL (11.4 inches), each constituting 

10% or greater of the overall abundance. Of the 75 individuals that were evaluated for condition factor, 

31% were alive, 64% dead and 5% mutilated. 
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Survey Date

Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06 Jan-07 

Impingement Density (#/1,000,000 cubic meters)

0

1

2

3

4

5

6

Figure 5.5-36. Mean concentration (# / 1,000,000 m3

 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of specklefin midshipman in HnGS normal operation impingement samples during 

2006. 

Survey Date

Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06 Jan-07 

Impingement Density (kg/1,000,000 cubic meters) 0.0

0.5

1.0

1.5

2.0

2.5

3.0

Figure 5.5-37. Mean biomass (kg / 1,000,000 m3

 [264.172 million gal] – wide bars) and standard error 

(narrow bars) of specklefin midshipman in HnGS normal operation impingement samples during 2006. 
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Impingement Density (#/1,000,000 cubic meters)

-40 -35 -30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40

Survey Date

1/1/2006 

2/1/2006 

3/1/2006 

4/1/2006 

5/1/2006 

6/1/2006 

7/1/2006 

8/1/2006 

9/1/2006 

10/1/2006 

11/1/2006 

12/1/2006 

1/1/2007 

Nighttime Daytime

Note: Negative nighttime values are a plotting artifact 

Figure 5.5-38. Mean concentration (# / 1,000,000 m3 [264.172 million gal]) of specklefin midshipman 

in normal operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling. 

Impingement Density (kg/1,000,000 cubic meters)

-25 -20 -15 -10 -5 0 5 10 15 20 25

Survey Date

1/1/2006 

2/1/2006 

3/1/2006 

4/1/2006 

5/1/2006 

6/1/2006 

7/1/2006 

8/1/2006 

9/1/2006 

10/1/2006 

11/1/2006 

12/1/2006 

1/1/2007 

Nighttime Daytime

Note: Negative nighttime values are a plotting artifact 

Figure 5.5-39. Mean biomass (kg / 1,000,000 m3 [264.172 million gal]) of specklefin midshipman in 

normal operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling. 
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Length category (mm SL)

30 60 90 120 150 180 210 240 270 300 330 360 390 420 450

Percent

0

2

4

6

8

10

12

N = 72

Mean = 227

Figure 5.5-40. Length (mm) frequency distribution for specklefin midshipman 

collected in normal operation impingement samples. 

5.5.2.7 Pacific sardine (Sardinops sagax) 

The genus Sardinops occurs in coastal areas of warm 

temperature zones of nearly all ocean basins. Pacific 

sardine range from Kamchatka, Russia to Guaymas, 

Mexico, Peru, and Chile (Miller and Lea 1972; 

Eschmeyer and Herald 1983). Similar lineages occur 

off Africa, Australia, and Japan. Pacific sardine is one 

of five species of herrings (Family Clupeidae) that 

could occur in the waters off the HnGS. 

5.5.2.7.1 Life History and Ecology 

Pacific sardine is epipelagic, occurring in loosely 

aggregated schools (Wolf et al. 2001). Spawning occurs year-round in the upper 50 m (164 ft) of the 

water column, with seasonal peaks occurring from April to August between Point Conception, California 

and Magdalena Bay, Baja California. Adults are believed to spawn two to three times per season (Fitch 

and Lavenberg 1971). The primary spawning area for the principal northern subpopulation (ranging from 

northern Baja to Alaska) is between San Francisco and San Diego, California, and out to about 241 km 

(150 mi) off shore, though they are known to spawn as far off shore as 563 km (350 mi). Butler et al. 

(1993) estimated fecundity at 146,754 eggs to 2,156,600 eggs per two- and ten-year-old females, 

respectively, with longevity estimated at 13 years. Eggs and larvae occur near the sea surface, and eggs 

require about three days to hatch at 15°C (59°F). 
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Sardines are filter feeding and prey on planktonic crustaceans, fish larvae, and phytoplankton (Wolf et al. 

2001). The average non-feeding swim speed of Pacific sardine is about 0.78 body lengths per second 

(BL/sec), while particulate feeding sardines exhibit swim speeds of 1.0 to 2.0 BL/sec; this equaled 

maximum speeds of 26 to 51 cm/s (10.2 to 20.1 in/s) (van der Lingen 1995). Pacific sardines are about 

115 mm (4.5 in) after one year, 173 mm (6.8 in) after two years, 200 mm (7.9 in) after three years, and 

215 mm (8.5 in) after four years (Hart 1973). They make northward migrations early in summer and 

return southward again in fall, with migrations becoming further with each year of life. Natural adult 

mortality has been estimated as 0.4/year (MacCall 1979). 

5.5.2.7.2 Population Trends and Fishery 

Pacific sardine supported the largest fishery in the Western Hemisphere during the 1930s and 1940s. 

However, the fishery collapsed in the 1940s and 1950s, leading to the establishment of the California 

Cooperative Oceanic Fisheries Investigations (CalCOFI) program in 1947, originally named the 

Cooperative Sardine Research Program. Extreme natural variability and susceptibility to recruitment 

overfishing are characteristic of clupeoid stocks, including Pacific sardine (Hill et al. 2006). Regimes of 

high abundance of sardines (S. sagax and S. pilchardus) have alternated with regimes of high abundance 

of anchovy (Engraulis spp.) in each of the five regions of the world where these taxa co-occur (LluchBelda et al. 1992). Both sardine and anchovy populations tend to vary over periods of roughly 60 years, 

although sardine have varied more than anchovy. Sardine population recoveries lasted an average of 30 

years (Baumgartner et al. 1992). The Pacific sardine population began increasing at an average rate of 

27% per year in the early 1980s, and recent estimates indicate the total biomass of age-1 and older 

sardines is greater than one million mt (Hill et al. 2006; NMFS 2007). 

Sardine landed in the U.S. fishery are mostly frozen and sold overseas as bait and aquaculture feed, with 

smaller amounts canned or sold for human consumption and animal food (Hill et al. 2006). Commercial 

landings of Pacific sardine in 2006 in Long Beach area catch blocks totaled 14,106,375 kg (31,098,710 

lbs) at a value of $1,629,681 (CDFG 2007). Los Angeles area landings (between Dana Point and Santa 

Monica) for 2005 totaled 24,143,616 kg (53,236,674 lbs) at a value of $2,344,817 (CDFG 2006). Los 

Angeles area landings based on the PacFIN database declined slightly after 2002, and annual landings 

since have ranged between 23,000,000 and 27,000,000 kg (50,715,000 and 59,535,000 lbs) (Table 5.5-

10). Between 2000 and 2005, annual sardine impingement at the HnGS ranged between 24 individuals 

(2002) and 146,723 individuals (2004) (MBC 2006). 

Table 5.5-10. Annual landings and revenue for Pacific sardine in the Los Angeles region 

based on PacFIN data. 

Year Landed Weight 

(kg) 

Landed Weight 

(lbs) Revenue 

2000 39,121,935 86,263,867 $4,187,391 

2001 40,755,801 89,866,542 $4,476,752 

2002 39,299,341 86,655,046 $3,826,155 

2003 24,422,289 53,851,147 $1,961,269 

2004 23,672,717 52,198,341 $2,255,501 

2005 24,143,507 53,236,434 $2,348,577 

2006 26,651,664 58,766,919 $3,240,006 
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During 1978-79, no Pacific sardine were impinged at HnGS (IRC 1981). It was the most abundant species 

during the yearlong study, and abundance was highest in May and June. From 2001 through 2005, only 

four sardines were impinged at the HnGS: one in 2002 and three in 2003 (MBC 2006). 

5.5.2.7.3 Sampling Results 

A total of 12 Pacific sardine were collected at the HnGS, resulting in an estimated annual impingement 

(calculated using actual cooling water flow volumes) of 90 Pacific sardine weighing 0.606 kg (1.336 lbs) 

(Table 5.5-2). Two individuals were impinged at Unit 6 (one on March 1, 2006 and one on September 13, 

2006) and 10 individuals were impinged at Unit 5 on September 6, 2006. The three individuals measured 

ranged from 92 to 124 mm SL, with an average size of 104 mm SL, indicating they were all 

approximately one year old. All of the individuals assessed for condition factor were dead. 

5.5.2.7.4 Modeling Results 

Pacific sardine life history parameters are presented in Table 5.5-11. von Bertalanffy parameters were 

taken as reported by Hill et al. (2006). Annual survival estimates were calculated based on daily mortality 

rates (0.998901) summarized in Butler et al. (1993). Age at 50% maturity was -0.25208 based on the 

length at 50% maturity (125 mm SL) first published by Ahlstrom (1996 cited in Butler et al. 1996). Three 

Pacific sardines were measured with lengths recorded as 92, 95, and 125 mm SL. Adult equivalents taken 

during actual operation of the cooling water system totaled 69 individuals, all taken during normal 

operation surveys. Recalculation of these estimations based on design (maximum) flow of the cooling 

water pumps indicates 75 adult equivalent Pacific sardines would have been taken at continuous full flow 

operation for the year. 

Table 5.5-11. Pacific sardine life history parameters used in equivalent adult modeling. 

 von Bertalanffy growth parameters** 

Daily Mortality 

(Z)* 

Surviva

l (S)* Linf k t0 

Age at 50% 

Maturity*** 

Length at 

50% 

Maturity*** 

0.998901 0.669315 244 mm SL 0.319 -2.503 -0.25208 125 mm SL 

*Calculated from Butler et al. 1993 

**Hill et al. 2006 

***Ahlstrom 1960 cited in Butler et al. 1996 

5.5.2.8 California Skate (Raja inornata) 

The California skate (Raja inornata) belongs to the family Rajidae, the skates. This species is olivebrown on the dorsal side and tan on the ventral, occasionally with dark mottling and two dark eyespots 

(Eschmeyer and Herald 1983; Miller and Lea 1982). California skates range is between Vancouver, 

British Columbia to central Baja California, Mexico, up to depths of 671 m (2,200 ft); however these 

skates are commonly found inshore and in shallow bays of less than 18 m (60 ft). Adult skates are 

generally solitary and live on sea bottom. California skates grow to a total length of 76 cm (30 in) (Zorzi 

et al. 2001). 
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5.5.2.8.1 Life History and Ecology 

Female California skates achieve sexual maturity at a total length of about 52 cm (21 in) and are 

oviparous, laying tough, permeable egg cases year-round after internal fertilization occurs (Ebert 2003; 

Zorzi et al. 2001). Little is known specifically regarding the California skate; however, typical 

elasmobranch reproductive strategies suggest late sexual maturity, small brood size, and low fecundity. 

The diet of the California skate is mainly composed of polychaete worms, shrimp, and other small benthic 

invertebrates. 

5.5.2.8.2 Population Trend and Fishery 

Commercial fishery for skates was historically minor but increased in the second half of the 1990s (Zorzi 

et al. 2001). California skates became an important commercial species in California, primarily caught as 

bycatch of other fisheries (Eschmeyer and Herald 1983; Ebert 2003). However in 1999, due to concerns 

of overfishing, the National Marine Fisheries Service implemented a Nearshore Fishery Management 

Plan to prevent depletion of commercially and recreationally important fish populations, including the 

California skate (NOAA 2006). During 1978-79, no California skates were impinged at HnGS (IRC 

1981). From 2001 through 2005, no California skates were impinged at the HnGS (MBC 2006). 

5.5.2.8.3 Sampling Results 

One California skate was collected at the HnGS, resulting in an estimated annual impingement (calculated 

using actual cooling water flow volumes) of eight individuals weighing 1.111 kg (2.450 lbs) (Table 5.5-

2). The individual was collected at Unit 5 on December 6, 2006. The individual measured was 175 mm 

TL, and was alive upon collection. 

5.5.2.9 Jack Mackerel (Trachurus symmetricus) 

Jack mackerel are not true mackerels, but a member of 

the jack family Carangidae, one of about twelve jack 

species that occur locally, including yellowtail (Seriola 

lalandi) and Mexican scad (Decapterus scombrinus), 

although most are more common offshore of Baja 

California (Eschmeyer and Herald 1983). Most jacks are 

streamlined, fast-swimming fish with deeply forked tails 

and narrow caudal peduncles. About 200 species in the 

jack family occur worldwide, mostly in warm seas. Most 

species school, and many are important sport or food 

fishes. 

Jack mackerel are torpedo-shaped, blue or green above 

and silver below, with a yellow to reddish caudal fin (Eschmeyer and Herald 1983; Love 1996). Jack 

mackerel commonly occur from southeast Alaska to at least the end of the Baja Peninsula, out to about 

1,900 km (1,200 miles). Young fish, less than six years old, and about 30 cm (12 in), often form dense, 

nearshore schools over reefs and near kelp and piers, but generally school in water less than 60 m (200 ft) 

deep (Eschmeyer and Herald 1983; Love 1996; Mason and Bishop 2001). Larger fish, those over about 15 

years and 50 cm (20 in), are found offshore as solitary fish or in loose aggregations. These large fish are 

known to move north and nearshore into the Gulf of Alaska seasonally with warm water, but large fish 

are also caught year-round off southern and Baja California. The distribution of fish between 6 and 15 

years is not well known. 

Photo Courtesy of NOAA 
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5.5.2.9.1 Life History and Ecology 

Jack mackerel have a lifespan of about 35 years, reaching a length of 81 cm (32 in) (Eschmeyer and 

Herald 1983; Love 1996). They grow fast to about 20 cm (8 in) in their first year, and then growth slows, 

with a 36-cm (14 in) fish about four-years old (Love 1996). Most (70%) individuals mature at one year, 

with 90% mature by their second year (Mason and Bishop 2001). Jack mackerel spawn about 100 to 500 

km (60 to 300 mi.) offshore of California from January through November, with spawning between Punta 

Eugenia and Point Conception from March through July (Love 1996; Mason and Bishop 2001). Spawning 

in the species begins with larger, offshore individuals in southern California and Mexico and proceeds 

northward as the season progresses. Nearshore spawning by younger individuals occurs later in the 

summer. Most spawning occurs in water between about 14-16°C (57-61°F). Jack mackerel are multiple 

spawners, with females on average spawning every five days and 25 times per year. Egg count is variable 

through the season, with each female releasing about 104,000 eggs during the first spawning of the year 

and then about 73,000 eggs during each subsequent spawning event (Mason and Bishop 2001). Eggs are 

about 1 mm (0.04 in) in diameter and float between 2 and 5 days before hatching, depending on 

temperature (Love 1996; Mason and Bishop 2001). 

Jack mackerel larvae feed on copepods, while juveniles take copepods and larger plankton species such as 

euphausiids, and juvenile squid and anchovy (Love 1996; Mason and Bishop 2001). The food preference 

of the older, offshore individuals is not known. Jack mackerel are fed on by large fish species including 

tuna, billfish, giant seabass and sharks and several marine mammals such as Pacific white-sided dolphin 

and California sea lion. Because of their relatively large size as adults, only smaller and young-of-theyear individuals are likely to be taken by sea birds such as cormorants. 

5.5.2.9.2 Population Trends and Fishery 

Jack mackerel, originally known as horse mackerel, was taken commercially in California as early as 

1888, but principally as incidental take of the coastal pelagic species (CPS) seine net fishery for market 

squid, Pacific sardine, Pacific mackerel and northern anchovy (Mason and Bishop 2001). Between 1926 

and 1946, jack mackerel accounted for less than 3% of the CPS fishery with annual landings of 181,437 

to 13,607,771 kg (4 million to 30 million lbs). During the 1940s and 1950s, the sardine fishery collapsed 

and Pacific mackerel landings were in decline. Consequentially, the jack mackerel fishery boomed and, in 

order to increase consumer appeal, the U.S. Food and Drug Administration changed the name “horse 

mackerel” to “jack mackerel”. Between 725,748 to 6,622,449 kg (1.6 million to 14.6 million lbs) of jack 

mackerel were landed from 1947 through 1979, equaling 6 to 65% of the annual CPS landings. During 

the late 1970s, the Pacific mackerel fishery showed an increase in population, thus drawing fishing efforts 

away from the jack mackerel. 

Awareness of overfishing, beginning with the collapse of the sardine and anchovy fishery, prompted the 

implementation of national programs to avoid future collapses (Mason and Bishop 2001). Jack mackerel 

were first categorized in the Pacific Coast Groundfish Fishery Management Plan in 1982 due to incidental 

landings of jack mackerel with Pacific whiting (hake) trawls, a species categorized as “groundfish”; yet 

fishery total catches were only restrained north of the 39° latitude. Concern for the jack mackerel 

population rose and pressure from southern California fishermen resulted in the inclusion of jack 

mackerel to the Coastal Pelagic Species Fisheries Management Plan (CPS FMP) in 1999. Currently, jack 

mackerel is a “monitored” species in the CPS FMP, meaning that stocks are monitored but federal fishery 
Haynes Generating Station 

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controls are not implemented (PFMC 2006). From the early 1990s on, jack mackerel landings have 

occurred from December to April at an average of 2% of CPS landings, less than 1,814,370 kg (4 million 

lbs) per year. 

Jack mackerel from the U.S. Fishery are generally canned; however, fresh jack mackerel are occasionally 

found in markets (Love 1996). The recreational fishery for jack mackerel is small when compared to the 

commercial fishery. Most of the landings derive from commercial passenger fishing vessel, with 

additional catches from anglers on fishing piers (Mason and Bishop 2001). This fishery remains a small 

contributor to the total catch of jack mackerel and high variability in the number of catches since 1980, 

numbering from 5,000 to over 350,000 fish. Landings reported in the Los Angeles region in the PacFIN 

(2007) database have fluctuated between about 100,000 and 3.6 million kg (220,000 and 7.9 million lbs) 

annually (Table 5.5-12). Commercial landings of jack mackerel in 2005 in southern California totaled 

115,719 kg (255,117 lbs) at a value of $16,367 (CDFG 2006). Landings from Long Beach catch blocks in 

2006 totaled 106,092.5 kg (233,890 lbs) at a value of $11,443 (CDFG 2007). During 1978-79, two jack 

mackerel were impinged at HnGS (IRC 1981). From 2001 through 2005, no jack mackerel were impinged 

at the HnGS (MBC 2006). 

Table 5.5-12. Annual landings and revenue for jack mackerel in the Los Angeles region 

based on PacFIN data. 

Year Landed Weight 

(kg) 

Landed Weight 

(lbs) Revenue 

2000 1,209,240 2,666,375 $225,723 

2001 3,623,138 7,989,020 $561,444 

2002 1,003,217 2,212,094 $201,797 

2003 133,373 294,087 $51,142 

2004 1,026,873 2,264,254 $248,547 

2005 166,590 367,330 $49,078 

2006 1,025,614 2,261,479 $168,442 

5.5.2.9.3 Sampling Results 

One jack mackerel was collected at the HnGS, resulting in an estimated annual impingement (calculated 

using actual cooling water flow volumes) of seven individuals weighing 0.477 kg (1.052 lbs) (Table 5.5-

2). The individual was collected at Unit 5 on April 26, 2006. The single individual collected was 

mutilated. 
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5.5.2.10 Vermilion rockfish (Sebastes miniatus) 

Vermilion rockfish (Sebastes miniatus) belong to 

the family Scorpaenidae. True to its common 

name, the vermilion rockfish coloration varies 

from bright red to dark dusky red and mottled with 

gray along the sides (Eschmeyer et al. 1983; Love 

et al. 2002). The species ranges from Prince 

William Sound, Alaska to central Baja California, 

Mexico, but are most abundant from northern 

California to northern Baja California. 

5.5.2.10.1 Life History and Ecology 

Vermilion rockfish inhabit depths from the subtidal zone to 436 m (1,440 ft). Most adults are found 

between 50 m to 100 m (165-495 ft), while juveniles tend to be more subtidal (Miller and Lea 1982; Love 

1996; Love et al. 2002). Adult vermilion rockfish generally aggregate in high relief areas, and can 

occasionally be found along the bottom of oil platforms or live solitarily in shallow-water caves (Love et 

al. 2002). Juvenile rockfish, however, are solitary and tend to inhabit sand patches between structures or 

near rocky substrata (Love et al. 2002). The largest length recorded for vermilion rockfish is 76 cm (30 

in) (Eschmeyer and Herald 1983; Love et al. 2002). 

Vermilion rockfish differ in size and age at maturity (Love et al. 2002). Some females have been recoded 

as mature at the length of 31 cm (12 in) at four years. However, all females are mature by 47 cm (19 in) 

and nine years. Recorded fecundity shows a range of 63,000 eggs in a female of 32 cm (12.5 in) to 

2,600,000 eggs in a female of 55 cm (21.5 in) (VenTresca 2001). Vermilion rockfish have been recorded 

displaying courtship behavior, wherein females undergo internal fertilization. Release of larvae with 

lengths of about 4.3 mm (0.2 in) occurs from July to March in southern California. When released, larvae 

are generally found in pelagic waters and settle in May near protective structures in shallower waters until 

they progressively move to deeper depths (VenTresca 2001; Love et al. 2002). Vermilion rockfish prey 

primarily on fish and benthic organisms including northern anchovies, lanternfish, squid, crabs, and 

octopi, but have been recorded feeding on salps, shrimp, copepods, and polychaetes. 

5.5.2.10.2 Population Trends and Fishery 

Historically, the commercial and recreational fishery has viewed vermilion rockfish as a highly prized 

market species. However due to its inclusion of a general market category of “rockfish, Group Red”, 

historical data on catch abundances are unreliable previous to 1994, when “Rockfish, vermilion” became 

a printed market category (VenTresca 2001). During the late 1990s, annual landings of vermilion rockfish 

declined when the NMFS implemented a Nearshore Fishery Management Plan in 1999 in an attempt to 

rebuild the nearshore fish population. As of 2004, recreational fishery landings (167,000 kg [368,172 

lbs]) remained higher than commercial landings (5,000 kg [11,024 lbs]) (MacCall 2005). The current 

recreational fishery often takes vermilion rockfish by hook-and-line anglers along California and is 

composed mostly of juvenile fishes (VenTresca 2001; Love et al. 2002). Vermilion rockfish is covered 

under the Pacific Groundfish FMP. 
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Photo: J. Forsythe 

Commercial landings in the Los Angeles area were only recorded in 2000 in the PacFIN database (Table 

5.5-13). In 2005, vermilion rockfish landings in the Los Angeles area totaled 1,671.6 kg (3,686 lbs) at a 

value of $3,686 (CDFG 2006). There were no commercial landings of vermilion rockfish reported from 

catch blocks in the Long Beach area, but landings in the Santa Monica Bay area catch blocks totaled 

191.2 kg (422 lbs) in 2006, at an estimated value of $913 (CDFG 2007). During 1978-79, no vermilion 

rockfish were impinged at HnGS (IRC 1981). From 2001 through 2005, no vermilion rockfish were 

impinged at the HnGS (MBC 2006). 

5.5.2.10.3 Sampling Results 

One vermilion rockfish was collected at the HnGS, resulting in an estimated annual impingement 

(calculated using actual cooling water flow volumes) of seven individuals weighing 0.014 kg (0.031 lbs) 

(Table 5.5-2). The individual was collected at Unit 6 on March 29, 2006. The single individual collected 

was dead upon collection, and was in the 40-mm size class. 

Table 5.5-13. Annual landings and revenue for vermilion rockfish in the Los Angeles region 

based on PacFIN data. 

Year Landed Weight 

(kg) 

Landed Weight 

(lbs) Revenue 

2000 78 172 $367 

2001 - - - 

2002 - - - 

2003 - - - 

2004 - - - 

2005 - - - 

2006 - - - 

5.5.3 Shellfish Impingement by Species 

Three shellfish taxa were impinged in sufficient numbers, and considered commercially/recreationally 

important, to warrant further analysis. These taxa were: California two-spot octopus (1.7% of total 

sampled abundance), California sea hare (1.0%), and market squid (0.4%). Combined, these taxa 

comprised 3% of the macroinvertebrates in impingement samples, and 50% of the biomass. 

5.5.3.1 California two-spot octopus (Octopus 

bimaculatus/bimaculoides) 

There are two similar octopus species that occur in southern 

California: Octopus bimaculatus and O. bimaculoides. Both are 

referred to as the California two-spot octopus since they are 

difficult to distinguish, and for more than 60 years were 

thought to represent a single species (Morris et al. 1980). O. 

bimaculoides ranges from San Simeon, California, to Bahia 

San Quintin, Baja California, and is found in a variety of 

habitats to depths of 20 m (66 ft) (Lang and Hochberg 1997). 

The sibling species O. bimaculatus has a similar geographic distribution, occurring from Santa Barbara, 

California, south to Punta Eugenia, Baja California, and in some locations within the Gulf of California. It 

also occurs in slightly deeper depths (to 50 m [164 ft]) (Morris et al. 1980; Lang and Hochberg 1997). 
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5.5.3.1.1 Life History and Ecology 

Both octopus species occur in a variety of habitats, including mudflats, intertidal zones, reefs, crevices, 

and kelp beds. O. bimaculoides females lay their eggs under rocks from late winter to early summer, and 

brood them continuously for two to four months (Morris et al. 1980). Females lay between 200 and 800 

eggs, depending on female size and condition (Lang and Hochberg 1997). The young remain on the 

bottom after hatching, and often move toward the intertidal. Adults feed on mollusks, crustaceans, and 

fishes. In the rocky intertidal zone, O. bimaculoides drills and feeds principally on limpets (Collisella and 

Notoacmea), snails (Tegula spp.), Pacific littleneck, and hermit crabs (Pagurus spp.) (Morris et al. 1980). 

They also feed on mussels (Mytilus spp.) and the Pacific calico scallop (Argopecten ventricosus) (Lang 

and Hochberg 1997). 

O. bimaculatus spawns throughout most of the year, though there is a distinct seasonal peak from April 

through July (Lang and Hochberg 1997). Hatching takes place in a relatively short time-frame since there 

is an inverse relationship between development time and water temperature (Ambrose 1981). Ambrose 

(1981) also reported an average clutch size of about 20,000 eggs for a female weighing about 260 g 

(0.573 lbs). After hatching, young octopuses are planktonic for several months, then settle to the bottom 

(Lang and Hochberg 1997). Juvenile O. bimaculatus feed on small crustaceans, while adults consume a 

wide variety of motile benthic invertebrates. 

5.5.3.1.2 Population Trends and Fishery 

Most California landings of octopus result from incidental catches in other fisheries (Lang and Hochberg 

1997). In 2005, commercial landings of octopus in the Los Angeles area totaled 183 kg (403 lbs) at a 

value of $558 (CDFG 2006). Commercial landings from Long Beach area catch blocks in 2006 totaled 

18 kg (39 lbs) at an estimated value of $105. From 2001 through 2005, annual impingement of octopus 

ranged from 0 to 1.3 individuals per survey, and averaged about 0.6 individuals per survey (MBC 2006). 

5.5.3.1.3 Sampling Results 

A total of 46 California two-spot octopus was collected in impingement samples, with an estimated 

annual impingement of 337 individuals weighing 54.8 kg (120.8 lbs) (Table 5.5-2). Forty-four of the 46 

individuals were collected during normal operations, with the other two collected during the marine 

growth control procedure at Unit 2 on November 14, 2006. Highest normal operation impingement 

abundance was recorded at Unit 1, which accounted for 56% of the total abundance, followed by Unit 6 

(30%), Unit 5 (8%), Unit 8 (formerly Unit 3) (4%) and Unit 2 (2%). No California two-spot octopus were 

impinged at the Unit 8 (formerly Unit 4) traveling screens. Biomass was highest at Unit 6 with 60% of the 

total, followed by Unit 1 (22%), Unit 5 (12%), Unit 8 (formerly Unit 3) (7%), and Unit 2 (less than 1%). 

California two-spot octopus was prevalent during the latter part of 2006, with peak impingement density 

recorded from July through early-September (Figure 5.5-41). Biomass followed a pattern similar to 

abundance, although the peak biomass occurred later in the year (in November and December) (Figure 

5.5-42). There was no clear diel pattern of impingement with respect to abundance or biomass, which is 

likely a result of the low abundance of this species (Figures 5.5-43 and 5.5-44). 

Length frequency analysis of 20 measured individuals indicated a mean arm spread (AS) of 370 mm 

(14.6 inches) (Figure 5.5-45). Of the 31 individuals that were evaluated for condition factor, 6% were 

alive, 58% were dead and the remaining 36% were mutilated. 
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Survey Date

Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06 Jan-07 

Impingement Density (#/1,000,000 cubic meters)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Figure 5.5-41. Mean concentration (# / 1,000,000 m3

 [264.172 million gal] – wide bars) and standard error 

(narrow bars) of California two-spot octopus in HnGS normal operation impingement samples during 

2006. 

Survey Date

Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06 Jan-07 

Impingement Density (kg/1,000,000 cubic meters) 0.0

0.2

0.4

0.6

0.8

1.0

1.2

Figure 5.5-42. Mean biomass (kg / 1,000,000 m3

 [264.172 million gal] – wide bars) and standard error 

(narrow bars) of California two-spot octopus in HnGS normal operation impingement samples during 

2006. 

 
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Impingement Density (#/1,000,000 cubic meters)

-20 -18 -16 -14 -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 14 16 18 20

Survey Date

1/1/2006 

2/1/2006 

3/1/2006 

4/1/2006 

5/1/2006 

6/1/2006 

7/1/2006 

8/1/2006 

9/1/2006 

10/1/2006 

11/1/2006 

12/1/2006 

1/1/2007 

Nighttime Daytime

Note: Negative nighttime values are a plotting artifact 

Figure 5.5-43. Mean concentration (# / 1,000,000 m3 [264.172 million gal]) of California two-spot 

octopus in normal operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling. 

Impingement Density (kg/1,000,000 cubic meters)

-5 -4 -3 -2 -1 0 1 2 3 4 5

Survey Date

1/1/2006 

2/1/2006 

3/1/2006 

4/1/2006 

5/1/2006 

6/1/2006 

7/1/2006 

8/1/2006 

9/1/2006 

10/1/2006 

11/1/2006 

12/1/2006 

1/1/2007 

Nighttime Daytime

Note: Negative nighttime values are a plotting artifact 

Figure 5.5-44. Mean biomass (kg / 1,000,000 m3 [264.172 million gal]) of California two-spot octopus 

in normal operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling. 
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Length category (mm AS)

4080

120160200240280320360400440480520560600640680720

Percent

0

2

4

6

8

10

12

N = 20

Mean = 370

Figure 5.5-45. Length (mm) frequency distribution for California two-spot 

octopus collected in impingement samples. 

5.5.3.2 California seahare (Aplysia californica) 

Seahares are opisthobranchs, gastropod mollusks 

with reduced shells or with no shells at all, as in the 

nudibranchs. Seahares, in the family Aplysiidae, are 

a very distinct group with an internal shell, deriving 

their common name from their humped shape and 

extended rhinophores (paired sensory projections 

from the head) that resemble a sitting hare’s body 

and ears (Beeman 1968). Four species in this group 

are known to occur in California, with the California 

seahare (Aplysia californica) the most conspicuous. 

California seahares are found in the Eastern Pacific 

along the California coast from Humboldt Bay to 

Gulf of California. 

5.5.3.2.1 Life History and Ecology 

California seahares are often very abundant on sheltered and rocky shores and in kelp beds from the low 

intertidal to 18 m (59 ft) depth, and on mud flats and bottoms of shallow bays, estuaries and harbors. 

They are among the largest of the local nearshore invertebrate species, with large individuals exceeding 

400 mm (15.7 inches) in length and weighing several kilograms (Morris et al. 1980). Young specimens 

are usually reddish, while older individuals can be reddish, brownish and/or greenish with a network of 

dark lines and spots. 
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Adult individuals are simultaneous hermaphrodites, but are unable to self-fertilize and must mate with 

other individuals (Morris et al. 1980). During mating, individuals may act as only male or female, or both 

sexes simultaneously, and chains or circles of mating individuals are occasionally observed. Eggs are 

deposited among rocks and seaweed, inter-and subtidally, in long, tangled, greenish-yellow strings 

containing up to a million eggs. Eggs hatch in about 12 days. Hatched veliger larvae stay in the plankton 

at least 34 days, after which they settle on red algae and undergo metamorphosis. After metamorphosis, 

individuals can double their weight every 10 days for three month before growth slows down. Individuals 

may attain sexual maturity within 120 days of hatching, although not yet fully grown. The life span of 

individuals is usually a year or less, and population numbers can vary greatly among years. 

The California seahare is herbivorous, feeding mainly during the day on a variety algae and eelgrass 

(Morris et al. 1980). Food is scented from a distance by receptor organs and the animal moves inchwormlike towards the food. When feeding, the animal tears off large pieces of plant material with its toothed 

radula, which is then swallowed and temporarily held in the esophagus, then passed to a muscular gizzard 

where the plant material is ground up and mixed with enzymes for digestion. Seahares show avoidance to 

some sea star and predaceous opisthobranch species, but the digestive gland of the sea hare contains toxic 

chemicals and few animals are known to prey on seahares following metamorphosis of the larvae (Morris 

et al. 1980; Silverstein and Campbell 1989). When irritated, California seahares exude a dark-purple ink 

to discourage harassment. The purple ink gets its color from pigments in red algae. Individuals milked of 

their ink then fed on only brown and green algae do not produce the purple dye. 

5.5.3.2.2 Population Trends and Fishery 

Seahares possess very large nerve cells, some up to 1 mm (0.04 inches) in diameter (Morris et al. 1980; 

Silverstein and Campbell 1989). Not only are the neurons large, many are consistently placed and 

distinctly colored, making it possible to identify corresponding cells in different individuals. The simple 

behavior of these animals along with the ease of study of the nerve cells make seahares ideal for research 

relating animal behavior to the structure and function of the nervous system. 

As a result, researchers provide a steady market for California seahares, supporting both seahare 

mariculture and a wild-caught sea hare fishery (Silverstein and Campbell 1989; CDFG 2007). In 2005, 

Los Angeles area landing of seahares totaled 4,783 kg (10,547 lbs) at an estimated value of $35,352 

(CDFG 2006). Commercial landings of seahares in 2006 in Long Beach area catch blocks totaled 

1,947 kg (4,293 lbs) at a value of $33,523 (CDFG 2007). From 2001 through 2005, annual seahare 

impingement ranged from 0 to 0.3 individuals per survey, and averaged about 0.1 individuals per survey 

(MBC 2006). 

5.5.3.2.3 Sampling Results 

A total of 28 California seahares was collected in impingement samples, with an estimated annual 

impingement of 195 individuals weighing 79.4 kg (175.1 lbs) (Table 5.5-2). All of the individuals were 

collected during normal operations. Highest normal operation impingement abundance was recorded at 

Unit 5, which accounted for 29% of the total abundance, followed by Unit 1 (24%), Unit 2 (21%), Unit 3 

(15%) and Unit 6 (11%). California seahare was not impinged at the Unit 8 (formerly Unit 4) traveling 

screens. Biomass was highest at Unit 5 with 42% of the total, followed by Unit 2 (24%), Unit 1 (21%), 

Unit 6 (9%), and Unit 8 (formerly Unit 3) (4%). 
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California seahare was most abundant during summer months, with peak impingement density recorded 

from June through August (Figure 5.5-46). Biomass followed a pattern similar to abundance (Figure 5.5-

47). Seahares were more frequently impinged during daytime than during nighttime, although the analysis 

was based on relatively few individuals (Figures 5.5-48 and 5.5-49). 

Survey Date

Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06 Jan-07 

Impingement Density (#/1,000,000 cubic meters)

0

1

2

3

4

Figure 5.5-46. Mean concentration (# / 1,000,000 m3

 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of California seahare in HnGS normal operation impingement samples during 2006. 
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Survey Date

Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06 Jan-07 

Impingement Density (kg/1,000,000 cubic meters) 0.0

0.2

0.4

0.6

0.8

1.0

1.2

Figure 5.5-47. Mean biomass (kg / 1,000,000 m3

 [264.172 million gal] – wide bars) and standard error 

(narrow bars) of California seahare in HnGS normal operation impingement samples during 2006. 

Impingement Density (#/1,000,000 cubic meters)

-12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12

Survey Date

1/1/2006 

2/1/2006 

3/1/2006 

4/1/2006 

5/1/2006 

6/1/2006 

7/1/2006 

8/1/2006 

9/1/2006 

10/1/2006 

11/1/2006 

12/1/2006 

1/1/2007 

Nighttime Daytime

Note: Negative nighttime values are a plotting artifact 

Figure 5.5-48. Mean concentration (# / 1,000,000 m3 [264.172 million gal]) of California seahare in 

normal operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling. 
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Impingement Density (kg/1,000,000 cubic meters)

-6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6

Survey Date

1/1/2006 

2/1/2006 

3/1/2006 

4/1/2006 

5/1/2006 

6/1/2006 

7/1/2006 

8/1/2006 

9/1/2006 

10/1/2006 

11/1/2006 

12/1/2006 

1/1/2007 

Nighttime Daytime

Note: Negative nighttime values are a plotting artifact 

Figure 5.5-49. Mean biomass (kg / 1,000,000 m3 [264.172 million gal]) of California seahare in normal 

operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling. 

5.5.3.3 Market squid (Loligo opalescens) 

Market squid range from offshore British 

Columbia to Bahia Asuncion, Baja California, 

including Guadalupe Island off Baja California 

(Morris et al. 1980; MBC 1987). However, they 

are found in highest numbers between Monterey 

and San Diego, California, and are found north of 

Puget Sound only during or following El Niño 

events. The distribution of this species is classified 

as ‘Transitional Endemic’ since market squid are 

limited to the California Current and the eastern portion of the Northeast Pacific Transition Zone. Market 

squid are managed under the Coastal Pelagic Species Fishery Management Plan (PFMC 1998). 

5.5.3.3.1 Life History and Ecology 

Eggs of the market squid are benthic, while juveniles and adults are considered pelagic (Fields 1965). 

They are actually found over the continental shelf from the surface to depths of at least 800 m (2,625 ft) 

(PFMC 1998). Recksiek and Kashiwada (1979) found larvae in much higher concentrations near bottom 

than in the water column. Mature squid form large spawning aggregations in nearshore waters, and in 

southern California, these usually occur from November through August (Fields 1965). 

Photo: Dan Dugan
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During copulation, a male holds the female from below, and a bundle of spermatophores is subsequently 

transferred from the mantle cavity of the male to a position near the female’s oviduct (Hurley 1977). In 

southern California, squid spawn primarily in winter (November through August), though spawning has 

also been recorded in July (Morris et al. 1980). Fields (1965) suggested nighttime spawning in market 

squid; however, recent observations suggest this species spawns exclusively during daytime (Forsythe et 

al. 2004). Market squid are terminal spawners, spawning once then dying. 

Age at first reproduction is 24–28 weeks (Yang et al. 1986). Egg capsules are usually deposited on sandy 

substrate, often at the edges of canyons or rocky outcroppings (McGowan 1954). Egg deposition occurs 

between depths of 5 and 55 m (16 and 180 ft), and is most common between 20 and 35 m (66 and 115 ft) 

(PFMC 1998). Each egg capsule contains 180 to 300 eggs (Morris et al. 1980). Egg development is 

dependent on water temperature; eggs hatch at 19–25 days at 17°C (63°F), 27–30 days at 15°C (59°F), 

and 30–35 days at 14°C (57°F) (Yang et al. 1986). Females produce 20–30 egg capsules, and each 

capsule is individually attached to the substrate (PFMC 1998). Fields (1965) reported four females 

depositing 17,000 eggs in 85 capsules in one evening, equivalent to about 21 capsules and 4,250 eggs per 

squid. Recksiek and Frey (1978) reported a fecundity of 4,000 to 9,000 eggs per female (MBC 1987). 

Macewicz et al. (2004) report an average fecundity of 3,844 oocytes based on an average female length of 

129 mm (5.1 inches) dorsal mantle length (DML). 

Young squid hatch within three to five weeks after the capsule is deposited (McGowan 1954; Fields 

1965). Newly hatched squid (paralarvae) resemble miniature adults and are about 2.5–3.0 mm 

(0.1 inches) in length. After hatching, young Loligo swim upward toward the light, bringing them to the 

sea surface (Fields 1965). 

Butler et al. (1999) determined growth averages about 0.6 mm (0.02 inches) DML per day, and maximum 

ages in 1998 were 238 days for females and 243 days for males. Yang et al. (1986) recorded a maximum 

life span of 235 and 248 days for two laboratory-reared populations. Yang et al. (1986), Butler et al. 

(1999), and Jackson (1998) determined that Fields (1965) and Spratt (1979) underestimated growth and 

overestimated longevity—squid were initially reported to live as long as three years. Growth increases 

exponentially during the first two months, then slows to logarithmically thereafter (Yang et al. 1986). 

Schooling behavior has been observed in squid as small as 15 mm (0.6 inches) DML (Yang et al. 1986). 

Squid spawned in early summer (August -May) will grow rapidly during the summer growing season 

when nutrients from increased upwelling cause plankton blooms. As spawning continues from June 

through September, newly hatched squid have less time available in the growing season, which can slow 

the growth rate (Spratt 1979). Adults measure up to 305 mm (12 inches) total length and weigh between 

56 and 84 g (0.12 and 0.19 lbs) (Vojkovich 1998), with spawning males normally being larger than 

females. Males reach 19 cm DML (7.5 inches), a maximum weight of about 130 g (0.29 lbs), and have 

larger heads and thicker arms than females (PFMC 1998). Females reach about 17 cm DML (6.7 inches) 

and a maximum weight of 90 g (0.20 lbs). 

Planktonic invertebrates are the primary food source of young squid (Spratt 1979). Squid feed mostly on 

crustaceans, and to a lesser degree fishes, cephalopods, gastropods, and polychaetes (Karpov and Cailliet 

1979). The diet of market squid changes with water depth and location, but does not differ much among 

size classes or between sexes (Karpov and Cailliet 1979). Squid captured in deeper water feed more 
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IM&E Final Report Impingement Study

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frequently on euphausiids and copepods, whereas squid captured near the surface feed predominantly on 

euphausiids, as well as cephalopods, fish, mysids, and megalops larvae. In spawning schools, 75% of 

stomachs examined had remains of market squid (Fields 1965). 

Cailliet et al. (1979) determined affinities of multiple species with market squid. In Monterey Bay, the 

species with the highest affinities with market squid were northern anchovy, Pacific electric ray (Torpedo 

californica), Scyphomedusae (sea jellies), plainfin midshipman (Porichthys notatus), Pacific sanddab 

(Citharichthys stigmaeus), and white croaker. 

5.5.3.3.2 Population Trends and Fishery 

Large-scale fluctuations are characteristic of the squid stock, due primarily to its short life span and from 

the influence of wide variations in oceanographic conditions (NMFS 1999). However, the short life 

history of this species allows for squid to recover after natural population declines as soon as ocean 

conditions improve. The best information indicates squid have a high natural mortality rate (approaching 

100% per year) and that the adult population is composed almost entirely of new recruits (PFMC 1998). 

In 1997, California passed Assembly Bill AB 364, which not only initiated closures and established a 

fishery permit fee, but designated funds from the permits to be used for squid research and management. 

The California fishery for market squid began in Monterey Bay in the late-1800s (Vojkovich 1998). It 

expanded into southern California only after the 1950s, and prior to 1987, catches in southern California 

rarely exceeded 20,000,000 kg (44,100,000 lbs). After that, landings increased four-fold until the fishery 

collapsed in 1998, and California squid fishers sought federal disaster assistance (Zeidberg et al. 2004). In 

California, most squid marketed for human consumption is frozen, but smaller amounts are canned or 

sold fresh (PFMC 1998). Squid are also sold live and frozen for bait. Los Angeles area commercial 

landings have varied substantially since 2000, ranging between 7.7 and 44.8 million kg (16.9 and 

98.8 million pounds) annually (PacFIN 2007), with both the total catch and market value increasing 

substantially the last four years (Table 5.5-14). Los Angeles area landings in 2005 totaled 31,59,678 kg 

(69,573,734 lbs) at an estimated value of $18,511,585 (CDFG 2006). Landings in Long Beach area catch 

blocks in 2006 totaled 4,896,450 kg (10,794,643 lbs) at an estimated value of $2,647,959 (CDFG 2007). 

From 2001 through 2005, annual impingement of market squid ranged from 0 to 0.1 individuals per 

survey, and averaged less than 0.1 squid fish per survey (MBC 2006). 

Table 5.5-14. Annual landings and revenue for market squid in the Los Angeles region 

based on PacFIN data. 

Landed Weight 

Year kilograms pounds Revenue 

2000 44,831,189 98,854,319 $11,360,252 

2001 39,163,504 86,355,527 $8,491,578 

2002 28,155,199 62,082,214 $6,430,766 

2003 7,703,122 16,985,383 $4,424,230 

2004 10,501,964 23,156,830 $4,845,324 

2005 31,808,088 70,136,834 $18,664,223 

2006 37,053,145 81,702,193 $20,370,612 
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5.5.3.3.3 Sampling Results 

A total of 11 market squid was collected in impingement samples, with an estimated annual impingement 

of 78 individuals weighing 1.4 kg (3.0 lbs) (Table 5.5-2). All of the individuals were collected during 

normal operations. Almost all of the normal operation impingement occurred at Unit 6 (91% of annual 

abundance), with the other 8% recorded at Unit 1. Biomass was highest at Unit 6 with 98% of the total, 

with the other 2% recorded at Unit 1. 

Impingement of squid occurred between March and June 2006, with peak impingement density recorded 

in mid-March and early-April (Figure 5.5-50). Biomass followed a pattern similar to abundance (Figure 

5.5-51). There was no clear diel pattern of impingement with respect to abundance or biomass, which is 

likely a result of the low abundance of market squid (Figures 5.5-52 and 5.5-53). 

Length frequency analysis of 11 measured individuals indicated a mean mantle length (ML) of 104 mm 

(4.1 inches), which roughly corresponds to squid five to six months old (Figure 5.5-54). Of the 11 

individuals that were evaluated for condition factor, 91% were dead and the remaining 9% were 

mutilated; no squid were alive when they were processed. 

Survey Date

Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06 Jan-07 

Impingement Density (#/1,000,000 cubic meters)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Figure 5.5-50. Mean concentration (# / 1,000,000 m3

 [264.172 million gal] – wide bars) and standard 

error (narrow bars) of market squid in HnGS normal operation impingement samples during 2006. 
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IM&E Final Report Impingement Study

5-67 

Survey Date

Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06 Jan-07 

Impingement Density (kg/1,000,000 cubic meters) 0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

Figure 5.5-51. Mean biomass (kg / 1,000,000 m3

 [264.172 million gal] – wide bars) and standard error 

(narrow bars) of market squid in HnGS normal operation impingement samples during 2006. 

Impingement Density (#/1,000,000 cubic meters)

-20 -18 -16 -14 -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 14 16 18 20

Survey Date

1/1/2006 

2/1/2006 

3/1/2006 

4/1/2006 

5/1/2006 

6/1/2006 

7/1/2006 

8/1/2006 

9/1/2006 

10/1/2006 

11/1/2006 

12/1/2006 

1/1/2007 

Nighttime Daytime

Note: Negative nighttime values are a plotting artifact 

Figure 5.5-52. Mean concentration (# / 1,000,000 m3 [264.172 million gal]) of market squid in normal 

operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling. 
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Impingement Density (kg/1,000,000 cubic meters)

-0.5 -0.4 -0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4 0.5

Survey Date

1/1/2006 

2/1/2006 

3/1/2006 

4/1/2006 

5/1/2006 

6/1/2006 

7/1/2006 

8/1/2006 

9/1/2006 

10/1/2006 

11/1/2006 

12/1/2006 

1/1/2007 

Nighttime Daytime

Note: Negative nighttime values are a plotting artifact 

Figure 5.5-53. Mean concentration (kg / 1,000,000 m3 [264.172 million gal]) of market squid in normal 

operation impingement samples during night (Cycle 3) and day (Cycle 1) sampling. 

Length category (mm ML)

405060708090

100110120130140

Percent

0

10

20

30

40

50

60

70

N = 11

Mean = 104

Figure 5.5-54. Frequency distribution of mantle length measurements (mm) for 

market squid collected in impingement samples. 
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6.0 IMPACT ASSESSMENT

6.1 IMPACT ASSESSMENT OVERVIEW: DATA AND APPROACH

Section 316(b) of the Clean Water Act regulates cooling water intake systems at electrical generating 

facilities, and requires the location, design, construction, and capacity of cooling water intake structures 

reflect the best technology available (BTA) for minimizing adverse environmental impacts (AEI). In 

2004, EPA published Phase II 316(b) regulations for existing power plants, which established 

performance standards for reducing entrainment by 60−90% and impingement mortality by 80−95%. 

However, the Phase II regulations were suspended by EPA in 2007. On May 20, 2007, EPA transmitted a 

memorandum to regional administrators informing them that the Phase II rule should be considered 

suspended, and that “...all permits for Phase II facilities should include conditions under Section 316(b) 

of the Clean Water Act developed on a Best Professional Judgment basis. See 40 CFR 401.14.” As 

written, the Clean Water Act does not specify required cooling water intake system (CWIS) technologies 

or methods by which EPA must make its determinations under Section 316(b). 

Prior to the publication of the Phase II regulations in 2004, regulators relied on EPA’s (1977) draft 

guidelines for evaluating adverse impacts of cooling water intake structures to determine compliance with 

Section 316(b). At the HnGS, the previous 316(b) demonstration evaluated entrainment and impingement 

impacts using several methods, including: 

1. Evaluation of IM&E losses relative to known source populations, and 

2. Assigning a relative level of impact for each taxa analyzed. 

Under the previous 316(b) evaluation, impact analyses were conducted using several techniques. 

Entrainment losses were compared to source water populations, and estimates of ichthyoplankton 

entrainment were evaluated using an equivalent adult model. Impingement losses were compared with 

source populations calculated from demersal fish surveys, and also compared to recreational and 

commercial fishing landings. Lastly, impingement mortality was compared with instantaneous mortality 

rates for three fish species. In summary, there were no significant effects from the HnGS on the standing 

crop and natural mortality rates of the taxa analyzed. The ultimate conclusion of the HnGS 316(b) 

demonstration was that there were no significant adverse impacts on nearshore fish populations in the 

Southern California Bight from the operation of the HnGS, and the configuration of the intakes 

represented BTA for minimizing AEI. The intake technology evaluation in the previous report also 

included an assessment on the effects of switching to alternative intake technologies based on the levels 

of potential impact. 

Since the new Phase II regulations were based on performance standards for reducing entrainment and 

impingement and did not explicitly rely on determining whether existing levels represented an AEI, EPA 

determined the “...performance standards reflect the best technology available for minimizing adverse 

environmental impacts determined on a national categorical basis.” Although AEI was not intended to be 

used in assessing compliance under the new regulations, the potential for AEI was still considered in 

determining the types of plants and water body where the new performance standards would apply. Plants 

with low capacity factors and low cooling water volumes were considered to be BTA since their cooling 

systems had a low potential for AEI. 
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In its 1977 draft guidance document, EPA indicated “Adverse aquatic environmental impacts occur 

whenever there will be entrainment or impingement damage as a result of the operation of a specific 

cooling water intake structure. The critical question is the magnitude of any adverse impact.” USEPA 

also clarified in the guidance document: “Regulatory agencies should clearly recognize that some level of 

intake damage can be acceptable if that damage represents a minimization of environmental impact.”

In the 2006 IM&E study, entrainment and impingement losses were measured by collecting samples at 

the HnGS unit’s screens for impingement sampling and in the vicinity of the intakes within Alamitos Bay 

for entrainment sampling. The purpose of this impact assessment is to put the measured losses into 

context, and to evaluate the potential for AEI due to the CWIS. 

6.1.1 CWIS impacts 

There are three general types of effects associated with cooling water intake structures: (1) thermal 

effects, (2) impingement effects, and (3) entrainment effects. Thermal effects are regulated under Section 

316(a) of the Clean Water Act and the Water Quality Control Plan for Control of Temperature in the 

Coastal and Interstate Waters and Enclosed Bays of California (California Thermal Plan). The recent 

NPDES permit for the HnGS indicated that the generating station continues to operate in compliance with 

the California Thermal Plan. Entrainment occurs when organisms are drawn into a cooling water intake 

structure and subsequently pass through the HnGS. Organisms large enough to become trapped on the 

traveling screens are impinged. 

In discussing the potential effects of the HnGS CWIS on fish and shellfish populations the first thing that 

needs to be considered is the life history of the species in the community. First of all, several fish species 

in the nearshore coastal areas around HnGS have early life stages that are not susceptible to entrainment. 

Live-bearers, such as surfperches, and some sharks and rays, produce young that are fully developed and 

too large to be affected by entrainment. In addition, for fishes with entrainable life stages, the period of 

time that they are vulnerable to entrainment may be relatively short. As the results for HnGS show, many 

species are only vulnerable to entrainment for a few days when they are newly hatched since their 

swimming ability increases rapidly with age and development. Gobies, which were one of the most 

abundant taxa entrained, have demersal eggs, which are not subject to entrainment. Also, with increased 

age young post larval fishes begin searching for adult habitat, usually on the bottom, where they are not 

susceptible to entrainment. From the standpoint of impingement effects, one of the most abundant groups 

of species in protected bays and estuaries, gobies, are generally not susceptible to impingement after 

transformation to the juvenile life stage because they are bottom-dwelling species that typically do not 

move up into the water column. This is also true of many flatfishes, which are bottom-dwellers and also 

tend to be strong swimmers. Even fish species that swim in the water column are generally not susceptible 

to impingement effects as they mature because they are able to swim against the slow approach velocity 

of the cooling water inflow. 

6.1.2 Review of IM&E Sampling Approach 

The Phase II 316(b) regulations required that IM&E studies include “Documentation of current 

impingement mortality and entrainment of all life stages of fish, shellfish, and any protected species 

identified previously and an estimate of impingement mortality and entrainment to be used as the 

calculation baseline.” For the purposes of this study the term ‘shellfish’ was interpreted as including 
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6-3 

commercially and recreationally important species of crustaceans (crabs, lobsters, shrimp, etc.) and 

mollusks (squid and octopus) that are harvested on a regular basis from the coastal areas surrounding the 

HnGS. This definition does not include organisms such as clams, mussels, and other crustaceans and 

mollusks that may only be harvested occasionally for recreational purposes, although the entrainment 

processing was expanded, at the request of the LARWQCB staff, to include all crab megalops stage 

larvae, and the impingement sampling quantified all of the organisms. This definition was used because 

‘shellfish’ could also be considered as including all species of shelled invertebrates, including 

zooplankton, and clarification of the term was not provided in the regulations. 

The Rule’s entrainment performance standard focused on addressing impacts to fish and shellfish rather 

than lower tropic levels such as phyto- and zooplankton. EPA recognized the low vulnerability of phytoand zooplankton in its 1977 draft 316(b) guidance (USEPA 1977). There were several reasons why there 

is a low potential for impacts to phyto- and zooplankton and why it made sense for the USEPA to focus 

on effects on fish and shellfish. The reasons included the following: 

• The extremely short generation times; on the order of a few hours to a few days for 

phytoplankton and a few days to a few weeks for zooplankton; 

• Both phyto- and zooplankton have the capability to reproduce continually depending on 

environmental conditions; and 

• The most abundant phyto- and zooplankton species along the California coast have populations 

that span the entire Pacific or in some cases all of the world’s oceans. For example, Acartia tonsa, 

one of the common copepod species found in the nearshore areas of California is distributed 

along the Atlantic and Pacific coasts of North and South America and the Indian Ocean. 

Relative to the large abundances of phyto- and zooplankton, larval fishes make up a minute fraction of the 

total numbers of organisms present in seawater. The EPA has correctly focused on potential impacts on 

fishes and shellfishes because they are more susceptible to entrainment effects for the following reasons: 

• They have much shorter spawning seasons relative to phyto- and zooplankton. In many species, 

spawning occurs only once during the year; 

• Unlike phyto- and zooplankton that may be distributed over large oceanic areas, most fishes are 

restricted to the narrow shelf along the coast and in some cases have specific habitat requirements 

that further restrict their distribution; and 

• Unlike many phyto- and zooplankton, there is a greater likelihood of mortality due to entrainment 

in larval fishes, since many lower tropic level organisms are not soft bodied as is the case for 

finfish and are better able to tolerate passage through the cooling system. 

The impingement and entrainment sampling was therefore focused on fishes and shellfishes as required in 

the suspended 316(b) Phase II regulations. All of the fishes and shellfishes collected during the 

impingement sampling were counted and identified, while fish eggs and larvae, megalops stages of crabs, 

phyllosome larvae of spiny lobster, and squid larvae were identified and counted from the entrainment 

samples. The suspended 316(b) Phase II regulations provided latitude for focusing on the set of species 

that could be accurately quantified and that provided the necessary detail to support development of other 
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aspects of the CDS, and therefore, allowed for negotiating an acceptable compromise between the 

regulating agency and the discharger. The target group of organisms that were included in the entrainment 

sample processing was finalized at a January 12, 2006 meeting with staff from the LARWQCB and other 

resource agencies. 

The specific taxa (species or group of species) that were included in the assessment are limited to the taxa 

that are sufficiently abundant to provide reasonable assessments of impacts. For the purposes of this study 

plan, the taxa analyzed in the assessment were limited to the most abundant taxa that together comprised 

90−95% of all larvae entrained and/or juveniles and adults impinged by the generating station. The most 

abundant taxa were used in the assessment because they provide the most robust and reliable estimates for 

the purpose of assessing impacts. Since the most abundant organisms may not necessarily be the 

organisms that experience the greatest effects on the population level, the data were also examined to 

determine if additional taxa should be included in the assessment. For example, this might include 

commercially or recreationally important taxa, taxa with limited habitats, and any threatened or 

endangered fish or shellfish species. No listed species were entrained or impinged at the HnGS during the 

study and no additional taxa beyond the taxa selected based on sampling abundance were included in the 

assessment. 

Results for individual taxa from the impingement and entrainment sampling need to be combined, where 

possible, to evaluate the combined effects of the CWIS. This is done by extrapolating the numbers of 

adult and juvenile fishes impinged to the same age used in the adult equivalent loss (AEL) and fecundity 

hindcasting (FH) models for the entrainment data and in the equivalent adult model (EAM) for the 

impingement data. The age used in the AEL, FH, and EAM modeling was the age of first maturity where 

approximately 50% of the females in the population are reproductive. Unfortunately, the life history 

information necessary for the modeling is unavailable for most species so combined assessments were 

only possible for a few species including northern anchovy, gobies, and combtooth blennies. EAM could 

only be calculated for queenfish, northern anchovy, and Pacific sardine. 

6.1.3 Approaches for Assessment of CWIS Impacts 

Due to the suspension of the 316(b) Phase II rule, state and federal permit writers have been directed to 

implement Section 316(b) on a case-by-case basis using “best professional judgment”. In the case of the 

HnGS, the permit applicant is obligated to provide the Los Angeles RWQCB with the “best information 

reasonably available” to assist it in fulfilling its decision-making responsibility. To make Section 316(b) 

decisions, permit writers have relied on precedent from other cases and on USEPA’s (1977) draft 

“Guidance for Evaluating the Adverse Impact of Cooling Water Intake Structures on the Aquatic 

Environment: Section 316(b) P.L. 92-500.” 

As is clear from the statute, the permit writer must consider two basic issues in making a finding that an 

intake technology employs the BTA for minimizing AEI: 

1. Whether or not an AEI is caused by the intake and, if so, 

2. What intake structure represents BTA to minimize that impact. 

The usual approach for a 316(b) demonstration would be to consider the question of BTA only if a 

determination has been made that a facility is causing an AEI. 
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6.1.3.1 Adverse Environmental Impact (AEI) Standard 

Since there were no regulations defining AEI, permit decisions must be based on the EPA’s AEI 

interpretations provided in guidance documents issued since the 1970’s. In those documents, the EPA has 

indicated that assessment of AEI should be based on an evaluation of population level effects, not just 

losses of individual organisms. In its 1975 Draft BTA Guidelines, the EPA stated that “[a]dverse 

environmental impacts occur when the ecological function of the organism(s) of concern is impaired or 

reduced to a level which precludes maintenance of existing populations...”. Additionally, in the 1976 

Development Document, released in conjunction with the EPA’s previous Section 316(b) rules, the EPA 

said that “[t]he major impacts related to cooling water use are those affecting the aquatic ecosystems. 

Serious concerns are with population effects that...may interfere with the maintenance or establishment 

of optimum yields to sport or commercial fish and shellfish, decrease populations of endangered 

organisms, and seriously disrupt sensitive ecosystems.” 

EPA (1977) draft guidelines acknowledge that the determination of the extent of AEI when it is occurring 

is difficult to assess. They state that “Adverse aquatic environmental impacts occur whenever there will 

be entrainment or impingement damage as a result of the operation of a specific cooling water intake 

structure. The critical question is the magnitude of any adverse impact. The exact point at which adverse 

aquatic impact occurs at any given plant site or water body segment is highly speculative and can only be 

estimated on a case-by-case basis...” 

Due to the obvious difficulties with determining the extent of AEI, the document (USEPA 1977) provides 

some general guidelines. These involve determining the “relative biological value of the source water 

body zone of influence for selected species and determining the potential for damage by the intake 

structure” based on the following considerations of the value of a given area to a particular species: 

• principal spawning (breeding) ground; 

• migratory pathways; 

• nursery or feeding areas; 

• numbers of individuals present; and 

• other functions critical during the life history. 

Following this general approach provided by the USEPA (1977), additional criteria can be evaluated that 

are specific to the marine environment around HnGS that are directly applicable to the present 316(b) 

study: 

• distribution (pelagic, subtidal, nearshore subtidal & intertidal); 

• range, density, and dispersion of population; 

• population center (source or sink); 

• magnitude of effects; 

• long-term abundance trends (e.g., fishery catch data); 

• long-term environmental trends (climatological or oceanographic); and 

• life history strategies (e.g., longevity and fecundity). 
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By assessing the relative value of each of these criteria for a particular taxon, we will be able to better 

assess the extent of the impact that the loss of these animals has on the local environment and the 

population at large. 

6.1.4 Relating Measured Impacts to Source Populations 

The potential magnitude of the losses due to entrainment and impingement depend on many factors 

including the physical characteristics of the source water body, and the biological characteristics of the 

affected populations including the following: 

• Reproductive biology that affects the vulnerability of certain life stages, such as surfperches and 

sharks and rays with no planktonic larval phase, 

• Distribution and habitat preferences that affect vulnerability, and 

• Duration of time that larval and juvenile stages are vulnerable due to behavior, mobility, and 

habitat preferences. 

The criteria used to evaluate the potential for AEI need to be placed into a larger context using the 

characteristics of the source water and the biological community. This assessment focuses on a set of 

species that were collected during the study in adequate abundances to provide reasonable confidence in 

the estimates of entrainment and impingement effects. These species were also selected to be broad 

enough to include representatives from the different habitats and species groups present in the source 

water. As previously discussed (Section 6.1.1), not all of the fishes and shellfishes in the source water are 

subject to entrainment or impingement, and only a few species occur in high abundance in both 

entrainment and impingement samples. These differences in the vulnerability to entrainment and 

impingement occur due to different life histories of the species, and the differences in habitat preferences 

and behavior that may occur at different life stages. While these factors contribute to the potential 

magnitude of the losses due to entrainment and impingement we will focus primarily on the distribution 

of the species and their habitats to organize the assessment and determine which species are at greatest 

risk of AEI. Using this approach, an example of a species at high risk would be a rare or endangered 

species with a distribution that was limited to the area around the HnGS intake in Alamitos Bay. In 

contrast, a species at low risk of AEI would be one such as northern anchovy that is abundant over a large 

expanse of coastline. To determine the spatial extent of the effective source populations of larvae for 

modeling entrainment effects, data on water current flow and direction were collected during the study. 

The focus of the assessment will be on species with adult populations in the nearshore areas of Alamitos 

Bay that are directly affected by entrainment and impingement at the HnGS CWIS. Therefore, the 

following criteria from the list in the previous section can be used to focus the assessment on species with 

adult and larval distributions that would place them at greatest risk to entrainment and impingement 

effects: 

• distribution (pelagic, subtidal, nearshore subtidal & intertidal), 

• range, density, and dispersion of population; and 

• population center (source or sink). 
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These criteria relate directly to the habitats associated with the fish and shellfish potentially affected by 

entrainment and impingement. This approach to classification has been taken in recent studies of marine 

fishes of California (Horn and Allen 1978; Allen 1985; Allen and Pondella 2006) and will be used to 

organize the taxa included in this assessment. We have simplified the more detailed categorization of 

habitats used by Allen and Pondella (2006) which included several habitats used to define deeper offshore 

areas (Figure 6.1-1). These deeper offshore habitat types can be combined for the purposes of our 

assessment since the taxa associated with those habitats are generally not at risk due to entrainment and 

impingement and were collected in very low numbers. The habitats defined by Allen and Pondella (2006) 

have been simplified for this assessment to the following habitat types: 

• bays, harbors, and estuaries; 

• subtidal and intertidal rocky reefs and kelp beds; 

• coastal pelagic; 

• continental shelf and slope; and 

• deep pelagic including deep bank and rocky reefs. 

The taxa included in this assessment were categorized into these habitat types (Table 6.1-1). Taxa that 

occur in more than one habitat will be included in the habitat group that best reflects the primary 

distribution for the taxa and if a primary habitat cannot be identified, the one that places them at greatest 

risk to the effects of entrainment and impingement. For example, silversides occur in both bay and harbor, 

and coastal pelagic habitats but since their occurrence in bay and harbor habitats places them at greater 

risk to power plant effects they will be treated along with other taxa specific to that habitat. This raises an 

important point in regards to impact assessment. Taxa that occupy several different habitats will be less at 

risk from power plant impacts especially if at least one of the habitats is not directly affected by 

entrainment and impingement. For example, white croakers occur in bays and harbors where they are 

directly at risk to impingement and entrainment at HnGS but also in sandy shallow nearshore areas where 

they are not at risk. 

This approach to assessing AEI is consistent with a recent trend in fisheries management to ecosystem 

based management (Larkin 1996, Link 2002; Mangel and Levin 2005). This approach recognizes that 

commercial fishing stocks can only be protected if the habitats and other components of the ecosystem are 

protected. An ecosystem-based approach also addresses other human activities in addition to fishing and 

the environmental factors that affect an ecosystem, the response of the ecosystem, and the outcomes in 

terms of benefits and impacts on humans. In this context it will help identify the habitats most at risk to 

CWIS effects and help identify a broader context for the effects relative to the entire ecosystem. If 

restoration were to be allowed as a compliance alternative, this approach to assessment would focus the 

restoration scaling with the appropriate species from the identified habitats. 
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Figure 6.1-1. Marine habitat types in California (from Allen and Pondella [2006]). 
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Table 6.1-1. Habitat associations for taxa included in assessment of CWIS effects at the HnGS. Primary 

habitat in bold, upper case and secondary habitat in lower case. 

 Fishery Habitats 

Scientific name Common name 

S-Sport, 

C-Comm.

bays, 

harbors

reefs, 

kelp 

beds 

coastal 

pelagic shelf 

Fishes 

Atherinopsidae unid. silversides S, C X x

Cymatogaster aggregata shiner perch S X x 

Engraulidae unid. anchovies C X 

Genyonemus lineatus white croaker S, C x X x 

Gobiidae unid. CIQ goby complex X 

Hypsoblennius spp. combtooth blennies X x

Porichthys myriaster specklefin midshipman X x 

Raja inornata California skate C x X 

Sardinops sagax Pacific sardine C x X 

Sebastes miniatus vermilion rockfish S, C X 

Seriphus politus queenfish S X x

Syngnathidae pipefishes X 

Trachurus symmetricus jack mackerel S, C x X 

Shellfishes/Invertebrates 

Aplysia californica California seahare C x X 

Loligo opalescens market squid S X 

Octopus spp. California two-spot 

octopus C x X 

6.2 SUMMARY OF ENTRAINMENT AND IMPINGEMENT RESULTS

The following section summarizes the combined results of the entrainment and impingement studies at 

HnGS to provide an overview of annual impacts to marine life that are directly attributable to operations 

at the generating station. Earlier sections of the report provide greater detail and explanation of the results 

on individual species, and the information in this section provides an overview of the major results. In 

addition, for those species such as northern anchovy that were affected by both entrainment of eggs and 

larvae and impingement of juveniles and adults, the data are summarized together for all life stages. In 

order to compare predicted effects of IM&E on such species, calculated losses are standardized to a 

common age-class that represents fishes at the age of maturity for that species. In later sections, the 

information on calculated losses is compared to long-term population trends and then discussed in terms 

of adverse environmental impacts. 

6.2.1 Taxa Composition 

Data from the bi-weekly entrainment surveys conducted at the HnGS cooling water intakes were used to 

calculate that an estimated 3.65 billion fish larvae and 1.69 billion fish eggs were entrained through the 

generating station CWIS in 2006 (Table 6.2-1). If all circulating water pumps had been in operation 

during the entire year, larval entrainment would have increased by 24% to 4.53 billion, and egg 
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entrainment would have increased by 25% to 2.12 billion. Approximately 50% of the larvae were gobies, 

25% were silversides, 20% were combtooth blennies, 2% were white croaker, and thirty-two other species 

each contributed about 1% or less of the annual total. Larvae from 36 taxa were represented in the 

collections. Many of the larvae and eggs could not be positively identified to the species level, and this 

added some uncertainty to the estimates of annual entrainment for individual species. The most abundant 

taxonomic group of fish eggs in the samples were unidentified eggs (71%), followed by the composite 

category of sand flounder eggs (11%). Eggs of approximately 13 fish taxa were represented in the 

collections. A complete listing of all of the taxonomic categories identified during the study is presented 

in Appendix F. 

There were an estimated 14.9 million target shellfish larvae entrained represented by 9 taxa (Table 6.2-1). 

Shore crab megalops comprised 29% of the annual entrainment of target invertebrate larvae. Species with 

commercial fishery value included spider crabs with 0.6 million megalops entrained under actual flows 

(0.8 million for design flows) while market squid hatchlings had 0.2 million paralarvae entrained under 

actual flows (0.3 million for design flows; Table 4.5-4). 

Data from the weekly normal operations sampling and the five heat treatment surveys were used to 

estimate that annual fish impingement at the HnGS from a total of 60 taxa groups was 53,442 individuals 

weighing 529.8 kg (1,168 lbs) based on actual cooling water flows, and 56,613 individuals weighing 

556.5 kg (1,227 lbs) based on design cooling water flows (Table 6.2-2). The most abundant species by 

number impinged were queenfish, topsmelt, northern anchovy, and bay pipefish while specklefin 

midshipman, round stingray, and Pacific electric ray contributed to these species to substantially increase 

the total biomass impinged. 

Annual macroinvertebrate impingement estimates at the HnGS were 20,346 individuals weighing 

268.8 kg (592.7 lbs) from 49 taxa based on actual cooling water flows, and 21,773 individuals weighing 

293.8 kg (647.7 lbs) based on design cooling water flows (Table 6.2-3). Red jellyfish was the most 

abundant species, followed by the nudibranch Hermissenda crassicornis, tuberculate pear crab, and 

yellow shore crab. Combined these species accounted for 60% of the sampled impingement abundance. 
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Table 6.2-1. Rank and estimated annual entrainment of most common fish larvae, fish eggs, 

and target shellfishes at HnGS in 2006. 

Rank Taxa 

Est. Annual 

Entrainment 

(actual flows) 

Est. Annual 

Entrainment 

(designflows) 

% Comp 

(actual flows) 

Cumulative % 

Comp. 

Fish Larvae 

1 gobies 1,828,364,516 2,334,220,376 50.10 50.10 

2 silversides 920,323,104 1,062,818,072 25.22 75.32 

3 combtooth blennies 732,022,349 915,313,887 20.06 95.38 

4 white croaker 75,425,299 96,188,344 2.07 97.45 

5 anchovies 22,673,541 27,301,289 0.62 98.07 

31 Other taxa 70,399,582 91,802,117 1.93 100.00 

 3,649,208,392 4,527,644,084 

Fish Eggs 

1 unidentified fish eggs 1,191,101,773 1,474,924,676 70.58 70.58 

2 sand flounder eggs 183,531,130 236,704,432 10.88 81.46 

3 fish eggs 90,493,059 109,555,973 5.36 86.82 

4 sanddab eggs 63,124,903 80,387,665 3.74 90.56 

5 white croaker eggs 57,836,910 86,480,192 3.43 93.99 

8 Other taxa 101,508,151 129,615,937 6.01 100.00 

 1,687,595,926 2,117,668,875 

Target Shellfishes 

1 shore crab megalops 4,264,792 5,217,248 28.71 28.71 

2 kelp crabs megalops 3,629,771 4,586,866 24.44 53.15 

3 pea crabs megalops 2,031,387 2,574,200 13.68 66.82 

4 unidentified crab megalops 1,949,343 2,464,009 13.12 79.94 

5 Brachyura crab megalops 1,549,133 1,826,174 10.43 90.37 

4 Other taxa 1,430,273 1,827,475 9.63 100.00 

 14,854,700 18,495,973 
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Table 6.2-2. Rank and estimated annual impingement of the most common fish taxa at HnGS in 2006 by 

estimated abundance and weight for actual and design normal flows. Heat treatment mortality included. 

Rank Common Name 

Total No. 

Actual Flows 

Total No. 

Design Flows 

% Total

Actual Flows 

Cumulative 

% Total

Actual 

Flows 

1 queenfish 30,946 32,389 57.91 57.91 

2 topsmelt 6,315 6,747 11.82 69.72 

3 northern anchovy 3,443 3,923 6.44 76.16 

4 bay pipefish 3,157 3,286 5.91 82.07 

5 northern anchovy larvae 2,351 2,590 4.40 86.47 

6 pipefish, unid. 1,373 1,490 2.57 89.04 

7 white croaker 861 877 1.61 90.65 

8 specklefin midshipman 620 632 1.16 91.81 

9 shiner perch 582 628 1.09 92.90 

10 giant kelpfish 462 517 0.86 93.77 

50 Other taxa 3,332 3,534 6.23 100.00 

 53,442 56,613 

 

Total Wt. (kg) 

Actual Flows 

Total Wt. (kg) 

Design Flows 

% Total 

Actual Flows 

Cumulative 

% Total 

Actual 

Flows 

1 specklefin midshipman 157.23 161.77 29.68 29.68 

2 round stingray 98.05 105.66 18.51 48.18 

3 Pacific electric ray 97.59 97.59 18.42 66.60 

4 topsmelt 29.44 32.40 5.56 72.16 

5 bat ray 24.64 24.66 4.65 76.81 

6 queenfish 19.47 20.36 3.67 80.48 

7 shiner perch 12.03 13.33 2.27 82.75 

8 jacksmelt 11.53 13.80 2.18 84.93 

9 midshipman, unid. 11.29 13.01 2.13 87.06 

10 diamond turbot 9.63 9.64 1.82 88.88 

 50 Other taxa 58.93 64.27 11.12 100.00 

 529.83 556.48 
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Table 6.2-3. Rank and estimated annual impingement of the most common invertebrates at HnGS in 2006 

by estimated abundance and weight for actual and design normal flows. 

Heat treatment mortality included. 

Rank Common Name 

Total No. 

Actual Flows 

Total No. 

Design Flows 

% Total

Acutal Flows 

Cumulative 

% Total

Actual 

Flows 

1 red jellyfish 4,562 4,850 22.42 22.42 

2 hermissenda 2,900 3,020 14.25 36.68 

3 tuberculate pear crab 2,560 2,794 12.58 49.26 

4 yellow shore crab 2,272 2,482 11.17 60.42 

5 California aglaja 1,697 1,878 8.34 68.77 

6 moon jelly 1,102 1,165 5.42 74.18 

7 Xantus swimming crab 691 712 3.40 77.58 

8 scallop, unid. 624 683 3.07 80.64 

9 intertidal coastal shrimp 506 536 2.49 83.13 

10 zebra leafslug 446 484 2.19 85.32 

 46 Other Taxa 2,986 3,169 14.68 100.00 

 20,346 21,773 

 

Total Wt. (kg) 

Actual Flows 

Total Wt. (kg) 

Design Flows 

% Total 

Actual Flows 

Cumulative 

% Total 

Actual 

Flows 

1 California seahare 79.41 93.13 29.54 29.54 

2 moon jelly 57.38 59.60 21.34 50.89 

3 Calif. two-spot octopus 54.78 57.88 20.38 71.27 

4 California aglaja 32.29 35.92 12.01 83.28 

5 red jellyfish 16.55 17.43 6.16 89.44 

6 Xantus swimming crab 9.26 9.56 3.45 92.88 

7 California bubble 3.52 3.59 1.31 94.19 

8 ring-spotted dorid 2.49 2.80 0.93 95.12 

9 yellow shore crab 1.99 2.18 0.74 95.86 

10 tuberculate pear crab 1.90 2.07 0.71 96.57 

 46 Other Taxa 9.23 9.68 3.43 100.00 

 268.80 293.83 

6.2.2 Temporal Occurrence 

Greatest densities of larval fishes occurred in May and August, and the least numbers of fishes occurred 

in November (Figure 4.5-1). Fish eggs also peaked in abundance from March−April with lows occurring 

in January and November (Figure 4.5-2). Although this is a typical pattern that is associated with 

spawning during spring upwelling periods in high productivity coastal waters, some species have welldefined seasonal spawning peaks that may occur in either winter or summer months. Larvae and eggs 

were generally more abundant in samples collected at night than those collected during the day in most 

surveys (Figure 4.5-3 and 4.5-4). 
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The highest fish abundance during weekly normal operation impingement surveys occurred from July to 

September 2006 (Figures 5.5-1 and 5.5-2), while biomass was highest from April to May 2006 (Figures 

5.5-3 and 5.5-4). Invertebrate impingement was highest from April to May, while biomass was variable 

with peaks in late-March, late-April, and early-August. In general, fish impingement abundance was 

greatest during nighttime, though biomass was greater during the day (Figures 5.5-5 and 5.5-6). 

6.2.3 Combined Analysis and Modeling Results for Selected Species 

Several species of fishes and shellfishes that were abundant in either the entrainment or impingement 

samples, had recreational or commercial fishery value, or were federally managed species were analyzed 

in detail in Sections 4 and 5. Some of the larval taxa had sufficient information available on their life 

history to estimate losses based on conversion to adult equivalents. In addition, some of the impinged taxa 

abundances could also be scaled to adult equivalents. The results of these analyses are summarized by 

actual flow rates at HnGS in 2006 (Table 6.2-4) and design flow rates for the HnGS CWIS (Table 6.2-5). 
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Table 6.2-4. Summary of entrainment and impingement sampling results and model output for common fish and inverteb

actual flows at HnGS in 2006. 

Species Common Name 

Est. Annual 

Larval Ent. 

(millions) 

Est. Annual 

Egg Ent. 

(millions) 

ETM

PM (%) 2*FH AEL 

Annual

Imping.

Estimate 

Fishes Gobiidae2 gobies 1,828.4 0 25.15 3,932,562L 1,671,266L 7 

Atherinopsidae unid.3 silversides 920.3 11.5 40.95 6,315 

Hypsoblennius spp. combtooth blennies 732.0 0 13.89 836,002L 1,783,945L 32 

Genyonemus lineatus white croaker 75.4 57.8 0.63 64E 861 

Engraulis mordax northern anchovy 22.7 11.1 0.76 8,600C 20,634L 5,7944 

Seriphus politus queenfish 2.5 0 30,946 Syngnathus spp. pipefishes 3.1 − 4,553 

Porichthys myriaster specklefin midshipman − − 620 

Cymatogaster aggregata shiner perch − − 582 Sardinops sagax Pacific sardine 0.3 0 90 Raja inornata California skate − − 8 

Trachurus symmetricus jack mackerel 0 0 7 

Sebastes miniatus vermilion rockfish 0 0 7 

Invertebrates 

Octopus spp. California two-spot octopus − − 337 

Aplysia californica California seahare − − 195 

Loligo opalescens market squid 0.2 − 78 

1standardized impingement adult equivalent mortality 2only cheekspot goby collected in impingement samples 3only topsmelt was collected in abundance in impingement samples 4Engraulis mordax larvae collected from impingement sampling are combined with adults 

Model estimates indicate whether the number was based on eggs (E), larvae (L), or both combined (C). 
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Table 6.2-5. Summary of entrainment and impingement sampling results and model output for common fish and inverteb

design flows at HnGS in 2006. 

Species Common Name 

Est. Annual 

Larval Ent. 

(millions) 

Est. Annual 

Egg Ent. 

(millions) 

ETM

PM (%) 2*FH AEL 

Annual

Imping.

Estimate 

Fishes Gobiidae2 gobies 2,334.2 0 31.7 5,020,588L 2,133,657L 7 

Atherinopsidae unid.3 silversides 1,062.8 20.8 46.9 6,747 

Hypsoblennius spp. combtooth blennies 915.3 0 17.7 1,045,330L 2,230,628L 32 

Genyonemus lineatus white croaker 96.2 86.5 0.79 96E 877 

Engraulis mordax northern anchovy 27.3 14.0 0.92 10,364C 24,845L 6,5134 

Seriphus politus queenfish 2.9 0 32,389 Syngnathus spp. pipefishes 3.8 − 4,801 

Porichthys myriaster specklefin midshipman − − 632 Cymatogaster aggregata shiner perch − − 628 Sardinops sagax Pacific sardine 0.3 0 98 Raja inornata California skate − − 9 

Trachurus symmetricus jack mackerel 0 0 7 

Sebastes miniatus vermilion rockfish 0 0 7 

Invertebrates Octopus spp. California two-spot octopus − − 353 

Aplysia californica California seahare − − 221 

Loligo opalescens market squid 0.3 − 78 

1standardized impingement adult equivalent mortality 2only cheekspot goby collected in impingement samples 3only topsmelt was collected in abundance in impingement samples 4Engraulis mordax larvae collected from impingement sampling are combined with adults 

Model estimates indicate whether the number was based on eggs (E), larvae (L), or both combined (C). 
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6.3 ASSESSMENT OF TAXA BY HABITAT TYPE

The following sections present assessments for taxa from the five habitat types simplified from Allen and 

Pondella (2006). A general discussion of the habitat and the potential risk to the habitat due to HnGS 

operation will be followed by discussion of the specific impacts to the fishes and shellfishes included in 

the assessment for each habitat type (Table 6.1-1). 

6.3.1 Background on Oceanographic Setting and Population Trends 

Water temperatures and current patterns have a significant effect on marine faunal composition. 

Understanding the nature of the variability in these physical factors is essential for explaining long-term 

population trends for many marine species. The Southern California Bight, defined as the nearshore 

coastal area from Point Conception south into Baja California, is a transition zone between the cool 

temperate Oregonian fauna, to the north and the warm temperate San Diegan fauna to the south. This 

transition is caused by the geology and oceanic current structure of the region. The source of cold water is 

the California Current, the eastern branch of the North Pacific Gyre. The strength of the California 

Current varies on many time frames. On a multi-decadal scale it oscillates between a warm and cold 

phase referred to as the Pacific Decadal Oscillation (PDO). During the warm phase the PDO is relatively 

weaker than average, while during the cold phase it is stronger than average. This multi-decadal 

oscillation has had a significant effect of the Southern California Bight (SCB) and the most pertinent 

debate concerns when it will switch back to a cold phase (Bograd et al. 2000; Durazo et al. 2001; LluchBelda et al. 2001). During the cold phase, the bight is colder than average and dominated by the 

Oregonian fauna. The opposite is the case for the warm phase; the bight is warmer than average and 

dominated by the San Diegan fauna. There have been three transitions in the PDO over the last century. 

The most recent oscillation of the PDO caused a regime shift starting in the late 1970’s that was 

completed by the end of the 1982−1984 El Niño, the largest El Niño recorded at that time (Stephens et al. 

1984; Holbrook et al. 1997). 

The strength of the PDO varies annually and the most important phenomenon with respect to this 

variation is the El Niño Southern Oscillation (ENSO). This oscillation consists of two components, El 

Niño and La Niña periods. El Niño causes the California Current to weaken and move offshore as warm 

subtropical water moves into the bight. The rebound from this event is the shift to La Niña, which in 

effect is manifested as a strengthening of the California Current and generally cooler water in the bight. 

Either phase of an ENSO generally lasts 1−2 years, depending upon their strength, and are particularly 

important for understanding fish dynamics in the SCB for a variety of reasons. First, in the El Niño phase, 

the bight is warmed and mobile warm-water fishes and invertebrates immigrate or recruit into the region 

(Lea and Rosenblatt 2000; Pondella and Allen 2001). Cold water forms migrate out of the region, move 

into deeper (cooler) water or are extirpated. During the La Niña phase, the SCB usually, but not always, is 

cooler than normal, and we observe an increase in cold temperate (Oregonian fauna) organisms through 

the same processes. Highly mobile organisms will immigrate or emigrate from the bight during these 

periods; and on smaller spatial scales less mobile organisms may exhibit offshore versus onshore 

movements. However, the resident fauna tends not to be altered on such short time frames when 

compared to the magnitude of the PDO. 
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In the decade prior to this study there were three major events that affected the California Current System 

that need to be explained in order to understand the oceanographic setting of this study period. The first 

was the 1997−98 El Niño, the strongest recorded event of its kind. This was followed by a series of four 

cold water years (1999−2002) including the strongest La Niña on record (Schwing et al. 2000; Goericke 

et al. 2005). The possible return to the cold water phase of the PDO did not occur since 2003−2004 was 

described as a ‘normal’ year (Goericke et al. 2005). This normal year turned out to be the beginning of an 

extended warm phase that has persisted through 2006 (Peterson et al. 2006; Figure 6.3-1). Thus, the 

oceanographic context for this study can best be described as a warm phase of the PDO that has persisted 

for three years. Prior to this warm phase were four unusually cool years. 

Newport Pier Sea Surface Temperature

1970197119721973197419751976197719781979198019811982198319841985198619871988198919901991199219931994199519961997199819992000200120022003200420052006

Temperature Deviation (°C)

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5 El Niño

La Niña

Warm Phase

PDO Transition

Figure 6.3-1. Sea surface temperature anomalies for Newport Pier, California. Values are ± the longterm average (1925-2006). 

To determine the current population status of fishes and invertebrates in the SCB requires placing this 

data into an appropriate long-term context. From an oceanographic standpoint, the influences that were 

associated with change over time are the PDO, the ENSO, and the associated ocean temperature changes. 

These oceanographic metrics are interconnected with each other and have effects in the SCB on varying 

time scales. In order to understand the responses of organisms in the SCB to these various environmental 

metrics, it is important to realize the general trends for the region (Brooks et al. 2002) and that each taxon 

may have a unique response to these metrics based upon its life history characteristics and evolution. 

In addition, to the real time responses these organisms have to oceanographic parameters, anthropogenic 

influences also have significant effects. Currently, the most extensively studied anthropogenic effects are 

related to over fishing and the various management actions associated with fishing. In the SCB, all of the 

top-level predators (with the exception of marine mammals) were over fished during the last seven 

decades (Ripley 1946; Love et al. 1998; Allen et al. in press; Pondella and Allen, in review). The effects 
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of fisheries were also species specific, as the effort, type of fishery and associated management actions 

vary case by case. Some fishes were reserved for recreational anglers (e.g., kelp bass, barred sand bass) as 

they were historically over fished by commercial fishers (Young 1963); others were primarily commercial 

species (e.g., anchovies); while others are extracted by both fisheries (e.g., California halibut). Fishery 

data may or may not reflect actual population trends due to socioeconomic considerations such as market 

value, effort, management actions, etc. Fishery independent monitoring programs produce the best 

population time series metrics and also allow non-commercial species to be evaluated. 

6.3.1.1 Habitat Associations and Fisheries 

Entrained larvae were categorized in terms of the habitat types typically utilized by juveniles and adults, 

and the type of fishery, if any, that the species supports. Most larval taxa were from species typically 

found associated with the types of habitats in close proximity to the intake: bay, shelf sand bottom, and 

rocky reef. Species primarily associated with the bays and harbor habitat (e.g., gobies, blennies) had the 

highest number of taxa entrained and impinged (66.7%; Table 6.3-1) and the greatest number entrained 

and impinged (98.7% and 75.0% respectively). Sport fishery species accounted for approximately 27.4% 

of the total number of larvae entrained and commercial fishery species accounted for 28.4%, while 

species with no direct fishery value comprised the majority (71.5%) of the larvae entrained. (Note that 

some species such as white croaker were classified as both a sport and commercial fishery species). 

Approximately 80% of the impinged species and biomass were from fish and rays that have no direct 

fishery value. 

Table 6.3-1. Percent of larvae entrained (abundance) or adults/juveniles impinged (biomass) 

associated with general habitat types and fisheries. 

Attributes 

Entrained % 

of taxa 

Entrained %

of abundance 

Impinged % 

of taxa 

Impinged % 

of biomass 

Habitat Association 

Continental shelf / slope 39.39 2.55 31.67 28.62 

Bays, Harbors 66.67 98.71 66.67 74.97 

Rocky reef, Kelp 39.39 21.23 33.33 8.89 

Coastal pelagic 27.27 28.31 30.00 15.32 

Deep pelagic 3.03 0.01 0.00 0.00 

Fishery 

Sport 39.39 27.43 36.67 18.56 

Commercial 33.33 28.35 33.33 15.18 

None 45.45 71.51 53.33 79.72 

Note: Percentages do not total 100% because species may have more than one associated habitat and fishery. 

The percentages of taxa associated with different habitats are very similar for both entrainment and 

impingement with the largest percentage of the taxa being associated with the bay and harbor habitat 

where the intake is located (Table 6.3-1). The percentages for bay and harbor taxa increase for abundance 

and biomass since these taxa were entrained and impinged in much higher numbers than taxa from other 

habitats. As the percentages show, many of these are not targeted by sport or commercial fishing. 

Although fishes and shellfishes from other habitats occur in bay and harbors, the taxa with the greatest 

potential for CWIS losses from HnGS will be the taxa that only occur in that habitat such as gobies and 

pipefishes (Table 6.1-1). 
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6.3.2 Bay and Harbor Habitats 

This habitat type includes, bay, harbors and estuaries that are either entirely marine and largely influenced 

by tidal movement of seawater, or estuarine areas where seasonal freshwater input lowers salinities in 

some areas of the habitat. Much of the nearshore habitat in the vicinity of HnGS is of the bay and harbor 

type including Alamitos Bay, Anaheim Bay and the much larger Los Angeles-Long Beach Harbor 

Complex nearby. Although no undisturbed wetland areas still exist within the highly developed Harbor 

Complex, there is a small wetlands area, Cerritos Wetland, inside Alamitos Bay, and extensive salt marsh 

areas within Anaheim Bay. Characteristic fishes from these habitats in Alamitos Bay would include 

deepbody anchovy, bay pipefish, and bay blenny (Allen and Pondella 2006). Approximately two-thirds of 

the fish species and almost all of the entrained fish larvae collected during the IM&E sampling had some 

dependency on bay and harbor habitats during at least some stage of their life, and it is considered the 

primary habitat for six fish taxa included in this assessment: CIQ gobies, silversides, combtooth blennies, 

specklefin midshipman, shiner perch, and pipefishes (Table 6.1-1). While CIQ gobies and pipefishes 

occur almost exclusively in these habitats, two species of combtooth blennies, the rockpool blenny 

(Hypsoblennius gilberti) and mussel blenny (Hypsoblennius jenkinsi), also inhabit shallow intertidal and 

subtidal rocky reef habitats, and silversides, specklefin midshipman, and shiner perch also occur on the 

outer coast. 

Annual entrainment of goby larvae was estimated to be 1.8 billion larvae based on actual flow volumes 

and 2.3 billion larvae based on design flow volumes (Tables 6.2-4 and 6.2-5). No goby eggs were 

entrained because eggs are laid in nests and are not vulnerable to entrainment until they hatch as larvae. 

The entrainment and source water data on larval concentrations were used to estimate that 25% of the 

larval goby populations were potentially lost due to entrainment based on actual flows (Table 6.2-4). 

Based on the design flows, this estimate increases to 31.7% (Table 6.2-5). The entrainment losses were 

also used to estimate that the larvae entrained would have resulted in the production of 1.7-3.9 million 

adult gobies based on actual flow volumes. Gobies were not common in impingement sampling because 

they generally occur on the bottom and not in the water column where they would be subject to 

impingement. A single cheekspot goby was collected during impingement sampling, which extrapolated 

out to seven cheekspot gobies impinged at HnGS using actual or design flow volumes in 2006. 

Silversides were the second most abundant species entrained and impinged at HnGS in 2006, represented 

by topsmelt, jacksmelt and grunion. An estimated 920.3 million larvae and 11.5 million eggs were 

entrained at HnGS in 2006 based on actual flows. Based on design flows, these numbers increased to 

1,062.8 million larvae and 20.8 million eggs. An estimated 41-47% of the larval silverside population in 

Alamitos Bay was lost due to entrainment based on actual and design flows. Only topsmelt was collected 

in abundance in the impingement samples, with an estimated 6,315 topsmelt weighing 29.4 kg (64.9 lbs) 

impinged at HnGS in 2006 based on actual flows; or based on design flows, an estimated 6,747 

individuals weighing 32.4 kg (71.4 lbs) were impinged. Topsmelt and jacksmelt deposit their eggs on 

submerged aquatic vegetation or shallow structures in bays and harbors, and the larvae were much more 

abundant on the east side of Alamitos Bay at the entrainment station location than in other parts of the bay 

(Figure 6.3-2). The greatest concentrations were entrained during nighttime surveys in May, and it is 

possible that the high concentrations of newly-hatched larvae within the marina area were attracted to the 

brightly lighted areas within the marina near the HnGS intake where they were subsequently entrained 

into the cooling water flows. 
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IM&E Final Report Impact Assessment

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Atherinopsidae (Silversides)

0

200

400

600

800

1,000

1,200

1,400

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

2006

Larval density (# /1,000 m3

)

Entrainment

Alamitos Bay

Figure 6.3-2. Comparison between silverside larval densities at entrainment station (E3) and 

Alamitos Bay stations (H2-H4) during monthly plankton tows in 2006. 

Annual entrainment of combtooth blennies larvae was estimated at 732.0 million based on actual flows 

and 915.3 million based on design flows. An estimated 0.8-1.8 million adult equivalents were lost due to 

entrainment at HnGS and approximately 14% of the larval combtooth blenny populations were lost due to 

entrainment based on actual flow volumes. Using the design flow volumes, an estimated 1.0-2.2 million 

adult equivalents were lost due to entrainment, and approximately 18% of the larval populations were lost 

due to the CWIS at HnGS. Combtooth blennies are similar to gobies in that they have adhesive demersal 

eggs that are not vulnerable to entrainment. Adult combtooth blennies, which could be identified to the 

species level, were impinged in low numbers. The largest impingement occurred for the rockpool blenny, 

which has a broader distribution than the other two species that includes nearshore rocky habitat. The 

total estimated annual impingement for all species of blenny was 32 (25 rockpool blennies and 7 mussel 

blennies). Combtooth blennies, especially mussel blennies, can utilize submerged artificial substrates 

(pier pilings, dock floats, breakwater material) and their associated fouling communities for shelter and 

spawning habitat. The slips for approximately 4,000 boats in Alamitos Bay provide abundant habitat for a 

large local population of combtooth blennies and this explains why their larvae were entrained in large 

numbers. Most blenny larvae that were captured were recently hatched, based on size frequency 

distributions, and reached peak concentrations during summer months. 

An estimated 3.1-3.8 million pipefish larvae were also entrained at HnGS using actual and design flows, 

respectively. In addition, 4,553-4,801 juvenile or adult pipefishes were impinged (Tables 6.2−4 and 

6.2-5). Other bay and harbor species that were collected in the impingement sampling, but were not 

susceptible to entrainment, included specklefin midshipman and shiner perch. Specklefin midshipman had 
Haynes Generating Station 

IM&E Final Report Impact Assessment

6-22 

the highest impingement biomass with 157.2 kg (346.6 lbs) with a total of 620 individuals estimated to be 

impinged based on actual flows. Using the design flows, this number increases to 161.8 kg (356.7 lbs) 

with 632 individuals impinged. Shiner perch were the fifth most abundant species in the impingement 

sampling, with 582-632 individuals impinged using actual and design flows, respectively. Shiner perch 

are highly mobile species and are widespread among nearshore sandy habitats as well as rocky reef and 

kelp habitats. 

If additional mortality rates from IM&E from both HnGS and nearby Alamitos Generating Station were 

causing long-term declines in fishes within Alamitos Bay, this should be reflected in overall changes to 

larval densities. Most of these organisms are affected through entrainment since the juveniles and adults 

of species such as gobies and blennies occupy benthic habitats within the bay where they are less 

susceptible to the effects of impingement. However, there is uncertainty regarding the magnitude of the 

impacts in relation to environmental variables and other stressors that can cause population changes. 

However, the earlier 316(b) study in 1978−1979 documented average entrainment densities of silverside 

larvae at <10 per 1,000 m3 (264,172 gal), but in 2006 the average densities had increased to 778 per 

1,000 m3 (264,172 gal). CIQ goby and combtooth blenny densities, on the other hand, were lower than 

recorded during the earlier study, so the historical data are ambiguous in this regard. There are no longterm historical data available on blenny or goby populations within Alamitos Bay, although the higher 

larval densities from the earlier study (ca. 4,000 per 1,000 m3

 [264,172 gal] for blennies and 3,000 per 

1,000 m3

 [264,172 gal] for gobies) suggests a substantially greater spawning biomass in the late 1970s as 

compared to 2006 when larval densities were 16% and 55% of the 1978−1979 densities, respectively. 

Even with a substantial fraction of the source larval production in Alamitos Bay cropped by power plant 

entrainment, the bay habitat continues to sustain a thriving population of gobies, blennies, and silversides 

as evidenced by their abundant larval concentrations. In a lagoon or bay such as Alamitos Bay that is 

significantly affected by tidal exchange, many of the larvae are inevitably lost to the system due to export 

by outgoing tidal currents despite behavioral adaptations that cause larvae to migrate toward the bottom 

or move to areas with less current and minimize export (Barlow 1963; Pearcy and Myers 1974; Brothers 

1975) or, in larger systems, have mechanisms that allow some larvae to return to the bay after a period of 

development in offshore waters. Larvae that are transported into coastal waters can provide genetic 

exchange between estuarine areas along the coast by moving back into bays with incoming tidal currents 

(Dawson et al. 2002), but most of these exported larvae experience much higher mortality rates in the 

open ocean than those that are retained in their natal estuaries. 

Demographic-based estimates of projected losses assume that there is available habitat to support the 

additional production in the source water area, which is not usually the case in the example of substrateoriented or territorial species like gobies. In contrast, species that live in open water environments, such 

as silversides, are generally not limited by habitat availability but by other factors such as food 

availability, oceanographic conditions, or predation. In Alamitos Bay where there is a limited amount of 

benthic habitat, density–dependent mortality may be a substantial factor affecting post-settlement recruits, 

similar to the conclusions of Brothers (1975) on goby populations in Mission Bay, San Diego. Therefore, 

projections of adult equivalents based on larval entrainment likely overestimate actual adult losses. For 

example, similar levels of entrainment mortality were estimated for the South Bay Power Plant in south 

San Diego Bay (Tenera 2004). Data from a previous entrainment data and long-term data on adults 
Haynes Generating Station 

IM&E Final Report Impact Assessment

6-23 

indicated that the population in south San Diego Bay was stable and not affected by the additional larval 

mortality due to entrainment. Unfortunately, complementary data on adult abundances for these studies, 

including HnGS, are usually not available. 

In terms of potential economic losses resulting from CIQ goby, combtooth blenny, and topsmelt IM&E, 

there are no direct impacts because they have no fishery value, except for the occasional use of larger 

specimens as fishing bait and a small recreational fishery for topsmelt. Larval reductions could have some 

effect on the trophic structure of the source water through the loss of available forage for predators. 

However, any potential effects would not be directly measurable due to the high natural variation in the 

system and the unknown compensatory response of other species present in the bay and nearshore 

environment. 

6.3.3 Rocky Reef and Kelp Bed Habitats 

Physical structure and food resources are essential factors in promoting fish abundance and diversity. 

Shallow rocky reefs and the giant kelp (Macrocystis spp.) forests often associated with them provide both 

factors. Much of the shoreline of Alamitos Bay consists of hard intertidal and subtidal substrates, such as 

concrete bulkheads and piers. Common species in these assemblages include kelp bass, barred sand bass, 

black perch, opaleye, halfmoon, California sheephead, senorita, garibaldi, salema and zebraperch 

(Stephens et al. 2006). Although the presence and extent of giant kelp affects the abundance of some reef 

fishes, many other factors can also affect their distributions, and it is not unusual to find many of the 

species characteristic of kelp bed habitats in other shallow water locations. Common species of fishes and 

target invertebrates that are typically associated with rocky reef habitats that were impinged at HnGS 

included the vermilion rockfish, California seahare and California two-spot octopus (Table 6.1-1). No 

species primarily associated from this habitat were entrained because there are no significant patches of 

kelp bed and outer coastal reef habitat in Alamitos Bay. Impacts to representative species from this 

habitat are briefly discussed. 

The intake structure at HnGS is located in a sand and mud habitat within Alamitos Bay. Species 

associated with rocky reef and kelp habitats do migrate between areas and occasionally find suitable 

habitat in bays and harbors due to the presence of eelgrass, rock jetties, and other structures that provide 

shelter, especially for juveniles that may recruit into these habitats after being transported into Alamitos 

Bay as larvae. While some individuals may recruit and grow within small habitat patches it is more likely 

that adults take up temporary residence when they encounter such habitat patches during their 

movements. For example, a single juvenile vermilion rockfish, usually associated with deeper offshore 

reefs, was collected in the impingement sampling, resulting in an estimated seven vermilion rockfish 

impinged at HnGS based on actual or design cooling water flows. None were collected during 

impingement sampling from 2001-2005. Thus, impacts to this species due to the CWIS at HnGS are 

minimal. 

Whereas vermilion rockfish are exclusively usually associated with rocky reef habitat, octopus and 

California seahare have broader habitat distributions and do occur in bays and harbors. An estimated 337 

octopus with a biomass of 55 kg (121 lbs) were estimated to be impinged at HnGS in 2006 based on 

actual flows. Based on design flows, these numbers increased to an estimated 353 individuals at 58 kg 

(128 lbs). A total of 195 California seahares weighing 79 kg (175 lbs) was impinged at HnGS in 2006 and 

these numbers increased to an estimated 221 individuals weighing 93 kg (205 lbs) using the design flows. 
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IM&E Final Report Impact Assessment

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The annual losses due to impingement of invertebrate species associated with rock reefs and kelp habitats 

were low in comparison to the fishery take for these species. In 2005, an estimated 183 kg and 4,783 kg 

of octopus and seahare was commercially harvested (CDFG 2006). Taxa such as octopus, California 

seahare and others that occur across a number of habitats will be less susceptible to CWIS impacts than 

species with more specific associations with habitats directly affected by the CWIS. 

6.3.4 Coastal Pelagic Habitats 

Several species entrained or impinged at HnGS are characteristic of the coastal pelagic zone, which was 

expanded to include the surf zone for the purposes of this assessment. These included northern anchovy, 

white croaker, Pacific sardines, queenfish, jack mackerel, and market squid (Table 6.1-1). Some of these 

species, such as northern anchovy and white croaker, can be considered habitat generalists because they 

are also be found in bays and a variety of other shallow water locations (Allen and Pondella 2006). 

Juveniles of most of these species also tend to be abundant in the shallower depths of the habitat range as 

demonstrated by the small size distributions collected during the impingement sampling. 

The estimated annual loss of northern anchovy due to operation of the HnGS CWIS included 22.7 million 

larvae based on actual flow volumes, and 27.3 million based on design flow volumes (Table 6.2-5). An 

estimated 11.1 million eggs were entrained using the actual flow volumes, or 14 million based on the 

design flow volumes. These estimates were used to calculate a loss of 8,600-20,600 adult equivalents 

using actual flows and a loss of 10,000-25,000 adult equivalents based on design flows. Northern 

anchovy ranges widely throughout the southern California bight and the proportion of larvae entrained in 

the source waters from Alamitos Bay were correspondingly low (less than 1%). Annual impingement of 

northern anchovy was estimated as 5,794 individuals with a combined weight of 6.3 kg (13.3 lbs) based 

on actual flows and an estimated 6,513 individuals weighing 7.3 kg (16.1 lbs) based on design flows 

(Tables 6.2-4 and 6.2-5). An estimated 1,840-2,117 equivalent adults were lost due to impingement at 

HnGS in 2006 based an actual and design flows, respectively. An estimated 0.3 million Pacific sardine 

larvae were entrained at HnGS in 2006 (Table 6.2-4). Annual impingement of Pacific sardine ranged from 

an estimated 90-98 individuals weighing 0.61-0.68 kg (1.3-1.5 lbs) based on actual and design flow 

volumes respectively. Based upon the impingement estimates, 69-75 equivalent adult Pacific sardine were 

lost due to impingement. 

The evidence suggests that large-scale oceanographic phenomena, and not localized perturbations such as 

intake effects, are responsible for the population-wide changes seen in these two species. Northern 

anchovy and Pacific sardine are two indicator organisms for the PDO in the California Current System, 

(Chavez et al. 2003; Norton and Mason 2005; Horn and Stephens 2006). Northern anchovy dominates 

during the cold water phase and Pacific sardine during the warm water phase. Scale deposition of these 

two species in the anoxic Santa Barbara basin is one tool used for reconstructing the phases of the PDO 

over the past 2,000 years (Baumgartner et al. 1992; Finney et al. 2002). The commercial catch of northern 

anchovy follows this pattern and by 1983 the catch of northern anchovy had basically disappeared in 

California (Mason 2004). The faunal switch associated with the PDO at the end of the 1970s was really 

completed in the Southern California Bight with the 1982−84 El Niño (Stephens et al. 1984; Holbrook et 

al. 1997), the largest El Niño recorded at that time. During the strong La Niña years (1999-2002) there 

was resurgence in catch of this stock. However, a return in catch of northern anchovy and a corresponding 

stock increase in Southern California will undoubtedly be delayed until the next cold phase of the PDO. 
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IM&E Final Report Impact Assessment

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The difference in the entrainment estimates for northern anchovy between the 1979−1980 (IRC 1981) and 

the 2006 studies probably reflects changes in the oceanographic environment. The estimated annual 

entrainment during the previous study was 580 million compared with 23−27 million from the 2006 

study. The recent entrainment estimate is approximately 4% of the estimate from the previous study. This 

reduction is similar to the decrease in the landings from Los Angeles area ports over the same period 

which were 38,383,362 kg (84,620,828 lbs) in 1981 (data before 1981 not available from PACFIN) and 

averaged only 1,351,669 kg (2,979,921 lbs) from 2000−2006 (Table 4.5-7) or 2% of the 1981 landings. 

The total losses from both entrainment and impingement from the 2006 study were extrapolated to 

23,000−27,000 fishes at the age of 50% maturity. The length at that age, 95 mm (3.7 in), was used to 

predict a weight of 5.0 g (0.18 oz) using a best fit model (Weight=0.0005e

0.0242*Length) derived from length 

and weigh data for the northern anchovy collected from the HnGS impingement samples. The total 

predicted weight of the CWIS losses amounted to approximately 0.01% of the average landings at Los 

Angeles area ports from 2000−2006 (Table 4.5-7) with a total value of eleven to thirteen dollars. These 

values do not represent significant AEI to northern anchovy, especially since this species has a broad 

distribution throughout the SCB. 

White croaker and queenfish are two common members of the croaker family that are found in Alamitos 

Bay and also in the nearshore sand bottom habitat⎯queenfish as a pelagic species and white croaker as a 

bottom-associated species. White croaker was the fourth most abundant larvae entrained with 75.4-96.2 

million larvae entrained based on actual or design flows. An estimated 57.8-86.5 million white croaker 

eggs were also entrained at HnGS in 2006. This taxa group was the ninth most abundant species impinged 

at HnGS in 2006, with 861-877 individuals weighing 5.8-7.5 kg (12.8-16.5 lbs) respectively based on 

actual and design flows. Using the egg entrainment, an estimated 64-96 adult equivalents were lost due to 

entrainment at HnGS (Tables 6.2-4 and 6.2-5). Proportional mortality due to entrainment was less than 

1% using either actual or design flows in the calculations. Queenfish larvae were the fourteenth most 

abundant larvae entrained with 2.5-2.9 million larvae based on actual or design flow volumes (Tables 6.2-

4 and 6.2-5), but were the most abundant species impinged with approximately 31,000-32,000 individuals 

weighing 19.5-20.4 kg (42.9-45.0 lbs) respectively. These estimates were used to calculate that 

13,971-14,595 equivalent adults were lost due to impingement at HnGS in 2006. The majority of the 

queenfish impinged were small young-of-the-year and likely use the habitat within Alamitos Bay as 

nursery grounds. 

Recreational and commercial catch data for white croaker indicating a declining fishery were not 

consistent with the fishery independent data. Recreational and commercial catches both declined from 

1980-2006 (Figure 6.3-3a). Overall, the declines in white croaker recreational and commercial catch, 

especially in the late 1990s, show the same patterns from impingement data at southern California plants 

described by Herbinson et al. (2001). The impingement of white croaker at the Huntington Beach 

Generating Station (HBGS) just south of Alamitos Bay shows low impingement throughout the 1990s 

(Figure 6.3-3b). The impingement of white croaker in 2005 was similar to levels recorded during the early 

1980s. Based on the analysis of long-term patterns of change in croakers relative to ocean warming events 

by Herbinson et al. (2001), the increase in white croaker may be in response to the prolonged cooler water 

temperatures that have persisted in the southern portion of the California current since 1999 (Peterson et 

al. 2006). In contrast to the fishery and impingement data, trawls collected as part of NPDES monitoring 
Haynes Generating Station 

IM&E Final Report Impact Assessment

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programs for the Huntington Beach Generating Station (HBGS) and the Haynes, Harbor, and Alamitos 

Generating Stations show fluctuations in abundance without any clear trends (Figure 6.3-3c). The trawls 

are collected just outside the bay and show an increasing trend from 2003-2005. This increase is 

consistent with recent impingement data from HBGS that also show an increase over the same period. 

Catches of queenfish fluctuated over time in the various time-series analyses, but have shown increases in 

recent years that, similar to white croaker, may be in response to the prolonged cooler water temperatures 

since 1999 (Peterson et al. 2006). In the recreational fishery, catches were relatively consistent over time, 

fluctuating between 38,000 and 292,000 fish per year with the exception of one peak in 2002 (Figure 6.3-

4a). Impingement of queenfish at the HBGS downcoast from Alamitos Bay shows a sharp drop through 

the 1980s with low fluctuating levels through the 1990s until after 2000 when levels began increasing 

(Figure 6.3-4b). Although this may be a response to the cooling trends in ocean temperatures, Herbinson 

et al. (2001) do not report a similar decline for queenfish in their analysis of impingement data from 

several southern California power plants. Both the catch data and impingement data are not adjusted for 

numbers of fishers and plant cooling water flow. This may explain why the data from trawls conducted 

off Huntington Beach and Alamitos Bay show much more variable results (Figure 6.3-4c). All three data 

sets show increases in recent years that may be a response to ocean conditions. 
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a) Recreational and Commercial Catch 

0

500

1000

1500

2000

2500

3000

1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006

Year

Recreational Catch 

(1000s of Fish)

0

100

200

300

400

500

600

700

800

900

Commercial Catch 

(1000s of lbs.)

Recreational

Commercial

b) HBGS Impingement 

0

500

1,000

1,500

2,000

2,500

1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004

Year

Impingement (kg)

c) Huntington Beach and LA Harbor-Alamitos Trawls 

0

10

20

30

40

50

60

70

80

1978 1982 1986 1990 1994 1998 2002 2006

Year

Fish per Trawl Minute

Harbor-Alamitos

Huntington Beach

Figure 6.3-3. White croaker fishery and population trends: a) recreational and commercial landings for 

Los Angeles area ports from RecFIN and PacFIN databases; b) Huntington Beach Generating Station 

(HBGS) impingement average annual biomass; and c) NPDES trawl data with average number of fish 

per trawl minute for HBGS and Harbor, Haynes and Alamitos Generating Stations, collected off 

Huntington Beach and inside the Los Angeles-Long Beach Harbor breakwaters, respectively. 
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a) Recreational Catch 

b) HBGS Impingement 

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004

Year

Impingement (kg)

c) Huntington Beach and LA Harbor-Alamitos Trawls 

0

10

20

30

40

50

60

1978 1982 1986 1990 1994 1998 2002 2006

Year

Fish per Trawl Minute

Harbor-Alamitos

Huntington Beach

Figure 6.3-4. Queenfish fishery and population trends: a) recreational landings for Los Angeles area 

ports from RecFIN database; b) HBGS impingement average annual biomass; and c) average number 

of fish per trawl minute for HBGS and Harbor, Haynes and Alamitos Generating Stations, collected off 

Huntington Beach and inside the Los Angeles-Long Beach Harbor breakwaters, respectively. 

0

200

400

600

800

1000

1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005

Year

Recreational Catch 

(1000s of Fish)
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One of the target invertebrates selected for analysis was the market squid, Loligo opalescens, because of 

its wide distribution and commercial fishery importance. Large-scale fluctuations are characteristic of the 

squid stock, due primarily to its short life span and the influence of variations in oceanographic conditions 

(NMFS 1999). Los Angeles area commercial landings ranged between 7.7 and 44.8 million kg (16.9 and 

98.8 million pounds) annually from 2000−2006 with both the total catch and market value increasing 

substantially during the last two years (PacFIN 2007). Projected annual losses of squid paralarvae due to 

entrainment was from an estimated 0.2−0.3 million larvae for actual and design flows, respectively. There 

was not enough information available on natural mortality rates to project adult equivalents from this 

number of larvae, but the total impingement was estimated as 78 adults annually using either actual or 

design flows. This is very small compared to the annual take from the commercial fishery, which has 

grown over recent years to be the largest fishery in California. 

In summary, the coastal pelagic habitat is extensive within the southern California bight, and most of the 

common fish species that are part of this assemblage are wide-ranging. Most have a directed commercial 

or sport fishery and their populations are generally sensitive to large-scale oceanographic influences. The 

changes in abundance that appear to fluctuate in response to ocean conditions indicate that the effects of 

impingement or entrainment are probably not significant since power plant impacts should occur as a 

long-term downward trend in abundance. Since the HnGS is located in Alamitos Bay it does not affect 

this habitat directly and given the wide distributions of most of the component species, including 

distributions in other habitats where they are not as susceptible to CWIS effects, there is no indication that 

the facility adversely impacts these populations. Two coastal pelagic fishes, Pacific sardine and jack 

mackerel, were included in the assessment because they are under federal management. Both were 

collected in very low numbers during the impingement sampling and only a single Pacific sardine larva 

was collected during entrainment sampling, mainly because of their primarily offshore distribution. 

6.3.5 Shelf Habitats 

Shelf habitats include several different habitats from Allen and Pondella (2006) including inner, middle, 

and outer shelf, and shallow slope habitats. The abundance, biomass, and other population attributes of 

the fish assemblages in these habitats increase from the inner to outer shelf (Allen 2006). Allen attributed 

this gradient to the increased variability in ocean conditions on the inner shelf due to runoff, pollution, 

and a variety of other factors. A variety of flatfishes and other species dominate the fish assemblages on 

the soft mud and sandy bottoms in these habitats. Fishes characteristic of the inner and middle shelf 

include California halibut, bay goby, California tonguefish, bigmouth sole, hornyhead turbot, and 

California skate (Allen and Pondella 2006). Fishes characteristic of the outer shelf and slope include 

plainfin midshipman, Pacific sanddab, pink seaperch, curlfin turbot, Dover sole, longspine thornyhead, 

and California rattail (Allen and Pondella 2006). 

While the shelf species are treated in this assessment as an assemblage, it is apparent that the only 

potential impacts from HnGS entrainment and impingement would occur to fishes that inhabit the inner 

shelf close to shore. As pointed out by Allen (2006) the inner shelf is also more subject to highly variable 

ocean conditions caused by runoff, pollution, etc. Although this would increase the potential for impacts 

to these species, the location of the HnGS intake inside Alamitos Bay reduces the potential impacts to 

these species. As a result, the estimated effects of entrainment and impingement on the fishes from shelf 

habitats were low relative to species from other habitat types that occur in the vicinity of the intake. 
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The only taxa included in the assessment that is predominately distributed on the inner shelf was the 

California skate (Table 6.1-1). California skate would only be affected by impingement since they do not 

have planktonic larvae. They lay egg cases where the larvae develop until they hatch as small fully 

formed juveniles, which would not be subject to entrainment. Based on actual flows, an estimated 8 

individuals weighing 1.1 kg (2.4 lbs) were impinged at HnGS in 2006. Using the design flows, this 

estimate increased to 9 individuals weighing 1.2 kg (2.7 lbs). Since California skate is a highly mobile 

species, impacts to this group are considered insignificant. Impingement of other shelf species was low 

relative to other habitat types because these fishes are largely bottom dwellers and generally do not occur 

in the water column where the intakes are located. Entrainment was very low for shelf species since the 

larvae would have to be transported from offshore areas into Alamitos Bay. Although this did occur for 

several species, the total numbers of shelf species entrained was very low relative to all of the other 

habitat assemblages that occur in closer proximity to Alamitos Bay (Table 6.3-1). 

6.3.6 Deep Pelagic Habitats 

Deep pelagic habitats include several different habitats described by Allen and Pondella (2006) including 

deep slope, deep bank, and deep rocky reef habitats. This category also includes open ocean pelagic 

habitats. Some of these habitats are extremely productive and the fishes inhabiting these areas are the 

basis of large commercial fisheries. The fisheries in the areas outside the three-mile limit of California 

state waters are federally managed by the PFMC. Fishes characteristic of the deep shelf, bank and slope 

habitats include Pacific hake, splitnose rockfish, rex sole, sablefish, blackgill rockfish, and shortspine 

thornyhead. Several different species of rockfishes dominate the fish assemblages on the deep reef, shelf 

and canyon habitats including bocaccio, chilipepper, and greenspotted, greenstripe, rosethorn, and 

pinkrose rockfishes. Fishes characteristic of open ocean pelagic habitats include swordfish, striped marlin, 

several species of shark, albacore, and bluefin bigeye, and yellowfin tuna. Although the fishes 

characteristic of these habitats occasionally occur closer to shore their primary habitats are offshore in 

open water or at deep ocean depths. Only one larval fish associated with the deep pelagic habitat 

(Stenobrachius leucopsarus, 0.01%; Table 4.5-1) was collected in this study, and no species from this 

habitat were collected in impingement sampling; therefore there is a very low probability that CWIS 

impacts from HnGS would impact species from this habitat. 

6.4 CONCLUSIONS AND DISCUSSION

Impacts to SCB fish and invertebrate populations caused by the entrainment of planktonic larvae through 

the HnGS CWIS can only be assessed indirectly through modeling. The estimates from these models can 

be added to impingement estimates of juvenile and adult losses to estimate the total losses due to the 

HnGS CWIS. Three taxa (CIQ goby complex, combtooth blennies, and silversides) comprised 95% of all 

entrained fish larvae. Of the ten most abundant fish species entrained at HnGS, only two (white croaker 

and anchovies) have any direct commercial or recreational fishery value. All of the abundantly entrained 

species can be considered forage species for larger predatory fishes, sea birds, or marine mammals. 

Approximately 45% of the 33 different fish taxa entrained belonged to species with some direct fishery 

value (e.g., anchovies, silversides, croakers, sand basses, California halibut) even though most of those 

(except silversides and anchovies) were in very low abundance in the samples and as a result were not 

assessed for potential impacts. 
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The ETM procedure estimates the annual probability of mortality due to entrainment (PM). It puts the 

entrainment estimate into context by comparing it with a known source population at risk of entrainment. 

The greatest PM estimate for a target taxon was for the silverside complex with a predicted fractional 

larval loss of 40.9%. The next greatest probabilities of mortality were for CIQ gobies (25.2%) and 

combtooth blennies (13.9%). The spatial extent of the habitats potentially affected by entrainment is 

directly proportional to the estimate of time that the larvae are exposed to entrainment. All three of these 

species had local populations primarily located in the habitats of Alamitos Bay, and most larvae were 

entrained at sizes that indicated they were recently hatched. For example, the relatively high silverside 

mortality estimate resulted from of a single large pulse of larvae entrained in late May, probably from 

eggs that had been deposited on dock structures in the marina adjacent to the HnGS intakes. The modeled 

species with primarily nearshore (non-bay) distributions included white croaker and northern anchovy, 

and these had PM estimates well below 1%. These levels of additional mortality would be considered low, 

especially when the populations of these species extend over a much larger geographic range than the 

extrapolated source water bodies. No invertebrate taxa were modeled for entrainment impacts due to the 

low abundance of the target taxa (e.g., spiny lobsters, Cancer crabs). 

Compared to the IM&E study conducted at HnGS in 1978−1979 (IRC 1981), silverside larvae were 

nearly two orders of magnitude more abundant in the recent 2006 entrainment samples while other taxa 

analyzed in both studies were less abundant in 2006 (Table 6.4-1). Anchovy and croaker larvae in 

particular were significantly more abundant in the earlier study, due in part to the cooler water climatic 

regime in the SCB that favored populations of these taxa. The most abundant impinged species in 

1978−1979 were shiner perch (38%), Pacific pompano (14.9%), and white seaperch (12.5%), while in the 

2006 samples queenfish, topsmelt and northern anchovy were the numerically dominant species 

accounting for 75% of all impinged fishes. Annual fish biomass impingement (normal operations and heat 

treatments) was 1,344 kg (2,964 lbs) in 1978−1979 compared to 529.8 kg (1,168 lbs) in 2006. The 

operations and configuration of the HnGS cooling water system have remained largely unchanged since 

all units went into service with the exception of the replacement of the cooling water pumps at Units 3 & 

4 (now Unit 8). Therefore, changes in impingement and entrainment through time are most likely due to 

natural biological changes and not due to substantial changes in plant operations. 
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Table 6.4-1. Comparison of larval fish densities and total annual entrainment at HnGS 

from studies in 1978−1979 and studies in 2006. 

 

Mean Average Annual 

Density (#/1,000 m3

) 

Actual Annual 

Entrainment 

(millions) 

Species Common Name 1978−79 2006 1978−79 2006 

Larval Fishes 

Atherinopsidae silversides <10 778 12 920 

Engraulidae anchovies 560 20 580 22 

Gobiidae gobies 2,975 1,661 3,200 1,828 

Hypsoblennius spp. combtooth blennies 3,990 652 4,400 732 

Genyonemus lineatus white croaker 215 68 210 75 

Seriphus politus queenfish 60 2 53 3 

Pleuronichthys guttulatus diamond turbot <10 2 5 3 

Fish Eggs 

Engraulis mordax northern anchovy 420 10 230 11 

Sciaenid complex croakers 2,555 37 2,600 41 

Note: A volume of 1,000 m3 is equal to 264,172 gal. 

6.4.1 IM&E Losses Relative to 1977 USEPA AEI Criteria 

USEPA (1977) provided some general guidelines to determine the “relative biological value of the source 

water body zone of influence for selected species and the potential for damage by the intake structure” 

based on the following considerations of the value of a given area to a particular species: 

• principal spawning (breeding) ground; 

• nursery or feeding areas; 

• migratory pathways; 

• numbers of individuals present; and 

• other functions critical during the life history. 

Fishes in the vicinity of the HnGS intake structure in Alamitos Bay are characteristic of the fish 

assemblages found in other bays and harbors in southern California, as defined by Allen and Pondella 

(2006). The structural complexity of Alamitos Bay contributes to the habitat value of the area as a 

spawning and nursery ground for numerous species. The area in which the HnGS intake structure is 

located is the Long Beach Marina within Alamitos Bay which is a highly modified, dredged embayment 

that was once part of a natural wetland system. Of the three taxa (CIQ gobies, combtooth blennies, and 

silversides) that comprised 95% of all entrained larvae, all use embayments as primary spawning and 

nursery areas. For example, gobies are abundant in quiet-water areas with soft substrates where they 

inhabit burrows and lay their eggs. Blennies utilize the complex fouling communities on pilings, floating 

docks, and boat moorings to seek shelter and spawn demersal eggs, while silversides deposit adhesive egg 

masses to eelgrass or man-made structures. For the abundantly impinged species, size-frequency 

distributions indicated that almost all of the queenfish and most of the silversides were small, young-of-
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the-year fishes. Similar habitat complexity also occurs in the much larger Los Angeles-Long Beach 

Harbor complex west of Alamitos Bay, and so this type of habitat, although productive, is not unique to 

the area. Because these species have short life spans and their populations are likely limited by the 

availability of adult habitat (for gobies and blennies), the additional mortality due to entrainment would 

not be expected to substantially affect their local populations. Similar levels of entrainment mortality 

were estimated for gobies at the South Bay Power Plant in south San Diego Bay (Tenera 2004). Although, 

data from a previous entrainment data and long-term data on adults indicated that the population in south 

San Diego Bay was stable and not affected by the additional larval mortality due to entrainment, the 

populations in Alamitos Bay are affected by the operations of both the HnGS and Alamitos Generating 

Station. 

The issue in the EPA guidelines of fish migratory pathways relative to intake location primarily concerns 

anadromous fishes and situations where power plant intake locations are on or near rivers that may 

function as narrow migratory corridors for certain species. Because the HnGS intakes are not located with 

such a corridor, this issue is not of concern for any of the species that were impinged. 

The other points of concern relative to intake location and fish distribution are numbers of individuals 

present and other functions critical during the life history (i.e., high concentrations of individuals present 

in the area for reasons other than spawning, recruitment or migration). This may include a circumstance 

where, for example, prevailing currents or the proximity to certain bathymetric features attracts prey items 

for a predatory species and thus results in high concentrations of a species that may subsequently be at 

risk of impingement. None of the data collected during this study suggests that there are any species that 

are especially vulnerable to impingement or entrainment due to their behavior at any stage in their life 

history. This includes all common species as well as any special status species designated for protection 

under state or federal statutes. 

No federal/state threatened or endangered fish/shellfish species were identified in entrainment and 

impingement samples collected from HnGS. This is consistent with past entrainment and impingement 

sampling conducted at HnGS. Off southern California, species managed under the Magnuson-Stevens 

Fishery Conservation and Management Act are listed in the Coastal Pelagic Fishery Management Plan 

(FMP) and the Pacific Groundfish FMP. EFH includes all waters off southern California offshore to the 

Exclusive Economic Zone. Nine species covered under the two FMPs that occurred in entrainment and/or 

impingement samples at the HnGS are shown in Table 6.4-2. 
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Table 6.4-2. Fish and shellfish species under NMFS federal management or with CDFG special status 

entrained and/or impinged at HnGS in 2006 based on actual flow volumes. 

Species Common Name 

Management 

Group 

Estimated No. 

Larvae (based on 

Entrainment 

Samples) 

Juveniles/Adults 

(based on 

Impingement 

Samples)*

Engraulis mordax northern anchovy Coastal Pelagics 22,673,541 5,794 

Parophrys vetulus English sole Pacific Groundfish 260,975 −

Loligo opalescens market squid Coastal Pelagics 231,898 78 

Hypsypops rubicundus garibaldi CDFG 985,374 −

Sardinops sagax Pacific sardine Coastal Pelagics 255,242 90 

Merluccius productus Pacific hake Pacific Groundfish 243,832 −

Citharichthys sordidus Pacific sanddab Pacific Groundfish 304,664 −

Leuresthes tenuis California grunion CDFG 90,595,407 382 

Raja inornata California skate Pacific Groundfish 8 

Sebastes miniatus vermilion rockfish Pacific Groundfish − 7 

Trachurus symmetricus Jack mackerel Coastal Pelagics 7 *

Includes estimated numbers from normal impingement, and actual numbers from marine growth control surveys. 

6.4.2 IM&E Losses Relative to Other AEI Criteria 

Additional criteria that were evaluated because they were specific to the marine environment around 

HnGS included: 

• distribution (pelagic, subtidal, nearshore subtidal & intertidal); 

• range, density, and dispersion of population; 

• population center (source or sink); 

• magnitude of effects; 

• long-term abundance trends (e.g., fishery catch data); 

• long-term environmental trends (climatological or oceanographic); and 

• life history strategies (e.g., longevity and fecundity). 

The criteria of distribution, range, habitat, and population center all need to be considered relative to the 

magnitude of the effects. 

The magnitude of the CWIS losses due to HnGS were all relatively low for taxa that are primarily 

associated with other habitats. Not only were the estimated effects low for these taxa, the broad 

geographic distributions throughout the SCB for fishes such as northern anchovy, white croaker, 

queenfish, Pacific sardine, and jack mackerel further reduce the potential for any adverse environmental 

impacts (AEI). Alamitos Bay is not the source or primary habitat for many of the taxa and is not critical to 

these populations. Data on some of the fishes from other studies support the conclusion that there is very 

low risk of AEI due to the HnGS CWIS. 
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This low risk of AEI to these taxa is supported by fish impingement data that has been routinely measured 

for decades at several coastal power plants in southern California. The same core group of fish species 

continues to be impinged at these power plants, and there is no measurable effect on fish populations from 

the operation of the cooling water systems. For species that are harvested commercially, such as northern 

anchovy, the biomass of fish impinged is orders of magnitude less than annual commercial landings. 

These taxa seem to be responding to factors other than power plant impacts and several types of effects 

over time were found for the species in the detailed evaluation (Table 6.4-2). Anchovies disappeared from 

the commercial fishery after the regime shift and were essentially absent during the last two decades. Any 

time series data that extends to before or during this regime shift has evidence of this change. Other 

fisheries were declining (white croaker) while catch in the fishery independent monitoring programs 

found them to be either increasing or stable over time. Fisheries that were not declining (queenfish) had 

some type of positive correlation with ENSO’s and/or SST, while the declining fisheries did not. This 

indicates that the fishing effects may be masking the natural variation for these taxa. 

Table 6.4-3. Summary of positive time series findings for fish species in detail evaluation with 

respect to oceanographic variables (ENSO, SST, and PDO), fishing effects and the current population 

trends. 

 Taxon ENSO SST PDO 

Fishing 

Effects 

Current Population 

Trend 

Anchovies Yes Historic stable 

Silversides Yes none increasing 

White croaker Yes, declining increasing 

Queenfish 

Yes, 

positive 

Yes, 

positive Yes, stable stable 

Combtooth blennies 

Yes, 

positive Yes none stable 

After the faunal shift (i.e., post 1982−1984 El Niño), fishes that would be negatively affected by warming 

conditions were essentially extirpated from the nearshore environment of the San Pedro Bay area. This 

period was marked by general low fish productivity (Brooks et al. 2002) until the La Niña of 1999 and the 

following four-year cool water period. At this point, the catch or density of these stocks appeared to either 

increase or remain stable through 2006. 

Although it seems clear that there is very low risk of any AEI to taxa that are not primarily distributed in 

Alamitos Bay, the potential risk to the fishes included in the assessment that are primarily distributed in 

Alamitos Bay and associated with bay and harbor habitats is more difficult to assess. The estimated losses 

to gobies and blennies, primarily due to entrainment, are large but similar in magnitude to losses from 

other bays and harbors in southern California. Other data were available from these locations that showed 

the losses did not represent a significant risk to the populations. Similar data were not available for 

Alamitos Bay that could be used for assessing the potential for AEI One factor that reduces the potential 

risk to these taxa is the abundance of bay and harbor habitat in the areas surrounding Alamitos Bay. 

Larvae potentially lost due to entrainment at small sizes may be replaced by larvae transported into 

Alamitos Bay that were spawned in similar habitats which are abundant in the Los Angeles-Long Beach 

Harbor area potentially reducing the potential for AEI. 
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The low potential for AEI for most of the taxa entrained and impinged at HnGS is consistent with a recent 

review on population level effects of IM&E on harvested fish stocks (Newbold and Iovanna 2007). They 

modeled the potential effects of IM&E on populations of 15 East Coast fish stocks that are targeted by 

either commercial or recreational fisheries using empirical data on entrainment and impingement, life 

history, and stock size. For 12 of the 15 species, the effects of removing all of the sources of power plant 

entrainment and impingement were very low (less than 2.5%). For the other three species, the effects 

ranged from 22.8% for striped bass on the Atlantic coast to 79.4% for Atlantic croaker. Their overall 

conclusions were that population level effects were negligible for most fish stocks but could be severe for 

a few. They attributed the absence of large effects for most species to compensatory effects that are 

probably acting on the populations at some level. If there is strong density dependence acting on these 

populations during the life stages from the period when they are vulnerable to entrainment as larvae 

through the age of maturity, then they concluded that there should be very little potential for population 

level effects due to entrainment and impingement. 

The greatest potential for AEI at HnGS was for two groups of fishes, silversides and gobies, that are 

small, non-harvested species. Proportional mortality rates for the vast majority of other entrained species, 

including all species with fishery value, were much lower and closer in value to the levels that Newbold 

and Iovanna (2007) concluded represented little risk to the populations. 
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7.0 LITERATURE CITED

Ahlstrom, E. H. 1960. Synopsis on the biology of the Pacific sardine (Sardinops caerulea). Proc. World 

Sci. Meet. Biol. Sardines and Related Species, FAO, Rome. 2:415–451. 

Allen, L. G. 1976. Abundance, diversity, seasonality and community structure of fish populations in 

Newport Bay, California. M. A. Thesis, Calif. State Univ., Fullerton. 108 p. 

Allen, L. G. 1982. Seasonal abundance, composition, and productivity of the littoral fish assemblage in 

upper Newport Bay, California. Fish. Bull., U. S. 80:769–790. 

Allen, L. G. 1985. A habitat analysis of the nearshore marine fishes from Southern California. Bull. So. 

Calif. Acad. Sci. 84(3):133–155. 

Allen, L. G. 1999. Fisheries Inventory and Utilization of San Diego Bay, San Diego, California. Final 

Report: Sampling Period July 1994 to April 1999. Prepared for U.S. Navy and the San Diego Unified 

Port District. 

Allen, L. G. and D. J. Pondella, II. 2006. Ecological classification. Pp. 81–113 In The ecology of marine 

fishes: California and adjacent waters. L. G. Allen, D. J. Pondella II, and M. H. Horn (eds.). Univ. 

Calif. Press, Los Angeles, CA. 660 p. 

Allen, L. G. and E. E. DeMartini. 1983. Temporal and spatial patterns of nearshore distribution and 

abundance of the pelagic fishes off San Onofre-Oceanside, CA. Fish. Bull., U. S. 81(3):569–586. 

Allen, L. G. and M. H. Horn. 1975. Abundance, diversity and seasonality of fishes in Colorado Lagoon, 

Alamitos Bay, California. Est. Coast. Mar. Sci. 3:371–380. 

Allen, L. G., A. M. Findlay, and C. M. Phalen. 2002. Structure and standing stock of the fish assemblages 

of San Diego Bay, California from 1994 to 1999. Bull. So. Calif. Acad. Sci. 101(2):49–85. 

Allen, L. G., D. J. Pondella, II and M. A. Shane. In press. Documenting the return of a fishery: 

distribution and abundance of juvenile white seabass (Atractoscion nobilis) in the shallow nearshore 

waters of the Southern California Bight, 1995–2005. Fish. Res. 

Allen, L. G., M. H. Horn, F. A. Edmands II, and C. Usui. 1983. Structure and seasonal dynamics of the 

fish assemblage in the Cabrillo Beach area of Los Angeles Harbor, California. Bull. So. Calif. Acad. 

Sci. 82(2):47–70. 

Allen, L. G., M. M. Yoklavich, G. M. Cailliet, and M. H. Horn. 2006. Bays and estuaries. Pp. 119–148 In

The ecology of marine fishes: California and adjacent waters. L. G. Allen, D. J. Pondella II, and M. 

H. Horn (eds.). Univ. Calif. Press, Los Angeles, CA. 660 p. 

Allen, M. J. 2006. Continental Shelf and Upper Slope. Pp. 167–202 In The ecology of marine fishes: 

California and adjacent waters. L. G. Allen, D. J. Pondella II, and M. H. Horn (eds.). Univ. Calif. 

Press, Los Angeles, CA. 660 p. 

Allen, M. J. and K. T. Herbinson. 1991. Beam-trawl survey of bay and nearshore fishes of the soft-bottom 

habitat of southern California in 1989. CalCOFI Rep. 32:112–127. 
Haynes Generating Station 

IM&E Final Report Literature Cited

7-2 

Allen, M. J., A. K. Groce, D. Diener, J. Brown, S. A. Steinert, G. Deets, J. A. Noblet, S. Moore, D. Diehl, 

E. T. Jarvis, V. Raco-Rands, C. Thomas, Y. Ralph, R. Gartman, D. Cadien, S. B. Weisberg, and T. 

Mikel. 2002. Southern California Bight 1998 Regional Monitoring Program: V. Demersal Fishes and 

Megabenthic Invertebrates. So. Calif. Coastal Water Res. Project, Westminster, CA. 572 p. 

Allen, M. J., R. W. Smith, E. T. Jarvis, V. Raco-Rands, B. Bernstein, and K. Herbinson. 2003. Temporal 

trends in southern California nearshore fish populations relative to environmental influences. Paper 

presented at the So. Calif. Acad. Sci., Calif. State Univ. Northridge, 9 May 2003. 

Allen, M. J., S. L. Moore, K. C. Schiff, S. B. Weisberg, D. Diener, J. K. Stull, A. Groce, J. Mubarak, C. 

L. Tang, and R. Gartman. 1998 Southern California Bight 1994 Pilot Project: V. Demersal fishes and 

megabenthic invertebrates. So. Calif. Coastal Water Res. Project, Westminster, CA. 324 p. 

Allen, M. J., T. Mikel, D. Cadien, J. E. Kalman, E. T. Jarvis, K. C. Schiff, D. W. Diehl, S. L. Moore, S. 

Walther, G. Deets, C. Cash, S. Watts, D. J. Pondella II, V. Raco-Rands, C. Thomas, R. Gartman, L. 

Sabin, W. Power, A. K. Groce, and J. L. Armstrong. 2007. Southern California Bight 2003 Regional 

Monitoring Program: IV. Demersal Fishes and Megabenthic Invertebrates. So. Calif. Coastal Water 

Res. Project, Costa Mesa, CA. 

Ambrose, R. F. 1981. Observations on the embryonic development and early post-embryonic 

development of Octopus bimaculatus. The Veliger 24:139–146. 

Bane, G. W. and M. Robinson. 1970. Studies on the shiner perch, Cymatogaster aggregata Gibbons, in 

upper Newport Bay, California. Wassmann J. Biol. 28(2):259–268. 

Baumgartner, T. R., A. Soutar, and V. Ferreira-Bartrina. 1992. Reconstruction of the history of Pacific 

sardine and northern anchovy populations of the past two millennia from sediments of the Santa 

Barbara Basin, California. CalCOFI Rep. 33:24–40. 

Beck, D. S. and K. T. Herbinson. 2003. Declines in abundance of three nearshore surfperches off 

Huntington Beach, California, 1971–2001. So. Calif. Acad. Sci., Calif. State Univ. Northridge, 9 May 

2003. 

Beeman, R. D. 1968. The Order Anaspidea. The Veliger 3, Supplement:87–102. 

Bergen, D. R. and L. D. Jacobsen. 2001. Northern anchovy. Pp. 303–305 In California’s living marine 

resources: A status report. W. S. Leet, C. M. Dewees, R. Klingbeil, and E. J. Larson (eds.). Calif. 

Dept. of Fish and Game. 592 p. 

Bograd, S. J., P. M. DiGiacomo, R. Durazo, T. L. Hayward, K. D. Hyrenbach, R. J. Lynn, A. W Mantyla, 

F. B. Schwing, W. J. Sydeman, T. Baumgartner, B. Lavaniegos, and C. S. Moore. 2000. The state of 

the California Current, 1999–2000: forward to a new regime? CalCOFI Rep. 41:26–52. 

Bond, C. E. 1996. Biology of Fishes. Saunders College Publishing, San Diego, CA. 105 p. 

Boreman, J., C. P. Goodyear, and S. W. Christensen. 1978. An empirical transport model for evaluating 

entrainment of aquatic organism by power plants. USFWS. FWS/OBS-78/90, Ann Arbor, MI. 

Boreman, J., C. P. Goodyear, and S. W. Christensen. 1981. An empirical methodology for estimating 

entrainment losses at power plants sited on estuaries. Trans. Am. Fish. Soc. 110:253−260. 

Brewer, G. 1974. Thermal tolerance and sediment toxicity studies. Pp. 21–43 In Marine studies of San 

Pedro Bay, California, Part 3. D. F. Soule and M. Oguri (eds.), Allan Hancock Found., Univ. So. 

Calif., Los Angeles, CA. 86 p. 
Haynes Generating Station 

IM&E Final Report Literature Cited

7-3 

Brewer, G. D. 1978. Reproduction and spawning of northern anchovy, Engraulis mordax, in San Pedro 

Bay, CA. Calif. Dept. of Fish and Game 64(3):175−184. 

Brooks, A. J., R. J. Schmitt, and S. J. Holbrook. 2002. Declines in regional fish populations: have species 

responded similarly to environmental change? Mar. Freshwater Res. 53:189–198. 

Brothers, E. B. 1975. The comparative ecology and behavior of three sympatric California gobies. Ph.D. 

Dissertation, Univ. Calif. San Diego. 370 p. 

Butler, J. L., M. L. Granados G., J. T. Barnes, M. Yaremko, and B. J. Macewicz.1996. Age composition, 

growth, and maturation of the Pacific sardine (Sardinops sagax) during 1994. CalCOFI Rep. 37:152–

159. 

Butler, J. L., P. E. Smith, and N. C. H. Lo. 1993. The effect of natural variability of life-history 

parameters on anchovy and sardine population growth. CalCOFI Rep. 34:104−111. 

Butler, J., D. Fuller, M. Yaremko. 1999. Age and growth of market squid (Loligo opalescens) off 

California during 1998. CalCOFI Rep. 40:191–195. 

Cailliet, G. M., B. Antrim, D. Ambrose, S. Pace, and M. Stevenson. 1977. Species composition, 

abundance and ecological studies of fishes, larval fishes, and zooplankton in Elkhorn Slough. Pp. 

216–386 In Ecological and hydrographic studies of Elkhorn Slough, Moss Landing Harbor and 

nearshore coastal waters, July 1974 to June 1976. J. Nybakken, G. Cailliet, and W. Broenkow (eds.). 

Moss Landing Marine Lab., Moss Landing, CA. 

Cailliet, G. M., K. A. Karpov, and D. A. Ambrose. 1979. Pelagic assemblages as determined from purse 

seine and large midwater trawl catches in Monterey Bay and their affinities with the market squid, 

Loligo opalescens. CalCOFI Rep. 20:21–30. 

California Department of Fish and Game. 2006. Final California commercial landings for 2005. 

http://www.dfg.ca.gov/mrd/landings05.html. 

California Department of Fish and Game. 2007. 2006 Catch Block Data. Received from CDFG Marine 

Fisheries Statistical Unit, Los Alamitos, CA. Feb. 2007. 

California State Water Resources Control Board (Division of Water Quality – Bay Protection and Toxic 

Cleanup Program), California Department of Fish and Game (Marine Pollution Studies Laboratory), 

University of California Santa Cruz (Institute of Marine Sciences), and San Jose State University 

(Moss Landing Marine Laboratories). 1998. Sediment chemistry, toxicity, and benthic community 

conditions in selected water bodies of the Los Angeles Region: Final Report. Aug. 1998. 

Chavez, F. P., J. Ryan, S. E. Lluch-Cota, and M. Niquen. 2003. From anchovies to sardines and back: 

multi-decadal change in the Pacific Ocean. Science 299:217–221. 

City of Long Beach. 2007. Web site: http://www.ci.long-beach.ca.us/about/facts.asp. Accessed 7 March 

2007. 

Clark, F. N. 1929. The life history of the California jacksmelt, Atherinopsis californiensis. Calif. Dept. of 

Fish and Game Fish Bull. 16. 22 p. 

Clark, F. N. and J. B. Phillips. 1952. The northern anchovy (Engraulis mordax) in the California fishery. 

Calif. Dept. of Fish and Game Biol. Rep. 38(2):189–207. 
Haynes Generating Station 

IM&E Final Report Literature Cited

7-4 

Coleman, R. M. 1999. Parental care in intertidal fishes. In Intertidal Fishes: Life in Two Worlds. M. H. 

Horn, K. L. M. Martin, M. A. Chotkowski (eds.). Academic Press, San Diego, CA. 399 p. 

Cross, J. N. and J. E. Hose. 1988. Evidence for impaired reproduction in white croaker (Genyonemus 

lineatus) from contaminated areas off southern California. Mar. Environ. Res. 24:185–188. 

Dailey, M. D., J. W. Anderson, D. J. Reish, and D. S. Gorsline. 1993. The Southern California Bight: 

Background and setting. Pp. 1–18 In Ecology of the Southern California Bight: A synthesis and 

interpretation. M. D. Dailey, D. J. Reish, and J. W. Anderson (eds.). U. C. Press, Los Angeles, CA. 

926 p. 

Davies, I. E. and R. P. Bradley. 1972. Deep observations of anchovy and blue sharks from Deepstar 2000. 

Fish. Bull., U. S. 70:510−511. 

DeMartini, E. E. and R. K. Fountain. 1981. Ovarian cycling frequency and batch fecundity in the 

queenfish, Seriphus politus: attributes representative of serial spawning fishes. Fish. Bull., U. S. 

79(3):547–560. 

Durand, M. H. 1998. Fishmeal price behaviour: global dynamics and short-term changes. Pp. 465–480 In

Global versus local changes in upwelling systems. M. H. Durand, P. Cury, R. Mendelssohn, C. Roy, 

A. Bakun, and D. Pauly (eds.). Coll. Colloques et Séminaires. Orstom, Paris. 

Durazo, R., T. R. Baumgartner, S. J. Bograd, C. A. Collins, S. de la Campa, J. Garcia, G. Gaxiola-Castro, 

A. Huyer, K. D. Hyrenbach, D. Loya, R. J. Lynn, F. B. Schwing, R. L. Smith, W. J. Sydeman, and P. 

Wheeler. 2001. The state of the California Current, 2000–2001: A third straight La Niña year. 

CalCOFI Rep. 42:27–60. 

Ebert, D.A. 2003. Sharks, Rays, and Chimaeras of California. Univ. of Calif. Press, Berkeley, CA. 284 p. 

Emmett, R. L., S. L. Stone, S. A. Hinton, and M. E. Monaco. 1991. Distribution and abundance of fishes 

and invertebrates in west coast estuaries, Vol. II. Species life history summaries. ELMR Rep. No. 8. 

NOAA/NOS Strategic Environmental Assessments Division, Rockville, MD. 329 p. 

Environmental Quality Analysts, Inc. and Marine Biological Consultants, Inc. 1973. Huntington Beach 

Generating Station Thermal Effect Study. Final Summary Report. Prepared for Southern California 

Edison Company. Sept. 1973. 

Eschmeyer, W. N. and E. S. Herald. 1983. A field guide to Pacific Coast fishes of North America. 

Houghton-Mifflin Co., Boston, MA. 336 p. 

Feder, H. M., C. H. Turner, and C. Limbaugh. 1974. Observations on fishes associated with kelp beds in 

southern California. Calif. Dept. of Fish and Game Fish Bull. 160. 138 p. 

Fields, W. G. 1965. The structure, development, food relations, reproduction, and life history of the squid 

Loligo opalescens Berry. Calif. Dept. of Fish and Game Fish Bull. 131. 

Finney, B. P., I. Gregory-Evans, M. S. V. Douglas, and J. P. Smol. 2002. Fisheries productivity in the 

northeastern Pacific Ocean over the past 2,200 years. Nature 416:729–733. 

Fitch, J. E. and R. J. Lavenberg. 1971. Marine food and game fishes of California. Univ. Calif. Press, 

Berkeley, CA. 179 p. 

Fitch, J. E. and R. J. Lavenberg. 1975. Tidepool and nearshore fishes of California. Univ. Calif. Press, 

Berkeley, CA. 156 p. 
Haynes Generating Station 

IM&E Final Report Literature Cited

7-5 

Forsythe, J., N. Kangas, and R. T. Hanlon. 2004. Does the California market squid (Loligo opalescens) 

spawn naturally during the day or at night? A note on the successful use of ROVs to obtain basic 

fisheries biology data. Fish. Bull., U. S. 102(2):389–392. 

Frey, H. W. (ed.). 1971. California’s living marine resources and their utilization. Calif. Dept. of Fish and 

Game. 148 p. 

Fritzche, R. A. and P. Collier. 2001. Surfperches. Pp. 236–240 In California’s living marine resources: A 

status report. W. S. Leet, C. M. Dewees, R. Klingbeil, and E. J. Larson (eds.). Calif. Dept. of Fish and 

Game. 592 p. 

Fronk, R. H. 1969. Biology of Atherinops affinis littoralis Hubbs in Newport Bay. MS Thesis, Univ. 

Calif., Irvine. 106 pp. 

Garrison, K. J. and B. S. Miller. 1982. Review of the early life history of Puget Sound fishes. Fish. Res. 

Inst., Univ. Wash., Seattle, WA. FRI-UW-8216. 729 p. 

Goericke, R., E. Venrick, A. Mantyla, S. J. Bograd, F. B. Schwing, A. Huyer, R. L. Smith, P. A. Wheeler, 

R. Hooff, W. T. Peterson, F. Chavez, C. Collins, B. Marinovic, N. Lo, G. Gaxiola-Castro, R. Durazo, 

K. D. Hyrenbach, and W. J. Sydeman. 2005. The state of the California Current, 2004–2005: still 

cool? CalCOFI Rep. 46:32–71. 

Goldberg, S. R. 1976. Seasonal spawning cycles of the sciaenid fishes Genyonemus lineatus and Seriphus 

politus. Fish. Bull., U.S. 74(4):983−984. 

Goodyear, C. P. 1978. Entrainment impact estimates using the equivalent adult approach. USFWS, 

FWS/OBS-78/65, Ann Arbor, MI. 

Gregory, P. A. 2001a. Silversides. Pp. 243–245 In California’s living marine resources: A status report. 

W. S. Leet, C. M. Dewees, R. Klingbeil, and E. J. Larson (eds.). Calif. Dept. of Fish and Game. 592 

p. 

Gregory, P. A. 2001b. Grunion. Pp. 246−247 In California’s living marine resources: A status report. W. 

S. Leet, C. M. Dewees, R. Klingbeil, and E. J. Larson (eds.). Calif. Dept. of Fish and Game. 592 p. 

Hammann, M. G. and M. A. Cisneros-Mata. 1989. Range extension and commercial captures of the 

northern anchovy, Engraulis mordax Girard, in the Gulf of California, Mexico. Calif. Dept. of Fish 

and Game 75:49–53. 

Hart, J. L. 1973. Pacific fishes of Canada. Fish. Res. Board Can. Bull. 180. 740 p. 

Herbinson, K. T., M. J. Allen, and S. L. Moore. 2001. Historical trends in nearshore croaker (Family 

Sciaenidae) populations in southern California from 1977 through 1998. Pp. 253−264 In SCCWRP 

Annual Report 1999−2000. S. B. Weisberg and D. Hallock (eds.). So. Calif. Coastal Water Res. 

Project, Westminster, CA. March 2001. 308 p. 

Hill, K. T., N. C. H. Lo, B. J. Macewicz, and R. Felix-Uraga. 2006. Assessment of the Pacific sardine 

(Sardinops sagax caerulea) population for U.S. management in 2006. NOAA-TM-NMFS-SWFSC386. March 2006. 

Hobson, E. S. and J. R. Chess. 1976. Trophic interactions among fishes and zooplankters near shore at 

Santa Catalina Island, California. Fish. Bull., U. S. 74(3):567−598. 
Haynes Generating Station 

IM&E Final Report Literature Cited

7-6 

Hobson, E. S., W. N. McFarland, and J. R. Chess. 1981. Crepuscular and nocturnal activities of 

Californian nearshore fishes, with consideration of their scotopic visual pigments and the photic 

environment. Fish. Bull, U. S. 79(1):1−17. 

Holbrook, S. J., R. J. Schmitt, and J. S. Stephens, Jr. 1997. Changes in an assemblage of temperate reef 

fishes associated with a climate shift. Ecol. App. 7:1299−1310. 

Horn, M. H. and J. S. Stephens, Jr. 2006. Climate change and overexploitation. Pp. 621−635 In The 

Ecology of Marine Fishes, California and Adjacent Waters. L. G. Allen, D. J. Pondella, and M. H. 

Horn (eds.), U. C. Press, Los Angeles, CA. 660 p. 

Horn, M. H. and L. G. Allen. 1978. A distributional analysis of California coastal marine fishes. J. 

Biogeography. 5:23−42. 

Horst, T. J. 1975. The assessment of impact due to entrainment of ichthyoplankton. Pp. 107−118 In

Fisheries and Energy Production: A symposium (S. B. Saila, ed.). Lexington Books, D.C. Heath and 

Company, Lexington, MA. 

Hubbs, C. L. and L. P. Schultz. 1939. A revision of the toadfishes referred to Porichthys and related 

genera. Proc. U.S. Nat. Mus. (Smithsonian Inst.). 86(3060):473–496. 

Hunter, J. R. and B. J. Macewicz. 1980. Sexual maturity, batch fecundity, spawning frequency, and 

temporal pattern of spawning for the northern anchovy, Engraulis mordax, during the 1979 spawning 

season. CalCOFI Rep. 21:139−149. 

Hunter, J. R. and K. M. Coyne. 1982. The onset of schooling in northern anchovy larvae, Engraulis 

mordax. CalCOFI Rep. 23:246−251. 

Hurley, A. C. 1977. Mating behavior of the squid Loligo opalescens. Mar. Behav. Physiol. 1977(4):195–

203. 

Intersea Research Corporation (IRC). 1981. Haynes Generating Station Cooling Water Intake Study. 

316(b) Demonstration Program. Prepared for Los Angeles Department of Water and Power. Los 

Angeles, California. 

Jackson, G. D. 1998. Research into the life history of Loligo opalescens: where to from here? CalCOFI 

Rep. 39:101–107.

Jarvis, E. T., M. J. Allen, and R. W. Smith. 2004. Comparison of recreational fish catch trends to 

environment-species relationships and fishery-independent data in the southern California bight, 

1980–2000. CalCOFI Rep. 45:167–179. 

Jordan, D. S. and B. W. Evermann. 1896. The fishes of Middle and North America: A descriptive 

catalogue of the species of fish-like vertebrates found in the waters of North America. Rep. U. S. Fish 

Comm. v. 21 [1895] Append. 5, Pp. 207–584. 

Karpov, K. A. and G. M. Cailliet. 1979. Prey composition of the market squid, Loligo opalescens Berry, 

in relation to depth and location of capture, size of squid, and sex of spawning squid. CalCOFI Rep. 

20:51–57. 

Klingbeil, R. A., R. D. Sandell, and A. W. Wells. 1975. An annotated checklist of the elasmobranches 

and teleosts of Anaheim Bay. Pp. 79–90 In E. D. Lane and C. W. Hill (eds.). The marine resources of 

Anaheim Bay. Calif. Dept. of Fish and Game Fish Bull. 165. 
Haynes Generating Station 

IM&E Final Report Literature Cited

7-7 

Lang, M. A. and F. G. Hochberg (eds.). 1997. Proceedings of the Workshop on the Fishery and Market 

Potential of Octopus in California. Univ. So. Calif., Catalina Mar. Sci. Center, 31 Aug.–8 Sep. 1989. 

Smith. Inst., Wash. D.C. 191 p. 

Larkin, P. A. 1996. Concepts and issues in marine ecosystem management. Rev. in Fish Biol. and Fish. 

6:139–164. 

Lea, R. N. and R. H. Rosenblatt. 2000. Observations on fishes associated with the 1997–98 El Niño off 

California. CalCOFI Rep. 41: 117–129. 

Leet, W. S., C. M. Dewees, R. Klingbeil, and E. J. Larson. 2001. California’s Living Marine Resources: 

A Status Report. California Department of Fish and Game. 592 pp. 

Link, J. 2002. Ecological considerations in fisheries management: When does it matter? Fisheries 27:10–

17. 

Lluch-Belda, D. R., M. Laurs, D. B. Lluch-Cota, and S. E. Lluch-Cota. 2001. Long-term trends of 

interannual variability in the California Current System. CalCOFI Rep. 42:129–144. 

Lluch-Belda, D., R. A. Schwartzlose, R. Serra, R. Parrish, T. Kawasaki, D. Hedgecock, and R. J. M. 

Crawford. 1992. Sardine and anchovy regime fluctuations of abundance in four regions of the world 

oceans: a workshop report. Fish. Oceanogr. 1(4):339–347. 

Los Angeles Department of Water and Power (LADWP). Clean Water Act Section 316(b) Proposal for 

Information Collection for Haynes Generating Station, Final. October 2005. 57 p. plus appendices. 

Los Angeles Regional Contaminated Sediments Task Force (LARCSTF). 2005. Long Term Management 

Strategy. Section 2.8: Circulation and Sediment Transport. http://www.coastal.ca.gov/sediment/longterm-mgmt-strategy-5-2005.pdf. 

Love, M. S. 1996. Probably more than you want to know about the fishes of the Pacific coast. 2nd edition. 

Really Big Press, Santa Barbara, California. 381 p. 

Love, M. S., C. W. Mecklenburg, T. A. Mecklenburg, and L. K. Thorsteinson. 2005. Resource Inventory 

of Marine and Estuarine Fishes of the West Coast and Alaska. U. S. Dept. of the Interior, USGS, 

Seattle, WA. OCS Study MMS 2005-030. 

Love, M. S., G. E. McGowen, W. Westphal, R. J. Lavenberg, and L. Martin. 1984. Aspects of the life 

history and fishery of the white croaker, Genyonemus lineatus (Sciaenidae) off California. Fish. Bull., 

U. S. 82(1):179−198. 

Love, M. S., J. E. Caselle, and W. Van Buskirk. 1998. A severe decline in the commercial passenger 

fishing vessel rockfish (Sebastes spp.) catch in the southern California bight, 1980−1996. CalCOFI 

Rep. 39:180–195. 

Love, M. S., M. Yoklavich, and L. Thorsteinson. 2002. The Rockfishes of the Northeast Pacific. U.C. 

Press, Berkeley, CA. 405 p. 

MacCall, A. D. 1979. Population estimates for the waning years of the Pacific sardine fishery. CalCOFI 

Rep. 20:72–82. 

MacCall, A. D. 2005. Assessment of Vermilion Rockfish in Southern and Northern California, August 

2005. NOAA NMFS Southwest Fisheries Science Center. 128 p. 
Haynes Generating Station 

IM&E Final Report Literature Cited

7-8 

MacCall, A. D., K. R. Parker, R. Leithiser, and B. Jessee. 1983. Power plant impact assessment: A simple 

fishery production model approach. Fish. Bull., U.S. 81(3):613−619. 

MacDonald, C. K. 1975. Notes on the family Gobiidae from Anaheim Bay. Pp. 117–121 In E. D. Lane 

and C. W. Hill (eds.). The marine resources of Anaheim Bay. Calif. Dept. of Fish and Game Fish 

Bull. 165. 

Macewicz, B. J., J. R. Hunter, N. C. H. Lo, and E. L. LaCasella. 2004. Fecundity, egg deposition, and 

mortality of market squid (Loligo opalescens). Fish. Bull., U.S. 102(2):306–327. 

Mangel, M. and P. S. Levin. 2005. Regime, phase and paradigm shifts: making community ecology the 

basic science for fisheries. Phil. Trans. Royal Soc. London B360:95−105. 

Mason, J. and T. Bishop. 2001. Jack Mackerel. Pp. 309–311 In California’s living marine resources: A 

status report. W. S. Leet, C. M. Dewees, R. Klingbeil, and E. J. Larson (eds.). Calif. Dept. of Fish and 

Game. 592 p. 

Mason, J. E. 2004 Historical patterns from 74 years of commercial landings from California waters. 

CalCOFI Rep. 45:180–190. 

Matarese, A. C., A. W. Kendall Jr., D. M. Blood, and B. M. Vintner. 1989. Laboratory guide to early life 

history stages of northeast Pacific fishes. NOAA Tech. Rep. NMFS 80, 652 p. 

MBC Applied Environmental Sciences and Tenera Environmental. 2005. AES Huntington Beach 

Generating Station Entrainment and Impingement Study Final Report. Prepared for AES Huntington 

Beach L.L.C. and California Energy Commission, Sacramento, California. April 2005. 

MBC Applied Environmental Sciences. 1985. Santa Monica Bay sportfishing revitalization study. 

Prepared for Calif. Dept. of Fish and Game, Long Beach, CA. MBC Applied Environ. Sci., Costa 

Mesa, CA. 94 p. 

MBC Applied Environmental Sciences. 1987. Ecology of important fisheries species offshore California. 

OCS Study 86-0093. Prepared for Minerals Management Service, Pacific OCS Region. 251 p. 

MBC Applied Environmental Sciences. 1991. Distribution of juvenile California halibut (Paralichthys 

californicus) in bay and coastal habitats of Los Angeles, Orange, and San Diego Counties in 1990. 

Final Report. Prepared for So. Calif. Edison Co., Rosemead, CA. April 1991. 21 p. plus appendices. 

MBC Applied Environmental Sciences. 1994. Marine biological baseline study Queensway Bay, Long 

Beach Harbor. Prepared for City of Long Beach. ~153 p. plus appendices. 

MBC Applied Environmental Sciences. 1997. 316(b) Document for Scattergood, Haynes, and Harbor 

Generating Stations. Prepared for the Los Angeles Dept. Water and Power. April 1997. 

MBC Applied Environmental Sciences. 2004. Haynes Generating Station Entrainment Characterization 

Study. Prepared for Los Angeles Dept. Water and Power. December 2004. 

MBC Applied Environmental Sciences. 2006. National Pollutant Discharge Elimination System 2005 

receiving water monitoring report, Haynes and AES Alamitos L.L.C. Generating Stations, Los 

Angeles County, California. Prepared for the Los Angeles Dept. of Water and Power and AES 

Alamitos L.L.C. 78 p plus appendices. 
Haynes Generating Station 

IM&E Final Report Literature Cited

7-9 

MBC Applied Environmental Sciences. 2007. National Pollutant Discharge Elimination System 2006 

receiving water monitoring report, Haynes and AES Alamitos L.L.C. Generating Stations, Los 

Angeles County, California. Prepared for the Los Angeles Dept. of Water and Power and AES 

Alamitos L.L.C. 

McGowan, J. A. 1954. Observations on the sexual behavior and spawning of the squid, Loligo 

opalescens, at La Jolla, California. Calif. Dept. of Fish and Game 40(1):47–54. 

Middaugh, D. P., M. J. Hemmer, J. M. Shenker, and T. Takita. 1990. Laboratory culture of jacksmelt, 

Atherinopsis californiensis, and topsmelt, Atherinops affinis (Pisces: Atherinidae), with a description 

of larvae. Calif. Dept. of Fish and Game 76(1):4–13. 

Miller, D. J. and R. N. Lea. 1972. Guide to the Coastal Marine Fishes of California. Calif. Dept. of Fish 

and Game Fish Bull. 157. 249 pp. 

Moffatt & Nichol. 2004. Tidal and flood hydraulics study. Report prepared for the City of Long Beach, 

Dept. of Public Works, July 30, 2004. 25 p. 

Moore, S. L. 2001. Age and growth of white croaker (Genyonemus lineatus) off Palos Verdes and Dana 

Point, California. Pp. 154–163 In SCCWRP Annual Report 1999−2000. So. Calif. Coastal Water Res. 

Project, Westminster, CA. March 2001. 308 p. 

Moore, S. L. and P. W. Wild. 2001. White croaker. Pp. 234−235 In California’s living marine resources: 

A status report. W. S. Leet, C. M. Dewees, R. Klingbeil, and E. J. Larson (eds.). Calif. Dept. of Fish 

and Game. 592 p. 

Morris, R. H., D. P. Abbot, and E. C. Haderlie. 1980. Intertidal invertebrates of California. Stanford Univ. 

Press, Stanford, CA. 690 p. 

Moser, H. G. (ed.). 1996. The early stages of fishes in the California Current Region. CalCOFI Atlas No. 

33. Allen Press, Inc., Lawrence, KS. 1505 p. 

Moser, H. G., R. L. Charter, W. Watson, D. A. Ambrose, K. T. Hill, P. E. Smith, J. L. Butler, E. M. 

Sandknop, and S. R. Charter. 2001. The CalCOFI ichthyoplankton time series: potential contributions 

to the management of rocky-shore fishes. CalCOFI Rep. 42: 112–128. 

Moyle, P. B. and J. J. Cech. 1988. Fishes: An Introduction to Ichthyology. Department of Wildlife and 

Fisheries Biology, U.C. Davis. Prentice Hall, Englewood Cliffs, NJ. 

Murdoch, W. W., B. J. Mechalas, and R. C. Fay. 1989b. Technical Report to the California Coastal 

Commission. N. Integration of local repressions and increases in fish stocks with inplant losses. 

Murdoch, W. W., R. C. Fay, and B. J. Mechalas. 1989a. Final Report of the Marine Review Committee to 

the California Coastal Commission, MRC Doc. No. 89-02, 346 p. 

National Marine Fisheries Service. 1999. Our living oceans. Report on the status of the U.S. living marine 

resources, 1999. U.S. Dept. Commerce, NOAA Tech. Memo. NMFS-F/SPO-41. 301 p. 

National Marine Fisheries Service. 2007. Recreational sport fisheries data for southern California. 

http://swfscdata.nmfs.noaa.gov/latimes/. 

Nelson, J. S. 1994. Fishes of the World, 3rd Ed. John Wiley and Sons, Inc., New York. 600 p. 

Newbold, S. C. and R. Iovanna. 2007. Population Level Impacts of Cooling Water Withdrawals on 

Harvested Fish Stocks. Environ. Sci. Technol. 41 (7):2108–2114. 
Haynes Generating Station 

IM&E Final Report Literature Cited

7-10 

Ninos, M. 1984. Settlement and metamorphosis in Hypsoblennius (Pisces, Blenniidae). Ph. D. Thesis, 

Univ. of So. Calif. 86 p. 

Norton, J. G. and J. E. Mason. 2005. Relationship of California sardine (Sardinops sagax) abundance to 

climate-scale ecological changes in the California Current System. CalCOFI Rep. 46:83–92. 

PacFIN. 2007. Pacific Coast Fisheries Information Network. http://www.psmfc.org/pacfin/data.html. 

Pacific Fishery Management Council. 1983. Northern anchovy management plan incorporating the final 

supplementary EIS/OPIR/IRFA. Pac. Fish. Mgmt. Council, Portland, OR. 

Pacific Fishery Management Council. 1998. Coastal Pelagic Species Fishery Management Plan 

(Amendment 8 to the Northern Anchovy Fishery Management Plan). Dec. 1998. 

Pacific Fishery Management Council. 2006. Pacific Coast Groundfish Fishery Management Plan: For the 

California, Oregon, and Washington Groundfish Fishery as Amended through Amendment 19 

(including Amendment 16-4). Nov. 2006. 167 p. plus appendices. 

Parker, K. R. and E. E. DeMartini. 1989. Chapter D: Adult-equivalent loss. Technical Report to the 

California Coastal Commission. 33 pp. 

Parrish, R. H., C. S. Nelson, and A. Bakun. 1986. Transport mechanisms and reproductive success of 

fishes in the California Current. Biol. Ocean. 1(2):175−203. 

Peterson, B., R. Emmett, R. Goericke, E. Venrick, A. Mantyla, S. J. Bograd, F. B. Schwing, R. Hewitt, N. 

Lo, W. Watson, J. Barlow, M. Lowry, S. Ralston, K. A. Forney, B. E. Lavaniegos, W. J. Sydeman, D. 

Hyrenbach, R. W. Bradley, P. Warzybok, F. Chavez, K. Hunter, S. Benson, M. Weise, and J. Harvey. 

2006. The state of the California Current, 2005–2006: warm in the north, cool in the south. CalCOFI 

Rep. 47:30–74. 

Pondella, D. J., II and L. G. Allen. In review. Can we save the big fish? Marine Biology. 

Pondella, D. J., II and M. J. Allen. 2001. Proceedings of Special Symposium: New and Rare Fish and 

Invertebrate Species to California During the 1997−98 El Niño, So. Calif. Acad. Sci., May 20, 2000. 

D. J. Pondella, II and M. J. Allen (eds.). Bull. So. Calif. Acad. Sci. 100(3):129–251. 

Power, J. H. 1986. A model of the drift of northern anchovy, Engraulis mordax larvae in the California 

Current. Fish. Bull., U. S. 78(4):855−876. 

Public Service Electric and Gas Company (PSE&G). 1993. Appendix I—Modeling. Permit No. 

NJ0005622. Prepared by Lawler, Matusky, and Skelly Engineers, Pearl River, NY. Comments on 

NJPDES Draft, 82 p. 

RecFIN. 2007. Recreational Fisheries Information Network. http://www.psmfc.org/recfin/data.htm. 

Recksiek, C. W. and J. Kashiwada. 1979. Distribution of larval squid, Loligo opalescens, in various 

nearshore locations. CalCOFI Rep. 20:31–34. 

Recksiek, C.W. and H.W. Frey. 1978. Background of Market Squid Research Program, Basic Life 

History, and the California Fishery. Pp. 7–9 In Biological, Oceanographic, and Acoustic Aspects of 

the Market Squid, Loligo opalescens Berry. C. W. Recksiek and H.W. Frey (eds.). Calif. Dept. of 

Fish and Game Fish Bull. 169. 

Reish, D. J. and H. A. Winter. 1954. The ecology of Alamitos Bay, California, with special reference to 

pollution. Calif. Dept. of Fish and Game 40(2):105–121. 
Haynes Generating Station 

IM&E Final Report Literature Cited

7-11 

Ricker, W. E. 1975. Computation and interpretation of biological statistics of fish populations. Fish. Res. 

Board Can. Bull. 91, 382 p. 

Ripley W. E. 1946. The soupfin shark and the fishery. Calif. Dept. of Fish Game Fish Bull. 64:7–38. 

Robertson, D. R. and G. R. Allen. 2002. Shorefishes of the tropical eastern Pacific: an information 

system. Smithsonian Tropical Research Institution, Balboa, Panamá. 

Sakagawa, G. T. and M. Kimura. 1976. Growth of laboratory-reared northern anchovy, Engraulis 

mordax, from southern California. Fish. Bull., U. S. 74(2):271−279. 

Schlotterbeck, R. E. and D. W. Connally. 1982. Vertical stratification of three nearshore southern 

California larval fishes (Engraulis mordax, Genyonemus lineatus, and Seriphus politus). Fish. Bull., 

U. S. 80(4):895−902. 

Schwing, F. B., C. S. Moore, S. Ralston and K. M. Sakuma. 2000. Record coastal upwelling in the 

California Current in 1999. CalCOFI Rep. 41:148–160. 

Silverstein, M. and E. Campbell. 1989. Elkhorn Slough. Monterey Bay Aquarium Foundation. Monterey, 

CA. 64 p. 

Spratt, J. D. 1979. Age and growth of the market squid, Loligo opalescens Berry, from statoliths. 

CalCOFI Rep. 20:58–64. 

Stephens, J. S. Jr. 1969. Growth, longevity, and the effect of size on the biology of certain Blennioid 

fishes. Final Report. National Science Foundation GB 5940. 83 pp. 

Stephens, J. S. Jr., R. J. Larson, and D. J. Pondella. 2006. Rocky reefs and kelp beds. Pp. 227–252 In The 

Ecology of Marine Fishes: California and Adjacent Waters. L. G. Allen, D. J. Pondella II, and M. H. 

Horn. (eds.). Univ. Calif. Press, Berkeley. 660 p. 

Stephens, J. S. Jr., R. K. Johnson, G. S. Key and J. E. McCosker. 1970. The comparative ecology of three 

sympatric species of California blennies of the genus Hypsoblennius Gill (Teleostomi, Blenniidae). 

Ecol. Monogr. 40(2):213−233. 

Stephens, J. S., Jr. and D. J. Pondella, II. 2002. Larval productivity of a mature artificial reef: the 

ichthyoplankton of King Harbor, California, 1974–1997. ICES J. Mar. Sci. 59:S51–58. 

Stephens, Jr., J. S., P. A. Morris, K. E. Zerba, and M. Love. 1984. Factors affecting fish diversity on a 

temperate reef II: the fish assemblage of Palos Verdes Point, 1974–1981. Environ. Biol. Fish. 11:259–

275. 

Stevens, E. G. and H. G. Moser. 1982. Observations on the early life history of the mussel blenny, 

Hypsoblennius jenkinsi, and the bay blenny, Hypsoblennius gentilis, from specimens reared in the 

laboratory. CalCOFI Rep. 23:269−275. 

Stull, J. K. and C. Tang. 1996. Demersal fish trawls off Palos Verdes, southern California, 1973–1993. 

CalCOFI Rep. 37:211–264. 

Swift, C. C., J. L. Nelson, C. Maslow, and T. Stein. 1989. Biology and distribution of the tidewater goby, 

Eucyclogobius newberryi (Pisces: Gobiidae) in California. Contrib. in Science 404:1−19. 
Haynes Generating Station 

IM&E Final Report Literature Cited

7-12 

Tenera Environmental. 2004. South Bay Power Plant cooling water system effects on San Diego Bay; 

Volume II: Compliance with Section 316(b) of the Clean Water Act for the South Bay Power Plant. 

Prepared for Duke Energy South Bay, Chula Vista, CA. 

Tenera Environmental. 2007. EPS Cooling Water System Entrainment and Impingement of Marine 

Organisms: Effects on the Biological Resources of Agua Hedionda Lagoon and the Nearshore Ocean 

Environment. Prepared for NRG Cabrillo Encina Power Station, October 2007. 

United States Environmental Protection Agency. 1977. Guidance for evaluating the adverse impact of 

cooling water intake structures on the aquatic environment: Section 316(b) P.L. 92-500, 58 p. 

United States Environmental Protection Agency. 2002. Case study analysis for the proposed Section 

316(b) Phase II Existing Facilities Rule. EPA-821-R-02-002. 

USEPA. See United States Environmental Protection Agency 

Valle, C. F., J. W. O’Brien, and K. B. Wiese. 1999. Differential habitat use by California halibut, 

Paralichthys californicus, barred sand bass, Paralabrax nebulifer, and other juvenile fishes in 

Alamitos Bay, California. Calif. Dept. of Fish and Game Fish. Bull. 97:646–660. 

van der Lingen, C. D. 1995. Respiration rate of adult pilchard Sardinops sagax in relation to temperature, 

voluntary swimming speed and feeding behaviour. Mar. Ecol. Progr. Ser. 129:41–54. 

VenTresca, D. 2001. Vermillion rockfish. Pp. 189–190 In California’s living marine resources: A status 

report. W. S. Leet, C. M. Dewees, R. Klingbeil, and E. J. Larson (eds.). Calif. Dept. of Fish and 

Game. 592 p. 

Voightlander, C. W. 1980. If you can’t measure an impact, there probably is not an impact. Fifth National 

Workshop on Entrainment and Impingement. Session 1. 16 pp. 

Vojkovich, M. 1998. The California fishery for market squid (Loligo opalescens). CalCOFI Rep. 39:55–

60. 

Wang, J. C. S. 1986. Fishes of the Sacramento-San Joaquin Estuary and Adjacent Waters, California: a 

Guide to the Early Life Histories. Interagency Ecological Study Program for the Sacramento-San 

Joaquin Estuary, Technical Report 9. 

Ware, R. R. 1979. The food habits of the white croaker Genyonemus lineatus and an infaunal analysis 

near areas of waste discharge in Outer Los Angeles Harbor. Thesis, Calif. State Univ., Long Beach. 

August 1979. 163 p. 

Watson, W. 1982. Development of eggs and larvae of the white croaker, Genyonemus lineatus Ayres 

(Pisces: Sciaenidae) off the southern California coast. Fish. Bull., U. S. 80(3):403−417. 

Weather Underground. 2007. Web site: http://www.wunderground.com. Accessed 7 March 2007. 

Wellington, G. M. and B. C. Victor. 1989. Planktonic duration of one hundred species of Pacific and 

Atlantic damselfishes (Pomacentridae). Mar. Biol. 101:557−567. 

Wilson, D. C. and R. E. Millemann. 1969. Relationships of female age and size embryo number and size 

in the shiner perch, Cymatogaster aggregata. J. Fish. Res. Board Can. 267:2339−2344. 

Wolf, P., P. E. Smith, and D. R. Bergen. 2001. Pacific sardine. Pp. 299–302 In California’s living marine 

resources: A status report. W. S. Leet, C. M. Dewees, R. Klingbeil, and E. J. Larson (eds). Calif. 

Dept. of Fish and Game. 592 p. 
Haynes Generating Station 

IM&E Final Report Literature Cited

7-13 

Yang, W. T., R. F. Hixon, P. E. Turk, M. E. Krejci, W. H. Hulet, and R. T. Hanlon. 1986. Growth, 

behavior, and sexual maturation of the market squid, Loligo opalescens, cultured through the life 

cycle. Fish. Bull., U. S. 84(4):771–798. 

Zeidberg, L. D., W. Hamner, K. Moorehead, and E. Kristof. 2004. Egg masses of Loligo opalescens

(Cephalopoda: Myopsida) in Monterey Bay, California following the El Niño event of 1997–1998. 

Bull. Mar. Sci. 74:129−141. 

Zorzi, G. D., L. K. Martin and J. Ugoretz. 2001. Skates and Rays. Pp. 257−261 In California’s living 

marine resources: A status report. W. S. Leet, C. M. Dewees, R. Klingbeil, and E. J. Larson (eds.). 

Calif. Dept. of Fish and Game. 592 p.