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Moss Landing Power Plant 

Modernization Project 

316(b) Resource Assessment 

\ _ 

April 28, 2000 

Prepared for: 

©Duke Energy Moss Landing, LLC 

655 3rd Street P.M.B. 49 

Oakland, CA 94607 

TENERA s ivironmsfltsl One Market, Spear Tower, Suite 1850, San Francisco, CA 94105 

(415) 536-4744, FAX (415) 536-4714 

3427-A Miguelito Court, San Luis Obispo, California 93401 

(805) 541-0310, FAX: (805) 541-0421 

%o0p 
P.3 

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I 

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TENERA 

May 1,2000 

Mr. Roger W. Briggs, Executive Officer 

California Regional Water Quality Control Board, Central Coast Region 

81 Higuera Street, Suite 200 

San Luis Obispo, CA 93401-5427 

m 

MOSS LANDING POWER PLANT MODERNIZATION PROJECT 

SUBMITTAL OF 316(b) RESOURCE ASSESSMENT 

Dear Mr. Briggs: 

Pursuant to the requirements established in your July 21, 1999 "Requirements Letter" related to 

this project, Duke Energy has conducted various studies, perfonned evaluations, and submitted 

various draft and final reports. One ofthe required reports was the "draft 316(b) resource 

assessment report for the Moss Landing power plant", dated January 1, 2000. Copies of that draft 

report were also submitted to members ofthe Technical Working Group established under your 

Board's purview for this project (including other state agencies, your Board's consultants, and 

the Califomia Energy Commission's (CEC) consultant), and staff of the CEC. The draft report 

and subsequent revisions have been reviewed by the above listed recipients, and discussed at a 

number of Technical Working Group meetings. 

In order to process and analyze the full year's data, and review the report, the March 1, 2000 due 

date for the final 316(b) Demonstration report was extended to April 17, 2000. The report was 

completed ahead of schedule and distributed on April 4, 2000 to members ofthe Technical 

Working Group. At the last meeting on April 12, 2000 it was determined that with the 

incorporation of a few changes discussed at that meeting, the report would be ready for 

submittal. 

<"Ve ».W/ot S^or.- T„,., 0 , Ci"*o IDRfl - rr. (:--,_,„,c._, ^-.i;f„.,.,, Qjins.-i' a -£iz^ CTC_17.4_1 C»Y M , c v ^IP..*"! 1 * 
P.4 

The report has subsequently been prepared. Please find enclosed six copies of "Moss Landing 

Power Plant Modernization Project, 316(b) Resource Assessment. April 28, 2C00." If you wish 

to discuss any matters related to this repon, please don't hesitate to call Wayne Hoffman at 

(510) 251-6801 or me at (415) 536 3542. 

Sincerely yours, 

David L. Mayer 

President 

TENERA Environmental LLC 

cc: Mr. Michael Thomas, CCRWQCB (via letter to R. Briggs) 

Mr. Brad Hagemann, CCRWQCB (via letter to R. Briggs) 

Dr. Greg Cailliet, MLML 

Dr. Pete Raimondi, UCSC 

Dr. Mike Foster, MLML 

Ms. Deborah Johnston, CDF&G 

Mr. Dick Anderson, CEC (via CEC Docket distribution) 

Mr. Joe O'Hagan, CEC (via CEC Docket distribution) 

Mr. Michael Bowen, CCC 

Mr. John Dixon, CCC 

Dr. Jeff Paduan, Naval Postgraduate School 

Mr. Wayne Hoffman, Duke Energy 

Ms. Carol Raifsnider, Tenera Energy 

Mr. Lee Genz, MLPP 

Mr. Wayne Hoffman 

Mr. Brian Waters. Duke Energy 
P.5 

Moss Landing Power Plant 

Modernization Project 

316(b) Resource Assessment 

April 28, 2000 

Prepared for: 

©Duke Energy Moss Landing, LLC 

655 3rd Street P.M.B. 49 

Oakland, CA 94607 

TENERA & iron mental One Market, Spear Tower, Suite 1850, San Francisco, CA 94105 

(415) 536-4744, FAX (415) 536-4714 

3427-A Miguelito Court, San Luis Obispo, California 93401 

(805) 541-0310, FAX: (805) 541-0421 
P.6 

TABLE OF CONTENTS 

EXECUTIVE SUMMARY ES-1 

1.0 INTRODUCTION 1-1 

1.1 Development of the 316(b) Study Plans , 1-2 

1.2 Overview ofthe 316(b) Program 1-3 

1.2.1 Target Organisms Selected fpr Study 1-3 

1.3 Organization ofthe Report 1-4 

2.0 DESCRIPTION OF THE MOSS LANDING POWER PLANT AND CHARACTERISTICS OF THE 

SOURCE WATER BODY 2-1 

2.1 The Plant and its Cooling Systems 2-1 

2.1.1 Plant Cooling Water System Description and Operation 2-4 

2.2 Aquatic Biological Resources in the Vicinity of MLPP 2-12 

2.2.1 Elkhorn Slough/Moss Landing Harbor 2-12 

2.2.2 Monterey Bay 2-15 

3.0 ENTRAINMENT STUDY AND ASSESSMENT METHODS 3-1 

3.1 Entrainment Study 3-2 

3.1.1 Entrainment Sampling Methods 3-2 

3.1.2 Entrainment Sampling Frequency Rationale 3-4 

3.2 Source Water Study 3-4 

3.2.1 Source Water Sampling Methods 3-4 

3.2.2 Comparability of Surface and Oblique Towed Methodologies 3-6 

3.3 Laboratory Processing and Data Handling 3-7 

3.4 Sampling Sufficiency 3-8 

3.5 Assessment Methods 3-8 

3.5.1 Demographic Approaches 3-9 

3.5.2 Empirical Transport Model {ETM) 3-16 

4.0 ENTRAINMENT AND SOURCE WATER RESULTS 4-1 

4.1 Entrainment Study Results 4-1 

4.1.1 Sampling and Laboratory Processing Sufficiency 4-13 

4.1.2 Day-Night Comparison 4-17 

4.2 Source Water Study Results 4-21 

4.3 Gobiidae: Introduction 4-29 

4.3.1 Unidentified Gobies 4-30 

4.3.2 Unidentified goby results (53.2 percent) 4-35 

4.4 Bay Goby : 4-38 

4.4.1 Bay goby results (30.4 percent) 4-38 

4.5 BlackeyeGoby 4-44 

4.5.1 Blackeye goby results (3.0 percent) 4-50 

4.6 Pacific Staghorn Sculpin 4-52 

4.6.1 Pacific staghorn sculpin results (2.2 percent) 4-56 

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4.7 White Croaker 4-58 

4.7.1 White Croaker Results (2.1 percent) 4-62 

4.8 Blenniidae: Combtooth blennies 4-62 

4.8.1 Hypsoblennius Spp 4-62 

4.8.2 Blennies Hypsoblennius spp. Results (1.9 percent) 4-65 

4.9 Longjaw Mudsucker 4-68 

4.9.1 Longjaw Mudsucker Gillichthys mirabilis Results (1.2 percent) 4-71 

4.10 Pacific Herring 4-77 

4.10.1 Pacific herring Clupea pallasi results (0.9 percent) 4-81 

4.11 Rock Crabs Family Cancridae 4-84 

4.12 Hairy Rock Crab Cancer jordani 4-89 

4.12.1 Hairy Rock Crab Results (29.3 percent) 4-90 

4.13 Yellow Rock Crab Cancer anthonyi 4-94 

4.13.1 Yellow Rock Crab results (19.6 percent) 4-96 

4.14 Brown Rock Crab Cancer antennarius 4-99 

4.14.1 Brown Rock Crab Results (19.0 percent) , 4-100 

4.15 Dungeness Crab Cancer magister 4-104 

4.15.1 Dungeness Crab Results (14.7 percent) 4-108 

4.16 Red Rock Crab Cancer productus 4-109 

4.16.1 Red Rock Crab Results (9.8 percent) 4-110 

4.17 Slender Rock Crab Cancer gracilis 4-113 

4.17.1 Slender Rock Crab Results (7.1 percent) 4-114 

4.18 European Green Crab Carcinus maenas 4-118 

4.18.1 European Green Crab Carcinus maenas Results 4-121 

5.0 IMPINGEMENT EFFECTS 5-1 

5.1 Impingement Study 5-2 

5.1.1 Methods 5-2 

5.2 Life Histories of Abundantly Impinged Fishes 5-4 

5.2.1 Fishes 5-4 

5.2.2 Macroinvertebrates 5-12 

5.3 Impingement Effects 5-20 

5.4 Rate of Impingement and Intake Velocities 5-29 

5.4.1 Impingement Survival and Intake Velocities 5-31 

5.5 Conclusions 5-32 

6.0 COOLING WATER SYSTEM IMPACT ASSESSMENT 6-1 

6.1 Entrainment Effects Assessment 6-2 

6.2 Unidentified Gobies 6-4 

6.3 Bay Goby 6-8 

6.4 Blackeye Goby 6-11 

6.5 Longjaw Mudsucker 6-15 

6.6 Combtooth Blenny 6-18 

6.7 Pacific Herring 6-22 

6.8 White Croaker 6-25 

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6.9 Pacific Staghorn Sculpin 6-28 

6.10 Hairy Rock Crab 6-30 

6.11 Yellow Rock Crab 6-32 

6.12 Brown Rock Crab 6-34 

6.13 Dungeness Crab 6-36 

6.14 Red Rock Crab 6-37 

6.15 Slender Rock Crab 6-39 

6.16 Summary of Entrainment Effects 6-41 

6.17 Impingement Effects Assessment 6-46 

7.0 EVALUATION OF ALTERNATIVE INTAKE TECHNOLOGIES 7-1 

7.1 First-level Evaluation — Are the Technologies Proven and Available? 7-2 

7.1.1 Behavioral Barriers 7-4 

7.1.2 Diversion Systems 7-4 

7.1.3 Physical Barriers 7-4 

7.2 Second-Level Evaluation — Will The Technology Result In Biological Benefits? 7-6 

7.2.1 Closed-Cycle Cooling Water System 7-6 

7.2.2 Intake Location 7-7 

7.2.3 Behavioral Barriers 7-10 

7.2.4 Physical Barriers 7-11 

7.2.5 Fish Collection, Removal, and Conveyance Systems 7-13 

7.2.6 Intake Maintenance And Operational Modifications 7-15 

7.2.7 Conclusion: Biological Evaluation 7-19 

7.3 Third-Level Evaluation — Feasibility And Cost Analysis 7-20 

7.3.1 Seasonal Curtailment 7-20 

7.3.2 Closed-Cycle Cooling Systems 7-23 

7.3.3 Modified Vertical Traveling Screen and Fish Return System for the New CC 

Units Intake 7-30 

7.3.4 Reductions in Circulating Water Pump Operation 7-33 

7.3.5 Dredging the Intake Area 7-35 

7.3.6 Alternative Biofouling Treatment Schemes 7-35 

7.4 Summary and Conclusions 7-36 

7.4.1 Discussion 7-37 

7.4.2 Conclusions... 7-39 

8.0 REFERENCES 8-1 

LIST OF APPENDICES 

Appendix A. Estimating Total Annual Entrainment. 

Appendix B. Derivation ofthe Variance and Estimated Variance of 

Appendix C. Estimating Proportional Entrainment and the ETM Calculations. 

Appendix D. Delta Method for Calculating Variance. 

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Table of Contents 

LIST OF TABLES 

Table 2-1. Historic and Projected Specifications ofthe Cooling Water Intake Structures at 

MLPP, Units 1 through 5 and the New Combined-cycle Units 2-3 

Table 3-1. Common Entrainment Period and Peak Concentrations for the Eight Most 

Abundantly Entrained Larval Fish Taxa at MLPP during 1978-1980 (PG&E, 1983) 3-4 

Table 3-2. Collection Specifications for Source Water Sampling at MLPP 3-6 

Table 3-3. Data Requirements and Outputs for Three Approaches Proposed to Estimate Effects 

of Cooling Water Withdrawals at MLPP 3-11 

Table 3-4. Advantages and Disadvantages ofthe Three Approaches Proposed to Estimate 

Effects in the MLPP 316(b) Assessment 3-12 

Table 4-1. Mean Concentrations (#/1,000 m3) of all Larval Fish Taxa and Megalops Selected 

Crabs Collected in front ofthe MLPP Intakes: March 2, 1999 - February 24, 2000 4-4 

Table 4-2. Species found to be Unique to either the New Combined-cycle Units or the Units 6 

and 7 Intakes 4-13 

Table 4-3. Results of T-tests Comparing Larval Fish Concentrations at the New Combinedcycle Units and the Units 6 and 7 Intakes 4-14 

Table 4-4. Sample Collection Times by Cycle, Date and Source Water Stations, Harbor Mouth 

(HM) and Harbor Bridge (HB) 4-19 

Table 4-5. Ratio of Daytime and Nighttime Concentrations of Larval Unidentified Goby Taxa, 

Bay Goby, and Pacific Staghorn Sculpin Collected the Harbor Mouth (HM) Station to 

New CC Units Intake Station Entrainment Concentrations 4-19 

Table 4-6. Ratio Of Daytime and Nighttime Concentrations of Larval Unidentified Goby Taxa, 

Bay Goby, and Pacific Staghorn Sculpin Collected the Harbor Bridge (HB) Station to 

New CC Units Intake Station Entrainment Concentrations 4-20 

Table 4-7. Mean Concentrations (#/1,000 m3) of all Larval Fish Taxa, Cancer spp. Megalops, 

and European Green Crab Megalops Collected in the Source Water in the Vicinity of 

the MLPP: June 1999 - February 2000 4-25 

Table 5-1. Estimated Concentrations Based on Surveys taken from January 1, 1979 -

March 31, 1980 5-28 

Table 5-2. Existing and Projected Approach and Through-Screen Velocities for the Pittsburg 

Power Plants Units 1 through 4 and Units 5 and 6 Intakes 5-30 

Table 5-3. Impingement of Striped Bass at Various Approach Velocities 5-30 

Table 5-4. Survival (%) of Striped Bass Impinged Four Minutes at Various Water Velocities 5-31 

Table 6-1. Final ETM Output Unidentified Gobies Gobiidae spp 6-6 

Table 6-2. Annual Entrainment and FH Estimates for Unidentified Gobies Gobiidae spp.: 

March 1, 1999 - February 29, 2000 6-7 

Table 6-3. Final ETM Output Bay Goby Lepidogobius lepidus 6-9 

Table 6-4. Annual Entrainment and AEL Estimates for Bay Goby Lepidigobius lepidus: 

March 1, 1999 - February 29, 2000 6-10 

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Table 6-5. Final ETM Output for Blackeye Goby Coryphopterus nicholsi 6-12 

Table 6-6. Annual Entrainment and FH Estimates for Blackeye Goby Coryphopterus nicholsi: 

March 1, 1999 - February 29, 2000 6-13 

Table 6-7. Annual Entrainment and AEL Estimates for Blackeye Goby Coryphopterus nicholsi: 

March 1, 1999 - February 29, 2000 6-14 

Table 6-8. Final ETM Output for Longjaw Mudsucker Gillichthys mirabilis 6-16 

Table 6-9. Annual Entrainment and FH Estimates for Longjaw Mudsucker Gillichthys 

mirabilis: March 1, 1999 - February 29, 2000 6-17 

Table 6-10. Final ETM Output for Unidentified Blennies Hypsoblennius spp 6-19 

Table 6-11. Annual Entrainment and FH Estimates for Unidentified Blennies Hypsoblennius 

spp.: March 1, 1999 - February 29, 2000 6-20 

Table 6-12. Annual Entrainment and AEL Estimates for Unidentified Blennies Hypsoblennius 

spp.: March 1, 1999 - February 29, 2000 6-21 

Table 6-13. Final ETM Output for Pacific Herring Clupea pallasi 6-23 

Table 6-14. Annual Entrainment and FH Estimates for Pacific Herring Clupea pallasi: 

March 1, 1999 - February 29, 2000 6-24 

Table 6-15. Annual Entrainment and AEL Estimates for Pacific Herring Clupea pallasi: 

March, 1, 1999 - February 29, 2000 6-25 

Table 6-16. Final ETM Output for White Croaker Genyonemus lineatus 6-26 

Table 6-17. Annual Entrainment and FH Estimates for White Croaker Genyonemus lineatus: 

March 1, 1999 - February 29, 2000 6-28 

Table 6-18. Final ETM Output for Pacific Staghorn Sculpin Leptooottus armatus 6-29 

Table 6-19. Final ETM Output for Hairy Rock Crab 6-31 

Table 6-20. Annual Entrainment and FH Estimates for Hairy Rock Crab: March 1, 1999 -

February 29, 2000 6-32 

Table 6-21. Final ETM Output for Yellow Rock Crab 6-33 

Table 6-22. Annual Entrainment and FH Estimates for Yellow Rock Crab: March 1, 1999 -

February 29, 2000 6-34 

Table 6-23. Final ETM Output for Brown Rock Crab 6-35 

Table 6-24. Annual Entrainment and FH Estimates for Brown Rock Crab: March 1, 1999 -

February 29, 2000 6-36 

Table 6-25. Annual Entrainment and FH Estimates for Dungeness Crab: March 1, 1999 -

February 29, 2000 6-37 

Table 6-26. Final ETM Output for Red Rock Crab 6-38 

Table 6-27. Annual Entrainment and FH Estimates for Red Rock Crab: March 1, 1999 -

February 29, 2000 6-39 

Table 6-28. Final ETM Output for Slender Rock Crab 6-40 

Table 6-29 Annual Entrainment and FH Estimates for Slender Rock Crab: March 1, 1999 -

February 29, 2000 6-41 

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Table 6-30. Summary of Estimated MLPP New Combined-cycle Entrainment Effects for 

Abundant Fishes and Cancer Crabs Based on ETM, FH, and AEL Models 

(March 1999-February 2000) 6-44 

Table 7-1. Operational Feasibility of Intake Technologies and Operational Alternatives 

Considered for the Proposed MLPP Combined-cycle Units 7-3 

Table 7-2. Estimated Cost of Replacement Energy during two Periods of Operation Curtailment 

for the Moss Landing Combined-cycle Units 7-23 

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I Table of Contents 

LIST OF FIGURES 

Figure 2-1. The location ofthe Moss Landing Power Plant 2-2 

Figure 2-2. Existing MLPP Units 1 through 5 cooling water intake structure 2-5 

Figure 2-3. Proposed modernized MLPP combined-cycle cooling water intake structure 2-6 

Figure 2-4. Sectional view ofthe MLPP new combined-cycle units intake structure's traveling 

screens 2-7 

Figure 2-5. MLPP Units 6 and 7 cooling water intake structure 2-9 

Figure 2-6. Location ofthe MLPP Units 6 and 7 discharge structure 2-10 

Figure 3-1. Moss Landing Power Plant sampling locations 3-3 

Figure 3-2. Location of Monterey Bay nearshore MLPP ocean source water, Moss Landing 

Harbor, and Elkhorn Slough areas used in calculating source water and receiving 

water volumes 3-20 

Figure 4-1. Percent composition ofthe most abundant larval fish taxa and Cancer spp. 

megalops collected in entrainment surveys at the MLPP: March 1999 -

February 2000 4-4 

Figure 4-2. Mean, maximum and minimum cumulative numbers of species from 1,000 

iterations of data collected over 42 surveys at the new combined-cycle units intake 4-16 

Figure 4-3. Mean, maximum and minimum cumulative numbers of species from 1,000 

iterations of data collected over 42 surveys at the Units 6 and 7 intake 4-16 

Figure 4-4. Percent composition ofthe most abundant larval fish taxa collected in source water 

surveys at Elkhorn Slough, Moss Landing Harbor, and Ocean areas: June 1999 -

February 2000 4-22 

Figure 4-5. Percent composition ofthe most abundant megalopal cancer crab taxa collected in 

source water surveys at Elkhorn Slough, Moss Landing Harbor, and Ocean Areas: 

June 1999 - February 2000 4-24 

Figure 4-6. Mean survey concentrations (#/l,000 m3) of larval unidentified gobies at the MLPP 

new combined-cycle units intake: March 1999 - February 2000 4-32 

Figure 4-7. Concentrations (#/l,000 m3) of larval unidentified gobies at the new combinedcycle units intake separated by sample collection time: June 1999 - February 2000 4-32 

Figure 4-8. Source water concentrations (#/l,000 m3) of larval unidentified gobies at six 

stations near MLPP: June 1999 - February 2000 4-33 

Figure 4-9. Mean survey concentrations (#/1,000 m3) of larval bay goby at the MLPP new 

combined-cycle units intake: March 1999 - February 2000 4-38 

Figure 4-10. Concentrations (#/1,000 m3) of larval bay goby at the new combined-cycle units 

intake separated by sample collection time: June 1999 - February 2000 4-39 

Figure 4-11. Source water concentrations (#/1,000 m3) of larval bay goby at six stations near 

MLPP: June 1999 - February 2000 4-40 

Figure 4-12. Length frequency of all larval bay goby Lepidogobius lepidus lengths measured 

by source water and intake sampling locations (June 1999 - January 2000) 4-41 

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Figure 4-13. Length frequency of all larval bay goby Lepidogobius lepidus measured by high 

and low tide stage (June 1999 - January 2000) 4-42 

Figure 4-14. Scattergram plot of all larval bay goby Lepidogobius lepidus lengths measured by 

source water survey date (June 1999 - January 2000) 4-43 

Figure 4-15. Mean survey concentrations (#/1,000 m3) of larval blackeye goby at the MLPP 

new combined-cycle units intake: March 1999 - February 2000 4-47 

Figure 4-16. Concentrations (#/1,000 m3) of larval blackeye goby at the new combined-cycle 

units intake separated by sample collection time: June 1999 - February 2000 4-48 

Figure 4-17. Source water concentrations (#/l ,000 m3) of larval blackeye goby at six stations 

near MLPP: June 1999 - February 2000 4-49 

Figure 4-18. Pacific staghorn sculpin California state-wide landings: 1987- 1998 4-52 

Figure 4-19. Mean survey concentrations (#/l,000 m3) of larval Pacific staghorn sculpin at the 

MLPP new combined-cycle units intake: March 1999 - February 2000 4-53 

Figure 4-20. Concentrations {fill ,000 m3) of larval Pacific staghorn sculpin at the new 

combined-cycle units intake separated by sample collection time: June 1999 -

February 2000 4-54 

Figure 4-21. Source water concentrations {Ull ,000 m3) of larval Pacific staghorn sculpin at six 

stations near MLPP: June 1999 - February 2000 4-55 

Figure 4-22. White croaker landings and values California state-wide, Monterey area, and Moss 

Landing Harbor landings: 1987 to 1998 4-58 

Figure 4-23. Mean survey concentrations (#/l ,000 m3) of larval white croaker at the MLPP new 

combined-cycle units intake: March 1999 - February 2000 4-59 

Figure 4-24. Concentrations (#/l,000 m3) of larval white croaker at the new combined-cycle 

units intake separated by sample collection time: June 1999 - February 2000 4-60 

Figure 4-25. Source water concentrations {Ull ,000 m3) of larval white croaker at six stations 

near MLPP: June 1999 - February 2000 4-61 

Figure 4-26. Mean survey concentrations {Ul1,000 m3) of larval Hypsoblennius spp. at the 

MLPP new combined-cycle units intake: March 1999 - February 2000 4-65 

Figure 4-27. Concentrations (#/l,000 m3) larval Hypsoblennius spp. at the new combined-cycle 

units intake separated by sample collection time: June 1999 - February 2000 4-66 

Figure 4-28. Source water concentrations (#/1,000 m3) of larval Hypsoblennius spp. at six 

stations near MLPP: June 1999-February 2000 4-67 

Figure 4-29. Mean survey concentrations (#/l,000 m3) of larval longjaw mudsucker at the 

MLPP new combined-cycle units intake: March 1999 - February 2000 4-71 

Figure 4-30. Concentrations (#/l ,000 m3) of larval longjaw mudsucker at the new combinedcycle units intake separated by sample collection time: June 1999 - February 2000 4-72 

Figure 4-31. Source water concentrations {Ull ,000 m3) of larval longjaw mudsucker at six 

stations near MLPP: June 1999 - February 2000 4-73 

Figure 4-32. Length frequency of all larval longjaw mudsuckers Gillichthys mirabilis measured 

by source water and intake sampling locations (June 1999 - January 2000) 4-74 

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Table of Contents 

Figure 4-33. Length frequency of all larval longjaw mudsuckers Gillichthys mirabilis measured 

by high and low tide stage (June 1999 - January 2000) 4-75 

Figure 4-34. Scattergram plot of larval longjaw mudsuckers Gillichthys mirabilis lengths 

measured by source water survey date (June 1999 - January 2000) 4-76 

Figure 4-35. Pacific herring, sac-roe and roe-on-kelp California state-wide landings: 1987 -

1998 4-80 

Figure 4-36. Mean survey concentrations (#/l,000 m3) of larval Pacific herring at the Moss 

Landing Power Plant new combined-cycle units intake: March 1999 - February 2000 4-81 

Figure 4-37. Concentrations (#/l,000 m3) of larval Pacific herring at the new combined-cycle 

units intake separated by sample collection time: June 1999 - February 2000 4-82 

Figure 4-38. Source water concentrations {Ull ,000 m3) of larval Pacific herring at six stations 

near MLPP: June 1999 - February 2000 4-83 

Figure 4-39. Califomia state-wide (1979 -1998) and Ports of Monterey Bay (1986 - 1998) 

landings of rock crabs 4-87 

Figure 4-40. Mean survey concentrations (#/1,000 m3) of hairy rock crab megalops at the 

MLPP new combined-cycle units intake: March 1999 - February 2000 4-91 

Figure 4-41. Concentrations {Ull ,000 m3) of hairy rock rock megalops at the new combinedcycle units intake separated by sample collection time: June 1999 - February 2000 4-92 

Figure 4-42. Source water concentrations (#/l ,000 m3) of hairy rock crab megalops at six 

stations near MLPP: June 1999 - February 2000 4-93 

Figure 4-43. Mean survey concentrations {Ul 1,000 m3) of yellow rock crab megalops at the 

MLPP new combined-cycle units intake: March 1999 - February 2000 4-96 

Figure 4-44. Concentrations (#/l,000 m3) of yellow rock crab megalops at the new combinedcycle units intake separated by sample collection time: June 1999 - February 2000 4-97 

Figure 4-45. Source water concentrations (#/l,000 m3) of yellow rock crab megalops at six 

stations near MLPP: June 1999 - February 2000 4-98 

Figure 4-46. Mean survey concentrations {Ul 1,000 m3) of brown rock crab megalops at the 

MLPP new combined-cycle units intake: March 1999 - February 2000 4-101 

Figure 4-47. Concentrations {Ul 1,000 m3) of brown rock rock megalops at the new combinedcycle units intake separated by sample collection time: June 1999 - February 2000 4-102 

Figure 4-48. Source water concentrations (#/l,000 m3) of brown rock crab megalops at six 

stations near MLPP: June 1999 - February 2000 : 4-103 

Figure 4-49. Dungeness crab landings and value of landings from 1987 - 1998 for Monterey 

Bay ports and the port of Moss Landing 4-107 

Figure 4-50. Mean survey concentrations (#/l,000 m3) of dungeness crab megalops at the 

MLPP new combined-cycle units intake: March 1999 - February 2000 4-108 

Figure 4-51. Mean survey concentrations (#/1,000 m3) of red rock crab megalops at the MLPP 

new combined-cycle units intake: March 1999 - February 2000 4-111 

Figure 4-52. Concentrations (#/l,000 m3) of red rock rock megalops at the new combined-cycle 

units intake separated by sample collection time: June 1999 - February 2000 4-112 

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Table of Contents 

Figure 4-53. Mean survey concentrations (#/l,000 m3) of slender rock crab megalops at the 

MLPP new combined-cycle units intake: March 1999 - February 2000 4-115 

Figure 4-54. Concentrations (#/l,000 m3) of slender rock crab megalops at the new combinedcycle units intake separated by sample collection time: June 1999 - February 2000 4-116 

Figure 4-55. Source water concentrations {#11,000 m3) of slender rock crab megalops at six 

stations near MLPP: June 1999 - February 2000 4-117 

Figure 4-56. Mean survey concentrations (#/l,000 m3) of European green crab megalops at the 

MLPP new combined-cycle units intake: March 1999 - February 2000 4-121 

Figure 4-57. Source water concentrations (#/l,000 m3) of European green crab megalops at six 

stations near MLPP: June 1999 - February 2000 4-122 

Figure 5-1. Bocaccio landings from Monterey Bay ports 5-11 

Figure 5-2. Landings of combined market category for bocaccio/chilipepper 5-11 

Figure 5-3. Bocaccio landings from California 5-12 

Figure 5-4. Reported commercial bay shrimp landings in San Francisco, Monterey, and Moss 

Landing areas from 1986 to 1998 5-16 

Figure 5-5. Commercial market squid landings reported for California and Monterey Area 5-20 

Figure 5-6. Mean length of bocaccio collected in impingement samples at the Moss MLPP 

intakes (PG&E, 1983) ...5-22 

Figure 5-7. Number measured vs. total number of bocaccio collected in impingement samples 

at the MLPP intakes (PG&E, 1983) 5-23 

Figure 5-8. Mean monthly concentrations ofthe most abundantly impinged fishes at the MLPP 

intakes (PG&E, 1983) 5-24 

Figure 5-9. Mean monthly combined concentrations ofthe most abundantly impinged fishes at 

the MLPP Units intakes (PG&E, 1983) 5-26 

Figure 5-10. Mean monthly concentrations ofthe most abundantly impinged Cancer spp. crabs 

at the MLPP intakes (PG&E, 1983) 5-27 

Figure 7-1. MLPP alternative closed-cycle cooling mechanical draft cooling tower location 7-25 

Figure 7-2. MLPP alternative closed-cycle cooling natural draft cooling tower location 7-27 

Figure 7-3. MLPP alternative closed-cycle cooling air-cooled condensers location 7-29 

Figure 7-4. Traveling Water Screen Proposal Number 1 7-32 

Figure 7-5. Traveling Water Screen Proposal Number 1 (overhead view) 7-32 

E9-053.9 x MLPP 316(b) Resource Assessment 

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The purpose of this report is to evaluate alternative intake technologies for the possibility of 

cost-effectively lowering potential effects ofthe Moss Landing Power Plant's new combinedcycle (CC) units cooling water intake structure (CWIS). The new CWIS has been redesigned to 

reduce impingement effects ofthe existing Units 1 through 5 intake structure by lowering 

approach velocities, by installing modernized, angled rotating fish screens, and by removing a 

forebay tunnel that previous to 1996, trapped fishes and invertebrates. Entrainment effects ofthe 

existing CWIS will be significantly and directly reduced by the new units' 34 percent reduction 

in intake cooling water flow capacity. This reduction combined with the results ofthe 1999-

2000 entrainment field sampling leads to a projection of low entrainment impacts. An 

unidentified species group of gobies accounts for 53 percent of all the larval fish that will be 

entrained by the new CWIS. Our analysis of CWIS effects on this fish is complete. Only 7 

other taxa (species and groupings of species) offish combined with the unidentified goby make 

up 95 percent of all the entrained number offish larvae. The projected fractional losses of these 

species to the new CWIS and combined MLPP entrainment are low due to their source water 

abundance. The CWIS withdraws water from a source of inherently low species diversity. 

The report contains the completed assessment of alternative intake technologies. Based on 

available technologies and the relatively low entrainment and impingement impacts projected for 

the new CWIS, the redesigned CWIS represents best available technology for the site. The new 

traveling screens will lower screen approach velocities and operate to more consistently remove 

debris, reducing impingement rates that are caused by entanglement. Remaining low potential 

effects or other uncertainties associated with projected CWIS effects will be addressed as 

necessary by appropriate measures now being discussed with regulatory and resource agency 

representatives. Duke has proposed a number of environmental enhancement measures to 

address these uncertainties. 

The field studies and data analyses for the proposed modernization project followed the 316(b) 

Study Plan developed in coordination with the Technical Working Group established under the 

auspices ofthe Regional Water Quality Control Board. Findings ofthe completed 316(b) 

Demonstration resource assessment are presented graphically in the report, using the results of 

our 1999-2000 field studies. From these site surveys of weekly daytime and nighttime 

entrainment, and monthly source water larval fish concentrations, we have found that: 

o Only eight taxa of larval fishes made up 95 percent of entrained larvae. The intake location 

is in an area that has naturally low diversity, typical of bays and sloughs, unlike the myriad 

of species found in Monterey Bay's marine habitats, 

o Gobies (Family Gobiidae) comprised the overwhelming majority of this 95 percent, 

E9-053.9 ES-1 MLPP 316(b) Resource Assessment 

4-28-2000 
P.17 

Executive Summary 

• Three species of fish (Pacific herring, white croaker, and Pacific staghorn sculpin), having 

some commercial or recreational value, individually represented 5 percent ofthe eight taxa 

or species, 

• The proportional entrainment estimates were relatively low for all species analyzed; below 

standard fishery management practices for sustainable harvests of a total stock especially 

when referenced to total populations, 

• This year's entrained larvae are essentially the same composition, abundance, and 

distribution of last year's taxa collected at the beginning of our 12-month entrainment study, 

and 

• Our results are generally similar to the previous MLPP 316(b) Demonstration's finding of 

low potential impact and best available intake technology. 

Cancer spp. megalops concentrations collected from the same surveys of weekly daytime and 

nighttime entrainment, and monthly source water have shown that: 

• Six species of cancer crab megalops and unidentified cancer megalops were collected in 

entrainment surveys at the new CC units intake, 

• Four of these crab species (dungeness, brown rock, red rock, and yellow rock) have 

commercial importance, 

• The most abundant cancer crab (hairy rock crab) collected has no commercial value, 

• The proportional entrainment estimates were low for all species that could be analyzed. 

However, the estimates were typically based on a single survey PE value, and 

• The number of adult crabs that might have resulted from the entrained megalops was low 

based on Fecundity Hindcast {FH) model results. 

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A summary ofthe estimated entrainment effects from March 1999 through February 2000 ofthe 

new combined-cycle units for the most abundantly collected fishes and cancer crabs is presented 

below. These values are based on analyses using the Empirical Transport Model {ETM), and the 

Fecundity Hindcast {FH), and Adult Equivalent Loss {AEL) models. 

Unidentified gobies 

Bay goby 

Blackeye goby 

Longjaw mudsucker 

Hypsoblennius spp. 

Pacific herring 

White croaker 

Pacific staghom 

sculpin 

Total Entrainment 

2.7 x 10s 

1.5xl08 

1.6 x IO7 

8.0 x IO6 

1.7 x 10' 

4.4 x IO6 

8.6 x IO6 

« 

FH 

3oo;ooo 

» 

1,825 

497 

9,086 

235 

270 

» 

AEL 

r 

1,045,588 

16,636 

10,247 

» 

243 

* 

* 

ETM1'* 

0.026 

0.039 

0.043 

0.052 

0.111 

0.129 

0.016 

0.036 

ETM01* 

0.107 

0.21 

0.075 

0.089 

0.182 

0.134 

0.129 

0.118 

Hairy rock crab 

Yellow rock crab 

Brown rock crab 

Dungeness crab 

Red rock crab 

Slender rock crab 

Total Entrainment 

1.7 x 106 

0.5 x IO6 

0.8 x IO6 

0.3 x IO6 

0.2 x IO6 

1.7 x 107 

FH 

1,039 

131 

209 

167 

60 

239 

ETM1'* 

0.018 

* 

* 

* 

0.041 

0.025 

ETM** 

0.17 

* 

4 

ft 

0.041 

0.079 

'Unavailable information or value that could not be computed. 

(a) ETM values calculated using source water volumes 275, 21, and 2.2 m3 x 106. 

(b) ETM values calculated using source water volumes 21,21, and 2.2 m3 x 106. 

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Impingement studies reported in the previous 316(b) Demonstration showed that: 

o The three most abundantly impinged fishes (northern arichovy, shiner perch, and topsmelt) 

were impinged at higher rates at the Units 1 through 5 intake than at the Units 6 and 7 intake, 

o The majority of Cancer spp. crabs and Crangon spp. shrimps were impinged at higher rates 

at the Units 1 through 5 intake than at the Units 6 and 7 intake, and 

o No declines in the populations ofthe above listed species were found attributable to 

impingement. 

In addition to the above findings, modifications made to the Units 1 through 5 intake structure 

(shortening the intake conduit, lower approach velocities, and inclined traveling screens) will 

E9-053.9 ES-3 MLPP 316(b) Resource Assessment 

4-28-2000 
P.19 

Executive Summary 

reduce previous impingement rates. Alternative intake technologies were evaluated for use in 

the improved CWIS based on their: 

• Proven availability, 

• Potential to reduce CWIS biological effects and minimize population-level impacts, 

• Site feasibility, and 

• Cost-effectiveness performance. 

A stepwise evaluation process of these factors was employed to first determine a set of intake 

technologies that are available and proven for application at the CC site. A second stage analysis 

ofthe available and proven technologies was performed to evaluate the potential effectiveness of 

each alternative technology to reduce biological effects ofthe CWIS. The feasibility of intake 

technologies meeting both stage one and stage two evaluation criteria were analyzed and 

discussed in the report's preliminary conclusions on best technology available (BTA) for the 

modernization project's CWIS. The combined-cycle project CWIS is designed to correct the 

entrapment effect ofthe existing CWIS by removing the 350-foot shoreline tunnel to the 

traveling screens. This modification, in addition to reducing the new facility's flow capacity, 

will significantly reduce CC-CWIS impingement and entrainment effects and minimize the 

potential for impacts on source water populations of fish and invertebrates. 

The new power plant's 34 percent reduction in intake flow capacity from flows in the 1983 

316(b) demonstration studies of impingement and entrainment effects make it a relatively 

straightforward exercise to project a reduction in effects with the CC-CWIS. In addition to this 

significant reduction in entrainment and impingement effects, our report examines various 

proven and available intake technologies and their cost-effectiveness to reduce even further a 

very low potential for intake effects. An assessment of additional technology-based reductions 

in CWIS effects requires a site-specific understanding of both existing and projected CWIS 

biological effects and impacts. A wide range of site-specific information is available from 

previous source water and CWIS studies ofthe existing MLPP. A long-term study began in 

March 1999 to validate these previous findings and conclusions and assess present cooling water 

entrainment and biological conditions in the MLPP source water. This study was completed in 

February 2000. 

The design and operation ofthe cooling water system for the new combined-cycle units are 

described along with a discussion ofthe physical and biological characteristics ofthe source 

water. The findings of our long-term study that began in March 1999 were used in the biological 

evaluation of alternative CC-CWIS technologies. Separate sections ofthe report present 

information on CWIS entrainment and impingement at the power plant, followed by a 

E9-053.9 ES-4 MLPP 316(b) Resource Assessment 

4-28-2000 
P.20 

Executive Summary 

preliminary assessment of CWIS effects and potential population-level impacts used in 

evaluating the report's list of altemative technologies. 

The proposed new combined-cycle units CWIS design represents the best technology available 

for the site. From both past MLPP CWIS and source water studies and our present study 

findings, potential entrainment and impingement effects are relatively minor, and therefore any 

intake technology not already proposed would represent minor potential for further reductions. 

However the new combined-cycle CWIS's lower intake flows, improved traveling screen and 

elimination of forebay entrapment tunnels are proven and available alternative intake 

technologies that meet site engineering feasibility, and cost-effectiveness criteria. The 

implementation and benefit from these improved technologies are included in our assessment of 

best intake technology available for the new combined-cycle CWIS. 

E9-053 9 ES-5 MLPP 316(b) Resource Assessment 

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1.0 INTRODUCTION 

The following report presents the preliminary results of a cooling water intake technology 

evaluation required under Section 316(b) of the Federal Clean Water Act (CWA). A 316(b) 

demonstration program is currently being conducted at Duke Energy's Moss Landing Power 

Plant (MLPP) to evaluate power plant cooling water intake system effects and the proposed new 

combined-cycle units intake technology relative to Best Technology Available (BTA).1 Duke 

Energy is planning to modernize the power plant and has submitted its Application for 

Certification (AFC) to the California Energy Commission. Modernization project changes that 

are proposed for the existing intake are relatively minor facility modifications that will 

significantly reduce intake effects. The necessary National Pollutant Discharge Elimination 

System (NPDES) permitting process for this modernization project is being administered in 

parallel to the AFC process by the California Central Coast Regional Water Quality Control 

Board (RWQCB). This 316(b) report is submitted in accordance with the specifications ofthe 

RWQCB's "Requirements Letter" of July 21, 1999. 

The Clean Water Act's (PL 92-500 and 95-217) Section 316(b) requires that"... the location, 

design, construction, and capacity of cooling water intake structures reflect the best technology 

available for minimizing adverse environmental impact" (EPA, 1977). Because no single intake 

design can be considered to be the best technology available at all sites, compliance with the Act 

requires a site-specific analysis of intake-related organism losses and a site-specific 

determination ofthe best technology available for minimizing those losses. In this report, intakerelated losses resulting from entrainment (the drawing of organisms into the cooling water 

system) and impingement (the retention of organisms on the intake screens) are evaluated and 

discussed. Intake technologies are evaluated according to operating, engineering, and biological 

criteria; the best technology available for minimizing entrainment and impingement losses is 

recommended for the cooling water intake structure ofthe Moss Landing Power Plant new 

combined-cycle units. 

The first 316(b) demonstration program studies were conducted at the Moss Landing Power 

Plant from 1978 through mid-1980 (PG&E, 1983). This program followed the general guidance 

provided by the California State Water Resources Control Board (SWRCB), Environmental 

Protection Agency (EPA), California Department of Fish and Game (CDFG), and United States 

Fish and Wildlife Service (USFWS). Entrained and impinged organisms were sampled on a 

weekly basis to gather information on the species composition and abundance of organisms 

affected by the plant's cooling water system. Special studies were also conducted to examine the 

potential survival of entrained and impinged organisms. Data collected from numerous surveys 

1

 The RWQCB determined that the existing permitted intake represented the Best Technology Available based on 

the results ofthe previous 316(b) study (PG&E, 1983). 

E9-053.9 1-1 MLPP 316(b) Resource Assessment 

4-28-2000 
P.22 

1.0 Introduction 

near the plant were used in conjunction with CDFG commercial and sportfish landing data to 

examine the general trends in the populations of some of the species susceptible to the effects of 

the cooling water systems. The information gathered from these studies was used in conjunction 

with engineering and operating criteria to evaluate alternative intake technologies for the plant. 

The report concluded that there was no evidence that local populations were adversely affected 

by the operation ofthe MLPP. Furthermore, it was demonstrated that the feasible alternative 

intake technologies examined would not have substantially reduced biological losses at the plant 

on a cost-effective basis. 

The 316(b) demonstration was reviewed by several agencies including the SWRCB, RWQCB, 

CDFG, EPA, and USFWS. Questions raised by the agencies during the review process were 

answered in supplemental responses to the 316(b) Demonstration Report. The conclusion of 

these agencies was that no altemative intake technologies or changes to the operations ofthe 

power plant were required based on the information presented in the demonstration and 

information provided to the agencies during the review process. The modernization project has 

no plans to change the approved Units 6 and 7 intake facilities. 

1.1 Development of the 316(b) Study Plans 

In 1998 Duke Energy announced their plan to modernize the Moss Landing Power Plant. The 

RWQCB was contacted and a series of meetings were held to discuss the renewal ofthe plant's 

NPDES permit. The RWQCB assembled a team of experts to assist the Board's staff in their 

review ofthe design and implementation ofthe 316(b) studies. This team, the Technical 

Working Group (TWG), met periodically to discuss topics relevant to ongoing efforts at MLPP 

including the design ofthe 316(b) study plan. The study plan entitled Final Moss Landing 

Power Plant Modernization Project Cooling Water Intake and Discharge Study Plans, (Tenera, 

Inc., 1999) was submitted to the RWQCB on November 18, 1999. 

The design ofthe 316(b) field study program was based, in part, on information collected during 

previous studies ofthe potential effect on the aquatic communities of Moss Landing Harbor, 

Elkhorn Slough, and Monterey Bay resulting from operation ofthe Moss Landing Power Plant's 

cooling water systems. The three most significant studies were those conducted by PG&E 

relating to the effect ofthe cooling water discharges on the beneficial uses ofthe receiving 

waters at the MLPP (PG&E, 1973), the MLPP Units 1 through 5 316(a) demonstration program 

(PG&E, 1978), and the MLPP Cooling Water Intake Structures 316(b) Demonstration (PG&E, 

1983). The study plan was developed using information collected in these and other studies of 

the area in combination with state and federal 316(b) guidelines and was also based on input 

from the TWG. 

E9-053.9 1-2 MLPP 316(b) Resource Assessment 

4-28-2000 
P.23 

1.0 Introduction 

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Three modeling approaches for use in assessing entrainment and impingement losses were 

presented to the TWG. These approaches are adult equivalent loss {AEL), fecundity hindcasting 

{FH), and empirical transport model {ETM). These models were described in a draft report 

entitled, Moss Landing Power Plant Modernization Project Cooling Water System Intake Effects, 

Estimating Taxa Losses Caused by Entrainment and Impingement, that was submitted to the 

TWG September 1, 1999. The report was reviewed by the TWG and their comments were 

addressed. The report was incorporated into the Final Moss Landing Power Plant 

Modernization Project Cooling Water Intake and Discharge Study Plans (Tenera, Inc., 1999). 

1.2 OveirvBew of tb® 316(b) Program 

The basic objective ofthe 316(b) program is to provide a sufficient basis for regulatory agencies 

to determine whether the new combined-cycle cooling water intake structure (formerly the 

Units 1 through 5 intake structure) reflects the best technology available for minimizing adverse 

environmental impacts. To accomplish this objective, a field study program was designed and 

conducted to determine the extent of entrainment effects at the Moss Landing Power Plant. The 

numbers of aquatic organisms entrained are estimated from plankton samples collected in front 

ofthe intake structures. Samples collected in Monterey Bay, Moss Landing Harbor, and Elkhorn 

Slough provided estimates ofthe source water populations that may be affected by entrainment. 

Consistent with the final study plan, impingement studies were not conducted. The intake 

structure for the new combined-cycle units will be modified as part ofthe modernization project. 

Impingement rates at the modernized combined-cycle units intake are expected to decrease from 

those reported in PG&E (1983) as a direct result of these changes. 

1.2.1 Target Organisms Selected for Study 

The TWG selected the following aquatic organism groups to be the focus ofthe 316(b) 

entrainment study at the Moss Landing Power Plant: 

o Fishes (all life stages) 

o Cancer spp. (megalopal life stage) 

o European green crabs Carcinus maenas (megalopal life stage). 

Fishes and Cancer spp. crabs were selected because of their role in the ecosystem and because 

some of them have commercial or recreational value. European green crabs, an introduced 

invasive species, were selected because of concerns regarding their presence in the vicinity ofthe 

MLPP. 

E9-053.9 1-3 MLPP 316(b) Resource Assessment 

4-28-2000 
P.24 

1.0 Introduction 

This report presents the results ofthe model approaches applied to the concentrations ofthe most 

abundant fish taxa and all cancer crabs collected in the entrainment samples. Concentrations of 

all larval fish taxa are expressed as the number per 1,000 cubic meters (#/1,000 m3). 

For this report, we further narrowed the focus ofthe assessment of entrainment effects to the 

most abundant taxa of larval fishes and all cancer crabs. Based on the results of entrainment 

sampling to date, the eight most abundant entrained larval species or taxa groups of fishes were 

chosen for assessment in this report. They are unidentified gobies, bay goby, blackeye goby, 

Pacific staghorn sculpin, white croaker, blennies, longjaw mudsucker, and Pacific herring. All 

targeted cancer crab species were assessed. 

1.3 Organization of the Report 

This 316(b) demonstration is a summary and analysis ofthe data collected and processed from 

March 1999 through February 2000. All data from field collections are preliminary because 

laboratory processing quality control checks have not all been completed. This report includes 

Sections 1 through 8. The design and operation ofthe existing Units 6 and 7 intake structure as 

well as the proposed modernization project's intake structure are described in Section 2. The 

experimental design and study and assessment methods for the entrainment and source water 

studies are presented in Section 3. Section 4 presents the life histories, entrainment and source 

water survey results, and data comparisons with the previous entrainment study for the eight fish 

taxa listed above and the targeted crab species. Impingement data that were collected during the 

1979 - 1980 316(b) study have been reanalyzed to estimate the rate of impingement and are 

presented in Section 5. Entrainment and impingement effects are evaluated in Section 6. The 

best technology available (BTA) for the modernized intake system is assessed in Section 7. 

Literature cited in the report is listed in Section 8. 

E9-053 9 1-4 MLPP 316(b) Resource Assessment 

4-28-2000 
P.25 

2.0 DESCRIPTION OF THE MOSS LANDING POWER PLANT AND 

CHARACTERISTICS OF THE SOURCE WATER BODY 

This section describes the Moss Landing Power Plant (MLPP) and its aquatic environmental 

setting, focusing on the various features ofthe existing and proposed power plant design and 

operations related to the facility's aquatic environment. Section 2.1 describes the plant and its 

existing and proposed cooling water systems. Section 2.2 briefly characterizes the aquatic 

environment in the vicinity ofthe MLPP. An analysis of whether the modernized system 

represents the best technology available to minimize potentially adverse cooling water intake 

effects is given in Section 7. 

2.1 The Plant and its Cooling Systems 

The Moss Landing Power Plant is located on the eastern shoreline of Moss Landing Harbor. 

This medium sized harbor, which provides dock space for approximately 600 commercial and 

recreational vessels, is located about 110 miles (177 km) south of San Francisco. Moss Landing 

Harbor is located roughly midway between Santa Cruz and Monterey, California and is open to 

Monterey Bay (Figure 2-1). The plant is located in a relatively undeveloped area that includes 

industrial facilities, agricultural lands, sparse residences, recreational beaches, and tidal 

wetlands. The MLPP has two separate intake structures in Moss Landing Harbor for withdrawal 

of cooling water that is necessary to remove excess heat from the power generation process. 

One intake previously serviced the now retired Units 1 through 5 and is currently unused and a 

second intake structure services the presently operating Units 6 and 7. Cooling water from Units 

6 and 7 is discharged into Monterey Bay through two (one/unit) subsurface conduits. 

Historically, cooling water from Units 1 through 5 discharged into Elkhorn Slough. The design 

(historic), actual (current), and projected specifications ofthe new combined-cycle units cooling 

water intake structure (CWIS) are summarized in Table 2-1. 

The Moss Landing Power Plant (MLPP) currently produces up to about 1,500 MW from two 

steam boilers (Units 6 and 7). In addition, the MLPP site includes retired Units 1 through 5. 

Duke Energy proposes to replace the 1950s technology of Units 1 through 5 with two 530-MW 

high efficiency combined-cycle (CC) units. Each combined-cycle unit will consist of two 

advanced class combustion turbine generators, two heat recovery steam generators, and a single 

steam turbine generator. Only the new steam turbine generators will require a significant 

amount of ocean cooling water. About two-thirds ofthe total new power output will be 

produced by the combustion turbine generators, which require no ocean cooling water. 

E9-053.9 2-1 MLPP 316(b) Resource Assessment 

4-28-2000 
P.26 

2.0 Description of the Moss Landing Power Plant and Characteristics of the Source Water Body 

Francisco Region 

Shown 

in View 

Pacific 

Ocean 

Santa L 

vCruz j 

Moss 

Landing 

Power 

Plant 

Monterey JL MOSS 

Bay ^Landing 

Monterey 

Salinas 

W W E 

s 

Figure 2-1. The location ofthe Moss Landing Power Plant. 

E9-053.9 2-2 MLPP 316(b) Resource Assessment 

4-28-2000 
P.27 

2.0 Description of the Moss Landing Power Plant and Characteristics of the Source Water Body 

Table 2-1. Historic and Projected Specifications ofthe Cooling Water Intake Structures at MLPP, 

Units 1 through 5 and the New Combined-cycle Units. 

Note : Units 1 through 5 were retired in 1995. TBD = to be determined. 

Intake Flow Rate 

Units 1-3 and Units 4 and 5 Intake 

Historic 

(Design) 

381,000 (gpm) 

1,441 (mVmin) 

Units 1-5 

Projected'" 

(AFC Design as Revised) 

250,000 (gpm) 

946 (m'/min) 

New Combined-cycle Units 

Bar Racks 

Number 

Location 

Spacing OC 

Bar size 

6 

Shoreline 

4 (in.) 

10.2 (cm) 

3x3/8(in.) 

7.6 x 0.9 (cm) 

6 

Shoreline 

4 (in.) 

10.2 (cm) 

TBD 

Intake Conduits to Screenhouse 

Number 

Size 

Length 

Traveling Screens 

Location 

Number 

Manufacturer 

Mesh size 

Pumps per unit 

Location 

Number 

Manufacturer 

Type 

Capacity (each pump) 

2 

(a) 

9.3 x 10.6 (ft) 

2.8 x 3.2 (m) 

350(ft) 

107 (m) 

Vertical 

Onshore 

6 

Link Belt 

3/8 (in.) 

0.9 (cm) 

Units 1-3 

Onshore 

2 

Foster Wheeler 

Mixed flow singlestage vertical 

104.5 (cfs) 

2.96 (mVsec) 

46,900 (gpm) 

Units 4-5 

Onshore 

2 

Foster Wheeler 

Mixed flow singlestage vertical 

55.5 (cfs) 

1.57(m3/sec) 

24,900 (gpm) 

6 

10 fix 27ft deep 

- 1 0 (ft) 

~3(m) 

Inclined 

Shoreline 

6 

TBD 

5/16 (in.) 

0.8 (cm) 

Onshore 

3 (6,total) 

TBD 

TBD 

42,000 gpm 

Water velocities at maximum capacity, mean low, low water 

Approach to bar racks 

Through bar racks 

Approach to screens 

Through screens 

0.7 (fps) 

21.34 (cm/sec) 

0.9 (fps) 

27.43 (cm/sec) 

1.0 (fps) 

30.48 (cm/sec) 

2.4 (fps) 

73.15 (cm/sec) 

(2) 

(2) 

(2) 

(2) 

0.5 (fps) 

15 (cm/sec) 

0.6 (fps) 

18 (cm/sec) 

0.5 (fps) 

15 (cm/sec) 

0.6 (fps)(3) 

18 (cm/sec) 

(1) Units 1 through 5 intake structure modified to serve the new combined-cycle plant. 

(2) Information about bar racks and traveling screens applies to unit-group intakes (Units 1 through 5 share a common 

intake structure). 

(3) Through screen velocity based on 65 percent open screen area and 55° slope from horizontal. 

E9-053.9 2-3 MLPP 316(b) Resource Assessment 

4-28-2000 
2.0 Description of the Moss Landing Power Plant and Characteristics of the Source Water Body 

Therefore, the new combined-cycle units will be capable of generating about 1,060 MW while 

using about 250,000 gpm (946 mVmin) of once-through ocean cooling water (at 20 °F [11.1 °C] 

temperature increase). By comparison, the existing Units 6 and 7 require about 600,000 gpm 

(2,270 mVmin) of ocean cooling water (at 28 °F [15.5 °C] temperature increase) to generate 

1,500 MW. 

In addition to the new combined-cycle units, Duke Energy proposes to upgrade existing Units 6 

and 7 through replacement ofthe steam turbine high-pressure rotor, which will result in an 

additional 15 MW per unit of generation capacity. These two actions combined yield an 

additional 1,090 MW (i.e., 1,060 MW + 30 MW) and constitute the Modernization Project. 

2.1.1 Plant Cooling Water System Description and Operation 

2.1.1.1 Units 1 through 5 Cooling Water System: Previous Operation and 

Proposed Modifications 

Since 1995, Units 1 through 5 have been removed from service and use of that cooling water 

system has been discontinued. The existing intake system for Units 1 through 5, which will be 

renovated for the Project, is shown schematically in Figure 2-2. The common cooling water 

intake structure for Units 1 through 5 is located on the eastern shore of Moss Landing Harbor. 

Seawater drawn trirough bar racks at the entrance to the intake structure previously passed under 

the coast highway through approximately 350 feet of tunnel to reach the traveling screens and 

circulating water pumps located in a pumpwell structure inside the plant. Each ofthe five units 

had two circulating water pumps that historically pumped cooling water to the condensers 

through two conduits, one serving each condenser half. 

Figure 2-2 shows the major features ofthe existing intake structure. Bar racks, spaced 4 inches 

on center, and located about 350 feet in front ofthe six vertical traveling screens, prevented the 

entry of large objects into the cooling water system. The vertical traveling screens, with a mesh 

size of 3/8 inch, retained smaller objects. Materials retained by the screens were removed during 

screen rotation and washing. Screen rotation and washing were initiated automatically at 

approximately 24-hour intervals, or when the across-screen hydraulic pressure differential 

exceeded a predetermined maximum. 

The project proposes to modify the existing intake structure previously used for Units 1 through 5 

to serve the new CC units. The traveling screens for the modernized Units 1 through 5 intake 

will be located as close as practical to the shoreline, thus reducing the length ofthe intake tunnel 

upstream ofthe screens from 350 feet to approximately 10 feet (see Figure 2-3). The new 

traveling screens for the CC Units will be inclined at approximately 55 degrees from horizontal 

(Figure 2-4), and will

 h

e made of continuously woven 18 x 18 x 14 wire mesh with 3-inch tines 

E9-053.9 2-4 MLPP 316(b) Resource Assessment 

4-28-2000 
a a a • a C3 a. a • a C3 a • 

z.u uescripiion or ine moss Lanaing rower riant ana cnaracteristics or tne Source water Body 

' EXISTING INLET COOLING WATER STRUCTURE., 

UNITS 1 through 5, PLAN VIEW,__——"""*' 

i6a#--*f' 

BARRACKS 

STOP LOG GUIDE^ 

INTAKE SKIRT 

SILT DIVERSION (SHEET PILE) 

SHORELINE 

$5SSSF 

TRAVELING 

SCREENS „0 

A 

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Figure 2-2. Existing MLPP Units 1 through 5 cooling water intake structure. 

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PROPOSED INLET COOLING WATER STRUCTURE 

COMBINED CYCLE UNITS, PLAN VIEW PUMps 

INSTALL 

CUT FLOW PATH 

INSTALL NEW 

TRAVELING 

SCREENS 

REPAIR/REPLACE STOP LOG GUIDES 

REPLACE INTAKE SKIRT 

SILT DIVERSION (SHEET PILE) 

REPLACE EXISTING 45,900 GPM PUMPS 

WITH -12.000 GPM PUMPS , A to F 

I TEMPORARY 

COFFER DAM 

Figure 2-3. Proposed modernized MLPP combined-cycle cooling water intake structure. 

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35'3" 

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Figure 2-4. Sectional view ofthe MLPP new combined-cycle units intake structure's traveling screens. 

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2.0 Description of the Moss Landing Power Plant and Characteristics of the Source Water Body 

to assist with removal of accumulated eelgrass Zostera marina during the fall season. The wire 

mesh will have the equivalent of a 5/16 inch opening and will have the maximum width possible 

to fit between the existing stop log guides. The lower flow rate approaching the screens and 

higher cross-sectional area ofthe screen has the net effect of reducing the approach velocity at 

maximum capacity and mean low, low water, from the historic value of about 0.7 fps to 

approximately 0.5 fps for the new CC units. 

In addition, the internal walls ofthe intake structure will be modified to allow periodic heat 

treatment for removal of macroinvertebrates over the entire length ofthe intake system, from the 

shoreline screens to the condensers in the new CC units. Previously, it was possible to heat treat 

only the portion ofthe Units 1 through 5 intake system from the inland screenwell to the 

condensers, allowing organisms to more readily colonize the 350 feet of untreated intake tunnels 

upstream ofthe screens. Predation by these unremoved organisms was thought to significantly 

reduce the entrainment survival rate in the old Units 1 through 5 system. The heat treatment 

procedure is described in the following section. 

2.1.1.2 Units 6 and 7 Cooling Water System: Design and Operational Procedures 

The intake for the once-through seawater cooling system currently serving Units 6 and 7 is 

shown schematically in Figure 2-5. The intake structure, located on the shore 700 feet south of 

the Units 1 through 5 intake structure, consists of bar racks, traveling screens, and circulating 

water pumps. The cooling water flow of Unit 6 is separate from that of Unit 7. Separate 

subsurface conduits carry the discharge from each unit to a submerged offshore discharge 

structure located in Monterey Bay 2,400 feet from the plant, about 550 to 600 feet offshore, 

shown in Figure 2-6. 

Figure 2-5 shows the major features ofthe intake structure. Bar racks, spaced 4 inches on 

center, are located about 15 feet in front ofthe eight vertical traveling screens. The traveling 

screens are 3/8-inch mesh. Material retained by the screens is removed during screen rotation 

and washing. Washing is initiated automatically either by a timer, at approximately 24-hour 

intervals under normal operating conditions, or when the hydraulic pressure differential across 

the screen exceeds a predetermined maximum. During screen washing, spray nozzles wash the 

collected material into a surrounding sluiceway which empties into a screenwash wet well. The 

screenwash discharge, less the impinged materials, is returned to Monterey Bay by largediameter screen refuse pumps that empty into the discharge conduit of Unit 6. The impinged 

material that separates in the wet well is periodically removed by a local refuse collection 

contractor and trucked to a sanitary landfill for disposal. 

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2.0 Description of the Moss Landing Power Plant and Characteristics of the Source Water Body 

71'7" 

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Figure 2-5. MLPP Units 6 and 7 cooling water intake structure. 

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2.0 Description of the Moss Landing Power Plant and Characteristics of the Source Water Body 

600 

SCALE 

1,200 FEET 

GENERAL CONFIGURATION 

POWER PLANT UNITS 1-5 

AND UNITS 6 & 7 

COOLING WATER SYSTEMS 

DUKE ENERGY MOSS LANDING LLC 

MOSS LANDING POWER PLANT 

Figure 2-6. Location ofthe MLPP Units 6 and 7 discharge structure. 

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2.0 Description of the Moss Landing Power Plant and Characteristics of the Source Water Body 

The new CC units cooling water discharge will combine with the existing Units 6 and 7 cooling 

water discharge lines on-shore, inside the plant. There are no design changes to the existing 

Units 6 and 7 outfall structures located as shown in Figure 2-6. The tops ofthe discharge pipes 

are located approximately 20 feet off the bottom and 20 feet below the surface. The net effect of 

adding the new CC units discharge cooling water to the Units 6 and 7 discharge flow in the 

existing 12 foot diameter lines is to increase the velocity in the pipe from approximately 5.9 feet 

per second to approximately 8.6 feet per second at maximum flow. It should be noted that in the 

future, at energy demands at the MLPP of less than about 1,000 MW, the velocity in each pipe 

will be reduced to approximately 2.5 feet per second as only the two new more efficient 

combined-cycle plants will be operating. 

A chemical feed system consisting of a storage tank with injection pumps is used intermittently, 

as necessary, to supply sodium hypochlorite (12 to 14 percent bleach solution), a biofouling 

inhibitor, into the incoming cooling water supply lines immediately after the Units 6 and 7 intake 

screens and before the condensers, to reduce biofouling ofthe condenser. Residual chlorine will 

not exceed the permitted quantity of 200 parts per billion (ppb) at the outfall. The procedures 

and chemical limits are closely regulated by the Regional Water Quality Control Board 

(RWQCB). The new CC units will utilize a similar system, except that the hypochlorite solution 

injection point will be located at the condenser inlets. 

Integral to the design ofthe circulating water system will be provisions for demusseling. 

Demusseling is required, from time to time, to remove flow obstructions within the circulating 

cooling water system. This procedure will utilize the online condensers of both units to supply 

heated cooling water into the cooling water supply line and intake tunnel by reversing the flow 

through the part ofthe system being treated. The amount of time necessary to demussel an inlet 

tunnel at treatment temperature is dependent on the water temperature, but is typically 1 hour. 

The total treatment cycle from beginning to end is expected to take 4 to 6 hours. The intake stop 

logs on the tunnel being treated are closed to prevent flow of heated water to the harbor. At the 

same time, the discharge line from the condenser feeding the line being treated is closed. The 

heated treatment water flows into the active intake tunnel when the stop logs on the treated 

tunnel are closed. The discharge ofthe unit receiving blended cold intake and recycled v 

treatment water is restricted to force part ofthe flow through a crossover line to the unit being 

treated. The balance ofthe water flows through the partially closed discharge valve to the 

discharge tunnels. At the end oftreatment, the discharge valves and intake stop logs are opened 

and the circulation pumps restarted. This procedure is repeated, as necessary, approximately 

every 4 to 6 weeks in each unit. Units 6 and 7 currently employ this procedure for demusseling 

the inlet cooling water tunnels, a process which is also currently regulated by the RWQCB. 

Closure ofthe stop logs assures that heated cooling water is discharged only to the permitted 

discharge outfall and not to the harbor by reverse flow through the intake structure. This process 

E9-053.9 2-11 MLPP 316(b) Resource Assessment 

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2.0 Description of the Moss Landing Power Plant and Characteristics of the Source Water Body 

is conducted solely for control of marine growth in the cooling water intake lines and is not 

intended to provide any backwash cleaning ofthe condensers. 

As described above, the new CC units will also incorporate the capability for periodic heat 

treatment of cooling water intake lines. 

2.2 Aquatic Biological Resources in the Vicinity of MLPP 

The MLPP is situated at the intersection of three distinct marine geographic areas: Elkhorn 

Slough (tidal lagoon), Moss Landing Harbor, and Monterey Bay. Each of these areas has its 

own unique aquatic biological habitats. Distinct aquatic habitats present within the boundaries 

of Moss Landing Harbor and Elkhorn Slough include shallow open water, submerged aquatic 

vegetation, sanaVmud/salt flats, fresh/salt/brackish marshes, rocky subtidal and intertidal. 

Distinct habitats present in Monterey Bay include sandy beach, rocky intertidal and subtidal and 

open water areas. 

2.2.1 Elkhorn Slough/Moss Landing Harbor 

Elkhorn Slough is a narrow, shallow water embayment that extends 6.2 miles inland from the 

eastern margin of Monterey Bay. As it extends inland, it gradually narrows and decreases in 

depth. Tidal mud flats and pickleweed {Salicornia spp.) marsh extend the length ofthe slough. 

The drainage basin for Elkhorn Slough is small, only 226 square miles in area. The land near the 

slough is used primarily for agriculture. Shallow open water and lagoon habitats comprise the 

majority of aquatic habitat provided by the Elkhorn Slough and Moss Landing Harbor complex. 

Several changes have occurred in the hydrology and channel geomorphology since the time of 

the PG&E entrainment and impingement studies in 1978-1980 (Malzone and Kvitek, 1994; 

Oxman, 1995; Lindquist, 1998). In the mid 1980s several dikes and levees surrounding pasture 

lands were reopened to tidal flow. These changes increased the surface wetlands by 48 percent 

and the tidal volume by 43 percent (Malzone and Kvitek, 1994). The increased volume of water 

exchanged with the tides has increased both the rate of erosion and the velocity ofthe tidal 

currents (Philip Williams and Associates, 1992, cited in Lindquist, 1998; Malzone and Kvitek, 

1994). Recent studies ofthe effects of this erosion on the trophic ecology ofthe slough 

(Lindquist, 1998) and studies ofthe prey availability for harbor seals (Oxman, 1995) provide 

updated information on the species composition of adult fishes in the slough. Yoklavich et al. 

(Draft, 1999) discuss data collected from numerous studies (past and present) on fish 

assemblages found in Elkhorn Slough habitats and surrounding marine waters. 

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2.0 Description of the Moss Landing Power Plant and Characteristics of the Source Water Body 

The varied marine and estuarine habitats within Elkhorn Slough provide habitat for at least 97 

species offish (representing 40 families) (Yoklavich et al., 1992; Draft, 1999). Most (76) of 

these species are marine species from Monterey Bay. Fish species utilizing the slough were 

divided by Yoklavich et al. (Draft, 1999) into several groups. Immigrant marine species 

typically use the slough for spawning or as a nursery ground. These species include the northern 

anchovy Engraulis mordax, Pacific herring Clupea pallasi, and cabezon Scorpaenichthys 

marmoratus. Numerous species of flatfish including the speckled sanddab Citharichthys 

stigmaeus, English sole Parophrys vetulus, sand sole Psettichthys melanostictus, starry flounder 

Platichthys stellatus, California halibut Paralichthys califomicus, and several species of turbot 

are also considered immigrant marine species. Fish species considered permanent residents 

include the Pacific staghorn sculpin Leptooottus armatus, black surfperch Embiotoca jacksoni, 

striped mullet Mugil cephaius, bay pipefish Syngnathus leptorhynchus, and five species of 

gobies. Partial residents, or species that live or reproduce in the slough but migrate to the ocean 

during certain seasons or life stages, include the jacksmelt Atherinopsis californiensis, shiner 

Cymatogaster aggregata and white Phanerodon furcatus surfperches, leopard shark Triakis 

semifasciata, and bat ray Myliobatis californica. Species primarily associated with freshwater 

include the American Alosa sapidissima and threadfin Dorosoma petenense shad, mosquitofish 

Gambusia affinis, prickly sculpin Cottus asper, threespine stickleback Gasterosteus aculeatus, 

and striped bass Morone saxatilis. Few non-native species have been noted (yellowfin goby 

Acanthogobius flavimanus, mosquitofish, American shad, and striped bass). 

In 1991, otter trawls were conducted as part of a study offish availability as prey items for 

harbor seals (Oxman, 1995). Otter trawls were conducted monthly for a year (1991) in Elkhorn 

Slough in an effort to establish seasonal trends of fish availability and distribution. The trawls 

were taken at the same three stations (Bridge, Dairies, and Kirby Park) sampled by Nybakken et 

al. (1977) and reported by Yoklavich et al. (1992) in the main channel ofthe slough. Eightythree daytime otter trawls captured 1,955 fish representing 41 species. The 29 nighttime trawls 

at two stations (Dairies and Bridge) resulted in 1,461 fishes representing 39 species. The lower 

numbers caught during the day may have been a result of fishes avoiding the net. 

More then 90 percent ofthe fishes taken in the daytime and nighttime trawls were represented by 

11 species. These fishes included shiner surfperch Cymatogaster aggregata, English sole 

Parophrys vetulus, staghorn sculpin Leptocottus armatus, California tonguefish Symphurus 

articauda, speckled sanddab Citharichthys stigmaeus, white surfperch Phanerodon furcatus, 

cabezon Scorpaenichthys marmoratus, black surfperch Embiotoca jacksoni, and lingcod 

Ophidion elongatus. Pipefish Syngnathus spp. was caught during the daytime trawls and brown 

rockfish Sebastes auriculatus was caught at night. 

Oxman (1995) reported that overall there was a slight change in the 1991 diurnal fish 

assemblage from that reported by Yoklavich et al. (1992) during 1974-1976. These changes 

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2.0 Description of the Moss Landing Power Plant and Characteristics of the Source Water Body 

included a decrease in the mean number of fish per tow, species diversity decrease at the Bridge 

and Dairies stations, and species diversity increases at Kirby Park. Species absent from the 1991 

daytime trawls that were present in 1974-1980 trawls included topsmelt Atherinops affinis, 

jacksmelt Atherinopsis californiensis, Pacific herring Clupea pallasi, threadfin shad Dorosoma 

pelenense, sand sole Psettichthys melanosticus, blue rockfish Sebastes mystinus, queenfish 

Seriphus politus, and night smelt Spirinchus starksi. Several species were less abundant. 

English sole, cabezon, lingcod, and California tonguefish increased in relative abundance and 

density. 

Oxman (1995) stated that there was a significant change in fish assemblages at the Bridge and 

Dairies stations since the 1974-1980 otter trawls. Several species were absent and many were 

caught in less abundance in the 1991 tows. English sole, lingcod, and California tonguefish 

increased in relative abundance and density. 

Lindquist (1998) collected fishes in otter trawls to provide information on their feeding habits 

from four stations in Elkhorn Slough from May 1996 to May 1997. He analyzed 11 species of 

fish from nine families. The species were yellowfin goby Acanthogobius flavimanus, topsmelt 

Atherinops affinis, speckled sanddab Citharichthys stigmaeus, arrow goby Clevelandia ios, 

Pacific herring Clupea pallasi, shiner perch Cymatogaster aggregata, northern anchovy 

Engraulis mordax, Pacific staghorn sculpin Leptocottus armatus, white surfperch Phanerodon 

furcatus, English sole Parophrys vetulus, and California tonguefish Symphurus atricauda. These 

species accounted for 96 percent ofthe total abundance from the otter trawls. Of those species 

all but yellowfin goby and California tonguefish were dominant fishes during studies conducted 

in Elkhorn Slough in the 1970s (Lindquist, 1998). 

Yoklavich et al. (Draft, 1999) discussed several distinct habitat types which have been sampled 

within the slough. Different sampling methods were used for each habitat type (otter trawl, 

beach seine, and channel nets). The most abundant and diverse family of fishes within the 

slough and surrounding coastal waters are the embiotocids. Shiner perch C. aggregata was the 

most common species found throughout the habitats studied and the Pacific staghorn sculpin 

L. armatus was the most abundant species in upper slough areas. Several large elasmobranchs 

are also relatively common within the slough (bat ray M. californica, shovelnose guitarfish 

Rhinobatos productus, gray smoothhound Mustelus califomicus, and leopard shark T. 

semifasciata; Yoklavich et al. Draft, 1999; San Filippo, 1994). 

Yoklavich (Draft, 1999) concluded that in general, fish assemblages present in Elkhorn Slough 

in the 1990s are characterized by decreased abundance at most sample sites as well as less 

diversity than in the past. Within the last twenty years a homogenization offish assemblages 

appears to have occurred between the lower main channel and tidal channels. These changes 

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2.0 Description of the Moss Landing Power Plant and Characteristics of the Source Water Body 

have coincided with the continued erosion and scouring of smaller channels to the point that they 

are now similar (in habitat type) to the main channel (Malzone and Kvitek, 1994). 

The most abundantly collected fishes from studies reported in Nybakken et al. (1977), Yoklavich 

et al. (1991), from PG&E impingement studies in 1978-80 (PG&E, 1983), and from Lindquist's 

work in 1996-97 generally have remained the same. Northern anchovy, shiner perch, and Pacific 

herring were some ofthe most abundantly collected fishes from all three of these studies. 

Topsmelt was the only species collected in high numbers in impingement samples that was not 

collected in the other two studies. Oxman's (1995) studies in 1991 however, showed greater 

differences in species composition when compared to the other studies with the exception ofthe 

presence of shiner perch. This species was collected in high numbers in the slough from all 

studies. Fishes that were not collected in Oxman's study but were present in high numbers in all 

other studies were northern anchovy and Pacific herring. Both of these missing species were 

again collected in high numbers in Lindquist's 1996-97 studies. 

Monterey Bay, California's largest open-coast embayment, is formed by the extent of shoreline 

between Santa Cruz and Monterey and by the offshore depths ofthe Monterey submarine 

canyon. The opening ofthe bay is 23 miles across and 10 miles wide. Four main tributaries, the 

Pajaro River, Elkhorn Slough, the Salinas River, and the San Lorenzo River flow into the bay. 

The bay's immense supply of cold, nutrient-rich, ocean water is exchanged tidally with the 

Elkhorn Slough and harbor located midway along the bay shoreline at the head ofthe canyon. 

Monterey Bay lies within the boundaries ofthe Monterey Bay National Marine Sanctuary 

(MBNMS). The MBNMS extends from 7 miles north ofthe Golden Gate Bridge to Cambria 

Rock in northern San Luis Obispo County. The sanctuary contains about 400 statute miles of 

coastline and extends an average of 30 miles offshore. Its total area is 5,322 square miles. The 

MBNMS was officially established in 1992 by the authority ofthe Secretary of Commerce under 

the 1972 Marine Protection, Research and Sanctuaries Act. The MBNMS is one of fourteen 

marine sanctuaries in the United States under the jurisdiction ofthe National Oceanic 

Atmospheric Association (NOAA) ofthe U.S. Department of Commerce. 

Monterey Bay is characterized by a gently sloping shelf cut by a system of submarine canyons, 

the largest of which is the Monterey Submarine Canyon. The head of this canyon is located off 

ofthe entrance to Moss Landing Harbor. The depth ofthe canyon ranges from 60 feet to 2,800 

feet. The canyon is 650 feet wide at the head and approximately 7.5 miles wide at the mouth of 

Monterey Bay. 

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Monterey Bay's sandy beach habitat extends in nearly a continuous reach of approximately 20 

miles from Santa Cruz to Monterey, encompassing the Moss Landing area. Beach habitat in the 

area of Moss Landing is exposed to high-energy waves from the northwest. Large quantities of 

sand are annually transported on and off the beach shoreline by strong waves and longshore 

currents. The continuously changing nature of this habitat favors mobile invertebrate and fish 

species that adjust quickly to the depletion and accretion of sediments. Relatively few species 

are able to adjust to this habitat. 

The marine resources of Monterey Bay support a variety of commercial fisheries (Starr et al., 

1998). Many ofthe fisheries are very dynamic. Landings are driven by the demands ofthe 

market, the abundance ofthe target species, and attempts by the regulators to reduce harvest. As 

new markets are found for species that were previously unmarketable or of low value, annual 

landings of those species can increase rapidly. Landings from other fisheries decline as 

fishermen fill the demands ofthe new markets. Regulation offish harvest, entry into a fishery, 

gear usage, and season length can have a pronounced effect on landings. Fisheries also decline 

and expand with the cycles of abundance and scarcity ofthe targeted species. Long-term overexploitation of many fish stocks along the Pacific Coast has decreased the abundance of adult 

fishes and recently led to more restrictive regulation of harvest levels. Some regulations were 

made because of concerns regarding declines in populations. Declines in landings often follow 

regulatory efforts and may not directly reflect species abundance. Because ofthe complexity of 

the forces driving fish harvest in the Monterey Bay area, generalizations about fish abundance 

based on landing data must be made carefully. CDFG catchblock data from 1975 through 1998 

were used for the following analysis of commercially important fish species present in the 

Monterey Bay region. Because of inconsistencies in catchblock reporting, landings cited for a 

species or market category by catchblock are generally smaller than landings reported by port. 

Fishes and invertebrates are harvested from the Monterey area using a variety of fishing 

methods. A majority ofthe fishes landed in Monterey ports between 1975 and 1998 was taken 

with purse seine and trawl nets. Set gillnets have traditionally been used to harvest California 

halibut Paralichthys califomicus, rockfish Sebastes spp., white croaker Genyonemus lineatus, 

and a variety of sharks. Commercial fishermen use trolling gear to harvest salmon and albacore 

during the seasons when they are abundant in the area. Hook- and line- gear has traditionally 

been used to harvest rockfish Sebastes spp. and lingcod Ophiodon elongatus over rocky reefs 

near the canyon. Set longlines, which are now prohibited in nearshore waters (within 1 mile), 

are used in the Monterey canyon area to take sablefish Anoplopoma fimbria and grenadier 

(Family Macrouridae). Fish traps and "stick gear" are used in the recently established live 

rockfish fishery. Traps are also used to take rock crabs Cancer spp. and Dungeness crab Cancer 

magister. 

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2.0 Description of fhe Moss Landing Power Plant and Characteristics of the Source Water Body 

The most effective gear for certain species, in terms of biomass harvested, is the purse seine. 

Purse seining is used to harvest pelagic species such as market squid Loligo opalescens, Pacific 

sardine Sardinops sagax, northern anchovy Engraulis mordax, and both Pacific mackerel 

Scomber japonicus and jack mackerel Trachurus symmetricus. Market squid has consistently 

been one ofthe top two species landed in the Monterey area. Between 10 and 20 million pounds 

of squid are typically landed at Monterey ports each year. Northern anchovy and Pacific sardine 

rank second and third in pounds landed, however, the fishery has shifted from northern anchovy, 

which were abundant in the 1970s and 1980s, to sardines which have dominated the fishery in 

recent years. Both Pacific mackerel and jack mackerel rank among the top 10 species landed. 

Pacific mackerel landings peaked in the early 1980s, ranking between first and fifth from 1980 

to 1986. Landings of Pacific mackerel have also been high in the Monterey area during the 

1990s. Landings of jack mackerel have ranked between second and twelfth for 19 ofthe past 24 

years. Both species of mackerel were also landed in the market category "unspecified mackerel" 

which ranked first in 1994 and second for the next 2 years. Pacific herring Clupea pallasi have 

also sustained high levels of harvest through most ofthe period. The fishery is somewhat cyclic 

and peak landings from the area occurred in 1982, 1987, and 1996. Reported landings of Pacific 

herring ranged from over 560,000 pounds in 1987 to 52 pounds in 1997 and averaged around 

165,000 pounds annually. No landings were reported for the catchblock area during 1991 and 

1998. 

Commercial trawlers in the area target a variety of demersal fish species, or groundfish. There 

are several distinctly different trawl fisheries in Monterey Bay. The species targeted depends 

largely on what permits the boats, or owners/captains have been able to acquire. The harvest of 

groundfish species is closely regulated by the Pacific Fisheries Management Council and 

National Marine Fisheries Service. The DTS complex (Dover sole, thornyhead, and sablefish) is 

targeted only by vessels with federal limited-entry groundfish permits. The harvest ofthe DTS 

complex is second to that of purse seiners in terms of biomass. Dover sole Microstomus 

pacificus, which ranked eleventh in total pounds landed between 1975 and 1998, did not rank 

within the top ten species until 1985. Thomyheads Sebastolobus spp. and sablefish are more 

valuable per pound than Dover sole and these species have recently had more restrictive quotas. 

Sablefish have consistently sustained high levels of harvest. Longspine thomyheads 

Sebastolobus altivelis and shortspine thomyheads Sebastolobus alascanus were not heavily 

exploited until the mid-1980s, when new markets for the species opened in Japan. 

Trawlers with federal groundfish permits also target splitnose Sebastes diploproa and aurora 

rockfish Sebastes aurora (Rosefish market category), widow rockfish Sebastes entomelas, 

bocaccio rockfish Sebastes paucispinis, chilipepper rockfish Sebastes goodei, and Sebastes 

complex species. The Sebastes complex is composed of a mixture of rockfish species that do not 

have specific quotas. Sebastes complex species are often landed in the market category 

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"unspecified rockfish." Unspecified rockfish landings consistently rank within the top ten fish 

categories harvested from the Monterey Bay area. The years of peak harvest for this market 

category were in the mid-1980s and early 1990s. Bocaccio and chilipepper rockfish landings 

were combined into one market category until bocaccio became a federally regulated quota 

species. Bocaccio have sustained consistently high levels of harvest until recently when a 

decline in their abundance prompted regulators to drastically reduce quotas. Both chilipepper 

rockfish and the market category rosefish have been heavily exploited in the 1990s. Both were 

removed from the Sebastes Complex quota and given individual quotas in 1999. Limited entry 

trawlers also commonly land rex sole Errexzachirus, petrale sole Eopsetta jordani, English sole 

Parophrys vetulus, lingcod, grenadiers, and skate/skate wings {Raja spp.). 

Trawlers without a federal groundfish permit also harvest groundfish (except DTS), however, 

these "Open Access" fishermen are subject to more restrictive quotas. Because of restrictive 

rockfish quotas, the open access trawl fishery generally targets demersal fish species such as 

California halibut, white croaker, sole, and Pacific sanddab Citharichthys sordidus. Starry 

flounder Platichthys stellatus, turbot Pleuronichthys spp., and Pacific angel shark Squatina 

californica are among the non-target species caught in this fishery that are considered saleable 

by-catch. Sanddab harvest was variable during this period and ranged from 177 pounds in 1984 

to nearly 530,000 pounds in 1998. From CDFG catchblock data, the average annual harvest of 

sanddabs was around 82,000 pounds. Sanddabs ranked twenty first in pounds landed between 

1975 and 1998. White croaker are also harvested by open access trawlers and ranked thirteenth 

overall. Landings of white croaker from the area are somewhat cyclic and ranged from 4,246 

pounds in 1984 to nearly 642,000 pounds in 1980. The average annual landing of white croaker 

from Monterey Bay from 1975 through 1998 is around 180,000 pounds. White croaker 

consistently ranked among the top ten species harvested in the area (annually) from the mid1970s through the early 1980s. Pink shrimp Pandalus eous and spot prawns Pandalus 

platyceros have become the target of a large number of open access trawlers with shrimp or 

prawn permits. The pink shrimp fishery is seasonal and highly cyclic. Peaks of harvest and 

fishing effort are often followed by steep declines in both. Spot prawn harvest in the area 

consistently remained at a relatively low level (average of less than 9,000 pounds annually) until 

1991. Since 1991 the annual harvest has risen steadily to nearly 190,000 pounds (by 1998). The 

fishery is currently being driven by the high prices paid for live spot prawns. 

Gillnets have been an effective gear used in the past to harvest a variety of species. California 

halibut are the target ofthe fishery, however, white seabass Cynoscion nobilis, white croaker, 

and several shark species are also regularly landed by gillnetters. Concern over sea otter 

mortality resulted in regulation ofthe depth in which gillnets could be set. Currently, gillnets 

cannot be set inside of 30 fathoms (55 m or 180 ft) of water. The annual harvest of halibut from 

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2.0 Description of fhe Moss Landing Power Plant and Characteristics of fhe Source Water Body 

the area ranged from around 4,000 pounds in 1984 to approximately 180,000 pounds in 1997. 

The average harvest from 1975 to 1998 was about 57,000 pounds. Gillnet boats targeting 

rockfish generally set their nets in water depths from 50 to 120 fathoms (91m to 220 m or 300 ft 

to 720 ft). Rockfish gillnetters target "red" rockfish (vermilion rockfish Sebastes miniatus, 

yelloweye rockfish Sebastes ruberrimus, canary rockfish Sebastes pinniger, copper rockfish 

Sebastes caurinus, greenspotted rockfish Sebastes chlorostictus, etc.) but land large numbers of 

bocaccio, chilipepper, and bank rockfish Sebastes rufus, as well as lingcod. Recent regulation of 

open access rockfish harvest has eliminated much ofthe gillnet effort for rockfish. 

The commercial troll fleet in the Monterey Bay area targets king salmon Oncorhynchus 

tshawytscha and albacore Thunnus alalunga when they are in season and available. The salmon 

fishery has traditionally been one ofthe more lucrative fisheries in the bay for small, 

independent commercial fishermen. King salmon harvested within the area rank within the top 

ten, in terms of pounds landed annually, for all years (from 1975 to 1998) except 1985 and 1988. 

King salmon ranked seventh in total pounds landed for the period. Silver salmon Oncorhynchus 

kisutch was the tenth ranked species in 1975. Albacore are caught by trollers in the outer regions 

of Monterey Bay during years when warmer water is relatively close to land. They consistently 

ranked within the top ten species landed from the area throughout the 1970s and 1980s. 

Albacore ranked tenth in total pounds landed from 1975 to 1998. Many boats landing albacore 

in area ports fished areas outside the bay. Some commercial trollers also target rockfish during 

the season when salmon fishing is closed. By modifying their gear and fishing methods, these 

fishermen have traditionally targeted red rockfish but also catch a significant number of 

bocaccio, chilipepper rockfish, and lingcod. Between 1980 and 1998 annual harvest (for all 

gears) of red rockfish (market category 959) ranged from 90 pounds to over 250,000 pounds. 

The average annual harvest (Monterey area) for the group over the last 20 years is approximately 

92,000 pounds. The red rockfish market category ranked twenty-fourth in total pounds landed 

from 1975 to 1998. 

During the early 1990s a new fishery evolved to supply the market demand for live fish. The 

fishery targets nearshore rockfish species (grass rockfish Sebastes rastrelliger, gopher rockfish 

Sebastes carnatus, brown rockfish Sebastes auriculatus, china rockfish Sebastes nebulosus, etc.) 

and cabezon Scorpaenichthys marmoratus. Fishes are taken from the intertidal zone down to 

depths of 30 m (100 ft) with hook and line gear or traps and kept alive in holding tanks. Kelp 

greenling Hexagrammos decagrammus and lingcod are not target species in this fishery, but are 

commonly landed. Harvest of species from the nearshore reefs within Monterey Bay and coastal 

areas adjacent to the bay increased dramatically as the fishery expanded. Harvest levels peaked 

for many species during 1995 and 1996. Over-exploitation of this previously unregulated 

resource, along with recent regulation, has resulted in a moderate decline in landings for most 

species. 

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2.0 Description of the Moss Landing Power Plant and Characteristics of the Source Water Body 

The Monterey Bay area also supports a moderate-sized crab fishery. Dungeness crab and two 

species of rock crab are harvested from the Monterey area. Dungeness crab landings vary with 

the species' abundance near the southern end of its range. Harvest reported from the area ranged 

from around 1,000 pounds landed in 1988 to approximately 112,000 in 1998. Landings of 

Dungeness crab from the area have increased significantly in the 1990s and ranked between 

eleventh and thirteenth in pounds landed annually between 1994 and 1996. Pacific rock crab 

Cancer antennarius and red rock crab Cancer productus are typically landed in the combined 

market category "Unspecified rock crab" or their claws are removed landed in the "crab claws" 

market category. Rock crab landings are generally small, but ranged from 12 pounds in 1976 to 

around 134,000 pounds in 1989. There was significant variation in the pounds of crab claws 

landed. From reported catchblock data between 1986 and 1998, annual landings of crab claws 

ranged from around 81,200 pounds in 1987 to 1 pound in 1997. 

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3.0 ENTRAINMENT STUDY AND ASSESSMENT METHODS 

Moss Landing Power Plant withdraws water for cooling purposes from an intake located in Moss 

Landing Harbor. The cooling water is pumped from the harbor through screens that have 3/8 

inch (0.9 cm) mesh designed to exclude anything greater than the diameter ofthe plant's 

condenser tubes. Entrainment occurs when organisms small enough to pass through the 3/8-in 

(0.9 cm) mesh are drawn through these screens into the power plant's cooling water system 

where they are subsequently exposed to stressful conditions — pressure changes, shear forces, 

thermal changes, chemical changes, and collisions with surfaces. 

The major objective of this 316(b) study is to characterize entrainment at the Moss Landing 

Power Plant's new combined-cycle intake (formerly the Units 1 through 5 intake). Field data on 

the composition and abundance of potentially entrained larval fishes and cancer crab megalops 

provide a basis to refine estimates ofthe total number and types of these organisms passing 

through the power plant's cooling water intake system. Estimates of fractional losses due to 

entrainment by the new intake structure were obtained from data collected on source water 

populations of entrainable fish larvae and Cancer spp. megalops. 

The modifications to the new combined-cycle intake cooling water flows will alter previously 

assessed entrainment rates. Data from samples collected in front ofthe intakes for the new 

combined-cycle units were used to evaluate entrainment effects. These data were used, 

assuming 100 percent entrainment mortality, with data collected from the source water to assess 

the potential impact to fishery resources. The studies were designed to address the 

following questions: 

• Have changes occurred in MLPP's source water bodies that would lead to alteration 

ofthe estimates of abundance or distribution of source water stocks of entrainable 

larval fishes or cancer crab megalops? 

• What is the potential impact ofthe power plant's cooling water system on larval 

fishes and cancer crabs? 

These results also provide site- and species-specific information used to evaluate the potential 

effectiveness of intake modifications for minimizing the potential effects of entrainment and to 

evaluate available intake technologies for the new combined-cycle units ofthe Moss Landing 

Power Plant. 

The Moss Landing Power Plant entrainment studies are focused on fishes (all life stages), 

Cancer spp. (megalopal life stage), and European green crabs Carcinus maenas (megalopal life 

stage). A description of laboratory processing methods is also provided. 

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3.0 Entrainment Study and Assessment Methods 

3.1 Entrainment Study 

This study was designed to quantify the current composition and abundance of entrained larval 

fishes and European green and cancer crab megalops at MLPP. Planktonic fish eggs were not 

quantified in this study. Although there are descriptions of many marine eggs, the taxonomy 

remains difficult and is very time consuming. 

3.1.1 Entrainment Sampling Methods 

Towed net sampling began March 2, 1999 and continued through February 24, 2000. Samples ' 

taken from in front ofthe intakes for the new combined-cycle units and for Units 6 and 7 were 

collected by towing a bongo frame with 0.71 m (2.3 ft) diameter openings and equipped with two 

335 pm mesh plankton nets and codends. Samples were collected over a continuous 24-hour 

period; each period was divided into six, 4-hour sampling cycles. Two tows were conducted 

during each cycle. Samples were collected at stations located directly in front ofthe intake 

stmctures for both the new combined-cycle units and for Units 6 and 7 (Figure 3-1). Sample 

collection methods were similar to those developed and used by the California Cooperative 

Oceanic and Fisheries Investigation (CalCOFI) in their larval fish studies (Smith and 

Richardson, 1977). The bongo nets were lowered as close to the bottom as possible. Once the 

nets were at the correct depth, the boat was moved forward and the nets retrieved at an oblique 

angle (winch cable at a 45° angle). The winch retrieval speed was constant at approximately 

1 ft/sec. Each net mouth was fitted with a calibrated flowmeter to record the water volume 

filtered. 

The target water volume filtered by both bongo nets combined was 40 m3 (20 m3/net). The 

sample volume was checked when the nets reach the surface. If the target volume was not 

collected, the nets were placed back in the water and the tow repeated so that the targeted volume 

was reached. Upon successful completion of a tow, the nets were retrieved from the water and 

all ofthe collected material was rinsed into the codend. The contents of both nets were 

combined into a single, labeled jar (constituting one sample) immediately after collection and 

were preserved in ethanol (ETOH). Preservation using ETOH allows specimen identifications to 

be genetically validated or allows for age and growth studies should the need arise. Each sample 

was given a serial number based on the location, date, time, and depth of collection. In addition, 

that information was logged onto a sequentially numbered data sheet. The sample's serial 

number was used to track it through laboratory processing, data analyses, and reporting. 

Sampling at the new combined-cycle units and Units 6 and 7 intakes occurred once per week 

during the peak larval fish season (November through June) and every other week during the offpeak period (Section 3.1.2). All ofthe entrainment samples collected from the new CC units and 

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3.0 Entrainment Study and Assessment Methods 

the Units 6 and 7 intakes have been sorted and all of the larval fishes and targeted crabs have 

been identified. Quality control resorts and taxonomic re-identifications are nearly complete. 

Similarity was tested for fish data from all surveys (Surveys 1 through 42) from samples 

collected in front ofthe two intake complexes. The results of these tests are discussed in 

Section 4. 

Figure 3-1. Moss Landing Power Plant sampling locations. 

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3.0 Entrainment Study and Assessment Methods 

3.1.2 Entrainment Sampling Frequency Rationale 

Using peak periods of larval abundance from a previous MLPP entrainment study (PG&E, 1983; 

Table 3-1), a rationale was developed for the proposed sampling frequency. The eight taxa 

presented in Table 3-1 represent 94 percent ofthe total abundance of larval fishes entrained 

during the years 1978-1980. The observed seasonality of larval abundance from MLPP (PG&E, 

1983) corresponds well to reported seasonality from the literature on larval fishes (Matarese et 

al., 1989; Moser, 1996) and with a previous study conducted in 1974 - 1978 near the site ofthe 

present survey effort (Yoklavich et al., 1992). Thus, it was proposed to concentrate the sampling 

efforts (one 24-hr period per week) during the periods of peak larval abundance observed at 

MLPP for the majority ofthe eight taxa represented in Table 3-1. Specifically, increased 

sampling efforts from the beginning of November through the end of June (i.e., greater collection 

frequency) encompassed the majority of spawning peaks for these eight taxa. Notably, the 

observed spawning peak for longjaw mudsucker is not encompassed within the months described 

above. However, the year-round presence and continuation of biweekly sampling during the 

remainder ofthe year (July through October) is expected to adequately document the presence 

and abundance of this species. 

Table 3-1. Common Entrainment Period and Peak Concentrations, in order of Abundance, for the 

Eight Most Abundantly Entrained Larval Fish Taxa at MLPP during 1978-1980 (PG&E, 1983). 

Name 

Northern anchovy (Engraulis mordax) 

Gobies (Gobiidae) 

Silversides (Atherinidae) 

Smelts (Osmeridae) 

Pacific Staghorn sculpin (Leptooottus armatus) 

White croaker (Genyonemus lineatus) 

Longjaw mudsucker (Gillichthys mirabilis) 

Pacific herring (Clupea pallasi) 

Most Common Entrainment 

Period 

November to April 

Year-Round 

November to April 

January to September 

September to May 

August to April 

Year-Round 

Two spawning periods: December 

to March and May to Early August 

Peak Concentration 

(number/ m3) 

5.4 (March) 

2.5 (January) 

2.7 (March) 

4.2 (February) 

0.5 (February) 

0.7 (November and December) 

0.5 (September and October) 

0.5 (January) and 1.3 (June) 

3.2 Source Water Study 

3.2.1 Source Water Sampling Methods 

The study was designed to characterize the source water composition, abundance, and 

distribution of larval fishes and megalopal stages of Cancer spp. and European green crabs. The 

entrainment concentrations and intake volumes were compared to source water concentrations 

and source water volumes to provide estimates of fractional loss as well as assist in the definition 

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3.0 Entrainment Study and Assessment Methods 

of source population boundaries. A description of how the source water volumes were 

calculated is presented in Section 6. 

Samples were collected at six stations (Table 3-2) monthly in one of two ways; oblique tows for 

the ocean and harbor stations and push nets for the Kirby Park and Dairies stations. The 

locations for the source water stations are shown in Figure 3-1. The following three stations 

were chosen to conform to locations previously studied by Nybakken et al. (1977): (1) between 

the Highway 1 Bridge and the entrance to the Moss Landing Harbor, (2) near the Dairies, and 

(3) near Kirby Park. The remaining three station locations were chosen based on discussions 

with the Technical Work Group during the September 15, 1999 meeting. One additional station 

was added in the mouth ofthe entrance and one ocean station located approximately one mile 

(1.6 km) to the north of the harbor entrance and one ocean station located approximately one 

mile (1.6 km) to the south ofthe harbor entrance (Figure 3-1). Two samples of at least 40 m3 

were collected in daylight at each station during one high and one low tide. Source water 

sampling was scheduled to occur during the same 24-hour period as the entrainment collections. 

Sampling at the harbor entrance and ocean stations consisted of an oblique tow using the same 

methodology described above. Sampling at the Dairies and Kirby Park stations (Figure 3-1) 

consisted of pushing a 0.71 m (2.3 ft) diameter net of 335 fam mesh on the surface in front of a 

moving boat. All source water samples were processed in the laboratory. 

Additional sampling ofthe Harbor Mouth and Harbor Bridge stations was requested by the TWG 

at the January 18, 2000 meeting. The sampling of these stations will be conducted during the 

same cycles as the entrainment sampling at the intakes. These additional data will be used to 

provide more information about the diel distribution of larval fishes. 

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3.0 Entrainment Study and Assessment Methods 

Table 3-2. Collection Specifications for Source Water Sampling at MLPP. 

Station Name 

Ocean North 

Ocean South 

Harbor Mouth 

Harbor Bridge 

Units 6 and 7 

Intake 

Dairies 

Kirby Park 

Description 

One mile north of ML harbor mouth, at the 

20-meter depth contour. 

One mile south of ML harbor mouth, at the 

20-meter depth contour. 

Entrance to Moss Landing Harbor from 

Monterey Bay; between the north and south 

breakwaters. 

Moss Landing Harbor channel at Highway 1 

bridge. 

Moss Landing Harbor channel at MLPP Units 

6 and 7 intake structure. 

Elkhorn Slough main channel about 2.2 km 

(1.4 miles) inland from the Highway 1 bridge. 

Elkhorn Slough main channel about 6.2 km 

(3.9 miles) inland from the Highway 1 bridge. 

Location 

(Lat. / Long.) 

36°48.84'N/ 

121° 48.40'W 

36°47.44'N/ 

121°48.52'W 

36°48.38'N/ 

121° 47.40'W 

36°48.292'N/ 

121°47.150'W 

36°48.292'N/ 

121°47.130'W 

36°48.74'N/ 

121°45.70'W 

36° 50.40'N/ 

12T44.75' W 

Station Depth at 

MLLW 

(m / ft) 

20 m / 66 ft 

20 m / 66 ft 

7 m/23 ft 

7 m/23 ft 

5.5 m/18 ft 

4m/13ft 

3 m/ 10 ft 

3.2.2 Comparability of Surface and Oblique Towed Methodologies 

Similar to past studies, the MLPP larval fish studies used two different types of sampling gear to 

collect samples. Both types were selected to solve a particular sampling challenge associated 

with different station locations. 

Obliquely towed nets collect a bottom-to-top water column sample and pushed nets sample a 

fixed depth, typically at the surface. In the case ofthe MLPP studies, both gear types used 

plankton nets that were equipped with 335 |im mesh to collect the same size of planktonic 

organisms and used calibrated flowmeters to measure the volume ofthe sample. It is not 

expected that sampling efficiency will vary significantly between obliquely-towed nets and 

pushed nets. Although obliquely towed nets vs. pushed nets would be presented with different 

water to sample, it is unlikely that the samples collected by the two different methods would 

produce statistically different estimates ofthe water column's larval concentrations. Both types 

of gear had the same diameter net mouths, used the same mesh net, had reduced (McGowan and 

Brown, 1966) or no bridle effects (e.g., push net), and were towed at the same speeds. 

These nets are designed to sample plankton efficiently and to minimize biases commonly 

associated with sampling planktonic organisms (McGowan and Brown, 1966; Tranter and Smith, 

1968). They are conical (widest at the opening) which promotes tumbling of planktonic 

organisms down the net sides toward the codend as water is filtered out and away from the net 

axis. This type of filtration also has the advantage of causing very little damage to the planktonic 

organisms aiding in both the laboratory processing and identification phases of sample analysis. 

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3.0 Entrainment Study and Assessment Methods 

However, the fine mesh size of these nets (335 p:m) makes them susceptible to clogging under 

certain conditions (e.g., algal blooms or high turbidity). Clogged nets can be preceded by a 

pressure wave reducing filtration efficiency, warning mobile zooplankters ofthe net's approach 

(McGowan and Brown, 1966), and introducing unmeasured bias into the resulting samples due 

to avoidance and escapement. 

Larval fishes and other planktonic organisms have patchy vertical distributions 

(e.g., Schlotterbeck and Connally, 1982; Brewer and Kleppel, 1986; Gray, 1993; Moser and 

Smith, 1993; Gray, 1998) which present unique challenges to representative sampling. The 

rationale for the use of an oblique tow is that the vertical concentrations of larval fishes vary 

significantly in the water column and sampling at only one depth would produce a sample bias 

when estimating total water column abundance. For instance, variations in vertical current 

stratification or distribution of planktonic organisms are integrated by the representative 

sampling of each sampling stratum (Simpson, 1959; Smith et al., 1968). The pushed net, while 

fished at a fixed depth, is used in shallow areas where turbulent tidal flow potentially eliminates 

water column stratification of larvae (i.e., the vertical larval distribution should be 

homogeneous). 

Vertical distribution differences are integrated when using an obliquely-towed net and sampling 

the entire water column and are nullified by shallow water turbulent mixing in the case ofthe 

pushed-net sampling. It is expected that obliquely towed net samples at the deeper Moss 

Landing Harbor sampling locations and pushed-net samples at the shallow Elkhorn Slough 

sampling location will be similarly representative of water column plankton concentrations. 

Furthermore, if slight differences exist between the towed and pushed nets, it is probable that 

these differences could not be statistically detected. 

3.3 Laboratory Processing and Data Handling 

During laboratory processing all larval fishes and the megalopal stage of Cancer spp. were 

removed from the samples. European green crab Carcinus maenas megalops were searched for 

and removed from the samples. Fish eggs were not removed from the samples. Although there 

are descriptions of many marine eggs, the taxonomy remains difficult and time consuming. 

Larval fishes and targeted crab species megalops were identified to the lowest taxonomic level 

possible by TENERA'S in-house taxonomists. In addition, the lifestages of larval fishes were 

identified and recorded on the data sheet. A laboratory quality control (QC) program for all 

levels of laboratory sorting and taxonomic identification was applied to all samples. The QC 

program also incorporated the use of outside taxonomic experts to provide taxonomic QC and 

resolve taxonomic uncertainties. 

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Lengths of larval bay goby and longjaw mudsucker were obtained using a computer imaging 

system and Optimas image analysis software. A quality assurance program was maintained for 

the system operator. The image analysis software was interfaced directly to Microsoft Excel and 

subsequently linked to the MLPP database in Microsoft Access. 

Laboratory data sheets were coded with species or taxon codes. These codes were verified 

against species/taxon lists and signed off by the data manager. The data were then entered into a 

computer database for analysis. 

3=4 SampDnimg Sufficiency 

Species accumulation curves were calculated to assess the adequacy ofthe sampling effort 

(Krebs, 1989). A species accumulation curve depicts the number of new species (species not 

encountered before) collected during repeated sampling efforts. It is in effect a mnning tally of 

the number of species collected. The tally is cumulative so each species is counted only once. 

Generally, the slope of a species accumulation curve is steepest during early sampling efforts 

when new species are frequently encountered. As sampling continues fewer new species are 

collected so the slope ofthe curve tends toward zero. This trend may be confounded when 

computing a species accumulation curve over time and when sampling larval fishes, due to the 

reproductive cycles of species within the community. Species accumulation curves were 

computed from the mean, maximum, and minimum number of species sampled from 1,000 

random iterations ofthe data to help account for seasonal differences in reproductive cycles 

among species. Results are presented in Section 4.1.1. 

3.5 Assessment Hetlhiodls 

li Larval sampling at the cooling water intakes at the new combined-cycle units provided periodic 

estimates of daily as well as annual larval entrainment at the MLPP. Estimates of entrainment 

• loss, in conjunction with demographic data collected from the fisheries literature, permits 

modeling of adult equivalent loss {AEL) and fecundity hindcasting {FH). Additional sampling at 

I

the potential source populations of larvae in the source water areas of Moss Landing Harbor, 

Elkhorn Slough, and Monterey Bay provides the information that is combined to estimate a total 

annual harvest mortality probability using the Empirical Transport Model {ETM). Considering 

I the guidelines established in the EPA draft document (EPA, 1977) and given the constraints of 

the data and available demographic information for the larvae entrained, the TWG will determine 

B which taxa within these groups will be included in more detailed analyses of entrainment effects 

when sufficient data have been collected. The data requirements, assumptions, outputs, 

advantages, and disadvantages of these approaches are summarized in Tables 3-3 and 3-4. In the 

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MLPP 316(b) study, we will use each approach (i.e., AEL, FH, and ETM) as appropriate for each 

taxon to assess effects of entrainment losses. 

Adult equivalent loss models evolved from impact assessments that compared power plant losses 

to commercial fisheries harvests and/or estimates ofthe 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) provided an early 

example ofthe equivalent adult model {EAM) to convert numbers of entrained early life stages of 

fishes to their hypothetical adult equivalency. Goodyear (1978) extended the method to include 

the extrapolation of impinged juvenile losses to equivalent adults. 

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, 

adult crabs, or biomass. We will use two different but related demographic approaches in 

assessing entrainment effects at MLPP: AEL, which expresses effects as absolute losses of 

numbers of adults, and FH, which estimates the number of adult females whose reproductive 

output has been eliminated by entrainment of larvae and megalops. 

Age-specific survival and fecundity rates are required for AEL and FH. Adult-equivalent loss 

estimates require survivorship estimates from the age at entrainment to adult recmitment; FH 

requires egg and larval or megalopal survivorship until entrainment. Furthermore, to make 

estimation practical, the affected population is assumed to be stable and stationary, and agespecific survival and fecundity rates are assumed to be constant over time. Each of these 

approaches provides estimates of adult fish and crab losses that may still need to be placed into 

context regarding standing fish/crab stocks. 

Species-specific survivorship information (e.g., age-specific mortality) from egg, larvae, and 

megalop to adulthood is limited for many of the taxa likely to be considered in this assessment. 

Thus, in many cases, these rates must be inferred from the literature along with their measures of 

uncertainty. Uncertainty surrounding published demographic parameters is seldom known and 

rarely reported, but the likelihood that it is very large should be considered when interpreting 

results from the demographic approaches for estimating entrainment effects. For some wellstudied species (e.g., northern anchovy Engraulis mordax), portions of their early mortality 

schedules and fecundity have been reported (e.g., Parker, 1980; Zweifel and Smith, 1981; 

Hewitt, 1982; Hewitt and Methot, 1982; Hewitt and Brewer, 1983; Lo 1983, 1985, 1986; 

McGurk, 1986). Because the accuracy ofthe estimated entrainment effects from AEL and FH 

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3.0 Entrainment Study and Assessment Methods 

will depend on the accuracy of age-specific mortality and fecundity estimates, lack of 

demographic information may limit the utility of these approaches. 

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3.0 Entrainment Study and Assessment Methods 

Table 3-3. Data Requirements and Outputs for Three Approaches Proposed to Estimate Effects of 

Cooling Water Withdrawals at MLPP. 

Approach 

Proportional 

Entrainment 

(PE) 

Data Required 

• Taxon-specific estimates of 

entrainment losses. 

• Comparable life-stage 

estimates of taxon's 

abundance (concentration) 

in source water. 

Assumptions 

• Source water samples 

are representative of 

the composition and 

abundance of larvae 

and megalops in the 

study area. 

• Entrainment samples 

are representative of 

the organisms 

entrained in the 

cooling water. 

Output 

• Estimated fraction of 

larval and megalopal 

concentration 

removed from the 

source water by 

entrainment. 

Adult Equivalent 

Loss 

(AEL) 

• Taxon-specific estimates of 

entrainment and 

impingement losses. 

• Age-specific mortality 

schedules for selected taxa 

from entrainmentimpingement to some 

predetermined life stage 

(e.g., recruitment). 

• Fishery resource abundance 

estimates for relative 

impact assessments. 

• Age-specific mortality 

rates are constant for 

the population. 

• Population at longterm equilibrium for 

relative impact 

assessments (not 

required for 

calculations). 

• Entrainment samples 

are representative of 

the organisms 

entrained in the 

cooling water. 

• Number of animals 

that would have 

survived to adulthood 

had they not been 

entrained or impinged 

by the intake. 

Fecundity Hindcast 

(FH) 

• Taxon-specific estimates of 

entrainment and 

impingement losses. 

• Species- and age-specific 

adult fecundity. 

• Age-specific mortality 

schedules for selected taxa 

from parturition/hatch to 

entrainment/impingement. 

• Age-specific mortality 

rates are constant for 

the population. 

• Population at longterm equilibrium for 

relative impact 

assessments (not 

required for 

calculations). 

• Entrainment samples 

are representative of 

the organisms 

entrained in the 

cooling water. 

• Number of sexually 

mature females 

represented by the 

losses of reproductive 

output due to 

entrainment and/or 

impingement. 

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| Table 3-4. Advantages and Disadvantages ofthe Three Approaches Proposed to Estimate Effects 

in the MLPP 316(b) Assessment. 

| Approach 

^ Proportional 

1 Entrainment 

• {PE) 

1 Adult Equivalent 

TM Loss 

(AEL) 

1 Fecundity Hindcast 

(FH) 

E9-053.9 

Advantages 

• Empirical estimate of PE compares 

larvae or megalops entrained to 

larvae or megalops in the source 

water. 

• Age- and species-specific 

survivorship data not required. 

• Entrainment/impingement losses 

are expressed as adults facilitating 

the interpretation of populationlevel impacts. 

• Common usage in 316(b) studies. 

• Entrainment/impingement losses 

are expressed as adults facilitating 

the interpretation of populationlevel impacts. 

3-12 

Disadvantages 

• Monterey Bay taxa (e.g., Genyonemus 

lineatus) not adequately sampled in 

present design. 

• Local adult population sizes not well 

described by fishery catch data for . 

mixed species (e.g., Sebastes spp., 

Pleuronectidae, etc.). 

• Scaling intake effects up to population 

level impacts will be problematic. 

• Difficult to interpret for entrained 

organisms in broad taxonomic 

categories (e.g., Gobiidae spp.) 

containing multiple life-histories. 

• Age- and species-specific mortality 

data are little known or unavailable for 

many organisms that are 

entrained/impinged by the intakes. 

• Local adult population sizes not well 

described by fishery catch data for 

mixed species (e.g., Sebastes spp., 

Pleuronectidae, etc.). 

• Age- and species-specific mortality 

data are little known or unavailable for 

many organisms that are 

entrained/impinged by the intakes. 

• Local adult population sizes not well 

described by fishery catch data for 

mixed species (e.g., Sebastes spp, 

Pleuronectidae, etc). 

• Scaling intake effects up to population 

level impacts will be problematic. 

• Age- and species-specific fecundity 

data have not been previously reported 

for many organisms that are 

entrained/impinged by intakes. 

MLPP 316(b) Resource Assessment 

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3.0 Entrainment Study and Assessment Methods 

The precursor to the AEL and FH calculations is an estimate of total annual larval and megalopal 

entrainment. An estimate of larval and megalopal entrainment at the new combined-cycle units 

intake will be based on periodic tow samples with total annual entrainment at MLPP expressed 

as 

tT = tcc (1) 

where Ecc is the estimate of total entrainment at the new combined-cycle units intake 

(Appendix A). Estimates of total entrainment at the intake are based on two-stage sampling 

designs, with days within periods and replicate tows within days. The within-day sampling is 

based on a stratified random sampling scheme with 4 temporal strata corresponding to tidal flows 

(Appendix A). 

3.5.1.1 Adult Equivalent Loss (AEL) 

The AEL approach uses estimates ofthe abundance ofthe entrained or impinged organisms (i.e., 

ET) to project the loss of equivalent numbers of adults based on mortality schedules and age-atrecruitment. The primary advantage of this approach is that it translates power plant-induced 

early life-stage mortality into numbers of adult fishes and adult cancer crabs that are familiar 

units to resource managers. Adult equivalent loss does not require source water estimates of 

larval or megalopal abundance in assessing effects. 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). 

However, the need for age-specific mortality estimates can be reduced by various forms of 

approximation as show by Saila et al. (1997). They describe an AEL and apply it to six years of 

entrainment and two years of impingement data for winter flounder Pleuronectes americanus, 

red hake Urophycis chuss, and pollock Pollachius virens at the Seabrook Station, in New 

Hampshire, and contrast these with equivalent adult losses of winter flounder at Pilgrim Station, 

another coastal power plant. Their model assumes an adult population at equilibrium, a stable 

age distribution, a constant male:female ratio, and an absence of density-dependent (i.e., 

compensatory) mortality between entrainment and recmitment to the adults. 

Starting with the number of age class / larvae entrained (EA, it is conceptually easy to convert 

these numbers to an equivalent number of adults lost (AEL) at some specified age class from the 

formula: 

AEL^Efi (2) 

1=1 

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3.0 Entrainment Study and Assessment Methods 

where 

n = number of age classes; 

E- = estimated number of larvae and megalops lost in age class /; and 

St = survival probability for the ith class to adulthood (Goodyear, 1978). 

Age-specific survival rates from larval and megalopal stages to recmitment into the fishery must 

be included in this assessment method. For some commercial species, natural survival rates are 

known after the fishes or crabs recmit into the commercial fishery. For the earlier years of 

development, this information is not well-known and may be lacking for non-commercial 

species. 

The information on survival probabilities in Equation (2) will likely be unknown, in which case a 

simplified AEL expression can be written as 

AEL = ET-SA (3) 

where 

SA = survival from the average age of larval entrainment to adulthood. 

The exact variance for Equation (2) can be expressed as 

Var(AEL) = E2

T • Var(JET) + S2A • Var[sA) + Var{ET)• Var(SA). 

The behavior of estimator (3) for AEL appears log-linear, suggesting that an approximate 

confidence interval can be based on the assumptions that ln( AEL) is normally distributed and 

uses the pivotal quantity 

In AEL-\n AEL 

\Var{AEL) 

i AEL2 

A 90 percent confidence interval for AEL was estimated by solving for AEL and setting Z equal 

to ±1.645, i.e. 

AEL-e v AEL to AEL-e V AEL 

3.5.1.2 Fecundity Hindcasting (FW) 

The FH approach compares larval and megalopal entrainment losses with adult fecundity to 

estimate the amount of adult female reproductive output eliminated by entrainment and thereby 

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3.0 Entrainment Study and Assessment Methods 

hindcasts the numbers of adult females effectively removed from the reproductively active 

population. The accuracy of these estimates of effects, as with those ofthe AEL above, is 

dependent upon accurate estimates of age-specific mortality from the egg and early larval or 

megalopal stages to entrainment. 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 loss by converting entrained larvae and 

megalops back into females (i.e., hindcasting). 

A potential advantage of FH is that survivorship need only be estimated for a relatively short 

period ofthe larval stage (i.e., egg to larval or megalopal entrainment). The method requires 

age-specific mortality rates and fecundities to estimate entrainment effects and some knowledge 

ofthe abundance of adults to assess the fractional losses these effects represent. This method 

assumes that the loss of a single female's reproductive potential is equivalent to the loss of an 

adult fish or crab which may be inaccurate. 

In the FH approach, the total of larval entrainment for a species \ET\ will be projected backward 

to estimate the number of breeding females required to provide the numbers of larvae and 

megalops seen in the entrainment samples. The estimated number of breeding females (FH) 

whose fecundity is equal to the total loss of entrained larvae and megalops would be calculated 

as follows: 

FT v=' *J 

where 

vv = number of weeks the larvae or megalops are vulnerable to entrainment; 

Ej = estimated total entrainment for they'th week (/' = 1,..., vv); 

Sj = survival rate from eggs to larvae ofthe stage present in they'th week (J = 1,..., vv); 

FT = 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 (5) are fecundity FT and very early survival rates [SA 

from spawning to weeky ofthe survey. Descriptions of these parameters may be limited for 

many species and are a possible limitation ofthe method. Typically, the information for the finegrained age stmcture ofthe Equation (5 ) will not be available, and the FH calculations will be 

reduced to 

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3.0 Entrainment Study and Assessment Methods 

^ Erf 

FH=W (6) 

where 

SL = survival from egg to the average age of larval entrainment. 

The variance for the FH calculations [Equation (6)] is 

Var(FH) = (FH)2 CV(ETf +CV(PT) +CV(sLf (7 ) 

where, in general, 

r\ 2 Var{

0

) 

CV{0

) =^r 

The behavior of estimator (7) for FH appears log-linear, suggesting that an approximate 

confidence interval can be based on the assumptions that \n{FH ) is normally distributed and 

uses the pivotal quantity 

InFH-lnFH 

\Var{FH) 

V FH2 

A 90 percent confidence interval for FH was estimated by solving for FH and setting Z equal to 

±1.645, i.e. 

V FH2

 tn ru .„ V FH2 

{FH) 

•|.U*tJ, ( 7 

FHe v TM2 to FH-e 

3.5.2 Empirical Transport Model (ETM) 

The empirical transport model {ETM) has been proposed by the U.S. Fish and Wildlife Service to 

estimate mortality rates resulting from cooling water withdrawals at power plants (Boreman 

et al., 1978, 1981). Variations of this model have been discussed in MacCall et al. (1983) and 

used to assess impacts (Parker and DeMartini, 1989). The ETM has 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. The ETM approach was also used at the Diablo 

Canyon Power Plant in central California. We will employ a method similar to that described by 

MacCall et al. (1983) and used by Parker and DeMartini (1989) while under contract to the 

Marine Review Committee in their final report to the California Coastal Commission (Murdoch 

et al., 1989) for San Onofre Nuclear Generating Station on the coast of southern California. 

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m 

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3.0 Entrainment Study and Assessment Methods 

Empirical transport modeling permits the estimation of annual 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 generalized form of ETM 

incorporates many time-, space-, and age-specific estimates of source water larval and megalopal 

mortality as well as information regarding spawning periodicity and duration, most of which are 

limited or unknown for the marine taxa being investigated. 

At MLPP, the larval and megalopal source population has a priori been defined as those larvae 

and megalops in the Monterey Bay, Moss Landing Harbor, and Elkhorn Slough as shown in 

Figure 3-2. 

3.5.2.1 Source Water and Receiving Water Volumes 

A variety of methods were used to estimate the volumes ofthe source and receiving water bodies 

associated with the Moss Landing Power Plant. The methods used to determine the static water 

volumes of Moss Landing Harbor, Elkhorn Slough, and a prescribed nearshore portion of 

Monterey Bay (ocean source water) are presented below. Where it is applicable, the methods 

used to determine the daily tidal exchange ofthe individual water bodies are also given. 

Monterey Bay (nearshore) / MLPP Ocean Source Water 

The volume of Monterey Bay water providing MLPP cooling water was estimated by two 

methods. The first method was based on the rationale that the majority of entrained bay species 

originated in the shallow bay habitats in contact with nearshore currents reaching the harbor 

entrance. Ocean bottom depths immediately in front ofthe harbor's entrance plunge rapidly into 

the Monterey Canyon. The bay's depths to the north and south shoal to become broad sand and 

mud bottom plains characteristic ofthe bays' nearshore habitat for white croaker and Pacific 

staghorn sculpin; the only bay species appearing in MLPP entrainment samples in any number. 

The volume of this nearshore, source-water habitat was calculated for the area one kilometer 

north and one kilometer south ofthe harbor entrance out to a depth of 50 m. In discussions with 

the Technical Working Group and California Energy Commission staff, it was agreed to bound 

our estimate of Monterey Bay source water volume based on habitat with the daily tidal 

exchange volume ofthe harbor/slough. 

Methods and sources of information used to estimate this range of Monterey source water 

volume are described here. For the purposes of this study, the nearshore waters of Monterey 

Bay/MLPP ocean source waters are defined as those lying along a shoreline reach of 2,000 m to 

the north and south ofthe Moss Landing Harbor entrance and extending out to a depth of 50 m 

(Figure 3-2). The volume of this water body was calculated using the information provided by 

the National Oceanic and Atmospheric Administration (NOAA) chart # 18685 (31st edition, 

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3.0 Entrainment Study and Assessment Methods 

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1 

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1 

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an 

H 

I 

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May 16, 1998). The area described above was inscribed on the chart and then subsequently 

divided into small sectors of simple geometric shapes. The size ofthe sectors was dependent 

upon the nature ofthe complexity ofthe bottom characteristics within the sector. Areas with 

large expanses of bottom topography having fairly uniform slopes were enclosed within suitably 

large geometric sectors. Areas with more complex bottom topography, like those in the vicinity 

ofthe Monterey submarine canyon, were enclosed in relatively small sectors. The purpose of 

this exercise was to provide sectors that were of a size that allowed easy estimation ofthe 

average depth within the sector. When this was completed the surface area of each sector and its 

volume, based on the average depth within the sector, were calculated. When the sector volumes 

were totaled, the ocean source water volume was determined to be 275 x IO6m

3

. It should be 

noted that the depth soundings found on NOAA chart #18685 are given at Mean Lower Low 

Water (MLLW) (0.0 feet). The volumes ofthe other water bodies associated with the MLPP 

(see below) were subsequently adjusted to be representative of tidal conditions equivalent to 

Mean Sea Level (MSL) (+2.7 feet). The ocean source water volume, however, is little affected 

by tidal fluctuations since the border that defines its area, the 50-m isobath, also fluctuates in 

position with the rise and fall ofthe tides. 

Moss Landing Harbor 

The volume of Moss Landing Harbor was determined using methods similar to those used to 

determine the volume ofthe Monterey Bay nearshore /ocean source water. Depth soundings 

were again taken from NOAA chart #18685. The chart also contains detailed information on the 

dredge depths ofthe boat channels and turning basins within the harbor. The harbor was defined 

as the area from the ends ofthe breakwaters (harbor mouth) east to the mouth of Elkhorn Slough 

(Highway 1 bridge) and included the north and south arms ofthe navigable harbor (Figure 3-2). 

The harbor was divided into geometric sectors and the average depth, surface area, and sector 

volume were then calculated. The total volume ofthe harbor at MLLW was determined to be 

770,000 m3. The volume ofthe harbor at MSL was calculated by multiplying the total surface 

area ofthe harbor by the difference in tidal height between MSL and MLLW (2.7 feet) and 

adding the resulting number to the MLLW volume. Volume at MSL was calculated to be 1.15 x 

106m

3

. Daily tidal exchange for the harbor alone was calculated to be 1.03 x 106m

3

 based on a 

mean tide range of 3.6 feet and the calculated harbor area. 

Elkhorn Slough 

In the 1983 316(b) Demonstration report, Pacific Gas and Electric Company listed the total 

volume of Elkhorn Slough at MSL to be 4.8 x IO6 m3 (PG&E, 1983). Since that time channel 

erosion, accompanied by dike and levee breaches, have increased the total surface area and tidal 

volume ofthe system (Figure 3-2). Malzone and Kvitek (1994) reported a 43 percent increase in 

tidal volume and a 48 percent increase in the total surface area ofthe system over the decade 

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3.0 Entrainment Study and Assessment Methods 

preceding their work. Based on bathymetric surveys conducted in 1993 and direct tidal 

measurements taken within the slough, they calculated the total tidal volume of the system to be 

5.55 x IO6 m3. This equates to a daily (25-hr) tidal exchange of 11.1 x IO6 m3 for the slough 

system. Using the data collected during the 1993 surveys, Malzone (1999) calculated the total 

volume ofthe Elkhorn Slough system to be 10 x IO6 m3 at MSL. 

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3.0 Entrainment Study and Assessment Methods 

Monterey Bay (nearshore) 

MLPP Ocean Source Water 

Figure 3-2. Location of Monterey Bay nearshore MLPP ocean source water, Moss Landing Harbor, and 

Elkhorn Slough areas used in calculating source water and receiving water volumes. 

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3.0 Entrainment Study and Assessment Methods 

The purpose ofthe ETM calculations is to estimate the probability of mortality of larvae and 

megalops associated with power plant entrainment. The calculations require not only the 

abundance of larvae and megalops entrained but also the abundance ofthe larval and megalopal 

populations at risk of entrainment. The sampling at the cooling water intakes is used to estimate 

entrained numbers. 

On any one sampling day, the conditional entrainment mortality can be expressed as 

E

T 

PE

u = T " (9) 

R

u 

where 

Ej: - total numbers of larvae entrained on they'th day (j = 1, ...,d{) ofthe iih temporal 

sampling stratum (/ = 1,..., L); 

Rjj = numbers of larvae at risk of entrainment, i.e., abundance of larvae in Monterey Bay 

(MB), Moss Landing Harbor (MLH), and Elkhorn Slough (ES). 

In rum, the abundance of entrained larvae and megalops can be expressed as the entrainment 

numbers at the new combined-cycle units intake where 

E

T

v-r.E^ (10) 

and EyC is the entrainment abundance at the new combined-cycle units intake on they'th 

sampling day. With the larval and megalopal source populations a priori defined, the abundance 

of larvae and megalops at risk can then be directly expressed as 

R,j =

 V

m • DmiJ + V^ • Dmmj + VES-DESij (H) 

where V denotes the water volume and D, the average larval and megalopal concentration in a 

source population during the //th sampling day. Combining Equations (9-11), the probability of 

entrainment for a larvae and megalop in the three source populations during the (/th sampling 

day can be estimated (Appendix C) by 

pec 

PE = = ^ r-^r-

(VMB ' DMBij + ^MLH ' L^MBij + 'ES ' ^EStj 

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3.0 Entrainment Study and Assessment Methods 

PE = 

E? 

*MB ' ^MBij + 'MLH ' L>MBij + * ES ' ^ESij I ^^f 

The ETM model uses the periodic estimates of PEtj to estimate the annual probability of 

entrainment mortality (PM). 

How the ETM calculations incorporate the individual estimates of PEtj depends on the nature of 

the entrainment process and on the namre ofthe spawning and hatching sequence ofthe fish or 

crab species. Model formulation will differ whether there is a single synchronous breeding or 

whether there is multiple overlapping breeding by the species. In the case of a single 

synchronous breeding within a survey period, the ETM can be formulated as 

pM=i-iif{\-PE,)D' (n) 

1=1 

where D. = number of days that larvae or megalops are susceptible to entrainment in the rth 

sampling period and f - the fraction ofthe spawning that occurred during the ith sampling 

period. In Equation (13), the estimated entrainment mortality probability PE. is assumed to be 

representative ofthe daily mortality during the £>, period of time. 

In the case where there are multiple non-overlapping spawnings, the ETM calculations can be 

formulated as 

h=\-tXfij(\-PEij)D* (14) 

i=I > ! 

where ftj = fraction of the spawning that occurred during the i/th sampling period, Dtj = the 

number of days in the i/th sampling period, and di are the number of broods in the i'th sampling 

period. Equation (14) assumes the population-wide probability of entrainment is the essence of 

the ETM approach of MacCall et al. (1983). If this population is stable and stationary, then PM 

is also an indicator ofthe effects on the fully recmited age classes when no compensatory natural 

mortality is assumed. 

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4.0 Entrainment and Source Water Results 

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4D© ENTRADNMENT AMD SOURCE WATER RESULTS 

Larval fish and targeted crab species data presented in this section are from entrainment and 

source water samples that have had the laboratory processing procedure completed. Entrainment 

data are from weekly 24-hour surveys conducted from March 2, 1999 through June 30, 1999 and 

from surveys conducted every other week from July through October 1999. Data from the 

weekly surveys in NovembeiTT^^TlTro^ 2000 from the new combined-cycle units 

intake are also discussed. The remaining samples collected from the Units 6 and 7 intake are 

currently being processed and the resulting data will be reported in the Final 316(b) 

demonstration. Data from all monthly source water samples from inception (June 1999) through 

Febmary 2000 are also presented. 

Based on discussions at the January 18, 2000 Technical Working Group meeting, we measured a 

sub-sample of bay goby Lepidogobius lepidus and all longjaw mudsucker Gillichthys mirabilis 

larvae from the following surveys: 

° the new combined-cycle units intake entrainment surveys that coincided with monthly 

source water surveys (June 1999 through January 2000), and 

o all source water samples (June 1999 through January 2000). 

These length data will be used to estimate the ages of larvae entrained and the larvae available 

from the source populations. These data are presented in Section 4.4 for bay goby and Section 

4.9 for longjaw mudsucker. Both species collected in the Febmary 2000 surveys are currently 

being measured and the data will be presented in the next report. 

4.H Enttiraiiiniinnieinilt Study ResyDtts 

Eight taxa of larval fishes comprised 95 percent of the total numbers of taxa collected in 

entrainment samples (Figure 4-la). The taxa, listed in decreasing order of abundance, were: 

unidentified gobies Gobiidae (53.2 percent), bay goby Lepidogobius lepidus (30.4 percent), 

blackeye goby Coryphopterus nicholsi (3.0 percent), Pacific staghorn sculpin Leptooottus 

armatus (2.2 percent), white croaker Genyonemus lineatus (2.1 percent), blennies Hypsoblennius 

spp. (1.9 percent), longjaw mudsucker Gillichthys mirabilis (1.2 percent), and Pacific herring 

Clupea pallasi (0.9 percent). Of the 95 percent, nearly 88 percent were represented by members 

of one Family—Gobiidae. This Family included the unidentified gobies, bay goby, blackeye 

goby, and longjaw mudsucker. 

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4.0 Entrainment and Source Water Results 

The life histories, range of populations, and habitat descriptions for these taxa are presented in 

Sections 4-3 through 4-10. Information is presented on the temporal and diumal concentrations 

of these taxa collected from in front of the intake of the new combined-cycle units. Mean 

entrainment concentrations (no./l,000m ) for all larval fishes separated by unit groups, for all 

surveys are presented in Table 4-1. Brief comparisons are made of these current data with the 

previous 1978 -1980 entrainment data (PG&E, 1983). The eight taxa listed above are discussed 

individually in Sections 4.3 through 4.10. Impact assessment analyses for these eight taxa are 

presented in Section 6. 

Six species of Cancridae and one unknown Cancer spp. megalops were collected in entrainment 

samples at the new CC units intake (Figure 4-lb). The species, listed in decreasing order of 

abundance were: hairy rock crab Cancer jordani (29.3 percent), yellow rock crab Cancer 

anthonyi (19.6 percent), brown rock crab Cancer antennarius (19.0 percent), dungeness crab 

Cancer magister (14.7 percent), red rock crab Cancer productus (9.8 percent), slender rock crab 

Cancer gracilis (7.1 percent), and unidentified Cancer spp. (0.5 percent). 

The life histories, range of populations, and habitat descriptions for these rock crabs and the 

European green crab are presented in Sections 4-11 through 4-18. Mean entrainment 

concentrations (no./l,000 m3) for all targeted crab species, separated by unit groups, for all 

surveys are presented in Table 4-1. Impact assessment analyses for all megalopal Cancer spp. 

crabs are presented in Section 6. 

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4.0 Entrainment and Source Water Results 

Percent Composition of Entrained Larval Fishes 

Pacific herring 

0.9% 

longjaw mudsucker 

1.2% ~1 

Hypsoblennius spp. 

1.9% ~\ 

white croaker I 

2.1 % ~~\ I 

Pacific staghorn sculpin \ U< | 

2.2% ~\ ^Bv& 

blackeye goby Z ^HB | 

3.0% ~ y \ ^ | 

all others 

5.0% 

* "____f5l 

I unidentified gobies 

53.2% 

« * *«<*.V^ 3 

(b) 

Percent Composition of Entrained Cancer Crab Megalops 

unidentified cancer crabs 

0.5% 

dungeness crab 

14.7% 

hairy rock crab 

29.3% 

brown rock crab 

19.0% 

yellow rock crab 

19.6% 

slender rock crab 

7.1% 

Figure 4-1. a) Percent composition ofthe most abundant larval fish taxa and b) Cancer spp. megalops 

collected in entrainment surveys at the Moss Landing Power Plant: March 1999 through February 2000. 

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4.0 Entrainment and Source Water Results 

Table 4-1. Mean Concentrations (#/l,000 m3) of all Larval Fish Taxa and Megalops of Cancer spp. and 

European Green Crabs Collected in front of the Moss Landing Power Plant New Combined-cycle Units and 

Units 6 and 7 Intakes: March 2, 1999 through February 24, 2000. 

Taxon 

Ammodytes hexaptems 

Anedius lateralis 

Anedius spp. 

Atherinidae unid. 

Atherinops affinis 

Atherinopsis californiensis 

Aulorhynchus flavidus 

Bathytagus ochotensis 

Bathymastcridae unid. 

Blennioidei 

Brosmophycis marginato 

Cebidichthys violaceus 

Chamopsidae unid. 

Citharichthys sordidus 

Citharichthys uigntoeus 

Clinocouus aitalis 

Clupea pallasii 

Clupeidae unid. 

Oupeiformes 

Coryphopterus nicholsi 

Cottidae unid. 

Coitus asper 

Engraulis mordax 

Genyonemus lineatus 

Gibbonsia (pp. 

Gillichthys mirabilis 

Gobiesocidae unid. 

Gobiesox (pp. 

Gobiidae - t)pe 1 

Gobiidae unid. 

Hcxagrammidae unid 

Hypsoblennius spp. 

larva) 0th • damaged 

larval run fragment 

larval/posl-larva! fish. unid. 

Lepidogobius lepidus 

Leptocottus amtasus 

ieurogtossus stilbius 

Liparis jucenns 

Liparis spp. 

Oligocottus spp. 

Ophidiidac unid 

Ophiodon elongatus 

Osmeridae tnid 

Oxyiebius pictus 

Parophrys vetulus 

Pholididaeisiid 

Pleuronectes bilineatus 

Pleuronectes isatcpis 

Pleuronectidae unid. 

Pleuronectiformes unid 

Psettichthys melanostictus 

Ruscarius creaser! 

Sardinops sagax 

Scorpaenichthys mtumoraaa 

Sebastes spp. 

5>_Mi_urr spp. V 

Sebasses spp V_D 

Sebastes spp V_Dc 

Sebastes spp VD 

aVbajfrsspp. VP 

Sebasutobtu spp. 

Stenebntchius leucapsarus 

Stichaesdae unid. 

Syngnathidae tnid 

Syngnathus spp. 

Tarlelonbeania crenularis 

Typhlogobius cali/omienlis 

Cancer antennarius (megalops) 

Cancer anthonyi (megalopa) 

Cancer gracilis (megalopa) 

Cancer jordani (megalopa) 

Cancer magister (megalops) 

Cantor productus (megalops) 

Cancer spp. (megalops) 

Carcinus maenas (megalops) 

Common Name 

Pacific sand lance 

smcothhead sculpin 

sculpins 

silversides 

topsmelt 

jacksmelt 

tutesnout 

popeye Macksmelt 

ronquils 

Mennies 

red hrotula 

monkeyface eel 

tube Nennies 

Pacific sanddab 

speckled sanddab 

wooly sculpin 

Pacific herring 

herrings 

herrings and anchovies 

blackeye goby 

sculpins 

prickly sculpin 

norlhem anchovy 

white croaker 

clinid kelpfishes 

longjaw mudsucker 

clingfishes 

clingfishes 

gobies 

gobies 

greenlings 

blennies 

unidentified larval fishes 

unidoitificd larva] fishes 

unidentified larval fishes 

bay goby 

Pacific siaghom sculpin 

Califcrnia smoothtonguc 

slipskin Riailfish 

snailfishes 

sculpins 

cusk-cels 

lingcod 

smells 

painted greenling 

English sole 

gunnels 

rocksole 

butter sole 

flounders 

flatfishes 

sand sole 

rouchcheck sculpin 

Pacific sanbne 

cabezon 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

rcckfisha 

rockfishes 

thanyheads 

northern lampfish 

pricklebncks 

pipefishes 

pipefishes 

blue lantemfirii 

U ind goby 

FISH TOTALS: 

brown rock oab 

yellow rock crab 

slender rock crab 

hairy rock crab 

dungeness aab 

red rock (Tab 

unidentified cancer crabs 

European green crab 

CRAB TOTALS: 

Count 

191 

4 

35 

94 

19 

349 

2 

1 

1 

3 

1 

193 

19 

8 

12 

9 

830 

14 

13 

1.637 

124 

234 

223 

J.101 

17 

882 

1 

2 

2 

29.211 

2 

1.163 

67 

274 

29 

14.337 

1.431 

I 

1 

6 

24 

1 

1 

391 

10 

14 

3 

II 

2 

38 

28 

4 

3 

3 

3 

2 

18 

2 

29 

3 

1 

74 

340 

7 

4 

3 

25 

1 

33.618 

47 

55 

25 

124 

37 

28 

5 

5 

326 

Stave) 

March 2-3 

New CC Units 

N«I 2 

Cl. 

3 

1 

3 

20 

3 

7 

1 

2 

9 

7 

15 

1 

599 

4 

1 

143 

33 

5 

1 

4 

1 

865 

0 

Den. 

3.2 

1.2 

4.2 

26.1 

36 

9 3 

1.2 

2.6 

110 

8.3 

19.7 

16 

741.8 

4.3 

16 

183.9 

42.3 

7.3 • 

1.6 

6.3 

1.2 

1999 

Units 647 

N = 

Cl. 

1 

2 

9 

3 

7 

3 

29 

2 

13 

442 

3 

1 

32 

27 

5 

1 

1 

1 

1 

583 

0 

12 

Den. 

0.8 

3.1 

13.0 

4.5 

108 

3.2 

42.4 

3.1 

19.7 

651.0 

5.2 

1.5 

37.6 

41.7 

7.8 

1.3 

1.7 

1.3 

15 

Survey 2 

March S-9 

New CC Units 

N 

Cl. 

1 

1 

5 

1 

3 

II 

4 

3 

143 

1 

I 

182 

67 

24 

4 

7 

1 

3 

1 

463 

1 

1 

= 12 

Den. 

1.7 

1.2 

6 9 

15 

3.8 

15 9 

59 

4.1 

196.5 

15 

12 

262.9 

93.4 

360 

5.2 

9.5 

1.9 

4.3 

1.2 

1.4 

1999 

Uniu 647 

N=I 2 

Ct Den. 

8 12.9 

4 6.4 

6 9.8 

2 3.6 

7 11.8 

7 11.5 

103 167.4 

3 5.3 

142 2486 

1 17 

44 76.6 

18 29.4 

2 3.8 

1 1.7 

1 1.4 

3 4.8 

352 

0 

Survey3 

March 14-15. 1999 

New CC Units 

N = 

Ct. 

2 

2 

6 

4 

10 

4 

3 

1 

5 

629 

3 

3 

112 

28 

2 

2 

2 

1 

1 

820 

1 

1 

2 

12 

Den. 

2.8 

3 1 

8.5 

5.6 

140 

6.4 

4 0 

13 

7.6 

959 1 

4.5 

4 0 

159.2 

40 1 

2.4 

2.9 

3.0 

I.I 

1.3 

1.3 

1.3 

Units 647 

N = 

Cl. 

2 

1 

46 

1 

39 

7 

345 

1 

28 

15 

1 

1 

487 

0 

12 

Den. 

3.8 

2.2 

788 

1.7 

80.3 

13.1 

618.5 

1.8 

48.3 

239 

1.6 

1.7 

Survey 4 

Much 22-23.1999 

New CC Uniu 

N = 

a. 

7 

8 

1 

1 

7 

244 

1 

1 

6 

48 

4 

8 

336 

0 

12 

Den. 

103 

II.B 

13 

1.6 

103 

371,7 

1.7 

1.4 

9.3 

73.0 

5.9 

11.1 

Uniu 6*7 

N = 

a. 

2 

2 

30 

1 

8 

7 

7 

197 

1 

2 

25 

1 

1 

7 

291 

1 

1 

12 

Den. 

3.9 

35 

576 

2.1 

123 

12 6 

13 0 

3608 

19 

2.9 

44.1 

1.6 

1.4 

11.2 

1.8 

Surveys 

Mardl 30-31.1999 

New CC Uniu 

N=1 2 

Cl. 

4 

1 

9 

10 

1 

1 

8 

448 

I 

74 

17 

7 

1 

382 

1 

1 

Den. 

5.2 

1.2 

13.4 

15.3 

1.7 

1.5 

13 2 

689.2 

1.2 

1114 

24.3 

10.0 

1.3 

1.5 

Uniu 647 

N«1 2 

Ct. Den. 

1 1.5 

4 6 6 

13 22.3 

1 1.7 

4 6.9 

14 267 

498 861.4 

1 13 

24 446 

10 18.4 

1 1.3 

16 27.9 

2 3.6 

589 

0 

E9-053.9 4-4 MLPP 316(b) Resource Assessment 

4-28-2000 
P.71 

4.0 Entrainment and Source Water Results 

Table 4-1. (continued). Mean Concentrations (#/l,000 m3) of all Larval Fish Taxa and Megalops of 

Cancer spp. and European Green Crabs Collected in front ofthe Moss Landing Power Plant New 

Combined-cycle Units and Units 6 and 7 Intakes: March 2, 1999 through February 24, 2000. 

Taxon 

Ammodytes hexapserus 

Anedius lateralis 

Anedius spp. 

Atherinidae unid. 

Atherinops affinis 

Atherinopsis californiensis 

Aulorhynchus flavidus 

Bathylagus ochotensis 

Bathymasteridae taiid 

Blennioidei 

Brosmophycis marginata 

Cebidichthys \Holaceus 

Chamopsidae unid. 

Citharichthys sordidus 

Citharichthys stigmaeus 

Clinocottus totalis 

Clupea patlasii 

Clupeidae igiid. 

Clupeiformes 

Coryphopterus nicholsi 

Cottidae unid. 

Coitus asper 

Engraulis mordax 

Genyonemus lineatus 

Gibbonsia Ipp 

Gillichthys mirabilis 

Gobiesocidae unid. 

Gobiesox spp. 

Gobiidae - lype 1 

Gobiidae iniid. 

Hexagramnvdae tnid. 

Hypsoblennius spp. 

larval fish - damaged 

larva) fish fragment 

larval/post-larval fish. tnid. 

Lepidogobius lepidus 

Leptocottus armatus 

Leuroglossus slilbius 

Liparis fucensis 

Liparis spp. 

Oligocotlus spp. 

Ophidiidac taiid 

Ophiodon elongatus 

Osmeridae istid 

Oxyiebius pictus 

Parophrys vetulus 

Pholididac unid 

Pleuronectes bilineasus 

Pteuroaeclrs isaiepis 

Pleurcnedidae unid. 

Pleuronectiformes unid 

Psettichthys melanostictus 

Ruscarius creaseri 

Sardinops sagax 

Scorpaenichthys mamortuus 

Sebastes spp. 

Sebastes spp. V 

Sebastes spp V__D 

Sebastes spp. V_De 

Sebastes spp. VD 

Sebastes spp. VP 

Sebastolobus spp. 

Stenobrachius leucopsanu 

Slkhaeidae unid 

Syngnathidae unid 

Syngnathus spp. 

Tarieumbeania crenularix 

Typhlogobius caH/oeniensis 

Cancer amennariits (megalops) 

Cancer anthonyi (megalops) 

Cancer gracilis (megakps) 

Cancer jordani (megalops) 

Cancer magister (megalops) 

Cancer productus (megalopa) 

Cancer spp. (megalops) 

Carcinus maenas (megalops) 

Common Name 

Pacific sand lance 

smoothhead sculpin 

sculpins 

silversides 

topsmelt 

jacksmell 

tutesnoul 

popeye biacksmell 

ronquils 

blennies 

redtrotula 

menkeyface eel 

lube blennies 

Pacific sanddab 

speckled sanddab 

wooly sculpin 

Pacific boring 

herrings 

herrings and anchovies 

blackeye goby 

sculpins 

prickly sculpin 

northern anchovy 

white croaker 

clinid kelpfishes 

longjaw mudsucker 

clingfishes 

clingfishes 

gobies 

gobies 

greenlings 

Mennies 

unidentified larval fishes 

unidentified larval fishes 

unidentified larval fishes 

bay goby 

Pacific staghorn sculpin 

California smoothlongue 

slipskin snailfish 

snailfishes 

sculpins 

cusk-eels 

lingcod 

smclu 

painted greenling 

English sate 

gunnels 

rocksole 

culler sole 

flounders 

flatfishes 

sand sole 

rouchdieek sculpin 

Pacific sardine 

cabezon 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

thomyheads 

northern lampfuh 

pricklebncks 

pipefishes 

pipefishes 

blue lanlemfuh 

blind goby 

FISH TOTALS: 

brown rock crab 

yellow rock crab 

slender rock crab 

hairy rock crab 

dungeness crab 

red rock CTab 

unidentified cancer crabs 

European green crab 

CRAB TOTALS: 

Swvey6 

April 4-3. 1999 

New CC Uniu 

No 12 

a. 

3 

12 

4 

18 

6 

1 

10 

489 

1 

401 

3 

8 

2 

1 

3 

964 

1 

1 

Den. 

4.2 

17.3 

6 6 

25.9 

9 4 

1.6 

17 0 

722.8 

1.2 

485.5 

6 9 

9.4 

3.4 

1.7 

4.7 

1.6 

Uniu 647 

N = 

a. 

i 

4 

42 

1 

7 

IS 

2 

7 

1 

5 

303 

2 

23 

9 

5 

1 

431 

0 

12 

Den. 

15 

6.4 

73.8 

I.I 

104 

29.7 

2.6 

11.2 

15 

7.5 

494.3 

2.8 

36.7 

13.5 

6 8 

1.9 

Survey 7 

April 13-16.1999 

New OC Uniu Uniu 6*7 

N=1 2 N = 

a. 

12 

1 

II 

1 

6 

1 

8 

419 

4 

30 

3 

42 

1 

539 

2 

2 

4 

Den. Cl. 

1 

161 19 

1.4 2 

14 6 8 

1.9 

8.4 3 

14 1 

10.7 11 

1 

572.7 331 

5 1 

410 3 

4.1 3 

580 38 

1.4 

2 

429 

2.7 1 

1 8 

1 

12 

Den. 

IS 

306 

3.5 

12.6 

86 

1.8 

170 

1.3 

526.3 

7.6 

7.6 

60.7 

3.7 

1.6 

Survey8 

April 22-23.1999 

New CC Uniu Uniu6&7 

N 

Cl. 

1 

3 

8 

54 

2 

35 

1 

1 

6 

497 

165 

6 

2 

781 

6 

1 

7 

t. 12 N s 

Den. Cl. 

1.4 

2 

4.3 2 

I 

10.8 2 

79.7 39 

29 1 

4 

47.4 24 

1.4 

1.1 2 

9.1 3 

717.9 259 

1 

229.8 49 

8.3 1 

2.6 1 

1 

1 

393 

7.8 2 

1.2 

2 

12 

Den. 

3.2 

3.1 

1.7 

3.3 

67.3 

2.0 

6.7 

40.2 

3.4 

5.4 

459.7 

1.7 

86.6 

1.9 

16 

1.6 

1.5 

3.4 

Survey 9 

April 23-30. 1999 

New CC Uniu Uniu6&7 

N=I 2 N=I 2 

Cl. Den. Cl. Den, 

1 14 

1 1.4 

24 39.1 31 52.7 

2 3.0 14 23.7 

3 46 

3 4 7 9 15.3 

286 414.2 219 378.1 

1 II 

1 1.8 

54 75.1 25 369 

1 1.9 

3 4.2 10 16.9 

1 1.4 

375 314 

1 1.2 

1 1.6 

1 1 

Survey 10 

May 6-7. 1999 

New CC Uniu Units 647 

N = 

Cl. 

1 

38 

2 

56 

6 

509 

1 

15 

2 

1 

1 

1 

5 

638 

2 

2 

12 N=I 2 

Den. Cl. 

1.3 1 

1 

63.8 5 

3.7 8 

95.3 20 

1 

11.2 2 

872.6 274 

19 1 

22.3 7 

3.2 2 

1.6 

1 

1.3 

1 

1.9 

8.3 

324 

2.7 4 

4 

Den. 

1.9 

1.6 

8.7 

13.8 

37.0 

19 

4.1 

498.3 

1.9 

123 

4.2 

2.3 

1.9 

6.7 

E9-053.9 4-5 MLPP 316(b) Resource Assessment 

4-28-2000 
P.72 

4.0 Entrainment and Source Water Results 

Table 4-1. (continued). Mean Concentrations (#/l,000 m ) of all Larval Fish Taxa, Megalops of Cancer 

spp. and European Green Crabs Collected in front of the Moss Landing Power Plant New Combined-cycle 

Units and Units 6 and 7 Intakes: March 2, 1999 through February 24, 2000. 

Taxa) 

Ammodytes hexapterus 

Anedius lateralis 

Anedius spp. 

Atherinidae tmid. 

Atherinops affinis 

Atherinopsis californiensis 

Aulorhynchus ftm-idus 

Bathylagus ochotensis 

Bathymastcridae unid 

Blennioidei 

Brosmophycis marginasa 

Cebidichthys violaceus 

Chaenopsidae unid. 

Citharichthys sordidus 

Citharichthys stigmaeus 

Clinocotlus analis 

Clupea pallasii 

Clupeidae unid 

Clupeifismes 

Coryphopterus nicholsi 

Cmtidae unid 

Coitus asper 

Engraulis mordax 

Genyiinemus lineatus 

Gibbtmsia spp 

Gillichthys mirabilis 

Gobiesocidae unid. 

Gobiesox spp 

Gobiidae - type 1 

Gobiidae unid. 

Hcxagramnudne unid 

Hypsoblennius spp 

larval fish - damaged 

larval fish fragment 

larval/posl-larval fish. unid. 

lepidogobius lepidus 

leptocottus ormolus 

leuroglossus stilbius 

Liparis fucensis 

liparis spp. 

Oligoeoaus spp. 

Ophidiidac unid 

Ophiodon elongatus 

Osmeridae unid 

Oxyiebius pictus 

Parophrys vetulus 

Pbotididae unid 

Pleuronectes bilineasus 

Pleuronectes isaiepis 

Pleuronectidae unid. 

Pleuronectiformes unid 

Psettichthys melanostictus 

Ruscarius creased 

Sardinops sagax 

Scorpaenichthys marmoratus 

Sebastes spp. 

Sebastes spp. V 

Sebastes spp. V_D 

Sebastes spp. V_De 

Sebastes spp. VD 

Sebastes spp. VP 

Sebastolobus spp. 

Slenobrachius teucopsarus 

Slichaeidae unid 

Syngnathidae unid 

Syngnashus spp. 

Tarletonbeania crenularis 

Typhlogobius califomiensis 

Cancer antennarius (megalops) 

Cancer anthonyi (megalops) 

Cancer gracilis (megalops) 

Cancer jordani (megalops) 

Cancer magister (megalops) 

Cancer productus (megalops) 

Cancer spp. (megalops) 

Carrrmu maenas (megalops) 

Common Name 

Pacific sand lance 

smoolhhead sculpin 

sculpins 

silversides 

topsmelt 

jacksmelt 

tubesnout 

popeye Macksmelt 

rcnquils 

Ncnn.es 

redtrolula 

monkeyface eel 

lube blennies 

Pacific sanddab 

speckled sanddab 

wooly sculpin 

pacific herring 

herrings 

herrings and anchovies 

blackeye goby 

sculpins 

prickly sculpin 

norihon andiovy 

white croaker 

clinid kelpfishcs 

Icngjaw mudsucker 

clingfishes 

clingfishes 

gobies 

gobies 

greenlings 

blennies 

unidentified larval fishes 

unidentified larval fishes 

unidentified larval fishes 

bay goby 

Pacific slaghom sculpin 

Calilomia smouthtcngue 

slipskin snailfish 

snailfishes 

sculpins 

cusk-eels 

lingcod 

smeJU 

painted freenling 

English sole 

gunnels 

rock sole 

butter sole 

flounders 

flatfishes 

sand sole 

rouchcheek sculpin 

Pacific sardine 

cabezon 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

thomyheads 

northem lampfish 

pricklebacks 

pipefishes 

pipefishes 

blue lantanfish 

blind goby 

FISH TOTALS: 

brown rock crab 

yellow rock crab 

slender rock crab 

hairy rock crab 

dungeness (Tab 

red rock crab 

unidentified cancer crabs 

European green (Tab 

CRAB TOTALS: 

Survey 

May 13-14 

New CC Uniu 

N=12 

Cl. Den. 

1 14 

1 1.3 

6 8 6 

10 143 

9 12.2 

556 757.5 

1 1.2 

1 16 

4 5 1 

27 34.9 

5 6 4 

1 1.1 

4 4.7 

6 7.0 

1 I.I 

633 

2 2.3 

2 

II 

. 1999 

Units 647 

N = 

a. 

i 

i 

19 

2 

1 

1 

1 

2 

218 

21 

2 

1 

270 

0 

12 

Den. 

1.5 

13 

27.2 

2.5 

1.3 

IS 

1.5 

3 0 

323.8 

32.5 

2.5 

1.2 

Survey 12 

May 20-21. 1999 

New CC Uniu Uniu 647 

N 

Cl. 

1 

1 

1 

12 

1 

71 

1 

1 

6 

180 

3 

3 

31 

1 

1 

2 

316 

8 

7 

13 

= 12 N = 

Den. Cl. 

1.6 1 

1.6 

1.6 1 

16.5 2 

1.6 12 

2 

99 2 153 

16 

16 1 

8 8 14 

248.7 125 

4.8 4 

4.1 1 

41.6 44 

1.3 

1.3 3 

2.9 1 

364 

10.1 

8.3 

0 

12 

Den. 

1.5 

1.6 

3.0 

18.4 

3.1 

230.5 

1.5 

21.1 

185.8 

5 6 

1.4 

65.9 

4.6 

1.3 

Survey 13 

May 27-28 

New CC Uniu 

N=1 2 

Cl. Den. 

1 1.7 

1 1.3 

29 34 1 

2 2.7 

13 18.3 

1 1.2 

4 5.9 

404 563.7 

2 31 

31 43 0 

6 7.3 

494 

1 1.2 

1 

.1999 

Uniu 647 

N = 

Cl. 

2 

17 

3 

1 

6 

134 

1 

2 

21 

9 

196 

1 

1 

12 

Den. 

3.4 

24.9 

4.5 

16 

9 0 

211.2 

16 

2.7 

336 

13.0 

1.3 

Survey 14 

June 3-4 

New CC Uniu 

N = 

a. 

2 

9 

6 

31 

1 

3 

10 

649 

5 

84 

4 

1 

I 

826 

5 

1 

6 

12 

Den. 

2.5 

11.2 

9.1 

63.2 

I.S 

3.7 

144 

845.3 

7.6 

109.9 

5.5 

1.3 

1.5 

6.3 

1.2 

1999 

Uniu 647 

N = 

Cl 

1 

1 

12 

17 

2 

13 

221 

6 

1 

II 

1 

1 

1 

288 

2 

2 

12 

Den. 

1.5 

1.3 

206 

25.4 

2.9 

19.2 

341.3 

9 2 

18 

13.6 

1.5 

1.3 

1.5 

2.7 

Survey 13 

June 10-11 

New CC Uniu 

N 

Cl. 

2 

2 

7 

59 

22 

2 

783 

12 

2 

4 

69 

964 

0 

= 12 

Den. 

3 0 

2.9 

94 

77.3 

34.7 

2.4 

1164 6 

17.3 

3.2 

68 

85.9 

1999 

UntU 647 

N = 

a. 

1 

1 

10 

33 

1 

21 

290 

6 

14 

1 

1 

379 

0 

12 

Den. 

16 

1.7 

13 0 

490 

2 1 

42.3 

550.0 

10.1 

21.7 

1.7 

1.8 

E9-053.9 4-6 MLPP 316(b) Resource Assessment 

4-28-2000 
P.73 

4.0 Entrainment and Source Water Results 

Table 4-1. (continued). Mean Concentrations (#/l,000 m3) of all Larval Fish Taxa and Megalops of 

Cancer spp. and European Green Crabs Collected in front of the Moss Landing Power Plant New 

Combined-cycle Units and Units 6 and 7 Intakes: March 2, 1999 through February 24, 2000. 

Taxon 

Ammodytes hexapterus 

Anedius lateralis 

Anedius spp. 

Atherinidae unid. 

Atherinops affinis 

Atherinopsis californiensis 

A ulorhynchus flavidus 

Bathylagus ochotensis 

Baihymasieridae unid. 

Blennioidei 

Brosmophycis marginata 

Cebidichthys violaceus 

Chaenopsidae unid. 

Citharichthys sordidus 

Citharichthys • stigmaeu s 

Cl inor onus anal it 

Clupea pallasii 

Clupeidae unid. 

Clupei frames 

Coryphopterus nicholsi 

Crttidae unid. 

Coitus asper 

Engraulis mordax 

Genyonemus lineatus 

Gibbtmsia spp. 

Gillichthys mirabilis 

Gobiesocidae unid 

Gobiesox spp 

Gobiidae • lypc 1 

Gobudae unid. 

Hcxagramrnhlae unid 

Hypsoblennius spp. 

larval fish - damaged 

larval fish frapmem 

larvnl/pnsl-l.irvnl fish. unid. 

Lepidogobius lepidus 

LeptocOltus armatus 

Leuroglossus stilbius 

Liparis fucensis 

Liparis spp. 

OUgocottus *pp. 

Ophidiidac tnid 

Ophiodon elongatus 

Osmeridae untd. 

Oxyiebius pic tus 

Parophrys vetulus 

Pholididaeunid. 

Pleuronectes bilinear us 

Pleuronectes isaiepis 

neuroncclidae unid. 

Reuronectiformes unid. 

Psettichthys melanostictus 

Ruscarius crraseri 

Sardinops sagax 

Scorpaenichthys manrusratus 

Sebastes spp. 

Sebastes spp. V 

Sebastes spp. V_D 

Sebastes SRX V_De 

Sebasiesspp VD 

Sebastes spp. VP 

Sebastolobus spp. 

Stenobrachius Uucopsana 

Stichaeidae unid 

Syngnathidae unid. 

Syngnathus spp. 

Tarletonbeania crenularis 

Typhlogobius californiensis 

Cancer antennarius (megalops) 

Cancer anthonyi (megalops) 

Cancer gracilis (megalops) 

Cancer jordani (megalops) 

Cancer magister (megalops) 

Cancer productus (megalops) 

Cancer spp. (megalops) 

Carcinus maenas (megalops) 

Common Name 

Pacific sand lance 

srnoolhhead sculpin 

sculpins 

silversides 

topsmelt 

jacksmelt 

tubesnout 

popeye btacksmeli 

ronquili 

blennies 

red trotula 

monkeyface eel 

tube blennies 

Pacific sanddab 

speckled sanddab 

vrooly sculpin 

Pacific herring 

herrings 

herrings and anchovies 

Nackeye goby 

sculpins 

pnetly scut pin 

northern anchovy 

white croaker 

clinid kelpfishes 

longja*- mudsucker 

clingfishes 

clingfishes 

gobies 

gobies 

greenlings 

blennies 

unidentified larva) fishes 

unidentified larval fishes 

unidentified larval fishes 

bay goby 

Pacific staghorn sculpin 

California smooth tongue 

slipskin snailfish 

snailfishes 

sculpins 

cusk-eel s 

lingcod 

smells 

painted greenling 

English sole 

gunnds 

rock sole 

butter sole 

flounders 

flatfishes 

sand sole 

rouchchcek sculpin 

Pacific sardine 

cabezon 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

thomyheads 

northern lampfish 

pricklebadu 

pipefishes 

pipefishes 

blue laniemfish 

Mind goby 

FISH TOTALS: 

brown rock crab 

yellow rock crab 

slender rock crab 

hairy rock crab 

dungeness crab 

red rock crab 

unidentified cancer crabs 

European green crab 

CRAB TOTALS: 

Survey 16 

June 17-18. 1999 

New CC Uniu Uniu6A7 

N=M * N=I 2 

Cl. Den. Ct. Den. 

1 1.3 

7 12.3 5 9.3 

42 63.3 12 19.4 

1 1.0 

1 18 4 6 5 

231 3139 104 174.2 

17 25.0 6 10.3 

1 1.2 

80 93.8 27 38.9 

1 16 

5 6.6 2 3.2 

1 1.3 

386 162 

1 13 

0 1 

Survey 17 

June 24-25. 1999 

New CC Units Uniu 6*7 

N 

Ct. 

1 

6 

42 

2 

16 

694 

20 

4 

5 

1 

162 

1 

4 

1 

1 

960 

0 

>I2 N = 

Den. Cl. 

2 

1.2 

8.3 1 

57.3 15 

1 

2.4 

20.4 14 

892.7 321 

26.7 7 

5.2 2 

6.8 3 

1.4 

2106 57 

1.3 

51 6 

1.4 

1.2 

429 

0 

12 

Den. 

3.1 

1.4 

22.2 

1.3 

17.2 

4264 

9.8 

3.0 

4.4 

78.8 

8 1 

Survey 18 

July 12-13. 1999 

New CC Units Uniu 647 

N=I 2 N = 

Ct. Den. Ct. 

9 10.0 2 

1 

2 

23 26.9 7 

1 

6 9.3 7 

88 1414 127 

32 42.2 25 

2 3.3 

1 

61 68.6 8 

1 i o 

222 181 

1 

1 1.0 

1 1 

12 

Den. 

3.1 

2.5 

3.0 

12.9 

1.3 

13.0 

238.7 

39.8 

1.7 

12.5 

1.7 

Survey 19 

July 29-30. 1999 

New CC Uniu 

N=1 2 

Ct. 

1 

2 

12 

6 

97 

50 

2 

1 

58 

1 

230 

0 

Den. 

1.6 

3,3 

21.0 

11.2 

177.3 

85.1 

3.4 

1.7 

103.5 

1.6 

Units 6&7 

N = 

Ct. 

I 

I 

1 

15 

14 

247 

44 

2 

2 

78 

I 

1 

407 

0 

12 

Den. 

1.5 

1.8 

1.3 

25.0 

20.9 

417.3 

66.8 

3.6 

2.8 

108.2 

1.7 

1.3 

Survey 20 

August 12-13. 1999 

New CC Uniu Units 647 

N=12 N = 12 

Ct. Den. Q . Den. 

1 1.4 

2 2.9 

3 4.9 13 18.5 

6 10.7 10 14.7 

27 42.8 136 193.4 

42 69.2 103 142.1 

1 16 

66 99.7 13 21.1 

I 1.4 

147 277 

1 1.1 

1 1.5 

1 1.2 

1 2 

•One sample voided during laboratory processing. 

E9-053.9 4-7 MLPP 316(b) Resource Assessment 

4-28-2000 
P.74 

4.0 Entrainment and Source Water Results 

Table 4-1. (continued). Mean Concentrations (#/l,000 m3) of all Larval Fish Taxa and Megalops of 

Cancer spp. and European Green Crabs Collected in front of the Moss Landing Power Plant New 

Combined-cycle Units and Units 6 and 7 Intakes: March 2, 1999 through February 24, 2000. 

Taxon 

Ammodytes hexapterus 

Artedius lateralis 

Artedius spp. 

Atherinidae unid. 

Atherinops affinis 

Atherinopsis californiensis 

Auiorhynchus flavidus 

Bathylagus ochotensis 

Balhymasteridae unid 

Blennioidei 

Brosmophycis marginata 

Cebidichthys violaceus 

Chacnopsidae unid. 

Citharichthys sordidus 

Citharichthys stigmaeus 

Clinocottus analis 

Clupea pallasii 

Clupeidae unid. 

Clupeiformes 

Coryphopterus nicholsi 

Cottidae unid 

Cottus asper 

Engraulis mordax 

Genyonemus lineatus 

Gtbbonsia spp 

Gillichthys mirabilis 

Gobicsocidac unid. 

Gobiesox spp. 

Gobiidae- lypc I 

Gobiidae unid. 

Hexagramirtidac unid 

Hypsoblennius spp. 

larval fish - damaged 

larval fish fragment 

larval/posl-larval fish, unid 

lepidogobius lepidus 

Leptocoaus armatus 

Ijeuroglossus stilbius 

Liparis fucensis 

Liparis spp. 

OUgocottus spp. 

Ophidiidac unid 

Ophiodon elongatus 

Osmeridae unid. 

Orytebms pictus 

Parophrys vetulus 

fltotididae unid. 

Pieuronecies bilineatus 

Pleuronectes isotepis 

Pleuronectidae unid. 

Pleuronectiformes unid 

Psettichthys melanostictus 

Rustarius creaseri 

Sardinops sagax 

Scorpaenichihys marmoratus 

Sebastes spp. 

Sebastes spp. V 

Sebastes spp. V.D 

Sebastes spp. V_De 

Sebastes spp. VD 

Sebastes spp. VP 

Sebastolobus spp. 

Stenobrachius leucopsams 

Slichaeidae unid. 

Syngnathidae unid. 

Syngnathus spp. 

TaHetonbeania crenularis 

Typhlogobius californiensis 

Cancer antennarius (megalops) 

Cancer anthonyi (megalops) 

Cancer gracilis (megalops) 

Cancer jordani (megalops) 

Cancer magister (megalops) 

Cancer productus (megalops) 

Cancer spp. (megalops) 

Carcinus maenas (megalops) 

Common Name 

Pacific sand lance 

smoothhead sculpin 

sculpins 

silversides 

topsmelt 

jacksmelt 

tubesnout 

popeye Nacksmeli 

ronquili 

blennies 

redbrotula 

monkeyface eel 

tube blennies 

Pacific sanddab 

speckled sanddab 

wooly sculpin 

Pacific herring 

herrings 

herrings and anchovies 

Nackeye goby 

sculpins 

prickly sculpin 

northern anchovy 

white croaker 

clinid kelpfishes 

longjaw mudsucker 

clingfishes 

clingfishes 

gobies 

gobies 

greenlings 

Nennic* 

unidentified larval fishes 

unidentified larval fishes 

unidentified larval fishes 

bay goby 

Pacific staghorn sculpin 

California smoothtonguc 

slipskin (nailfish 

snajlfishes 

sculpins 

cusk-eels 

lingcod 

smelts 

painted greenling 

English sole 

gunnds 

rocksole 

butter sole 

flounders 

flatfishes 

sand sole 

rouchcheek sculpin 

Pacific sardine 

cabezon 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

ihcmytteads 

northern lampfish 

prickleback! 

pipefishes 

pipefishes 

blue lantern fish 

blind jw*y 

FISH TOTALS: 

brown rock crab 

yellow rock crab 

slender rock crab 

hairy rock crab 

dungeness crab 

red rock crab 

unidentified cancer crabs 

European green crab 

CRAB TOTALS: 

Survey 21 

Aug. 31 -Sep. 1.1999 

New CC Uniu 

N=I 2 

Ct. Den. 

14 20.7 

1 1.5 

1 14 

64 88.8 

7 10.3 

111 159.3 

143 210.1 

1 14 

143 164.6 

3 4.4 

2 2.9 

1 1.4 

I 1.0 

494 

2 2.9 

2 

Uniu6&7 

No 

Ct. 

5 

8 

I 

1 

1 

2 

40 

2 

140 

118 

3 

55 

1 

377 

4 

4 

12 

Den. 

8.8 

11.0 

1.5 

1.2 

14 

3.1 

57.5 

3.3 

195.6 

172.1 

4,0 

74.9 

1.4 

6.3 

Survey 22 

September 16-17. 1999 

New CC Uniu 

N=1 2 

Ct. Den. 

8 12.1 

1 1.5 

75 111.2 

1 1.4 

7 10.3 

294 438.0 

182 270.8 

1 1.6 

192 277.1 

1 1.5 

2 2.9 

764 

6 9.1 

7 10.5 

13 

Uniu 6A7 

N=12 

Cl. Den. 

2 2.7 

1 1.2 

57 77.1 

14 19.5 

422 578.4 

154 2114 

2 2.6 

176 241.2 

2 2.3 

I 1.2 

831 

0 

Survey 23 

Sep. 30-Oct 1. 1999 

New CC Uniu Uniu 647 

N=I 2 N = 

Cl. Den. Ct. 

2 

2 3.4 2 

17 28.4 4 

1 1.5 

1 

1 

7 11.8 6 

107 179.9 171 

22 37.2 20 

1 

2 34 2 

118 206.6 97 

276 307 

3 9.2 6 

5 

32 63.0 54 

1 2.2 1 

38 66 

12 

Den. 

2.9 

2.9 

5 8 

19 

1.0 

8.9 

252.1 

29.8 

1.4 

2.9 

144.3 

108 

8.9 

101.1 

1.9 

Survey 24 

October 14-15, 1999 

New CC Uniu Uniu6&7 

N=I 2 Nal 2 

Ct. Den. Cl. Den. 

I 2.6 

2 3.3 

59 89.4 91 128.1 

2 2.6 

18 27.3 7 8.7 

277 428.6 405 524.8 

39 60.7 33 42.5 

4 54 

163 234.8 194 226.2 

4 6.4 2 2.3 

1 2.6 

562 740 

3 4.1 

3 6.9 4 5.0 

8 4 

Survey 23 

Oaober 28 - 29.1999 

New CC Uniu UniU6A7 

N = 

a 

i 

5 

20 

1 

19 

186 

13 

2 

345 

3 

395 

0 

12 N= 12 

Den. Ct. Den. 

2 2.6 

1.7 

8 2 8 11.9 

33 1 10 15.4 

1.8 

2 2.9 

32.3 17 27.0 

308.9 182 272.7 

20.8 9 143 

2.7 

471.5 215 331.0 

4.6 5 6.7 

430 

0 

E9-053.9 4-8 MLPP 316(b) Resource Assessment 

4-28-2000 
P.75 

4.0 Entrainment and Source Water Results 

Table 4-1. (continued). Mean Concentrations (#/l,000 m3) of all Larval Fish Taxa and Megalops of 

Cancer spp. and European Green Crabs Collected in front of the Moss Landing Power Plant New 

Combined-cycle Units and Units 6 and 7 Intakes: March 2, 1999 through February 24, 2000. 

Taxon 

Ammodytes hexapterus 

Anedius lateralis 

Anedius spp. 

Atherinidae latid. 

Atherinops affinis 

Atherinopsis cali/omiensis 

Auiorhynchus flavidus 

Bathylagus ochotensis 

Balhymasteridac 1st id 

Blennioidei 

Brosmophycis marginata 

Cebidichthys violaceus 

Chamopsidae tnid. 

Citharichthys sordidus 

Citharichthys stigmaeus 

Clinocottus analis 

Clupea pallasii 

Clupei-lae unid. 

Clupeiformes 

Coryphopterus nicholsi 

Cottidae unid. 

Cottus asper 

Engraulis mordax 

Genyonemus lineatus 

Gibhonsia spp 

Gillichthys mirabilis 

Gobiesocidae unid. 

Gobiesox spp. 

Gobiidae - type 1 

Gobiidae unid. 

Hexagrammidae unid 

Hypsoblennius spp. 

larval fish - damaged 

larval fish fragment 

larval/posl-larva] fish. i_nid. 

Lepidogobius lepidus 

Leptocottus armatus 

Leuroglossus stilbius 

Liparis fucensis 

Liparis spp. 

OUgocottus spp. 

Ophidiidac unid. 

Ophiodon elongalus 

Osmeridae unid. 

Oxyiebius pictus 

Parophrys vetulus 

PtKSididac unid 

Pleuronectes bilitteatus 

Pleuronectes isaiepis 

Pleuronectidae tnid. 

Pleuronectiformes unid. 

Pseaiehlhys melanostictus 

Ruscarius creaseri 

Sardinops sagax 

Scorpaenichthys marmoratus 

Sebastes spp. 

Sebastes spp. V 

Sebastes spp. V_D 

Sebastes (pp. V_De 

Sebastes spp. VD 

Sebastes spp. VP 

Sebaslotobia spp. 

Stenobrachius leucopsants 

Slichacidae unid. 

Syngnathidae tnid 

Syngnathus Eft). 

Tarletonbeania crenularis 

Typhlogobius californiensis 

Cancer antennarius (megalops) 

Cancer anthonyi (megalops) 

Cancer gracilis (megalops) 

Cancer jordani (megalops) 

Cancer magister (megalopa) 

Cancer productus (megalops) 

Cancer spp. (megalops) 

Carcinus maenas (megalops) 

Common Name 

Pacific sand lance 

smoothhead sculpin 

sculpins 

silversides 

topsmelt 

jacksmelt 

lubesnoul 

popeye blacksmelt 

ronquils 

blennies 

red brolula 

monkeyface eel 

tube Mennies 

Pacific sanddab 

speckled sanddab 

wooly sculpin 

Pacific heiTing 

horings 

herrings and anchovies 

Nackeye goby 

sculpins 

prickly sculpin 

northern anchovy 

while a*oaker 

clinid kelpfishes 

longjaw mudsucker 

clingfishes 

clingfishes 

gobies 

gobies 

greenlings 

blennies 

unidentified larval fishes 

unidentified larval fishes 

unidentified larval fishes 

bay goby 

Pacific staghorn sculpin 

Califomia smoothtonguc 

slipskin snailfish 

snaiirishcs 

sculpins 

cusk-ccls 

lingcod 

smelts 

painted greenling 

English role 

gunnels 

rocksole 

butter sole 

flounders 

flatfishes 

sand sole 

roudtcheck sculpin 

Pacific sardine 

cabexon 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

Ihcmyheads 

northern lampfish 

pricklcrjocks 

pipefishes 

pipefishes 

blue lanlemfish 

blind goby 

FISH TOTALS: 

brown rock crab 

yellow rock crab 

slender rock crab 

hairy rock crab 

dungeness erab 

red rock crab 

unidentified cancer crabs 

European green crab 

CRAB TOTALS: 

Survey 26 

November 4 

New CC Units 

N=1 2 

Q 

2 

1 

I 

1 

1 

20 

2 

6 

1 

30 

1.305 

8 

6 

457 

9 

1 

1.831 

1 

1 

2 

Den. 

2.9 

1.4 

1.2 

16 

1.4 

28.0 

2.6 

8.6 

1.2 

43 1 

1798.7 

12.0 

88 

655.2 

132 

1.4 

14 

1.4 

-5,1999 

Uniu 6*7 

N = 

Ct. 

1 

2 

1 

16 

6 

27 

772 

6 

3 

142 

14 

1 

1 

1 

993 

2 

1 

3 

12 

Den. 

II 

2.7 

1.3 

21.0 

7,6 

355 

1018.9 

8.2 

39 

188 9 

18.3 

1.2 

14 

1.1 

2.8 

13 

Survey 27 

November 11 • 12. 1999 

New CC Units Units 647 

N=12 N=I 2 

O. Den. Cl. Den. 

1 1.2 

170 2808 26 36 1 

1 19 

8 13.6 13 18.6 

18 28.4 26 38.3 

493 788.5 482 719.4 

12 197 1 1.2 

1 1.5 3 4 3 

609 1080.8 495 698.4 

10 160 22 328 

1.322 1,069 

3 5.1 

2 3.4 

1 1.7 

1 1.7 

7 0 

Survey 28 

November 18- 19.1999 

New CC Uniu Umts 647 

N=I 2 

a. 

4 

1 

12 

4 

7 

4 

13 

568 

6 

5 

1.689 

12 

2.325 

3 

2 

1 

1 

1 

8 

N = 

Den. Ct. 

4.8, 

1.4 

1 

18.1 2 

6.0 

9.4 3 

6 1 

189 12 

851.5 344 

8.8 2 

8.3 2 

2668.2 248 

16.1 6 

620 

3.9 3 

2.4 1 

1.2 

1.2 1 

1.4 

5 

12 

Den. 

1.7 

2.4 

5.2 

16.8 

488.3 

3.1 

2.7 

382.4 

9.2 

3.7 

1.2 

1.2 

Survey 29 

November 22 

New CC Uniu 

N = 

Ct. 

3 

4 

6 

8 

13 

208 

1 

1 

536 

18 

798 

1 

1 

2 

12 

Den. 

5.8 

7 6 

9 8 

143 

24.4 

3695 

19 

18 

905.7 

33.4 

19 

1.9 

-23.1999 

Uniu 6*7 

N = 

a 

10 

12 

1 

2 

14 

6 

31 

445 

1 

12 

138 

55 

727 

1 

1 

12 

Den. 

15.9 

204 

1.8 

3.2 

258 

109 

53.3 

749.5 

1.4 

194 

244.7 

92.3 

1.7 

Survey 30 

Decemher2 

New CC Uniu 

N=I 2 

Cl. 

15 

41 

1 

12 

5 

20 

1 

9 

390 

1 

5 

8 

534 

36 

1 

1.079 

1 

2 

1 

1 

1 

6 

Den. 

22.2 

53.6 

1.3 

17.0 

7.0 

288 

1.5 

124 

5450 

1.3 

7,6 

11.7 

769.2 

50.9 

1.3 

1.3 

3.2 

1.3 

1.3 

1.3 

•3.1999 

Uniu 6*7 

N=I 2 

Ct. 

14 

30 

3 

10 

3 

13 

5 

25 

663 

1 

6 

13 

332 

29 

20 

1 

1 

1.169 

1 

1 

1 

1 

4 

Den. 

16.5 

349 

3.7 

9.8 

36 

15.5 

5.8 

28.6 

745.5 

I.I 

6 6 

15 6 

3863 

33.5 

29.5 

1.6 

1.2 

I.I 

0 8 

1.3 

I.I 

E9-053.9 4-9 MLPP 316(b) Resource Assessment 

4-28-2000 
P.76 

4.0 Entrainment and Source Water Results 

Table 4-1. (continued). Mean Concentrations (#/l,000 m ) of all Larval Fish Taxa and Megalops of 

Cancer spp. and European Green Crabs Collected in front of the Moss Landing Power Plant New 

Combined-cycle Units and Units 6 and 7 Intakes: March 2, 1999 through February 24, 2000. 

Tasoi 

Ammodytes hexapterus 

Anedius lateralis 

Anedius spp. 

Atherinidae unid. 

Atherinops affinis 

Atherinopsis californiensis 

Auiorhynchus flavidus 

Bdlhylagus ochotensis 

Bathymasteridae unid 

Blennioidei 

Brosmophycis marginata 

Cebidichthys violaceus 

Otaenopsidaeunid.. 

Citharichthys sordidus 

Citharichthys stigmaeus 

Clinorottus analis 

Clupea pallasii 

Clupeidae unid 

Gtrpeiformes 

Coryphopterus nicholsi 

Cottidae unid 

Conus asper 

Engraulis mordax 

Genyonemus lineatus 

Gibbonsia spp 

Gillichthys mirahilis 

Gobiesocidae unid. 

Gobiesox spp 

Gobiidae - type 1 

Gobiidae unid 

Hesagrammidae unid 

Hypsoblennius spp. 

larval fish - damaged 

larval fish fragmenl 

larval/poRI-larval fish, unid 

Lepidogobius lepidus 

Leptocottus armatus 

Leuroglosxus slilbiut 

Liparis fucensis 

Liparis spp. 

Oligocoaus sjjp. 

Ophidiidae tni d 

Ophiodon elongatus 

Osmeridae unid 

Oxyiebius pictus 

Parophrys vetulus 

Pholitbdac mi d 

Pleuronectes bilinealus 

Pleuronectes isaiepis 

Pleuronectidae unid. 

Plcuraiectirormes unid. 

Psettichthys melanostictus 

Ruscarius ereaseri 

Sardinops sagax 

Scorpaenichthys marmoratus 

Sebastes spp. 

Sebastes spp. V 

Sebastes spp. V_ D 

Sebastes spp. V_.De 

Sebastes spp. V D 

Sebastes spft. VP 

Sebaslotoous stn. 

Stenobrachius teucopsarus 

Slicfcacidae unid 

Syngnathidae tni d 

Syngnathus spp. 

7an>lon_»ranj'd crenularis 

Typhlotobius califomiensis 

Cancer antennarius (megalops) 

Cancer anthonyi (megalqx) 

Cancer gracilis (megalops) 

Cancer jordani (megalops) 

Cancer magister (megalops) 

Cancer productus (megalqx) 

Cancer spp. (megalqts) 

Carcinus maenas (megalops) 

Common Name 

Pacific sand lance 

smoothhead sculpin 

sculpins 

silversides 

topsmelt 

Jacksmelt 

lubesnout 

popeye blacksmell 

rcsiquils 

blennies 

red trotula 

monkeyface eet 

tube blennies 

Pacific sanddab 

speckled sanddab 

wooly sculpin 

Pacific herring 

herrings 

herrings and anchovies 

Nackeye goby 

sculpins 

prickly sculpin 

northern anchovy 

white croaker 

clinid kelpfishes 

longjaw mudsucker 

cl_ngfist.es 

clingfishes 

gobies 

gobies 

granting* 

Ncnnics 

unidentified larval fishes 

unido.lir.cd larval fishes 

unidentified larval fishes 

bay goby 

Pacific slaghom sculpin 

California smoothlangue 

slipsktn snailfish 

snailfishes 

sculpins 

cusk-eels 

lingood 

smelu 

painted greenling 

English sole 

gunnels 

rock sole 

butler sole 

llounders 

flatfishes 

sand sole 

itsjch<_hcck sculpin 

Pacific sardine 

cabezot 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

thorn yheads 

northem IsirpTish 

pricklcbacks 

pipefishes 

pipefishes 

blue lanlemfish 

blind goby 

FISH TOTALS: 

brown rock crab 

yellow rock crab 

slender rock crab 

hairy rock crab 

dungeness crab 

red rock crab 

unidentified cancer crabs 

Etropean green crab 

CRAB TOTALS: 

Survey 31 

December 9 

New CC Uniu 

N = 12 

Cl Den. 

7 116 

5 8 1 

8 13.5 

5 7.9 

17 24.8 

321 532.5 

1 16 

1 1.8 

1 1 6 

482 772.7 

13 198 

4 5.7 

5 7.5 

870 

6 8.4 

1 I-S 

1 1.3 

8 

10. 1999 

Uniu 6&7 

N = 

Cl 

20 

3 

6 

2 

1 

45 

226 

2 

362 

22 

1 

2 

2 

694 

1 

6 

1 

8 

12 

Den. 

27.4 

3.9 

8.3 

2.5 

14 

6 0 8 

331.3 

3.9 

611.1 

32.8 

1.5 

3.3 

3.0 

1.3 

8 0 

1.2 

Survey 32 

December 16 

New CC Uniu 

N=1 2 

C i. Den. 

36 50 8 

6 8.2 

112 1701 

1 1.8 

9 12.7 

554 767.2 

11 16.2 

223 334.0 

163 224.7 

IS 24 4 

3 3.2 

1.133 

1 1.6 

13 16.3 

14 

17.1999 

Uniu 64 7 

N = 

Ct. 

6 

1 

8 

26 

1 

7 

351 

4 

12 

176 

108 

1 

3 

3 

707 

5 

3 

12 

Den. 

10.7 

1.2 

14.2 

4 3 0 

1 6 

1 0 9 

527.2 

6.5 

18.2 

250.7 

181.7 

1 6 

5.2 

4.4 

8 4 

Survey 33 

December 21 • 22.1999 

New CC Units Uniu 6* 7 

N = 

Ct 

3 

3 

1 

1 

13 

146 

13 

238 

1 

201 

36 

8 

1 

665 

2 

7 

1 

10 

12 N = 

Den. Ct. 

4.4 5 

4.3 8 

1.5 

1.2 3 

19.6 33 

226,4 47 

19.1 23 

347.2 191 

3 

1.7 4 

283.3 200 

3 6 9 69 

1 

12.7 3 

1.2 3 

597 

3.2 1 

1 1 0 2 

1.6 

3 

12 

Den. 

6.5 

11.8 

6.8 

47.6 

69.4 

35.0 

274.5 

3.7 

5.7 

257.2 

98.8 

1.2 

4.8 

3.5 

1.2 

2.9 

Survey 34 

December 29 - 30.1999 

New CC Uniu Units Ml 7 

N = 

Ct. 

1 

6 

1 

I I 

1 

6 

I I 

424 

5 

278 

17 

I 

2 

28 

792 

1 

1 

2 

12 N = 

Den. Ct. 

1 

1.6 

1 

10.7 3 

1.6 

18.6 3 

1.7 

9.2 1 

186 9 

714.5 233 

9.3 4 

460 6 69 

27.4 9 

1 6 

1 

1 

3 1 1 

40.3 25 

3 

364 

2.0 

2.0 

0 

12 

Den. 

1.7 

1 9 

5.3 

5 4 

1.6 

1 5 2 

395.7 

6 6 

119.6 

14.6 

1.7 

1.9 

1.3 

43.2 

5.2 

Survey 35 

January 6 - 7.2000 

New CC Uniu Uniu 6* 7 

N 

C l. 

3 

8 

1 

7 

5 

18 

216 

1 

317 

21 

1 

1 

599 

5 

1 

6 

= 12 N=I 2 

Den. Cl. Den. 

5.7 

15.7 12 22.1 

1.2 

146 10 16.7 

9.8 4 6.9 

36 5 I I 17 1 

426.2 146 254,5 

3 6 1 

1.8 6 H.O 

589 6 134 230 1 

39.2 20 34 4 

1 8 

1 8 

346 

9.5 1 1.7 

2.0 

1 

E9-053.9 4-10 MLPP 316(b) Resource Assessment 

4-28-2000 
P.77 

4.0 Entrainment and Source Water Results 

Table 4-1. (continued). Mean Concentrations (#/l,000 m ) of all Larval Fish Taxa and Megalops of 

Cancer spp. and European Green Crabs Collected in front of the Moss Landing Power Plant New 

Combined-cycle Units and Units 6 and 7 Intakes: March 2,1999 through February 24, 2000. 

Taxoi 

Ammodytes hexapterus 

Artedius lateralis 

Anedius spp. 

Atherinidae tnid. 

Atherinops affinis 

Atherinopsis californiensis 

Auiorhynchus flavidus 

Bathylagus ochotensis 

Balhymastcridac tnid 

Blennioidei 

Brosmophycis marginata 

Cebidichthys violaceus 

Chaenopsidae unid. 

Citharichthys sordidus 

Citharichthys stigmaeus 

Clinecoaus totalis 

Clupea pallasii 

Clupeidae unid. 

Clupei formes 

Coryphopterus nicholsi 

Cottidae tnid 

Cottus taper 

Engraulis mordax 

Genyonemus lineatus 

Gibbtmsia spp. 

Gillichthys mirabilis 

Gobiesocidae unid. 

Gobiesox spp. 

Gobiidae - type I 

Gobiidae mid. 

Hexagranvnidac unid. 

Hypsoblennius spp. 

larval fish - damaged 

larva) fish fragment 

larval/posl-larval fish. unid. 

Lepidogobius lepidus 

Leptocoaus armatus 

Leuroglossus stilbius 

Liparis fucensis 

Liparis tre, 

OUgocottus spp. 

Ophidiidaeinid 

Ophiodon elongatus 

Osmeridae unid 

Oxyiebius picats 

Parophrys vetulus 

Jmdididac tnid 

Pleuronectes tnlineatus 

Pleuronectes isaiepis 

Pleuronectidae unid 

Pleuroneaiformes tnid 

Psettichthys melanostictus 

Ruscarius crtaseri 

Sardinops sagax 

Scorpaenichthys marmoratus 

Sebastes spp. 

Sebasses spp. V 

Sebastes spp. VJ ) 

Sebastes spp. V_De 

Sebastes spp. VD 

Sebastes spp. VP 

Sebassoloous spp. 

Stenobrochiiu leucapsarus 

Stichaetdae unid 

Syngnathidae unid 

Syngnashus Sffi. 

Tarletonbeania crenularis 

Typhlogobius edifornienxis 

Cancer antennarius (megalops) 

Cancer anthonyi (megalops) 

Cancer gracilis (megalops) 

Cancer jordani (megakfM) 

Cancer magister (mcgakfM) 

Cancer productus (megalops) 

Cancer spp. (megalops) 

Carcinus maenas (megalops) 

Common Name 

Pacific sand lanoe 

smocthhead sculpin 

satlpins 

silversides 

topsmelt 

jacksmell 

tubesnout 

popeye biacksmelt 

rcnquils 

blennies 

redbrotula 

monkeyface eel 

tube blennies 

Pacific sanddab 

speckled sanddab 

wooly sculpin 

Pacific herring 

herrings 

herrings and anchovies 

Nackeye goby 

sculpins 

prickly sculpin 

northern andiovy 

white croaker 

clinid kelpfishes 

longjaw mudsucker 

clingfishes 

clingfishes 

gobies 

gobies 

greenlings 

Nenn.es 

unidentified larval fishes 

unidentified larval fishes 

unidentified larval fishes 

bay goby 

Pacific staghom sculpin 

California smoothtcngue 

slipskin snailftsh 

snailfishes 

sculpins 

cusk-eels 

lingcod 

smelu 

painted greenling 

English sole 

gunners 

rocksole 

butter sole 

flounders 

flatfishes 

sand sole 

rouchdieck sculpin 

Pacific sardine 

cabezon 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

thornyheads 

northsn lampftsh 

pricktebacks 

pipefishes 

pipefishes 

Nue lanltrofish 

Nindgoby 

HSH TOTALS: 

trown rock crab 

yellow rock crab 

slender rock crab 

hairy rock crab 

dungeness crab 

red rock crab 

unidentified cancer crabs 

European green crab 

CRAB TOTALS: 

Survey 36 

January 13 14.2000 

New CC Uniu Uniu 647 

N=I 2 N = 

Cl. Den. Ct. 

1 2.1 

1 

22 34.7 

2 

1 17 1 

3 5.2 6 

284 492.2 200 

2 

282 509.5 62 

29 486 20 

33 888 10 

1 2.1 

676 304 

1 2.1 

1 1.7 2 

1 1.7 

3 2 

12 

Den. 

1.8 

3.2 

1.7 

9.5 

319,0 

3,0 

98.7 

34.0 

17.0 

3.3 

Survey 37 

January 20-

NewCCUniu 

N = 

Cl 

3 

4 

1 

2 

3 

146 

1 

221 

56 

2 

1 

2 

2 

1 

445 

2 

1 

2 

5 

12 

Den 

3.7 

7.9 

2,0 

3.2 

6 0 

249.2 

1.7 

367.9 

104.3 

3 3 

2.0 

4.0 

3.4 

2 0 

3 9 

2.0 

4.0 

21.2000 

Uniu 6*7 

N = 

ci. 

1 

4 

1 

3 

1 

1 

2 

II 

5 

108 

121 

65 

3 

3 

1 

1 

2 

333 

1 

1 

12 

Den. 

1.9 

6.8 

1.7 

3.2 

2.1 

2 0 

3.5 

22.1 

9 1 

195 6 

209.4 

118.9 

3.6 

5.3 

2 1 

1.5 

3.2 

2.1 

Survey 38 

January 27 

New CC Uniu 

N = 

a. 

3 

18 

14 

1 

6 

2 

11 

3 

21 

2. 

414 

6 

305 

28 

9 

3 

2 

830 

1 

1 

12 

Den. 

4.8 

31.6 

23.9 

2.2 

120 

3.8 

20.8 

9.4 

33.7 

4.0 

792.8 

III 

577.1 

52.7 

16.7 

4.9 

3.1 

18 

28.2000 

Uniu 6*7 

N = 

Cl. 

2 

22 

3 

33 

3 

1 

8 

4 

13 

2 

254 

1 

2 

198 

33 

3 

1 

587 

1 

1 

2 

12 

Den. 

3.1 

32.2 

4.7 

610 

4.7 

1.9 

13.0 

6.4 

20.2 

3 2 

4464 

2.2 

3.5 

335.5 

569 

7.3 

1.6 

1.8 

1.7 

Survey 

Febniary3-

NewCCUniu 

N=I 2 

Ct. 

59 

6 

2 

66 

1 

3 

2 

2 

3 

3 

22 

5 

351 

2 

459 

37 

1 

1 

23 

3 

5 

2 

3 

1.061 

2 

1 

3 

Den. 

99.6 

9.8 

35 

1095 

1.4 

5 0 

34 

3.4 

4.6 

5 1 

37.4 

8.8 

601.2 

38 

797.0 

63.1 

1.7 

1.7 

38.3 

5.6 

8 5 

3.5 

5.0 

3.2 

1.7 

39 

4.2000 

UniU 6*7 

N c 

Cl. 

42 

1 

10 

1 

157 

2 

13 

4 

5 

2 

220 

3 

4 

177 

60 

28 

1 

2 

3 

737 

3 

3 

6 

12 

Den 

77.8 

1.9 

181 

14 

285.0 

34 

295 

7.0 

8 9 

35 

3938 

5.5 

7.2 

312.8 

106.3 

50.7 

1.7 

3.4 

5.2 

6 0 

3.6 

E9-053.9 4-11 MLPP 316(b) Resource Assessment 

4-28-2000 
P.78 

4.0 Entrainment and Source Water Results 

Table 4-1. (continued). Mean Concentrations (#/l,000 m3) of all Larval Fish Taxa and Megalops of 

Cancer spp. and European Green Crabs Collected in front ofthe Moss Landing Power Plant New 

Combined-cycle Units and Units 6 and 7 Intakes: March 2, 1999 through February 24, 2000. 

Taxai 

Ammodytes hexapterus 

Anedius lateralis 

Anedius spp. 

Atherinidae mid. 

Atherinops affinis 

Atherinopsis californiensis 

Auiorhynchus flavidus 

Balhylagus ochotensis 

Balhymasteridae tnid 

Blennioidei 

Brosmophycis marginata 

CebisSchthys violaceus 

Chaenopsidae tnid. 

Citharichthys sordidus 

Citharichthys stigmaeus 

Clinocotlus analis 

Clupea pallasii 

Clupeidae tnid. 

Clupeiformes 

Coryphopterus nicholsi 

Cottidae mid 

Cottus asper 

Engraulis mordax 

Genyonemus lineatus 

Gibbtmsia spp. 

Gillkhlhys mirabilis 

Gobiesocidae unid. 

Gobiesox spp. 

Gobiidae - type 1 

Gobiidae mid. 

Hexagrammidae mid. 

Hypsoblennius spp. 

larval fish - damaged 

larval fish fragment 

larval/post-larval fish. unid. 

Lepidogobius lepidus 

Leptocottus armatus 

Leuroglossus stilbius 

Liparis fucensis 

Liparis spp. 

OUgocottus spp. 

Ophidiidac mid 

Ophiodon elongatus 

Osmeridae mid 

Oxyiebius pkttts 

Parophrys vetulus 

Pholididae mid 

Pleuronectes bilineattts 

Pleuronectes isaiepis 

Pleuronectidae mid 

Pleuroneclifcnrcs mid 

Psettichthys melanostictus 

Ruscariiu crtaseri 

Sardinops sagax 

Scorpaenichthys mamtoratus 

Sebastes spp. 

Sebastes spp. V 

Sebastes spp. VJ> 

Srfxujes spp. V_De 

Sebastes spp. VD 

Sebastes spp VP 

Sebastatobus spp. 

Stenobrtschius leucopsarus 

Stieftacidac unid 

Syngnathidae tnid 

Syngnathtu spp. 

Tartetonbeania crenutaris 

Typhlotobius ealihmiensis 

Cancer anseimtsritts (megalops) 

Cancer anthonyi (megalops) 

Cancer gracilis (megalops) 

Cancer jordani (megalops) 

Cancer magister (megalops) 

Cancer productus (megalops) 

Cancer spp. (megakps) 

Carcinus maenas (megalops) 

Common Name 

Pacific sand lanoe 

smtxxhhcad sculpin 

sculpins 

silversides 

topsmelt 

jacksmell 

lubesnoul 

popeye Nacksmell 

ronquils 

Hennies 

redbrotula ' 

monkeyface eel 

tube blennies 

Pacific sanddab 

speckled sanddab 

wooly sculpin 

Pacific herring 

herrings 

herrings and anchovies 

blackeye goby 

sculpins 

prickly sculpin 

northern anchovy 

white croaker 

clinid kelpfishes 

longjaw mudsucker 

clingfishes 

clingfishes 

gobies 

gobies 

greenlings 

Mennies 

unidentified larval fishes 

unidentified larval fishes 

unidentified larval fishes 

bay goby 

Pacific staghorn sculpin 

Califomia smoothtongue 

slipskin snailftsh 

snailfishes 

sculpins 

cusk-eels 

lingcod 

stnelu 

painted greenling 

English sate 

gunnels 

rocksole 

butler sole 

flounders 

flatfishes 

sand sole 

rouchchcck sculpin 

Pacific sardine 

cabezon 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

thornyheads 

ncrthon lampTish 

pricklebncks 

pipefishes 

pipefishes 

blue lantonfish 

blind goby 

FISH TOTALS: 

brown rock crab 

yellow rock crab 

slender rock crab 

hairy rock crab 

dungeness trab 

red rock crab 

unidentified cancer crabs 

European green crab 

CRAB TOTALS: 

Survey 40 

February 10-

New CC Uniu 

N c 

Q. 

37 

1 

4 

1 

2 

10 

I 

4 

3 

1 

2 

79 

3 

728 

1 

7 

2 

240 

25 

1 

1 

3 

6 

1 

1 

1 

1.167 

2 

1 

3 

12 

Den. 

57.2 

16 

6.3 

16 

3.2 

14.8 

16 

5.9 

8.3 

14 

3.0 

132 0 

4.7 

1102 4 

14 

9.6 

2.7 

360.8 

380 

14 

1.7 

4.6 

9 6 

2 1 

1.4 

1.4 

3.2 

1.4 

1.2O0O 

Uniu 6*7 

N = 

a. 

28 

3 

1 

1 

1 

10 

1 

6 

1 

104 

2 

2 

313 

3 

17 

67 

14 

1 

2 

2 

1 

1 

381 

1 

1 

2 

12 

Den. 

45.5 

4.6 

16 

1.7 

17 

16 1 

14 

9 3 

19 

139.6 

3.0 

3.0 

491.1 

5 0 

27.7 

109.9 

21.7 

1.5 

3.2 

2.8 

1.5 

14 

14 

1.4 

Survey 41 

Fetruary 17 • 

New CC Uniu 

i N = 

Cl. 

26 

1 

1 

II 

4 

18 

5 

54 

4 

850 

8 

13 

160 

35 

1 

14 

1 

2 

2 

1 

8 

1 

1.220 

1 

1 

12 

Den. 

42.9 

1.3 

2.0 

185 

6 3 

309 

7.7 

87,0 

7.0 

13384 

14.3 

21.6 

' 248.3 

595 

1.5 

23.3 

2 1 

3.0 

3.1 

15 

12.6 

1.3 

1.3 

8.2000 

Uniu 6*7 

N = 

Cl 

2 

1 

1 

24 

3 

20 

17 

4 

45 

13 

314 

10 

3 

121 

47 

7 

4 

1 

9 

1 

647 

2 

1 

3 

12 

Den. 

3.0 

1.8 

17 

39.1 

5,0 

32.2 

28,5 

66 

73.1 

21.7 

537.7 

17.1 

4.9 

205.1 

78.9 

119 

6,7 

1.6 

14.8 

1.6 

3.5 

1.7 

Survey 42 

February 24-

NewCCUniu 

N c 

ci. 

5 

1 

3 

2 

10 

1 

I 

10 

2 

18 

3 

45 

II 

727 

1 

15 

29 

1 

107 

26 

1 

12 

1 

1 

1 

2 

24 

4 

4 

34 

142 

1 

8 

1,253 

0 

12 

Den 

7,7 

1.7 

4.1 

3 0 

169 

16 

1.3 

149 

2.5 

278 

4.6 

694 

165 

1088.4 

16 

218 

44.9 

15 

154.0 

410 

16 

19.3 

1.3 

16 

1.5 

3 0 

35.5 

5.5 

5.7 

526 

221.3 

1,8 

12.8 

25.2000 

Uniu 6*7 

N = 

Cl 

2 

1 

3 

1 

1 

5 

10 

19 

5 

3 

52 

14 

493 

4 

II 

161 

27 

17 

1 

7 

9 

3 

4 

1 

1 

21 

74 

1 

3 

934 

1 

2 

3 

12 

Den. 

3.0 

14 

4.6 

1.4 

1.2 

7.4 

14.4 

28.1 

7.4 

4.6 

74.7 

20.3 

707.9 

5.9 

16.2 

227.8 

399 

25.0 

1.2 

9.7 

12.2 

4 6 

3.5 

1.6 

1.2 

30.0 

107.4 

1.4 

4.3 

1.4 

3.2 

E9-053.9 4-12 MLPP 316(b) Resource Assessment 

4-28-2000 
P.79 

4.0 Entrainment and Source Water Results 

4.1.1 Sampling and Laboratory Processing Sufficiency 

The accumulation of species during entrainment sampling through July at MLPP followed 

expected patterns with rapid accumulation during early sampling efforts that decreased with 

continued sampling (Figures 4-2 and 4-3). Differences in the total number of taxa collected and 

the rate of taxa accumulation were noted between sampling stations. A total of 64 taxa was 

collected at the new combined-cycle units intake while 57 taxa were collected from the Units 6 

and 7 intake over the entire year of surveys. The taxa collected at the new combined-cycle units 

intake that were not collected at the Units 6 and 7 intake from March 2 through February 24, 

2000 are shown in Table 4-2. The taxa that were unique to the Units 6 and 7 intake are also 

shown in Table 4-2. 

Table 4-2. Species found to be Unique to either the New Combined-cycle Units or the Units 6 

and 7 Intakes. Data from Surveys 1 through 42. 

Taxa unique to the New combined-cycle Units intake 

Taxon 

Scorpaenichthys marmoratus 

Ophiodon elongatus 

Leuroglossus stilbius 

Bathymasteridae unid. 

Ophidiidae unid. 

Sebastes spp. VP 

Sebastes spp. V_D 

Pleuronectes isolepis 

Gobiidae - type I 

Gobiesocidae unid. 

Liparis spp. 

Brosmophycis marginata 

Hexagrammidae unid. 

Common Name 

cabezon 

lingcod 

California smoothtongue 

ronquil 

cuskeel 

rockfish 

rockfish 

butter sole 

unidentified goby 

unidentified clingfish 

unidentified snailfish 

red brotula 

greenling 

Taxa unique to the Units 6 and 7 intake 

Taxon 

Auiorhynchus flavidus 

Pleuronectes bilineatus 

Liparis fucensis 

Typhlogobius californiensis 

Bathylagus ochotensis 

Common Name 

tubesnout 

rock sole 

slipskin snailfish 

blind goby 

popeye blacksmelt 

Mean concentrations (#/m3) for fishes collected from the stations in front of the new combinedcycle units and the Units 6 and 7 intakes during Surveys 1 through 42 were based on two 

replicate samples collected at each location during a cycle. These data included all six cycles for 

Surveys 1 through 42. A total of 251 paired samples was analyzed to determine if differences in 

species abundances between the two sampling areas could be detected. If no differences were 

detected, laboratory processing could be reduced to a single representative location. Although 

70 larval fish taxa groups were collected from these samples, only 51 taxa were collected at both 

locations. 

The mean concentrations of the 51 taxa collected at both locations were analyzed statistically 

using a paired t-test (Table 4-3). The concentrations for both locations were transformed using 

E9-053.9 4-13 MLPP 316(b) Resource Assessment 

4-28-2000 
3

.80 

4.0 Entrainment and Source Water Results 

logio(x-f-.Ol) to look at relative differences between the two intakes and to account for some of 

the differences in abundance between sampling events. Of the 51 taxa collected in both areas, 

significant differences (a=0.05) between the two intakes were detected in seven taxa: blackeye 

goby Coryphopterus nicholsi, Pacific herring Clupea pallasi, white croaker Genyonemus 

lineatus, longjaw mudsucker Gillichthys mirabilis, prickly sculpin Cottus asper, bay goby 

Lepidogobius lepidus, and English sole Parophrys vetulus. Pacific herring, longjaw mudsucker 

and prickly sculpin were collected in significantly higher concentrations at the Units 6 and 7 

intake while the other four taxa were collected in significantly higher concentrations at the new 

combined-cycle units intake. 

Table 4-3. Results of T-tests Comparing Larval Fish Concentrations at the New Combined-cycle 

Units and the Units 6 and 7 Intakes Collected during Surveys 1 through 42. 

Taxon 

Pholididae unid. 

Gibbonsia spp. 

Atherinidae unid. 

Oxyiebius pictus 

Coryphopterus nicholsi 

Cebidichthys violaceus 

Engraulis mordax 

Artedius lateralis 

Pleuronectidae unid. 

Artedius spp. 

Stichaeidae unid. 

Syngnathus spp. 

Sebastes spp. 

larval/post-larval fish, unid. 

Citharichthys stigmaeus 

Citharichthys sordidus 

Clinocottus analis 

Chaenopsidae unid. 

Sebastes spp. V 

Sebastes spp. V__.De 

Ruscarius creaseri 

larval fish - damaged 

Hypsoblennius spp. 

Sebastes spp. VD 

Sebastolobus spp. 

Clupeiformes 

Clupea pallasii 

Log (x+.Ol) Differences Between New CC Units and Units 6 and 7 

Mean 

Difference 

-0.001211 

-0.004322 

0.007636 

0.006115 

0.048571 

0.017540 

-0.017797 

-0.000232 

0.000344 

-0.010929 

0.003327 

0.001362 

-0.000084 

0.005447 

0.007350 

0.000399 

0.003660 

-0.003356 

0.003238 

0.007043 

-0.001586 

-0.004484 

0.013933 

0.001323 

0.003738 

0.001750 

-0.100821 

No. 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

Std. Error 

0.032334 

0.055453 

0.140047 

0.055813 

0.347901 

0.170433 

0.172066 

0.034172 

0.104702 

0.108357 

0.043853 

0.040135 

0.024152 

0.086996 

0.071270 

0.054968 

0.053736 

0.076405 

0.054746 

0.108888 

0.042344 

0.146928 

0.236369 

0.030167 

0.067157 

0.077657 

0.305518 

T-Value 

-0.593 

-1.235 

0.864 

1.736 

2.212 

1.630 

-1.639 

-0.108 

0.052 

-1.598 

1.202 

0.537 

-0.055 

0.992 

1.634 

0.115 

1.079 

-0.696 

0.937 

1.025 

-0.593 

-0.483 

0.934 

0.695 

0.882 

0.357 

-5.228 

Probability 

ofT 

0.5535 

0.2181 

0.3885 

0.0838 

0.0279 

0.1043 

0.1025 

0.9144 

0.9585 

0.1113 

0.2306 

0.5914 

0.9560 

0.3222 

0.1035 

0.9084 

0.2816 

0.4871 

0.3497 

0.3065 

0.5536 

0.6292 

0.3513 

0.4879 

0.3788 

0.7214 

0.0000 

Power of 

Test 

0.0003 

0.0103 

0.0010 

0.1979 

0.8419 

0.1153 

0.1205 

0.0001 

0.0001 

0.0964 

0.0083 

0.0002 

0.0001 

0.0022 

0.1175 

0.0001 

0.0038 

0.0004 

0.0016 

0.0027 

0.0003 

0.0002 

0.0015 

0.0004 

0.0011 

0.0001 

1.0000 

E9-053.9 4-14 MLPP 316(b) Resource Assessment 

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P.81 

4.0 Entrainment and Source Water Results 

Table 4-3 (continued). Results of T-tests Comparing Larval Fish Concentrations at the New 

Combined-cycle Units and the Units 6 and 7 Intakes Collected during Surveys 1 through 42. 

Taxon 

Gillichthys mirabilis 

Ammodytes hexapterus 

Cottus asper 

Lepidopsetta bilineata 

Cottidae unid. 

Syngnathidae unid. 

Atherinopsis californiensis 

Genyonemus lineatus 

OUgocottus spp. 

Lepidogobius lepidus 

Gobiidae unid. 

Leptocottus armatus 

Parophrys vetulus 

Psettichthys melanostictus 

Osmeridae unid. 

Tarletonbeania crenularis 

Stenobrachius leucopsarus 

Clupeidae unid. 

Gobiesox spp. 

Pleuronectiformes unid. 

Sardinops sagax 

larval fish fragment 

Blennioidei 

Atherinops affinis 

Log (x+.Ol) Differences Between New CC Units and Units 6 and 7 

Mean 

Difference 

-0.046184 

0.006091 

-0.033287 

0.001814 

-0.022078 

0.000053 

0.024535 

0.058214 

-0.007439 

0.118776 

0.000754 

0.003605 

0.008119 

0.002889 

0.000797 

-0.003595 

0.015333 

-0.003167 

0.000156 

0.005266 

0.000715 

0.010356 

-0.000791 

-0.005257 

No. 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

251 

Std. Error 

0.292771 

0.115851 

0.205230 

0.047546 

0.195222 

0.031681 

0.216161 

0.224344 

0.088453 

0.499288 

0.440226 

0.280957 

0.052630 

0.038792 

0.222088 

0.068796 

0.148237 

0.071103 

0.024578 

0.079146 

0.011331 

0.245525 

0.031731 

0.078069 

T-Value 

-2.499 

0.833 

-2.570 

0.604 

-1.792 

0.027 

1.798 

4.111 

-1.332 

3.769 

0.027 

0.203 

2.444 

1.180 

0.057 

-0.828 

1.639 

-0.706 

0.101 

1.054 

1.000 

0.668 

-0.395 

-1.067 

Probability 

ofT 

0.0131 

0.4057 

0.0108 

0.5461 

0.0744 

0.9787 

0.0734 

0.0001 

0.1839 

0.0002 

0.9784 

0.8391 

0.0152 

0.2392 

0^9547 

0.4085 

0.1025 

0.4810 

0.9198 

0.2929 

0.3183 

0.5046 

0.6931 

0.2871 

Power of 

Test 

0.9903 

0.0009 

0.9964 

0.0003 

0.2562 

0.0001 

0.2637 

1.0000 

0.0193 

1.0000 

0.0001 

0.0001 

0.9806 

0.0072 

0.0001 

0.0008 

0.1206 

0.0004 

0.0001 

0.0032 

0.0023 

0.0004 

0.0001 

0.0035 

Preliminary results — quality control checks incomplete 

1 

I E9-053.9 4-15 MLPP 316(b) Resource Assessment 

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P.82 

4.0 Entrainment and Source Water Results 

Units 1-5 

70 

CO 

X 

CO 

I— 

o 

4fe 

CD 

> 

60 

50 

40 

30 

cu 

O 

20 

10 

r 10 

1 I ' ' ' ' I ' ' ' ' I ' ' ' ' I ' ' ' ' I ' ' ' ' I ' 

15 20 25 30 35 40 45 

Survey Number 

Figure 4-2. Mean (dotted line), maximum and minimum (dashed upper and lower lines) cumulative 

numbers of species from 1,000 iterations of data collected over 42 surveys at the new combined-cycle 

units intake. 

Units 6-7 

-p-i—IIIIIIII—111111111111111—111 1 -i—11111—| -

0 5 10 15 20 25 30 35 40 45 

Survey Number 

Figure 4-3. Mean (dotted line), maximum and minimum (dashed upper and lower lines) cumulative 

numbers of species from 1,000 iterations of data collected over 42 surveys at the Units 6 and 7 intake. 

E9-053.9 4-16 MLPP 316(b) Resource Assessment 

4-28-2000 
P.83 

4.0 Entrainment and Source Water Results 

The power of the data to detect a difference between intakes if one actually existed was 

calculated for the taxa groups with data from both intakes. In the taxa where no differences were 

detected, the low estimates of power (all < 0.80) indicated that it would be difficult to conclude 

from" the data for those taxa that no significant difference between intakes existed. Although 

statistical power usually increases with sample size it is also affected by variance. The variance 

increased with sample size reducing the power of the tests. The number of significant 

differences between units for the 51 taxa is greater than one would expect based on a 95 percent 

probability level. These data indicate that there are both qualitative and quantitative differences 

between the two intakes. 

4.1.2 Day-Night Comparison 

ETM and proportional entrainment (PE) values are based on daytime estimates of entrainment 

and source water larval concentrations. Because the unmarked Elkhorn Sough channel cannot be 

safely navigated other than during daytime hours, calculation of ETM values (and PM) must rely 

on daytime source and entrainment sampling results. Intake effects are also estimated when 

possible using fecundity hindcasting (FH) and adult equivalent loss (AEL) models based on 

daytime and nighttime entrainment samples. Twelve months of weekly entrainment samples 

(March 1999 to March 2000) have been collected for these analyses in the routine 24-hour 

entrainment sampling described in Section 3. 

Generally higher concentrations of larvae were collected in nighttime entrainment samples. 

These diurnal changes in larval concentrations found in our 24-hour samples results are 

important measurements in accurately estimating of total entrainment. The total entrainment 

values are used in both the fecundity hindcast (FH) and adult equivalent loss (AEL) models to 

estimate entrainment losses. These daytime and nighttime changes in the concentration of 

entrained larvae are unimportant using an ETM model of entrainment loss, if the ratio of 

entrainment to source water concentrations remain the same throughout the day. 

Since source water stations in the Elkhorn Slough could only be safely sampled during daylight 

hours, members of the TWG requested that we test for diurnal changes in proportional 

entrainment using two source water stations that could be safely sampled at night. A separate 

source water survey was conducted on January 27 and 28, 2000 and another conducted on 

February 3 and 4, 2000 at the Harbor Bridge (HB) and Harbor Mouth (HM) stations shown in 

Figure 3-1. Samples were collected to coincide with each of the six cycles in the 24-hour 

entrainment surveys. The time of day for each collection cycle 1 through 6 are listed in 

Table 4-4. Prior to completing these surveys and analyses, we first conducted a test using 

24-hour data from neighboring entrainment stations (new combined-cycle units and Units 6 

and 7 intakes). 

E9-053.9 4-17 MLPP 316(b) Resource Assessment 

4-28-2000 
P.84 

4.0 Entrainment and Source Water Results 

Results of 24-hour entrainment sampling (6 sampling cycles, four hours apart) clearly indicate 

significant increases in evening and nighttime larval abundance, peaking in the middle of the 

night. Hypothetically, increases in entrainment larval concentrations should be accompanied by 

similar, if not identical increases in source water concentrations. Since information on nighttime 

source-water concentrations is not available, we cannot make a direct test of this hypothesis. 

Instead, we compared the ratio of 24-hour larval concentrations collected at the neighboring 

Units 6 and 7 entrainment sampling station. 

Concentrations of unidentified Gobiidae, the most consistently abundant larval taxa, were used to 

provide the largest number of paired station samples. Results from 29 weekly 24-hr entrainment 

surveys (1-28 and 34) collected from the stations of the new combined-cycle and Units 6 and 7 

intakes were used in the comparison. Results from Survey 13, cycle 4; Survey 14, cycle 5 and 

Survey 16, cycle 5 were not used in the analysis due to the extreme, outlying nature of the three 

values. The values may represent either a rare set of yet unexplained circumstances or 

experimental error. We will continue to investigate these separated results. Concentrations from 

the two areas were compared by simple ratio of replicate samples as closely paired in time as 

possible. 

The test results indicate the ratio of unidentified Gobiidae larval concentrations between the two 

stations change roughly 75 percent between day and night. The decreased nighttime similarity of 

the two stations may reflect the presence of a hydraulic transition zone between the two stations, 

where more outgoing tidal flows from Elkhorn Slough bearing concentrations of larvae reach the 

combined-cycle area than the area of the Units 6 and 7 intake. The existence of such a hydraulic 

pattern would be amplified by the late nighttime hours (cycles 4 and 5) by higher concentrations 

of larvae from the slough. Although we continue below to compare these findings to results 

from nighttime samples collected at the Harbor Bridge and Harbor Mouth stations, the spatial 

effects seen in the first test results seem to preclude the possibility of converting daytime source 

water concentrations to nighttime concentrations. 

E9-053.9 4-18 MLPP 316(b) Resource Assessment 

4-28-2000 
P.85 

1 

I 

4.0 Entrainment and Source Water Results 

1 

1 

I 

1 

1 

1 

1 

1 

1 

I 

1 

I 

1 

Table 4-4. Sample Collection Times (PST) by Cycle, Date and Source Water Stations, Harbor 

Mouth (HM) and Harbor Bridge (HB). 

Cycle 

1 

2 

3 

4 

5 

6 

Harbor Mouth 

01/27/2000 02/03/2000 

10:55 11:12 

14:39 14:43 

18:42 18:49 

22:38 22:48 

2:51 2:47 

6:43 6:45 

1 

Harbor Bridge 

01/27/2000 02/03/2000 

10:45 10:58 

14:28 14:29 

18:32 18:37 

22:27 22:34 

2:34 2:33 

6:30 6:33 

The results of a daytime and nighttime survey of two source water stations revealed no clear 

pattern of either higher or lower entrainment proportions with respect to time of day. The 

concentrations ofthe three larval taxa, unidentified gobies, bay goby, and Pacific staghorn 

sculpin, that were consistently present in both entrainment and source water samples are 

compared in Tables 4-5 and 4-6. Ratios shown in the table were calculated by dividing the 

species' larval concentrations collected at the new CC units intake entrainment station by their 

concentrations at the Harbor Mouth (HM) and Harbor Bridge (HB) stations. The results are 

tabulated for the three taxa by survey date and the six sampling cycles. The average of all of the 

species' ratios by time of day (sampling cycle) ranges from 1.5 to 12.8 with minimum values of 

0.1 to maximum values of 57. The results were highly variable with no clear pattern of 

nighttime and daytime differences in proportion of entrainment and source water larval 

concentrations from the harbor stations. The effect of tidal currents on distribution of larval 

fishes from the Elkhorn Slough and Monterey Bay would be expected to represent a large source 

of variation among source water stations and the ratio of entrainment and source water 

concentrations. 

Table 4-5. Ratio of Daytime and Nighttime Concentrations of Larval Unidentified Goby Taxa, 

Bay Goby, and Pacific Staghorn Sculpin Collected at the Harbor Mouth (HM) Station to New CC 

Units Intake Station Entrainment Concentrations. 

HM 

Cycle 

i 

2 

3 

4 

5 

6 

Unidentified Gobies 

01/27/2000 

2.14 

2.25 

0.30 

1.07 

7.90 

0.45 

02/03/2000 

0.23 

0.34 

10.95 

* 

0.84 

14.57 

Bay Goby 

01/27/2000 

4.47 

19.99 

1.07 

1.28 

4.93 

0.39 

02/03/2000 

0.71 

1.03 

54.25 

57.10 

2.47 

21.07 

Pacific Staghorn 

Sculpin 

01/27/2000 02/03/2000 

* * 

0.41 0.25 

2.40 0.56 

2.71 1.60 

0.47 1.30 

3.42 0.98 

MEAN 

1.89 

4.05 

11.59 

12.75 

2.99 

6.81 

MIN 

0.23 

0.25 

0.30 

1.07 

0.47 

0.39 

MAX 

4.47 

19.99 

54.25 

57.10 

7.90 

21.07 

*No value can be computed. 

E9-053.9 4-19 MLPP 316(b) Resource Assessment 

4-28-2000 
P.86 

4.0 Entrainment and Source Water Results 

Table 4-6. Ratio of Daytime and Nighttime Concentrations of Larval Unidentified Goby Taxa, 

Bay Goby, and Pacific Staghorn Sculpin Collected at the Harbor Bridge (HB) Station to New CC 

Units Intake Station Entrainment Concentrations. 

HB 

Cycle 

1 

2 

3 

4 

5 

6 

Unidentified Gobies 

01/27/2000 02/03/2000 

2.20 0.19 

3.60 0.35 

0.24 2.95 

1.04 2.11 

1.27 0.70 

0.37 10.05 

Bay Goby 

01/27/2000 02/03/2000 

2.40 0.47 

8.98 1.29 

0.78 14.88 

1.21 6.72 

2.36 2.08 

0.34 23.36 

Pacific Staghorn 

Sculpin 

01/27/2000 02/03/2000 

5.62 * 

1.05 0.13 

1.78 0.99 

1.33 2.01 

0.74 2.03 

3.49 1.15 

MEAN 

2.18 

2.57 

3.60 

2.40 

1.53 

6.46 

MIN 

0.19 

0.13 

0.24 

1.04 

0.70 

0.34 

MAX 

5.62 

8.98 

14.88 

6.72 

2.36 

23.36 

*No value can be computed. 

E9-053.9 4-20 MLPP 316(b) Resource Assessment 

4-28-2000 
P.87 

1 

1 

1 

1 

1 

1 

1 

1 

1 

I 

1 

4.0 Entrainment and Source Water Results 

4__2 Sow©© Water Sttydy Resyflfti 

Nine monthly surveys have been conducted since the source water study began in June 1999. 

•

Initially three stations (Kirby Park, Dairies, and Harbor Bridge) were sampled. Three new 

stations (Figure 3-1) were added to the source water study in September 1999. Two of these 

stations are located in Monterey Bay (Ocean North and Ocean South) and one station is located 

• at the mouth of the Moss Landing Harbor (Harbor Mouth). Descriptions of station locations are 

provided in Table 3-2. Data from these new stations from September 1999 through February 

2000 are presented in this report. 

The source water was divided into three areas for the purpose of data assessment. To compute 

larval fish percent composition and to calculate proportional entrainment for "Elkhorn Slough" 

data were analyzed from the Kirby Park, Dairies, and Harbor Bridge stations for all nine surveys. 

"Moss Landing Harbor" data were calculated from samples collected at the Harbor Bridge and 

the new combined-cycle units and the Units 6 and 7 intakes on days when the source water 

surveys were conducted. The "Ocean" data were calculated from samples collected from the 

Harbor Bridge Station for the first three surveys (before the new stations were added) and from 

the new Harbor Mouth and the two new Ocean stations for Surveys 4 through 9. 

Eight taxa of larval fishes comprised nearly 95 percent of the total numbers of taxa collected in 

the Elkhorn Slough area (Figure 4-4). The taxa, listed in decreasing order of abundance were: 

unidentified gobies (60.4 percent), Pacific herring (10.9 percent), blennies Hypsoblennius spp. 

(6.8 percent), longjaw mudsucker Gillichthys mirabilis (5.1 percent), bay goby Lepidogobius 

lepidus (5.0 percent), Pacific staghorn sculpin Leptocottus armatus (4.1 percent), blackeye goby 

Coryphopterus nicholsi (1.6 percent), and northern lampfish Stenobrachius leucopsarus (1.1 

percent). 

Ninety-five percent of the total numbers of taxa collected in the Moss Landing Harbor area 

(Figure 4-4) was represented by many of the same taxa listed above. The taxa, listed in 

decreasing order of abundance were: unidentified gobies (48.4 percent), bay goby (30.5 percent), 

Hypsoblennius spp. (5.1 percent), blackeye goby (2.9 percent), northern lampfish (2.7 percent), 

Pacific staghorn sculpin (2.5 percent), longjaw mudsucker (1.6 percent), and white croaker 

G. lineatus (0.9 percent). 

Species composition was more varied at the Ocean area. Twelve taxa (including unidentified 

larval fishes) comprised 96 percent of all taxa (Figure 4-4). The taxa, listed in decreasing order 

of abundance were: unidentified gobies (36.2 percent), northern lampfish 5. leucopsarus (21A 

percent), unidentified rockfishes Sebastes spp. (6.9 percent), white croaker (4.4 percent), bay 

goby (4.1 percent), Hypsoblennius spp. (3.0 percent), thomyheads Sebastolobus spp. (3.0 

E9-053.9 4-21 MLPP 316(b) Resource Assessment 

4-28-2000 
P.88 

4.0 Entrainment and Source Water Results 

percent), Pacific staghorn sculpin (2.5 percent), unidentified larval fishes (2.4 percent), blue 

lanternfish Tarletonbeania crenularis (1.7 percent), unidentified flounders Pleuronectidae (1.5 

percent), and Pacific sand lance Ammodytes hexapterus (1.2 percent). 

Fishe* Collected In Oman Station* 

Fishes Collected in Elkhorn Slough 

northern lampfish 

blackeye goby 

1.6% 

staghorn sculpin 

4.1% 

longjaw mudsucker 

• 5 1% 

uwdsWiBlWd pot-siii 

36_2% 

unidentified gobies 

60.4% 

Fishes Collected in Moss Landing Harbor 

tongjaw mudsucker 

1.6% 

bay goby 

30.5% 

unidentified gobies 

48.4% 

Figure 4-4. Percent composition ofthe most abundant larval fish taxa collected in source water surveys 

at Elkhorn Slough, Moss Landing Harbor, and Ocean areas: June 1999 through February 2000. 

E9-053.9 4-22 MLPP 316(b) Resource Assessment 

4-28-2000 
P.89 

4.0 Entrainment and Source Water Results 

Mean source water concentrations (no./l,000 m3) for all larval fishes for all source water surveys 

are presented in Table 4-7. Source water concentrations of the eight most abundant taxa 

collected in the entrainment surveys (Section 4-1) are discussed individually in Sections 4-3 

through 4-10. 

Mean source water concentrations (no./l,000 m3) for all targeted crab species collected in source 

water surveys are presented in Table 4-7. Source water concentrations of the targeted crab 

species collected in the entrainment surveys (Section 4-1) are discussed individually in 

Sections 4-11 through 4-18. 

Three species of cancer crab megalops comprised 100 percent of the total numbers of taxa 

collected in the Elkhorn Slough area (Figure 4-5). The taxa, listed in decreasing order of 

abundance were: hairy rock crab Cancer jordani (50 percent), red rock crab Cancer productus 

(25 percent), and yellow rock crab Cancer anthonyi (25 percent). 

Species composition was more varied at the Moss Landing Harbor area. Five species of cancer 

crab megalops comprised 100 percent of the total numbers of taxa collected in the Moss Landing 

Harbor area (Figure 4-5). The taxa, listed in decreasing order of abundance were: hairy rock 

crab (36.4 percent), brown rock crab Cancer antennarius (34.7 percent), red rock crab (12.2 

percent), yellow rock crab (8.2 percent), and slender rock crab Cancer gracilis (8.2 percent). 

Five taxa of cancer crab megalops comprised 100 percent of the total numbers collected in the 

Ocean area (Figure 4-5). The taxa, listed in decreasing order of abundance were: hairy rock crab 

(66.9 percent), unidentified Cancer spp. (15.9 percent), brown rock crab (10.6 percent), slender 

rock crab (5.3 percent), and yellow rock crab (1.3 percent). 

E9-053.9 4-23 MLPP 316(b) Resource Assessment 

4-28-2000 
P.9Q 

4.0 Entrainment and Source Water Results 

Ocean Stations 

Cancer app. (megalops) 

15.9% 

Cancer antennarius 

(megalops) 

10.6% 

Elkhorn Slough Station* 

Cancer productus 

(megalops) 

25% 

Cancer anthonyi (megalops) 

1.3% 

Cancer gracilis (megalops) 

5.3% 

Cancer jordani (megatops) 

66 9% 

:er jordani 

•galops) 

50% 

Cancer anthonyi 

(megalops) 

25% 

Moss Landing Harbor 

Cancer productus 

(megalops) 

12.2% 

Cancer jordani (megalops) 

36.7% 

Cancer antennarius 

(megalops) 

34.7% 

Cancer anthonyi (megalops) 

6 2% 

Cancer gracilis (megalops) 

8.2% 

Figure 4-5. Percent composition ofthe most abundant megalopal cancer crab taxa collected in source 

water surveys at Elkhorn Slough, Moss Landing Harbor, and Ocean Areas: June 1999 through February 

2000. 

E9-053.9 4-24 MLPP 316(b) Resource Assessment 

4-28-2000 
Table 4-7. Mean Concentrations (#/l,000 m3

) of all Larval Fish Taxa, Cancer spp. Megalops, and European Green Crab Megalops 

Collected in the Source Water in the Vicinity ofthe Moss Landing Power Plant: June 1999 through February 2000. 

Taxon 

Agonidae unid. 

Ammodytes hexapterus 

Artedius spp. 

Atherinidae unid. 

Atherinopsis californiensis 

Bathylagus ochotensis 

Bathymasteridae unid. 

Blennioidei 

Cebidichthys violaceus 

Cbaenopsidae unid. 

Citharichthys sordidus 

Citharichthys stigmaeus 

Clinocottus analis 

Clupea pailasii 

Clupeidae unid. 

Clupeiformes 

Coryphopterus nicholsi 

Cottidae unid 

Cottus asper 

Engraulis mordax 

Genyonemus lineatus 

Gibbonsia spp. 

Gillichthys mirabilis 

Gobiidae unid. 

Hexagrammidae unid. 

Hypsoblennius spp. 

larval fish - damaged 

larval fish fragment 

tarval/post-larval fish. unid. 

Lepidogobius lepidus 

Leptocottus armatus 

Leuresthes tenuis 

Liparis spp. 

OUgocottus (pp. 

Osmeridae unid. 

Oxyiebius picius 

Paralichthyidae unid. 

Parophrys vetulus 

Pleuronectes bilineatus 

Pleuronectidae unid. 

Pleuronectiformes unid 

Psettichthys melanostictus 

Scorpaenichthys marmoratus 

Sebastes aurora 

Sebastes diploproa 

Sebastes jordani 

Sebastes spp. 

Sebastes spp. V 

Sebastes spp. V_De 

Sebastes spp. VD 

Sebastolobus spp. 

Stenobrachius leucopsarus 

Sttchaeidae unid 

Syngnathidae unid. 

Tarletonbeania crenularis 

Xeneretmus latifrons 

Cancer antennarius (megalops) 

Cancer anthonyi (megalops) 

Cancer gracilis (megalops). 

Cancer jordani (megalops) 

Cancer productus (megalops) 

Cancer spp. (megalops) 

Carcinus maenas (megalops) 

Common Name 

poachers 

Pacific sand lance 

sculpins 

silversides 

jacksmelt 

popeye Nacksmelt 

ronquils 

blennies 

monkeyface eel 

lube blennies 

Pacific sanddab 

speckled sanddab 

wooly sculpin 

Pacific herring 

herrings 

herrings and anchovies 

Nackeye goby 

sculpins 

prickly sculpin 

northem anchovy 

white croaker 

clinid kelpfishes 

longjaw mudsucker 

unidentified gobies ' 

greenlings 

Mennies 

unidentified larval fishes 

unidentified larval fishes 

unidentified larval fishes 

bay goby 

Pacific staghorn sculpin 

Califomia grunion 

snailfishes 

sculpins 

smells 

painted greenling 

lefteye flounders & sanddabs 

English sole 

rocksole 

flounders 

flatfishes 

land sole 

cabezon 

aurora rockfish 

splitnose rockfish 

shortbelly rockfish 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

thomyheads 

northem lampfish 

pricklebacks 

pipefishes 

Hue lantemfish 

Nackeye poacher 

FISH TOTALS: 

brown rock crab 

yellow rock crab 

slender rock crab 

hairy rock crab 

red rock crab 

unidentified cancer crabs 

European green crab 

CRAB TOTALS: 

Count 

I 

547 

8 

40 

97 

1 

2 

1 

75 

1 

13 

12 

2 

683 

1 

11 

62 

48 

38 

55 

399 

1 

214 

8.686 

2 

239 

7 

181 

12 

1,861 

465 

I 

1 

1 

216 

3 

2 

3 

3 

80 

27 

5 

9 

1 

1 

3 

12 

82 

2 

58 

92 

630 

1 

2 

37 

1 

15.038 

17 

2 

10 

110 

3 

24 

1 

167 

Survey 1 

June 17. 1999 

Mean Den. <#/IO0Om3) 

Kirbv Park Dairies Harbor Bridge 

N = 

Count 

34 

45 

366 

4 

2 

451 

0 

4 N= 4 N= 4 

Den. Counl Den. Count Den. 

1 2.7 

2 6.2 

1 4.3 

146.3 8 23.0 

1 3.0 . 

182.0 22 616 

1571.8 146 4143 7 33.7 

17.3 35 997 3 14 5 

1 4.3 

7.9 2 5.7 

1 6 0 

217 13 

0 0 

Survey 2 

July 12. 1999 

Mean Den. <#/IOOOm3) 

KJirbv Park pairies Hartvr Bridge 

N = 2 N = 4 N- 3 

Count Den. Counl Den. Count Den. 

1 4.5 

1 5.7 

2 102 

12 141.0 

72 845.7 12 49.2 12 58.3 

1 11.7 3 12 4 49 253.5 

2 7.9 2 9.0 

1 5.0 5 249 

85 18 72 

0 0 0 

Survey 3 

August 12. 1999 

Mean Den. (#/1000m3> 

Kirbv Park Dairies HartxT Bridze 

N = 4 N= 4 N= 4 

Counl Den. Counl Den. Counl Den. 

4 I7.| 

2 10 1 1 4.8 

14 57.4 27 137.3 12 53.2 

11 36 9 68 343.1 

1 4 4 

1 4.1 

27 96 18 

0 0 0 

E9-053.9 4-25 MLPP 316(b) Resource Assessment 

4-28-2000 

to 
Table 4-7 (continued). Mean Concentrations (#/l,000 m3

) of all Larval Fish Taxa, Cancer spp. Megalops, and European Green Crab 

Megalops Collected in the Source Water in the Vicinity ofthe Moss Landing Power Plant: June 1999 through February 2000. 

Taxon 

Agonidae unid. 

Ammodytes hexapterus 

Anedius spp. 

Atherinidae unid. 

Atherinopsis californiensis 

Bathytagus ochotensis 

Bathymasteridae unid 

Blennioidei 

Cebidichthys violaceus 

Chaenopsidae unid. 

Citharichthys sordidus 

Citharichthys stigmaeus 

Clinocottus analis 

Clupea patlasii 

Clupeidae unid. 

Clupeiformes 

Coryphopterus nicholsi 

Cottidae unid. 

Cottus asper 

Engraulis mordax 

Genyonemus lineatus 

Gibbonsia spp. 

Gillichthys mirabilis 

Gobiidae unid. 

Hexagrammidae unid. 

Hypsoblennius spp. 

larval fish • damaged 

larval fish fragment 

larval/potl-larval fish. unid. 

Lepidogobius lepidus 

Leptocottus armatus 

leuresthes tenuis 

Liparis spp. 

OUgocottus spp. 

Osmeridae unid. 

Oxyiebius (rictus 

Paralichthyidae unid 

Parophrys vetulus 

Pleuronectes btlineatus 

Pleuronectidae unid 

Pleuronectiformes unid. 

Psettichthys melanostictus 

Scorpaenichthys marmoratus 

Sebastes aurora 

Sebastes diploproa 

Sebastes jordani 

Sebastes spp. 

Sebastes spp- V 

Sebastes spp. V_De 

Sebastes spp- VD 

Sebastolobus spp. 

Stenobrachius leucopsarus 

Stichaeidae unid 

Syngnathidae unid. 

Tarletonbeania crertularis 

XeneretmuS lasifrons 

Cancer antennarius (megalops) 

Cancer anthonyi (megalops) 

Cancer gracilis (megalops) 

Cancer jordani (megalops) 

Cancer productus (megalops) 

Cancer spp. (megalops) 

Carcinus maenas (megalops) 

Common Name 

poachers 

Pacific sand lance 

sculpins 

silvenides 

jacksmelt 

popeye Nacksmelt 

ronquili 

blennies 

monkeyface eel 

tube Mennies 

Pacific sanddab 

speckled sanddab 

wooly sculpin 

Pacific herring 

herrings 

herrings and anchovies 

blackeye goby 

sculpins 

prickly sculpin 

northern anchovy 

while croaker 

dinid kelpfishes 

longjaw mudsucker 

unidentified gobies 

greenlings 

blennies 

unidentified larval fishes 

unidentified larval fishes 

unidentified larval fishes 

bay goby 

Pacific itaghom sculpin 

California grunion 

snailfishes 

sculpins 

smelts 

painted greenling 

lefteye flounders A sanddabs 

English sole 

rock sole 

flounders 

flatfishes 

sand sole 

cabezon 

aurora rockfish 

splitnose rockfish 

shortbelly rockfish 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

thomyheads 

northern lampfish 

pricklebacks 

pipefishes 

Hue lan lem fish 

Nackeye poacher 

FI5H TOTALS: 

brown rock crab 

yellow rock crab 

slender rock crab 

hairy rock crab 

red rock crab 

unidentified cancer crabs 

European green crab 

CRAB TOTALS: 

Kirbv Park 

N > 4 

Count Den. 

2 12.6 

50 314.9 

8 53.7 

60 

0 

Ppirics 

N » 4 

Count Den. 

1 6 3 

2 12.7 

2 10.8 

14 84.3 

9 55.5 

31 198.8 

59 

0 

Survey 4 

September 16. 1999 

Mean Den. (#/IOOOm3) 

Hartwr Bridse Harbor Mouth 

N * 4 N* 4 

Count Den. Count Den. 

1 5.0 

1 6.9 

1 4.9 2 135 

1 4 

0 0 

Ocean North 

N » 4 

Count Den. 

2 5.1 

3 7,1 

1 2.3 

6 

1 2 3 

2 5.6 

18 520 

16 39.1 

37 

Ocean South 

N = 4 

Count Den. 

1 2.9 

1 2.9 

1 2.3 

1 29 

4 

3 8.7 

3 

Kirbv Park Dairies 

N = 4 N = 4 

Count Den. Count Den. 

1 5.7 

1 5.2 

6 32-1 

38 131.7 184 965.8 

3 17.3 25 126.9 

2 9.2 

31 158.6 

41 250 

0 0 

Survey 5 

October 14. 1999 

Mean Den. (*/|000m3) 

Harbor Bridae Harbor Mouth Ocean North Ocean South 

N = 4 N= 4 N= 4 N= 4 

Counl Den. Count Den. Counl Den. Count Den. 

1 2.2 

1 2.4 1 2.5 

1 2.2 

1 2.0 

3 16.2 

61 3224 3 10.2 2 4.7 

8 44.9 3 10 3 3 6.9 

1 2.9 1 2.6 

48 254.3 I 3.4 

2 4.7 1 2.2 

120 8 9 5 

4 108 1 2.0 

1 3.6 2 4.5 

2 11.2 10 33.5 2 5.1 13 27.9 

1 2 6 1 2.0 

2 11 7 17 

E9-053.9 4-26 MLPP 316(b) Resource Assessment 

4-28-2000 

CO 
Table 4-7 (continued). Mean Concentrations (#/l,000 m3

) of all Larval Fish Taxa, Cancer spp. Megalops, and European Green Crab 

Megalops Collected in the Source Water in the Vicinity ofthe Moss Landing Power Plant: June 1999 through February 2000. 

Survey 6 

November 18, 1999 

Mean Den. (#/IOOOm3) 

Kirbv Park ppifies Harbor Bridge Harbor Mouth Ocean North Ocean South 

N « 4 N« 4 Ne 4 N- 4 N = 4 N = 4 

Count Den. Count Den. Count Den. Count Pen. Count Den. Count Den. 

Kirbv Park Dairies 

N = 2 N= 4 

Survey 7 

December 29. 1999 

Meai Dav <fl/IOOOm3) 

Harbor Bridge Harbor Mouth Ocean North Ocean South 

N = 4 N = 4 N = 4 N « 4 

Den. Counl Den. Count Den. Counl Den. Counl Den. Count Den. 

Agonidae unid. 

Ammodytes hexapterus 

Artedius spp. 

Atherinidae unid. 

Atherinopsis californiensis 

Bathylagus ochotensis 

Bathymasleridae unid 

Blennioidei 

Cebidichthys violaceus 

Chacnopsidae unid. 

Citharichthys sordidus 

Citharichthys stigmaeus 

Clinocottus analis 

Clupea pallasii 

Clupeidae unid 

Clupeiformes 

Coryphopterus nicholsi 

Cottidae unid. 

Cottus asper 

Engraulis mordax • 

Genyonemus lineatus 

Gibbonsia spp. 

Gillichthys mirabilis 

Gobiidae unid. 

Hexagrammidae unid. 

Hypsoblennius spp. 

larval fish - damaged 

larval fish fragment 

larval/post-larval fish. unid. 

Lepidogobius lepidus 

Leptocottus armatus 

Leuresthes tenuis 

Liparis spp. 

OUgocottus spp. 

Osmeridae unid 

Oxyiebius pictus 

Paralichthyidae unid. 

Parophrys vetulus 

Pleuronectes btlineatus 

Pleuronectidae unid. 

Pleuronectiformes unid 

Psettichthys melanostictus 

Scorpaenichthys marmoratus 

Sebastes aurora 

Sebastes diploproa 

Sebastes jordani 

Sebastes spp. 

Sebastes spp. V 

Sebastes spp. V_De 

Sebastes spp. VD 

Sebastolobus spp. 

Stenobrachius leucopsarus 

Stichaeidae unid 

Syngnathidae unid 

Tarletonbeania crenularis 

Xeneretmus tatifrons 

poachers 

Pacific sand lance 

sculpins 

silversides 

jacksmelt 

popeye Nacksmelt 

ronquili 

Mennies 

monkeyface eel 

tube Mennies 

Pacific sanddab 

speckled sanddab 

wooly sculpin 

Pacific herring 

herrings 

herrings and anchovies 

Nackeye goby 

sculpins 

prickly sculpin 

northern anchovy 

white croaker 

clinid kelpfishes 

longjaw mudsucker 

unidentified gobies 

greenlings 

blennies 

unidentified larval fishes 

unidentified larval fishes 

unidentified larval fishes 

bay goby 

Pacific staghorn sculpin 

Califomia grunion 

so ail fishes 

sculpins 

smells 

painted greenling 

lefteye flounders & sanddabs 

English sole 

rock sole 

flounders 

flatfishes 

sand sole 

cabezon 

aurora rockfish 

splitnose rockfish 

shortbelly rockfish 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

thomyheads 

northern lampfish 

pricklebacks 

pipefishes 

Nue lantemftsh 

Nackeye poacher 

8 44.9 

27 152.0 

31.6 

10649 

7.3 

116.2 

7 

127 

3 

12 

1 

264 

4906 

114 

45.8 

4.6 

13 

1 

4 

4 

32.2 

2 1 

8.3 

8.3 

12.7 

399,6 

6 

102 

.13.8 

844.9 

2 

30 

113 

1668 

24.7 

124.0 

25.6 

62.7 

2 

17 

3 1 

40 3 

I 

4 

5 

25 

2.0 

10.3 

11.4 

57.2 

FISH TOTALS: 25 20 

Cancer antennarius (megalops) 

Cancer anthonyi (megalops) 

Cancer gracilis (megalops) 

Cancer jordani (megalops) 

Cancer productus (megalops) 

Cancer spp. (megalops) 

Carcinus maenas (megalops) 

brown rock crab 

yellow rock crab 

slender rock crab 

hairy rock crab 

red rock crab 

unidentified cancer crabs 

European green gab 

2 

53 

4.2 

124.0 

2 

1 

4.2 

2.2 

E9-053.9 4-27 MLPP 316(b) Resource Assessment 

4-28-2000 
Table 4-7 (continued). Mean Concentrations (#/l,000 m3

) of all Larval Fish Taxa, Cancer spp. Megalops, and European Green Crab 

Megalops Collected in the Source Water in the Vicinity ofthe Moss Landing Power Plant: June 1999 through February 2000. 

Taxon 

Agonidae mid. 

Anttnodytes hexapterus 

Anedius spp. 

Atherinidae unid. 

Atherinopsis californiensis 

Bathylagus ochotensis 

Bathynusleridae unid 

Blennioidei 

Cebidichlhyt violaceus 

Qtaenopsidae unid. 

Citharichthys sordidus 

Citharichthys stigmaeus 

Clinocottus analis 

Clupea pallasii 

Clupeidae unid. 

Clupeiformes 

Coryphopterus nicholsi 

Cotlidse unid. 

Cottus asper 

Engraulis mordax 

Genyonemus lineatus 

Gibbtmsia spp. 

Gillichthys mirabilis 

Gobiidae unid. 

Hexagraimnidae unid 

Hypsoblennius spp. 

larval fish - damaged 

larval fish fragment 

larval/post-larva] (ish. unid. 

Lepidogobius lepidus 

Leptocoaut armatus 

Leuresthes tenuis 

Liparis spp. 

Otigocoaus spp. 

Osmeridae unid 

Oxyiebius pictus 

Paralichthyidae unid 

Parophrys vetulus 

Pleuronectes bilineatus 

Pleuroncctidae tnid. 

Pleuronectiformes unid 

Psettichthys melanostictus 

Scorpaenichthys marmoratus 

Sebastes aurora 

Sebastes diploproa 

Sebastes jordani 

Sebastes spp. 

Sebastes spp. V 

Sebastes spp. V_De 

Sebastes spp. VD 

Sebastolobus spp. 

Stenobrachius leucopsarus 

Stichaeidaeunid 

Syngnathidae unid. 

Tortelottbeania crenularis 

Xeneretmus latifrons 

Cancer antennarius (megalops) 

Cancer anthonyi (megalops) 

Cancer gracilis (megalops) 

Cancer jordani (megalops) 

Cancer productus (megalops) 

Cancer spp. (megalops) 

Carcinus maenas (megalcsps) 

Cofitmon Name 

paadKrs 

Pacific sand lance 

sculpins 

silversides 

jacksmelt 

popeye Nacksmelt 

ronquils 

blennies 

monkeyface eel 

tube blennies 

Pacific sanddab 

speckled sanddab 

woolysculpin 

Pacific herring 

herrings 

herrings and anchovies 

blackeye goby 

sculpins 

prickly sculpin 

northern anchovy 

while croaker 

clinid kelpfishes 

longjaw mudsucker 

unidentified gobies 

greenlings 

blennies 

unidentified larva] fishes 

unidentified larval fishes 

unidentified larval fishes 

bay goby 

Pacific staghorn sculpin 

California grunion 

snailfishes 

sculpins 

smelts 

painted greenling 

lefteye flounders A sanddabs 

English sole 

rocksole 

flounders 

flatfishes 

sand sole 

cabezon 

aurora rockfish 

splitnose rockfish 

shonbelly rockfish 

rockfishes 

rockfishes 

rockfishes 

rockfishes 

thomyheads 

northern lampfish 

pricklebacks 

pipefishes 

blue lantemfish 

Mackeye poacher 

FISH TOTALS: 

brown rock crab 

yellow rock crab 

slender rock crab 

hairy rock crab 

red rock aab 

unidentified cancer crabs 

European green crab 

CRAB TOTALS: 

KirtivPark 

N = 4 

Count Den. 

5 29.2 

1 4.7 

3 17.2 

34 191.8 

1 4.4 

1 4.7 

3 16.0 

20 93.3 

1 4.4 

69 

0 

Surveys 

January 20. 2000 

Mean Den. (I/I000m3) 

Dairies Harbor Bridne HarborMouth Ocean North Ocean South 

N = 4 N = 4 N a 

Count Den. Count Den. Count 

1 

1 

1 4.1 

4 14.8 1 3.7 3 

1 6 6 1 

1 

1 7.1 

1 6 6 2 

53 309.6 64 388.2 73 

5 

7 32.2 4 25.2 20 

3 19.7 1 

2 12.0 3 

3 

1 3.1 

1 5.7 

2 

69 77 116 

0 0 0 

4 N = 4 N= 4 

Den. Count Den. Counl Den. 

4.2 1 2.7 

7.3 

1 2.1 

15.2 

7.3 

6.1 1 2.3 1 2.0 

116 1 2 0 

423.1 1 2.3 19 37.8 

1 2.2 

23.5 

129.7 14 27.7 

6.1 8 19.4 

15.9 

17.2 2 4.0 

2 4.8 

6 144 

7 16 1 5 10.8 

9.7 19 44.7 3 6 9 

1 2.0 

43 48 

O 0 

KirWPi»|t 

N = 4 

Ccunt Den. 

11 47 0 

3 13.7 

331 1471.3 

1 4.7 

12 52.5 

37 163.4 

207 9182 

59 232.1 

661 

0 

Dairies 

N = 

Count 

2 

1 

3 

1 

3 

2 

5 

9 

68 

3 

21 

1 

5 

1 

1 

1 

5 

132 

0 

4 

Den. 

7.4 

3.5 

8.4 

4 6 

109 

9.3 

24.4 

266 

255.3 

10.9 

74.7 

4.6 

24.8 

5 0 

4.6 

5 0 

209 

Survey 13 

February 24. 2000 

Mean Den. («/KI00m3) 

Harbor Bndste Harbor M 

N = 4 N=4 

Count Den. Counl 

1 

1 6 4 

1 38 

2 

2 

9 47.8 7 

1 3.1 

2 

1 3.8 1 

5 27.4 3 

13 69 1 30 

2 10.2 3 

193 945.6 283 

1 

9 43.8 7 

1 

4 21.7 4 

10 45.2 6 

9 45.1 10 

11 529 16 

1 6 4 1 

1 6 1 1 

1 

1 6 1 2 

10 512 14 

28 148.4 66 

2 115 6 

312 470 

1 

1 

0 2 

outh 

Den 

4.7 

8.8 

9.4 

30.7 

9 0 

4.7 

13.5 

133.8 

12.3 

256.7 

4.1 

31.0 

4.7 

18.5 

270 

45.1 

73.1 

4.3 

4.9 

4.3 

8.2 

626 

293.7 

260 

4.7 

4.7 

Ocean Nonh 

N = 

Counl 

21 

3 

3 

1 

1 

1 

1 

35 

23 

7 

8 

4 

1 

10 

6 

1 

20 

13 

24 

311 

14 

310 

0 

4 

Den. 

50.1 

6.0 

9 6 

2 2 

18 

18 

2.4 

82.4 

51.3 

14.9 

167 

8.4 

1.8 

26.8 

10.8 

2.4 

42.9 

26.3 

50.0 

647.6 

30.2 

Ocean South 

N = 

Count 

1 

1 

2 

1 

1 

23 

SO 

13 

1 

1 

1 

5 

3 

1 

3 

39 

9 

24 

138 

12 

359 

0 

4 

Den. 

1.8 

1.8 

3.9 

2.8 

2.1 

49.0 

1780 

283 

1.8 

2 8 

2.2 

108 

6 3 

2.1 

5.8 

868 

204 

52.0 

289.9 

26.1 

E9-053.9 4-28 MLPP 316(b) Resource Assessment 

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4.3 0©boodla©o 11 unitmdm 

Gobies belong to a successful family (Gobiidae) of small, demersal fishes that are found 

worldwide in shallow tropical and subtropical environments. The family contains around 1,875 

species in 212 genera (Nelson, 1994; Moser, 1996). The Family Gobiidae is second only to the 

Family Cyprinididae (minnows) in total numbers of species (Moyle and Cech, 1988). 

Twenty-one goby species from 16 genera occur in the California Cooperative Oceanic Fisheries 

Investigations (CalCOFI) study area, from the northern California border to south of Baja 

California (Moser, 1996). 

Members of the goby family share a variety of distinguishing characteristics. Their body shape 

is elongate and can be either somewhat compressed or depressed (Moser, 1996). Most members 

ofthe family lack both a lateral line and swim bladder (Moyle and Cech, 1988). Gobies 

generally have two dorsal fins, the first consisting of 2 to 8 flexible spines and the second 

containing a spine and several segmented rays (Moyle and Cech, 1988; Moser, 1996). Their 

caudal fin is rounded and their pelvic fins are typically joined to form a cup-like disc 

(Moser, 1996). The eyes of most gobies are relatively large and are a dominant feature of their 

blunt heads (Moyle and Cech, 1988). Goby species are extremely variable in coloration. They 

range from the drab, cryptically colored species that inhabit mudflats to the striking, brightly 

colored species of tropical and subtropical reefs (Moser, 1996). 

One of the most important characteristics of the goby family is their small size. The smallest 

known vertebrate, which is mature at 8 to 10 mm (0.3 to 0.4 in.), is a goby species 

Trimmatom nanus from the Chagos Islands in the Indian Ocean (Moyle and Cech, 1988). The 

yellowfin goby Acanthogobius flavimanus, an introduced species that is native to China, is the 

largest goby species found along the California coast. It reaches a maximum total length (TL) of 

around 241 mm (9.5 in.) (Miller and Lea, 1972). Due to their size and evolved tolerances for a 

variety of environmental conditions, gobies have been able to colonize habitats that are 

inaccessible to most other fishes (Moyle and Cech, 1988). These include cracks and crevices in 

coral reefs, invertebrate burrows, mudflats, mangrove swamps, freshwater streams on oceanic 

islands and inland seas and estuaries (Moyle and Cech, 1988). 

Gobies generally occur in shallow marine habitats, however many members of the family are 

euryhaline and are able to tolerate very low salinities and even freshwater. Gobies are often the 

principal freshwater fish species on oceanic islands and are common in many of the rivers and 

streams in Asia (Moyle and Cech, 1988). A goby species Pandaka pygmaea from Luzon 

(Philippines), which is mature at 10 to 12 mm (0.4 to 0.5 in.), is the world's smallest freshwater 

fish. A number of goby species also have the ability to survive out of the water by "breathing" 

air. The longjaw mudsucker Gillichthys mirabilis can survive for days out of water if kept moist, 

E9-053.9 4-29 MLPP 316(b) Resource Assessment 

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1 4.0 Entrainment and Source Water Results 

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and the mudskipper Periopthalamus spp. regularly leaves the water to forage for terrestrial 

insects among mangrove roots and exposed rocks (Moyle and Cech, 1988). Gobies eat a variety 

of larval, juvenile, and adult crustaceans, mollusks, and insects. Many will also eat small fishes, 

fish eggs, and fish larvae. Gobies from the genus Gobisoma are known to "clean" other fishes of 

ectoparasites. In what could be defined as a parasitic relationship, one group of gobies feeds on 

the tube feet of their sea urchin hosts (Teylaud, 1971). 

Gobies are oviparous and produce demersal eggs which are generally elliptical in shape (Moser, 

1996), typically adhesive, and are attached to the nest substrate at one end. Parental care, often 

provided by the male, is common in the family (Moser, 1996). Hatched larvae are planktonic. 

The duration of the planktonic stage varies greatly within the family. Larval gobiids are 

distinctive and not easily confused with other fish larvae. Exceptions include certain life stages 

of eleotrids and scarids (Moser, 1996). 

Identification of larval gobiids to the species level is difficult. Larval gobies collected during 

MLPP entrainment sampling that could not be identified to the species level were left at the 

family level (Gobiidae) and are probably composed of some combination of the following 

species: arrow goby Clevelandia ios, cheekspot goby Ilypnus gilberti, and the yellowfin goby 

Acanthogobius flavimanus. At certain larval stages, bay goby Lepidogobius lepidus may share 

similar taxonomic characters making it difficult to separate from the other species, especially 

when the specimens are not in good condition. 

Myomere counts and dorsal pigmentation characteristics can be used to identify many larvae to 

the species level (Moser, 1996). A number of species cannot be separated unequivocally during 

certain larval stages (Moser, 1996). The arrow goby Clevelandia ios, cheekspot goby Ilypnus 

gilberti, and the shadow goby Quietula y-cauda cannot be differentiated during any larval stage 

(Moser, 1996). However, the known range ofthe shadow goby Q. y-cauda extends only as far 

north as Morro Bay in central California. Adult shadow gobies were not found in a recent study 

of fishes in the vicinity of the MLPP (Lindquist, 1998). Brothers (1975) reported difficulty in 

separating arrow goby from cheekspot goby that were less than 65 mm (2.6 in.) in length. 

The arrow goby C. ios and the cheekspot goby /. gilberti have overlapping ranges and occupy 

similar habitats. Both species inhabit burrows in mud flats and other shallow regions of bays and 

estuaries (Miller and Lea, 1972). The fecundity of the arrow goby (750 to 1,000 eggs) and the 

cheekspot goby (250 to 1,800 eggs) are similar (Wang, 1986). Eggs are demersal and adhesive, 

with filaments for anchoring to substrates (Wang, 1986). No fecundity information is available 

for the shadow goby. The northern range of the cheekspot goby extends to Tomales Bay (Miller 

and Lea, 1972). Arrow goby occupy the most extensive range (of the three), occurring from the 

E9-053.9 4-30 MLPP 316(b) Resource Assessment 

4-28-2000 
4.0 Entrainment and Source Water Results 

Gulf of California to Vancouver Island, British Columbia (Miller and Lea, 1972). Arrow goby 

are common in the Moss Landing-Elkhom Slough area and probably account for a majority of 

the unidentified larval gobies collected during MLPP entrainment sampling. The cheekspot 

goby has been documented in the area and may compose a portion of the Gobiidae category. 

Since it appears that arrow goby may account for a large portion of the larvae identified as 

Gobiidae, its demography will be used to estimate entrainment effects. Brothers (1975) 

estimated a two-month mortality for arrow goby larvae of 98.3 percent. Combining this estimate 

with species-specific fecundity and an assumption of stable age distribution, allowed us to 

calculate the number of adults potentially affected by larval entrainment mortality. 

Endangered tidewater goby Eucyclogobius newberryi adults were recently collected in Bennett 

Slough in October 1999 (M. Sazaki, CEC, pers. comm.). Larval tidewater goby can be 

distinguished from other gobies and none were collected during any entrainment or source water 

surveys at MLPP. 

4.3.2 Unidentified goby results (53.2 percent) 

Unidentified larval gobies comprised 53.2 percent of the total number of fishes collected in 

entrainment samples from the new CC units intake (Figure 4-1). They were collected in all 

entrainment surveys from March 2,1999 through February 24, 2000 from in front ofthe intake 

of new CC units (Figure 4-6). Peak concentration (1,799/1,000 m3) occurred on November 4, 

1999 and the lowest concentration (43/1,000 m3) occurred on August 12,1999. 

The diel distributions were plotted for concentrations of larval unidentified gobies collected in 

front of the new combined-cycle units intake (Figure 4-7). We analyzed only the entrainment 

surveys that coincided with the source water surveys from June 1999 through February 2000. 

Unidentified gobies were typically collected in highest concentrations during the nighttime 

between 2200 and 0300 hours PST except for the October 1999, and January and February 2000 

surveys. In October 1999 and January 2000, the peak diel concentration occurred after sunset at 

approximately 1830 hours PST. In January 2000, the peak diel concentration occurred during 

daylight at 1035 hours, and in February 2000 the peak occurred at dawn (0627 hours). 

E9-053.9 4-31 MLPP 316(b) Resource Assessment 

4-28-2000 
4.0 Entrainment and Source Water Results 

Unidentified Gobies Entrainment Mean Concentration 

1,800 

E MOO 

8 

g 800 

••-•I I fi a 

fffff*f««.ffff_rt*£fct.i£ff?g;?ffff]Fffff?»»skf;i i 

* B » 8 B » "* i * B = * « - » B j i j 1 j, " « ; * - Sj 8 __; s — — M 

Note: All data are preliminary. 

Figure 4-6. Mean survey concentrations (#/l,000 m3) of larval unidentified gobies at the Moss Landing 

Power Plant new combined-cycle units intake: March 1999 through February 2000. 

Unidentified Gobies Larval Entrainment Diel Mean Concentration 

— 2.500 

E 

§ 

E 2,000 

1 

. E 1 

• 

... . — • • . 1 H . 

I 

ll ll .!•! 1. 

1 

.iLn 

• i ll. 

Bana^'uss a 

Aug 12 

_t»t!S B-'B»!l« s"88SI I 

Sep 16 Oct 14 NovK 

2*8S--8S8S"~SBSS -

Note: These entrainment surveys were conducted at the same time as the source water surveys. Data are preliminary. 

Figure 4-7. Concentrations (#/l,000 m3) of larval unidentified gobies at the new combined-cycle units 

intake separated by sample collection time (PST): June 1999 through February 2000. 

E9-053.9 4-32 MLPP 316(b) Resource Assessment 

4-28-2000 
P.99 

4.0 Entrainment and Source Water Results 

Larval unidentified gobies were the most abundantly collected taxa from the Elkhorn Slough, 

Moss Landing Harbor, and the Ocean areas. As previously stated, adults of both arrow (C. ios) 

and cheekspot (/. gilberti) gobies and have been documented in the area. It is likely that some of 

these unidentified gobies are represented by these species, although the larval forms at certain 

stages cannot be distinguished from one another. Mean concentrations (#/l,000 m3) of 

unidentified gobies for all stations, by tidal cycle are presented in Figure 4-8. 

Unidentified gobies comprised 60 percent ofthe total larval fishes collected in the Elkhorn 

Slough area, 48 percent in the Moss Landing Harbor area, and 36 percent in the Ocean area from 

June 1999 through February 2000. Unidentified gobies were collected every month (Figure 4-8). 

They were collected from all stations sampled from June through December 1999 except in 

September and October 1999, when they did not occur at the Harbor Bridge (September only) 

and Ocean North stations. Peaks in concentrations for both the low tides and high tides occurred 

in the Elkhorn Slough area; high tide concentrations peaked (2,913/1,000 m3) in Kirby Park in 

June 1999 and the low tide peak concentration (1,682/1,000 m3) occurred at the Kirby Park in 

February 2000. Unidentified gobies were collected at both high and low tides from all stations in 

November 1999 and February 2000. (Figure 4-8). 

Unidentified Gobies Source Water Mean Concentrations 

1,000 

B High 

• Low 

5 

I 

3 

S 

c 

8 

I 

I 

s 

OOO OOO ooo J 

Jun 16 Jul 12 Aug 12 Sep 16 Ocl14 Nov 18 Dec 29 Jan 20 Feb 24 

Key—KP: Kirby Park; D: Dairies; HB: Harbor Bridge; HM: Harbor Mouth; ON: Ocean North; OS: Ocean South 

O Stations not included in study design until September. 

© Samples voided due to improper preservation. 

Figure 4-8. Source water concentrations (#/l,000 m3) of larval unidentified gobies at six stations near 

Moss Landing Power Plant: June 1999 through February 2000. 

E9-053.9 4-33 MLPP 316(b) Resource Assessment 

4-28-2000