# Brunswick 

# . Steam Electric Plant

1984 BIOLOGICAL 

# MONITORING REPORT

- 1

- 1

- 1 - ;



### BIOLOGY UNIT ENVIRONMENTAL SERVICES SECTION 

# CP&L
Carolina Power & Light CompanyBRUNSWICK STEAM ELECTRIC PLANT 

### 1984
BIOLOGICAL MONITORING REPORT 

### Prepared by:

C. Bened 

### i ct G. F. Booth K. N. Cates D. S. Cooke W. E. Herring K. A. MacPherson L. W. Po 11 ard M. E. Shepherd R. G. Sherfinski T. E. Thompson M. T. Tyndall W. Warren- 

### Hicks Juveni 1 e and Adu 1 t Imp i ngement 

## Project Scientist Entrainment , Larval Impingement Larval Fish Water Quality 

## Editor High Marsh 

# Statistics Discrete Depth 

### Nekton Survival Studies 

# Statistics
Biology Unit
Environmental Services Section

CAROLINA POWER & LIGHT COMPANY NEW HILL, NORTH CAROLINA
August 1985

Rev i ewed 

### and Approved by: 

# ~~

J . Principal Scientist Biology Unit 

# This report was prepared under my supervision 

## and direction , and accept full responsibility for its content.

Environmental Services SectionCOVER: This copy of this report is not a 

### controlled in Environmental Services Section Procedures. the original of this report subsequent to the 

### be obtained from: document as deta i led Any changes made to date of issuance can

Manager Envfronmental Services Section 

### Carol ina Power & Light Company Shearon Harris Energy & Environmental

Route 1 , Box 327
New Hi II , North Carol ina 27562 

### Center

Larval weakfish iCynoscio/l regalis); by. L. W. Pollard

### Acknowl edgments

Many thanks are extended to the individuals who without their assis

## tance and 

# long hours of 

# collection, identification, and processing of samples, this report would not have been 

# possible. Debbie Calhoun, Scott Cates, Donna 

### Coleman, Dana Eakins, 

# Della Lanier, Preston McLendon , Tina 

### Reece, and Scott Taylor dedicated many hours to the 

## laboratory and field support for 

### all studies. Steve Parrish assisted in field collections as

boat captain of the Pisces and constructed and ma 

### i nta i ned fie 1 

### d and 

### aboratory equipment.



### Thanks also go to Sandra 

## Pri ce and members of the Data Management & 

### Control Unit, 

### Biology Unit, and Word Processing Subunit at the 

### Shearon
Harri s 

### Energy & Envi 

### ronmenta 1 Center. 

## Special thanks 

# are given to 

# Drs. B. J. Copeland, Ronald Hodson Michael Weinstein , and Alan Wells for their review of this report. 

## A very special thank you is extended to Anne L. Lineback who spent long hours typing the many drafts associated with the preparation of this 

## report.Tab 1 e of Contents

Ac know 1 ed gme n t s . . 

### . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

### . . . . . . . . . . . . . . . .

Li st of Tabl es. 

### . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Li st of F i gu re s . . . . . . . . 

### . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

### . . . . . . . . . .

Metr i c- Eng 1 ish Convers; on Tab 1 e. . . . . . . . . . . . . . . . . 

### . . . . . . . . . . . . . . . . . . .

Execut; ve 

# Summary..................................................

1.0 INTRODUCTION. . . . . 

### . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

### . . . . . . . .

WATER QUALITY.............................................. 

# Introduction.............................................. Method s. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

### . . . . . . . . . . . . . . . . . . .

Results and Discussion.....................................

RIVER LARVAL FISH.......................................... Introduction....................... ........... 

# .......... ...

Method s . . . . . . . . . . . . . . 

### . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sample Collection and Processing........................... Data Analyses.............................................. Results and Discussion..................................... Domi nant Spec i es. 

### . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

### . . . . . . . .

Station Groupings.......................................... 

## Species-- Station Group Association......................... Ti me- 

### Ser i es Ana 

## ys is. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .



### Length- Frequency Ana 

## ys is. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .



# Summary....................................................

DISCRETE DEPTH............................................. 

# Introduction.............................................. 

# Methods...................................................
Samp 1 e Co 11 

## ect ion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .



### Data Anal ys 

## is. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

### . . . . . . . .

Results and Discussion..................................... Water Temperature and Salinity............................. Analysis of Variance and Duncan s Multiple Range Test Results......................................... 

### Croak er . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

### . . . . . . . . . . . . . . . . . . . .

Spot. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .



### Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . 

### . . . . . . . . . . . . . . . . . . . . . . . .

HIGH MARSH................................................. 

# Introduction.............................................. Method s. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

### . . . . . . . . . . . . . . . . . . .

Station Description........................................ Samp 1 i ng Me t hod s . 

### . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

### . . . . . . . .

i i 

### Page



### xv; i xv; i iTable of Contents 

### (cont i nued)

Data Ana lys is.. .. .... .. 

## . . . .. 

# .... ..... ..... .. . .... . 

# .... . . .. .

Results and Discussion..................................... Sediment Parameters........................................ Catch by Gear Type......................................... Relationships with Abiotic Variables....................... Seine.. .......... ........ .......... ..... ..... 

# ..............

Trawl......................................................
Spati al Analysi s..... .. .... . ... 

### .. . . . 

## ... .. .. . 

# ....... .. . . .. .

Wi thi n 

# Creek............................................... Within the Estuary......................................... Seasonal Distribution...................................... 

### Time- Series Analysis....................................... Alligator Creek............ ........ .......... ..............

Mottl s Bay. ...... 

# ................. ...................... ...

Walden Creek............................................... Baldhead Creek............................................. Return Basin Evaluation.................................... Summa ry and Conc 1 u s 

## ions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .



# NEKTON....................................................

I nt roduct i on. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

### . . . . . . . . . . . . . . . . .

Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

### . . . . . . . . . . . . . . . . . .

Resu 1 ts 

### and 0 i 

### scu s s i on. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Total Organi sms. . ... .... ... ... 

# ...... .. .. .. .. . ... .. 

## .... . . . ..

Seasonality, Recruitment, and Time- Series Analysis......... Bay anchovy................................................ 

# Spot....... .... 

# .............. ................ ... ........ ...



# Croaker.................................................... Menhaden..... ... ....................................... "

Brown shrimp......................... ...................... Blue crab....................... Weakfish....... ......................................... 

# ...

Pink White shrimp............................................... Total organi 

# sms............................................ Spatial Analysis........................................... You ng 

### -of - Year F 

### i nf ish. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Juvenile/Adult Finfish and Invertebrate 

# Catch.............. Diversion Structure Evaluation............................. 

### Summary and Concl us ions. .... .. .. ..... ... ..... 

# ........ .....



# .......................

shrimp................................................

ENTRA I NME NT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

### . . . . . . . . . . . . .



### Introduct i on. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

# Methods............. .. .. . . .. .. .. ... . 

# . ... 

# ..... ..... .... ...

Results and Discussion..................................... Dominant Species........................................... Seasonal ity and 

# Abundance.................................. Numbe 

## rEnt r a i ned . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Di e 1 Entrainment Special Study.................................. Flow Minimization.......................................... 

### Patterns. .. . . .... .. 

### . . . . .... .. 

# . .. ... 

# ... 

# ....... . . .. . 

# ....

i i i Page

7 -Tab 1 e of Contents 

### (cont i nued)

10. 10. 10. 10. 10. 10. 10. 

### 10. 10. 10. 

### 11.0 Summary and Conclusions....................................

SURVIVAL STUDIES........................................... 

# Introduction..............................................
Methods. ........... ...... .... ...... ...... 

# ..................

Collection................................................

Ho 1 ding Fac i 1 it i es . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

### . . . .

Stocking and Monitoring.............................. Definitions, Calculations, and Analyses.......... Results and Discussion........................... Total Organ 

### isms. . . ~ . . . . . . . . 

### . . . . . . . . . . . . . . . . . . . . . .

Speci es 

# Accounts................................. 

# Croaker....................................................
Spot...... .............. ...... ........... ............ Penaeid Postlarvae................................... Pink and White Shrimp................................ Brown Shrimp............................................... Blue Crab.................................................. 

# Weakfish.................................................. Bay Anchovy................................................ 

### St r i ped Mu 11 et . 

### . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

### . . . . . . . . . .



### Flounder. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

### . . . . . . . . .

Menhaden. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

### . . . . . . . . . . . . . . . . .

Mi sce 11 aneous 

### Spec i es. . . . . . . . . . . . . . . . . . . 

### . . . . . . . . . . . . . . . . . . .

Summary and Conc 1 u s 

## ions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

IMPINGEMENT (Larval)....................................... 

# Introduction..............................................

Methods... ..... ..... 

# ..... ........ ....... ....... ..... .......

Sample Collection.......................................... Sample Analysis............................................ Results and Discussion..................................... Dominant Species........................................... Seasonal i ty and Abundance.................................. Di el 

## Tidal Surv i val 

### Est i mates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

### . . . . . . . . .

Summary and Conc 1 us 

## ions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Patterns. ...... ......... .................. ............



# Patterns............................................

IMPINGEMENT (Juvenile and Adult)........................... 

### I nt roduct i on. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

### . . . . . . . . . . . . . . . . .



# Methods.............................. .. 

# ....................

Results and Discussion..................................... Spec i e s Compos i t i on. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

### . . . . . . .

Di e 1 

# Patterns.............................................
Flow Rates................................................. 

### Length- Frequency Di stri but 

# ions..... Estimated Survival Adjustments..... Summary and Conclusions............ 

### . . . . . . . . . . . . . . . . . . . . . . . . ...... ..... ....... ...... 

# ........................

REFERENCES. . . . . 

### . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

### . . . . . . . . . .

Page



### 10- 10- 

### 10- 10- 

### 10- 10- 10- 10- 10- 10-
11-Table of Contents (continued)

APPEND IX A Brunswick Steam Electric Plant Intake Modifications and Flow Minimization..........................................

APPEND IX 8 Statistical Explanation of Time- Series and Milivariate Analyses.... .... ........ .......... 

# .......................... ...

APPEND IX C River Larval Fish and Tucker Trawl Gear Comparison 

# Study.......................................................... Page

## Table

1.1 

## 1.2

1.3 List of Tables

BSEP 1984 biological monitoring program summary............
Species of fish and shellfish analyzed by program during 1984................................................ Species of fish and shellfish collected by program during 1984................................................ Annual mean density and the percentage of the 

## total mean density for the eight most abundant species collected in the river larval fish program, 1979- 

# 1984......
Principle component scores by station and ranked correlations of larvaljpostlarval organisms, water temperature, and salinity for the 1977- 1984 river larval fish data...........................................

Results of time- series analysis for river 

## larval fish data by station group indicating significant changes in density along with amount of variance explained by the model..................................... Results of analysis of variance for spot and croaker for the 1984 Cape Fear River discrete depth program........ Analysis of variance cell means for croaker densities collected in the 1984 Cape Fear River discrete depth

, .

samp, 1 ng 

# program...........................................
Results of analysis of variance cell means for spot densities collected in the 1984 Cape Fear River discrete depth sampling program............................
Sediment parameters for the high marsh seine 

### and trawl stations during 1984.......................................

Tota 1 catch and percent total of the ten most abundant species collected in the high marsh study during 1984...... Results of the principle component analysis by station for organisms collected by seines in the high marsh 

## study duri ng 1984.......................................... Results of the principle component analysis by station for organisms collected in Baldhead Creek by 

## trawl in the high marsh study during 1984........................... Results of the principle component analysis by station for organisms collected in Walden Creek by trawl in the high marsh study during 1984............................... 

### PageList of Tables (continued)

Tota 1 catch- per-uni t- effort by creek system for 12 selected species in the high marsh study during 1984....... Results of time-series analysis of high marsh data by creek showing trends in abundance from 1981 through 1984............................................... 

### Tota 1 number, percent total number , and annual catch

## per- unit-effort of the ten most abundant species collected in the nekton study during 1984.....................

Resu 1 ts of t ime-seri es ana lys i s 

## of nekton ri ver data indicating significant increase or decrease in CPUE for 1979 through 1984......................................
Results of the principle component analysis by station for young-of-year finfish collected in the nekton study, years 1983 and 1984 combined.............
Results of the principle component analysis by station for juveniles/adults collected in the nekton study, years 1983 and 1984 combined................. Results of analysis of variance and Duncan multiple range test for selected species utilized in the evaluation of the BSEP diversion structure during 1984................. .......... 

# ...... 

# ...............

Mean density and percent total of fish , penaeid 

## shrimp, and portuni d crabs entrained , September 

### 1978- August 1984...........................................
Entrainment densities at the BSEP from September 

### 1983 through Apri 1 1985.................................... 

### Entra i nment rates at the BSEP from September 1983 

### through Apri 1 1985.........................................

Reduct ion in 

### entra i 

## nment by number and mean dens i ty for selected species for the three special study periods..............................................
Comparative reductions in entrainment of total organisms due to flow minimization......................... Mean lengths of organisms examined during 96- 

### hour survival studies conducted at the BSEP during 1984 and 1985...................................................



### vi iList of Tables (continued)



### 10.

10.

10.

10. Survival percentages for organisms collected during

fast and slow screen operation at the BSEP during 1984 and 1985........ ..... ............... 

# ....... .... 

# ............

Survi va 

## 1 percentages for contro 1 organ isms co 11 

## ected for survival studies at the BSEP during 1984 and 1985......
Mean percent 96- hour unadjusted survival values for croaker held during survival studies at the BSEP during 1984 and 1985..............................................
Mean percent 96- hour unadjusted survival values for spot held during survival studies at the BSEP during 1984 and 1985....... ...... ..... 

# ............. ........ 

# ................

Mean percent 96- 

## hour unadjusted survival va lues for penaeid shrimp held during survival studies at the BSEP duri ng 1984 and 

# 1985..................................

Mean percent 96- hour unadjusted survival for blue crab held during survival studies at the BSEP during 1984 

# and . 1985..................................................

Mean percent 96- hour unadjusted survival for weakfish held during survival studies at the BSEP during 1984 

# and . 1985..................................................

Mean percent 96- hour unadjusted survival for mi 

# scellaneous species held during survival studies at the BSEP during 1984 and 1985..................................
Ranking by percent of total impingement of species collected in the BSEP larval impingement program during 1984....... .......... ..... ...... .............. .............

Total number of selected species collected by trip in larval impingement during 1984.............................
Overall percent survival and number of larval impinged organisms returned alive to the Cape Fear Estuary.......... A summary of expanded juvenile/adult impingement at the BSEP during 1984....................................... 

### A summary of expanded juveni e/adul t impi ngement by year at the BSEP........................................... A summary of juvenile/adult impingement by species at the BSEP during 1984....................................... Estimated survival of juvenile and adult organisms impinged during 1984.......................................



# viii 10-

10-

10-



### 10-F i aure



### 1.1



### 1.2

1.3 List of Fi 

## gures

River larval fish and water quality sampling locations in the Cape Fear Estuary during 1984.......................
High marsh sampling areas and nekton sampling locations in the Cape Fear Estuary during 1984....................... 

### Locat i on of divers 

## i on structure, s 1 u i ceways, and return basin at the Brunswick Steam Electric Plant................ 

### Bottom sal inity values for selected stations in the Cape Fear Estuary from September 1983 through December 1984..... Bottom temperature values for selected stations in the Cape Fear Estuary from September 1983 through December 

### 1984.. .. . . . 

# ........... .... .. .. . ... .. 

# ..... ....... .. ..... . . .

Results of principle component ordination on 1977- 

### 1984 river larval fish data.....................................
Results of time-series analysis of larvaljpostlarval 

## croaker co 11 

## ected at Stat ions 34 and 41 in the Cape F ea 

### rEs t u a r y, 1977 -

1984. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

### . .

Results of time-series analysis of larvaljpostlarval anchovy collected at Station 24 in the Cape Fear Estuary, 1977- 

# 1984.........................................

Results of time-series analysis of larvaljpostlarval flounder collected at Station 24 the Cape Fear Estuary, 

### 1977- 1984... ........... .............. ..... 

# ..... 

# ............

Results of time-series analysis of larvaljpostlarval

Gobiosoma spp. collected at Station 24 in the Cape Fear

E s tu ary, 1977- 

# 1984.........................................

Results of time-series analysis of larvaljpostlarval menhaden collected at Station 24 in the Cape Fear Estuary, 1977- 

# 1984.........................................

Results of time-series analysis of larvaljpostlarval mullet collected at Station 24 in the Cape Fear Estuary, 

### 1977- 

# 1984.................................................
Results of time-series analysis of larvaljpostlarval seatrout collected at Station 24 in the Cape Fear Estuary, 1977 -

1984. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

### . . . . . . .

Results of time-series analysis of larvaljpostlarval spot collected at Station 24 in the Cape Fear Estuary, 

### 1977- 1984..... ...... 

# .......................................

i x 

### PageList of Figures (continued)

Results of time-series analysis of postlarval shrimp collected at Station 24 in the Cape Fear 

## Estuary, 1977- 

# 1984.................................................

Results of time-series analysis of total larval/ postlarval organisms collected at Station 24 in the Cape Fear Estuary, 1977- 

# 1984...............................

A typical plot of cumulative length distributions showi ng a 

## greater percentage of small er croaker in downriver areas than upriver areas in 1983..............
Discrete depth sampling tide tabulation graph.............. Discrete depth sampling temperature profiles at Stations 25 and 34 in the Cape Fear River, February 6- 

### and 14- 17, 1984............................................ Discrete depth sampling salinity profiles at Stations 25 and 34 in the Cape Fear River , F ebru ary 6- 9 and 14- 

### 17, 1984........... .............. ...... 

# ........ ...... 

# ..........

Densities of croaker collected by period and depth at Stations 25 and 34 in the Cape Fear River , February 6- 

### and 14- 17, 1984............................................ Densities of croaker collected by tide and depth at Station 25 in the Cape Fear River, February 6- 9 and 

### 14- 

# , 1984................................................

Densities of croaker collected by tide, depth, and period at Station 25 in the Cape Fear River , February 6- 9 and 

### 14- , 1984..... ......... ...... .... 

# ..... 

# ...................

Dens i ties of croaker co 11 ected by tide and depth at Station 34 in the Cape Fear River, February 6- 9 and 

### 14- 

# , 1984................................................

Densities of spot collected by period and depth at Stations 25 and 34 in the Cape Fear River, February 6- 

### and 14- , 1984............................................ Densities of spot collected by tide and depth at Stations 25 and 34 in the Cape Fear River, February 6- 

### and 14- 17, 1984............................................ 

### Length- frequency distributions of spot collected in Walden Creek by trawl in the high marsh study during 

# 1984.......................................................List of Figures (continued)


### Length- frequency distributions of croaker collected in 

### Matti s Bay by trawl in the high marsh study during 1984.... 

### Length- frequency distributions of striped mullet collected in Walden Creek by seine in the high marsh study during 1984...................... ......... ...... ...........



### Length- frequency distributions of white mullet collected in Baldhead Creek by seine in the high marsh study during 1984.......................................... 

### Length- frequency distributions of flounder collected in Alligator Creek by trawl in the high marsh study during 1984.............. ........... 

# ..............................

Length- frequency distributions of menhaden collected in Walden Creek by trawl in the high marsh study during 1984........... ........ ........ ........... .... ....... ......



## Length- 

## frequency d 

## i stri but ions of bay anchovy co lected in Walden Creek by trawl in the high marsh study during 1984.......................................... 

### Length- frequency distributions of mummichog collected in Walden Creek by seine in the high marsh
study during 

# 1984.....................i.................... Length- frequency distributions of Atlantic silverside collected in Baldhead Creek by seine in the high marsh study during 1984.......................................... 

### Length- frequency distributions of brown shrimp collected in Walden Creek by trawl in the high marsh 

### study dur i ng 1984.......................................... 

### Length- frequency distributions of pink shrimp collected in Walden Creek by trawl in the high marsh study during 1984.......................................... 

### Length- frequency distributions of blue crab collected in Walden Creek by trawl in the high marsh study during 

# 1984.......................................................

Results of time-series analysis for flounder collected in Alligator Creek in the high marsh study from 1981 through 1984............................................... Results of time-series analysis for spot collected in 

## All igator Creek in the high marsh study from 1981 through 1984...............................................List of Figures (continued)

Results of time-series analysis for menhaden collected in Alligator Creek in the high marsh study from 1981 through 1984...............................................Results of time-series analysis for bay anchovy collected in Alligator Creek in the high marsh study from 1981 through 1984..........................................
Results of time- series analysis for flounder collected in Mott 

## I s Bay in the high marsh study from 1981 

## through- 

# 1984...............................................

Results of time-series analysis for spot collected in 

### Mott I s Bay in the high marsh study from 1981 through 1984.... ... ....... 

# .......... .......... ............ .........

Results of time- series analysis for brown shrimp 

## collected in Mottl s Bay in the high marsh study from 1981 through 1984..........................................
Results of time- series analysis for pink shrimp collected in Mott 

## I s Bay in the high marsh study from 1981 through 1984...............................................
Results of time- series analysis for white mullet collected in Mott 

## I s Bay in the high marsh study from 1981 through 1984..................... .............. 

# ............

Results of time-series analysis for croaker collected in Walden Creek in the high marsh study from 1981 through 1984............................................... Results of time-series analysis for striped mullet
co 11 ected in Walden Creek in the high marsh study from 1981 through 1984..................................... Results of time-series analysis for flounder collected in Walden Creek in the high marsh study from 1981 through 1984.....................................Results of time-series analysis for menhaden collected in Walden Creek in the high marsh study from 1981 through 1984..........................................Results of time-series analysis for menhaden colected in Ba dhead Creek in the high marsh study from 1981 through 1984..........................................Results of time-series analysis for croaker collected in Baldhead Creek in the high marsh study from 1981 through 1984.....................................


## xiiList of Fiqures 

## (continued)

Results of time-series analysis for spot collected in Baldhead Creek in the high marsh study from 1981 through 1984...............................................Results of time-series analysis for blue crabs collected in Baldhead Creek in the high marsh study from 1981 through 1984..................................... Results of time-series analysis for brown shrimp collected in Baldhead Creek in the high marsh study from 1981 through 1984.....................................
Results of time-series analysis for pink shrimp collected in Baldhead Creek in the high marsh study from 1981 through 1984..................................... 

## Cumulative length- frequency analysis of spot colected by trawl in upper Walden Creek and the return basin in the high marsh study during 1984........... 

## Cumulative length- frequency analysis of croaker
co 11 ected by trawl in upper Walden Creek and the return basin in the high marsh study during 1984........... 

## Length- frequency distributions of bay anchovy collected in nekton trawls during 1984........................ Results of time-series analysis for juvenile/adult 

## bay anchovy co 11 ected in nekton 

## small trawl s at 

# Stations 1, 4. 7 and 8 combined for 1979 through 

# 1984......
Results of time-series analysis for young-of- year bay 

## anchovy co 11 ected in nekton 

## small trawl s at Stat 

## ions 1, 7. and 8 combined for 1979 through 1984................. 

## Length- frequency di 

## stri but ions of spot co 11 

## ected in nekton trawl s duri ng 1984.................................. Results of time-series analysis for juvenile/adult spot collected in nekton small trawls at Stations , and 8 combined for 1979 through 1984................. Results of time-series analysis for young-of- year spot collected in nekton small trawls at Stations 1, 4, 7, and 8 combined for 1979 through 1984....................... 

## Length- frequency distributions of croaker collected in nekton trawls during 1984...............................



# xiiiList of Figures 

## (continued)

Results of time- series analysis for juvenile/adult croaker collected in nekton small trawls at Stations

, and 8 combined for 1979 through 1984..............

Results of time- series analysis for young-of- 

## year croaker collected in nekton small trawls at Stations

, and 8 combined for 1979 through 1984.............. 

### Length- frequency distributions of menhaden collected in nekton trawls during 1984............................... Results of time-series analysis for juvenile/adult menhaden collected in nekton small trawls at Stations

8, and 10 combined for 1981 through 

# 1984.......

Results of time- series analysis for young- 

## of- year menhaden collected in nekton small trawls at Stations 1, 2, 4 , 7, 8, and 10 combined for 1981 through 

# 1984....... Length- frequency distributions of brown shrimp collected in nekton trawls during 1984...............................
Results of time-series analysis for brown shrimp collected in nekton small trawls at Stations 1, 4 , and 8 combined for 1979 through 1984.................... 

### Length- frequency distributions of blue crab collected in nekton trawls during 1984............................... Results of time-series analysis for blue crab collected in nekton small trawls at Stations 1, 4, 7, and 8 combined for 1979 through 1984............................. 

### Length- frequency distributions of weakfish collected in nekton trawls during 1984...............................
Results of time-series analysis for young-of- 

## year weakfish collected in nekton small trawls at Stations

, and 8 combined for 1979 through 1984.............. 

### Length- frequency distributions of pink shrimp collected in nekton trawls during 1984...............................
Results of time-series analysis for pink shrimp collected in nekton small trawls at Stations 1, and 8 combined for 1979 through 1984....................... 

### Length- frequency distributions of white shrimp collected in nekton trawls during 1984........................



### xivList of Figures (continued)

Results of time-series analysis for white shrimp collected in nekton small trawls at Stations 1 , 4 , 7 and 8 combined for 1979 through 1984.......................
Results of time- series analysis for total organisms collected in nekton small trawls at Stations 1, 4 , 7 and 8 combi ned for 1979 through 1984....................... 6-Principle component ordination of the nekton young

## of- year finfish data for 1983 and 1984 

# combined............
Principle component ordination of the nekton juvenile/ adult data for 1983 and 1984 combined......................
Results of time- series analysis for juvenile/adult spot co 11 ected in the intake canal by the nekton trawl for 1981 through 1984...................................... Results of time-series analysis for juvenile/adult 

## croaker co 11 ected in the intake cana' by the nekton trawl for 1981 through 1984................................ Results of time-series analysis for juvenile/adult 

### menhaden co 11 ected in the intake canal by the nekton trawl for 1981 through 1984................................ 

## Cumulative length- frequency analysis of spot collected by the nekton trawl inside and outside the diversion structure during 1984......................................
Cumu 1 at 

## i ve 1 ength- 

## frequency anal ys i s of croaker co lected by the nekton trawl inside and outside the diversion structure during 1984............................

Cumu 1 at 

## i ve ength- frequency ana 1 ys is of menhaden co lected by the nekton trawl inside and outside the diversion structure during 1984............................ 

### Length- frequency distributions of menhaden collected by the nekton trawl inside and outside the diversion 

## structure duri ng 1984...................................... Density of total fish entrained at the BSEP from May 1974 through August 1984................................... Density of croaker entrained at the BSEP from May 1974 through August 1984........................................ Density of flounder entrained at the BSEP from May 1974 through August 1984........................................List of Figures (continued)



### 10.

10.



### 10.

10. Density of menhaden entrained at the BSEP from May 1974

through August 1984........................................ Density of mullet entrained at the BSEP from May 1974 through August 1984........................................ Density of shrimp entrained at the BSEP from May 1974 through August 1984........................................ Density of spot entrained at the BSEP from May 1974 through August 1984........................................ Density of anchovy entrained at the BSEP from May 1974 through August 1984........................................

Density of Gobionellus spp. entrained at the SSEP from May 1974 through August 1984...............................

Density of Gobiosoma spp. entrained at the BSEP from May 1974 through August 1984............................... Density of seatrout entrained at the BSEP from May 1974 through August 1984................................... Entrainment day/night mean densities for total fish. September 1974 through August 1984......................... Time line depicting initiation dates of the Brunswick Steam Electric Plant modifications and maximum flow/unit from June 1981 through April 1985..........................
Mean percent survival of croaker during survival studies conducted at the BSEP during 1984 and 

# 1985.........
Survival/mortality comparisons of spot by size class collected during fast screen operation at the BSEP during 1984- 1985 survival studies.......................... 

### 7~27



## Day/night comparison of juveni lejadult impingement at the BSEP during 1984....................................... 10- Mean monthly rates of water entrained at the BSEP, 

## January- December, 1977- 1982 and 1984....................... 10- 

## Length- frequency distributions of bay anchovy and 

### menhaden imp i nged at the SSE P, January- December 1984....... 10- 

## Length- frequency di 

# stribut ions of spot and croaker impinged at the BSEP, January- December 1984................ 

### 10-



### xvi

## Metric- English Conversion Table



### Length


## 1 micron (~m) = 4. 0 x 10- 5 inch 

## 1 millimeter (mm) = 1000 um = 0. 

### 04 inch 

## 1 centimeter (em) = 10 mm = 0. 4 inch 

## 1 meter 

## (m) = 100 em = 3. 

## 28 feet 

## 1 kilometer (km) = 1000 m = 0. 62 mile



### Area

1 square meter (m ) = 10. 

## 76 square feet 1 hectare = 10, 

### 000m 

## 2 = 2. 47 acres
Weight 

## 1 milligram (~g) = 3. 5 x 10- 5 ounce 1 gram (g) = 1000 mg = 0. 035 ounce 1 kilogram (kg) = 1000 9 = 2. 2 pounds



### Volume

1 milliliter 

## (ml) = 0. 034 fluid ounce 1 liter = 1000 ml = 0. 

## 26 gallon 1 cubic meter per second 

## (cms) = 35. 7 cubic feet per second 

## (cfs)
Temperature

Degrees centigrade (O C) = 5/9 (O F - 32)



## xvii

### Execut i ve Summary



### This report 

### contains the results of 

# biological monitoring efforts conducted in the Cape Fear Estuary and around the Brunswick Steam Electric 

### Plant in 

# 1984. In addition to the results contained in earlier 

## reports, two new studies were conducted in 

# 1984. The installation of fine- mesh screens on the BSEP intake 

## structure reduced the entrainment of organi sms through the cooling 

# system. This resulted in large numbers of 

## small fish 

# and invertebrates being impinged on the screens and subsequently returned 

### to the estuary via the fish 

# return flume. To estimate these numbers, a larval impingement program was initiated in conjunction with the juvenile 

### and adult impingement program. Further , survival studies which estimated 

### the number of 

### sel ected organi 

# sms returned to the estuary a 1 i ve 

## were also
begu n in 

### 1984.

During 1984 

### , the overall hydrographic conditions in the estuary did 

### not change substantially from previous years, except an 

## increased freshwater flow occurred in the late winter and early spring. These flows 

### were similar to those in 

## 1983 but were hig. 

# her than in previous years. 

### These 

## high- flow conditions depressed the salinity levels in the estuary during recruitment of many selected species which in turn affected the abundance and distributions of these organisms.



### Samples of populations of 

### fish and invertebrates in the 

## estuary during their various life stages indicated that no 

## unexplained trends
occurred in 

# 1984. For example, the river larval fish study indicated that 

### the abundance and distributions of 

### larval and postlarval organisms were unchanged from previous 

# years. Samples of the 

## successive ife stages in 

### the tidal creeks indicated that the abundance during residency of some 

### species decreased in the 

### upper estuary. This decrease was a result of 

## high- flow conditions during recruitment which effectively prevented organisms from establishing residence in the upper estuary in the numbers ob

### served during previous years. The juvenile and adult fish and 

## shellfish
reflected the trends of the organisms in the 

### tidal creeks. Any 

## decreases in abundance was attributed to high- 

## flow conditions and the cycl ic nature of many organisms residing in the nursery 

## areas.



## xviii

### Additional studies indicate that the modifications made to the BSEP

intake are effective in improving survival of all ife stages of impinged 

# organisms. The diversion structure 

### prevents larger individuals of the 

## populations from entering the intake canal and from the possibility of 

# being impinged. This is important in that these larger individuals are or 

### will soon be members of the 

### reproducing populations. 

## These individuals have survived the high natural mortality of the younger life stages and 

### have increased their chances of 

### propagation. While the number of organ

### isms impinged has increased greatly due to the installation of fine-mesh 

# screens, there has been a 

### correspond i ng decrease in 

### organi sms entra i ned through the plant. Therefore, fewer organisms have been permanently lost 

### from the estuary. 

## Survival studies indicate that substantial numbers of the organi 

# sms impinged are 

### returned to the 

## estuary al ive whi 

## ch further
reduced the impact of the 

# BSEP. Finally, the flow-minimization 

### scheme, which was fully implemented in July 

### 1983, was also effective in further 

### reduci ng entra i nment and imp i ngement.


## Evidence accumulated in 1984 

### , as well as previous years, 

## indicates that the ope 

## rat i on of the BSEP has not affected the 

## abundance, seasonality, or distributions of organisms in the 

# estuary. Environmental conditions have been and continue to be the dominant 

# force influencing the population of the commercial and/or recreational organisms in the 

### CFE.



## xix

### 1.0 INTRODUCTION



### In January 1981 Carolina Power & Light Company (CP&L) was issued a permi t to discharge coo 

### 1 i ng water from the Brunswi ck 

### Steam E ectri c Pl ant 

### (BSEP) to 

# the Atlantic Ocean 

### under the National Pollutant 

## Discharge 

## Elimination System (NPDES). Water used for cooling is drawn from the Cape 

### Fear River 

# (CFR). One stipulation of 

### the permit was 

# that biological monitoring be continued that would provide sufficient information to allow 

# for a continuing assessment of the 

### impact of the BSEP on the Cape Fear 

## Estuary (CFE) with particular emphasis on the marine fisheries. With some modification, this biological monitoring requirement was a continuation of research that had been conducted on the CFE by various investigators since 

### 1976, and as a result, some programs in this report will discuss trends 

## from 1976 to 

# 1984. Earlier BSEP annual biological monitoring 

## reports (CP&L 1982, 

### 1983) contain more detailed sampling methodology and station descriptions than are included in this 

## report.

Another stipulation of the permit was the requirement for the construction of two intake mod ifications to reduce entrainment and 

### impingement. A permanent fish diversion structure was built across the mouth of 

### the intake 

### canal to 

# prevent arger fi sh and shell fi 

## sh from enteri 

## ng the
cana 1 and 

## from be 

## i ng imp i nged at the 

# plant. The effect i venes s of 

## the structure is 

### discussed in the 

## nekton and impingement sections of 

# this 

# report. In addition, fine-mesh 

## (l-mm) screens were installed on two of 

# the four trave 1 i ng 

## screen as semb 1 i es 

### on each un 

# i t to reduce entra i nment. The effectiveness of this modification is addressed in the entrainment and larval impingement sections of this 

# report. In addition to these modifications, the NPDES permit also required a reduction in the volume of cool

### ing water used by the plant. This flow minimization scheme and the 

### two. intake modifications are discussed in more detail in Appendix A.

As a result of the plant modifications, two new studies were added to 

# the program in 

# 1984 (Table 1. 

# 1). Larval impingement was 

## added to 

## determine how 

## many larvae 

# were impinged on the fine- 

## mesh traveling 

# screens. Percent survival was studied to 

## determine how many impinged organisms were returned to the estuary alive.

## The study periods evaluated in this report differ by 

# program. The



### entra i nment program reports on data co 11 ected from September 1983 through 

# April 

# 1985. The river larval fish program reports on data collected from 

## September 1983 through 

## August 1984 to correspond to 

### periods of 

## larval recruitment, while the nekton, high marsh, and impingement programs report 

# on data collected from 

# January through December 1984. 

## The survival program reports on data collected from April 1984 through April 

### 1985.

The stations 

### sampled by each program are 

### shown in 

# Figures 1.1 and 

# 1.2. Figure 1.1 contains the sampling locations for the 

# river larval fish, discrete depth, and entrainment programs, while Figure 1. 2 shows the 

### high marsh and nekton 

### sampling locations. Because several stations were 

### sampled in 

### each creek by the high marsh program, the entire 

## creek is designated as a 

### sampling area. A more detailed illustration of specific 

### sampling locations within 

# these areas can be found in the 

## 1981 annual report (CP&L 1982). 

# A list of fish and shellfish on which statistical analyses were 

## performed is presented by program in Table 1. 

# 2. The majority of these are recreationally and/or commercially important species and, with few excep

## t ions, are 

## ocean spawned. The others were ana yzed becau 

## se they occur in 

# arge numbers with i 

# the estuary 

# and 

# are cons i dered i nd i 

# cators of 

# estuarine conditions. A list of all the fish and shellfish collected by 

# each program is presented in 

## Table 1.3. A full description of 

## the
ana 1 yses used is presented in Append 

### i x B.Tab 1 e 

### 1.1 BSEP 1984 biological monitoring program summary.



### Program 

### Sampling Locations Samp 1 i ng 

### Frequency

Entrai nment
Impingement (larval) Imp i ngement (juvenile and adult)
Water quality

River larval fish



### Oi screte 

## depth

Nekton Weekly Weekly Weekly

Once every week

Once every two weeks 

## September- May; once every month 

## June- August



## February- March (four 24- 

## hour tri ps)
Once every three 

### weeks 

### Discharge weir

Return flume

Return flume

Dutchman Creek (Station 

### 11) Walden Creek (Station 24) 

### Buoy 15 (Stat i on 15) 

### Buoy 19 (Stat i on 19) Buoy 25 (Station 

### 25) Buoy 29 (Station 

### 29) Buoy 35 (Station 35) Buoy 38 (Station 

### 38) 

### Buoy 42 (Stat ion 42) Dutchman Creek (Station 11) Walden Creek (Station 24) 

### Buoy 15 (Stat i on 18) Buoy 19 (Station 25) Buoy 29 (Station 

### 37) 

### Buoy 38 (Stat i on 34) Buoy 42 (Station 

### 41)
Buoy 19 (Station 

### 25) 

## Buoy 38 (Stat ion 34)
Freshwater drainage canal (Station 1) Slough east of Buoy 18 (Station 2) Intake canal west of 

### Buoy 19 (Stat i 

### on 4) Walden Creek (Station 7) 

### Sha 11 ows west of Buoy 23 (Station 8) ICW Marker 174 (Station 

### 10) ICW Marker 10 (Station 

### 14) Shallows east of Buoy 42 (Station 11) 

## Shallows southwest of Buoy 49 (Station 

### 15) 

### Sha 11 ows 

### southwest of Buoy 51 (Station 

### 16)Tab 1 e 

## (continued)

Program Samp 1 i ng 

### Frequency Samp 1 i ng 

### Locat ions

Nekton Alligator Creek 

# (Station 12)
Intake canal Inside di version 

# structure (Stat i on 6)
Between canal bends (Station 13) Adjacent to plant (Station 5) High marsh trawl and seine Once every three 

### weeks Ba 1 dhead Creek 

## Trawl: 7 stations 

# Seine: 2 stations
Wa 1 den Creek Trawl: 9 stations 

# Seine: 2 stations Mott I s Creek Bay 

## Trawl: 2 stations 

## Siene: 2 stations Alligator Creek Trawl: 4 stations 

## Return bas in 

## Trawl: 1 station Survival Dependent on organism 

## Return flume (experimental)



# availability Intake canal (controls)

## Table 1.2 Speci es 

# of fi sh and she 11 fi sh analyzed by 

### program.

Sc i ent 

## if i c Name Common Name 

### Program

C 1 

### upe i d ae 

### Bevoortia tyrannus At 1 ant i c 

### menhaden Engraul idae Anchoa hepsetus Striped anchovy ~J ~J 

### A. mitchilli Bay anchovy 

### Cypr i nodont i d ae Fundulus heteroclitus Mummi chog 

### F. majalis Striped killifish 

## Atherinidae Membras martinica Rough s i vers i de 

### enidia beryllina 

## Inland silverside

M. 

### menidia 

# Atlantic silvers ide 

### Sci aeni dae Cynoscion nebulosus 

## Spotted seatrout
~J ~J C. 

### regalis Weakfi sh Leiostomus xanthurus 

### Spot Micropogonias undulatus 

## Atlantic croaker Mugil idae Mugil cephalus Striped mullet J Xl 

### M. curema Wh ite mu 11 et 

### Gobiidae Gobionellus boleosoma Darter goby

G. 

## hastatus Sharpta i 1 goby

G. 

### shufeldti Freshwater goby 

### Gobiosoma bosci Naked goby

G. 

### ginsburgi Seaboard goby Trigl idae Prionotus spp. 

### Searob i n 

## sp. Both i dae 

## Paralichthys albigutta Gu If 

## flounder P. dentatus Summer flounder 

### P. lethostigma 

## Southern flounder Cynogloss idae 

### Symphurus plagiusa B 1 

### ackcheek tonguef ish



# L = Larval fish D = Discrete depth 

### E = Entra i 

# nment M = Hi gh marsh 

## S = Survival J = Spec; es grouped for ana lys is 

## purposes N = Nekton I = ImpingementTab 1 e 

### 1. 2 

### (cant i nued)

Scientific Name Common Name 

### Program



### Penaei dae Penaeus aztecus 

### Brown shrimp

P. 

### duorarum Pink shrimp 

## P. setiferus White shrimp 

## Trachypeneus constrictus Hardback shrimp 

### Portun i dae Callinectes sapidus Blue crab

C. 

### similus Lesser blue crab X..



## L : Larval fi 

# sh

D : Discrete depth 

# E : Entrainment M = High marsh S : Survi va J = Speci es grouped for ana lys is 

## purposes N = Nekton I = Imp 

### i ngementTable1.3Species of fish and shellfish collected by program during1984.Scientific NameCommon NameProgramCarcharhi ni daeRequi em sharksRhizoppionodon teppaenovaeAt 1 ant i csha rpnosesha rkDasyatidaeSti ngraysDasyatis sabinaAt 1 ant i cst i ngrayLepi sostei daeGarsLepisosteus osseusLongnose garAmi i daeBowfi nsAmia calvaBowfi nElopidaeTarponsElopssau2'USLadyfi shElops saupus(eptocepha1 us)Ladyfi sh(eptocepha1 us)Megalops atlantious(eptocephaus)Tarpon (eptocepha1 us)Albul idaeBonefi shes.....A LbuLavulpes(1 eptocephaus)Bonefi sh (1eptocephal us)--.JAngu ill idaeFreshwater eelsAnguilLa postpataAmeri can eelCongridaeConger eelsCongep ooeaniousConger eelOphi chthi daeSnake eelsMypophis punotatusSpeckled wormeelMYpophis punetatus(eptocepha 1 us)Speckled won" eel(lepto.Ophiohthus gomesiShrimp eelCl upei daeHerri ngsALosaspp.Unidentified shadALosa aestivaLisBlueback herringA LosamedioepisHi ckoryshadA LosapseudohapengusAlewifeL = Larvalfi shD = Di screte depthN = NektonE = Entrainillent0= Hi ghmarshI = Juvenil e andClrtUlt impi ngernentLI= Larvalimpl ngernentTable 1.3(cont i nued)Sc ient Hi cNameCommon NameProgramA LosasapidissimaAmeri can shadBrevoortia tyrannusAt 1 ant i cmenhadenDorosoma ~epedianumGi zzardshadDorosoma petenenseTh readf i nshadOpisthonema ogLinumAtlantic threadherringEngraul i daeAnchovi esAn~hoaspp.Uni denti fi edanchovyAnehoa hepsetusStri redanchovyAn~hoa mit~hiL~iBay anchovyUmbri daeMudmi nnowsUmbra pygmaeaEastern mudminnowSynodontidaeL izardfi shes.....Synodus foetensInshore1 izardfi shCypri ni daeCarps and minnowsillcyprinusoorpwCommon carpNotemigonu8 ~ryso~eu~a8Golden shinerCatostomi daeSuckersErimyzon suoettaLake chubsuckerIctal uri daeBullhead catfishesI~ta~urusspp.Uni dent ifi ed bullheadI ~ta~urus ~atusWhite catfishI~ta~urus furoatusBlue catfishI etaLurus punotatusChannelcatfishBatrachoi di daeToadfi shesOpsanus tauOyster toadfi shGobiesocidaeCl i ngfi shesGobiesoxspp.Un ident ifi edcl i ngfi shGobiesox strumosusSk illetfi shL = Larvalfi sh0 = Oi scretedepthN = NektonE = EntrainmentM = High marshI = J uveniland adultlmpi ngernentLI= Larvalimpl ngementTable 1.3(cont i nued)Scientific NameCommon NameProgramGad i daeCodfi shesUrophyoiss pp.Uni dent ifi edhakeUrophyois fLoridanaSouthern hakeUrophyois regiaSpot tedhakeOphidi idaeCusk-eel sBrotuLa barbataBearded brotul aOphidion weLshiCrested cusk-eelExocoet i daeFlyi ngfi shesHyporhamphuB unifasoiatusHa 1fbeakBelonidaeNeedl efi shesStrongyLuY'a marinaAtlanticneedlefishCypri nodont i daeKill ifishesCyprinodon variegatusSheepshead minnowf-'FunduLusspp.Unidentified killifishI.DFunduLus heterooLitusMummi chogFunduLus majaLisStriped killifishPoeci 1 i idaeL i vebearersGambusiaaffinisMosquitofi shAtheri ni daeSi 1versi desMembras martinieaRough sivers ideMenidia beryLLinaInland silversideMenidia menidiaAtlantic silversideSyngnath i daePi pefi shesHippocampus erectusLined seahorseSyngnathusS pp.Unidentified pipefishSyngnathus fuscusNorthern pi pefiSyngnathus LouisianaeChai n pi pefi shL = Larvalfi sh0 = Discrete depthN = NektonE = Entra i nmentM = High marshI = Juvenileand adul t impi ngementLI= Larval, mp i ngementTable 1.3(cont i nued)Scientific NameCommon NameProgramCentropomi daeSnooksentropomusundeeimaLisSnookPerci chthyi daeTemperate bassesMoronespp.Uni dent ifi edwhi tebassMorone saxatilisSt ri ped bassSerrani daeSea bassesentropristis philadelphieaRock sea bassMYeteropereaspp.Uni dent ifi ed grouperMYeteroperea mierolep~sGagCent ra rch i daeSunfi shesentrarehus maeropterusF 1 iI--'Enneaeanthus ehaetodonBl ackbanded sunfi shLepomisspp.Unidentified sunfishI--'Lepomis auri tUgRedbreast sunfi shLepomis gibbosusPumpki nseedLepomis gulosusWarmouthLepomis maeroehirusBluegillLepomis mierolophusRedear sunfi shMieropterus salmoidesLargemouth bassPomoxisspp.Uni dent ifi ed crappiPomoxis nigromaou latusBlack crappi ePerci daePerchesPerea flaveseensYellow perchPomatomi daeBl uefi shesPomatomus galtatrixB 1uefi shRachycent ri daeCobi asRaehyeentron eanadumCobi aCarangi daeJacksaranxhipposCrevalle jackL = Larvalfi shD = Di scretedepthN = NektonE = Entrainmentt~ = Hi gh marshI = J uveniland adultlmpi ngementLI= Larvallmpi ngementTable 1.3(cant i nued)Scientific NameCommon NameProgramLlChLoPosBombpus BhpysupusAtlanticbumperSeLene vomepLoakdownTpaBhinotus faLBatusPermitLutj an i daeSnappersLutjanusanaHsMutton snapperLutjanusgpiseusGray snapperGerrei daeMojarrasDiaptepus QUpatusI ri shpompanoEuBinostomusS pp.Unidentified mojarraEuBinostomus apgenteusSpatfin majarraEuBinostomus guLaSil ver jennyHaemu 1 i d aeGruntsI-'OrthopristisBhrysopteraPi gfi shI-'SparidaePorgi esI-'ArBhosargus probatocephaLusSheepsheadLagodon phomboidesPinfishSciaenidaeDrumsBairdieLLa chrysouraSilver perchCynoscion nebuLosusSpotted seat routCynoscion regaLiaWeakfi shLarimus fasBiatusBanded drumLeiostomus xanthurusSpotMenticirrhusspp.Unidentified kingfishMenticirrhus ameriBanusSouthern kingfishMiBropogonias unduLatusAtlantic croakerpogonias cromisBlack drumSBiaenops aGeLLatusRed drumSteLLifer LanceoLatusStar drum, XL = Larvalfi shD = Di screte depthN = NektonE = EntrainmentM = High marshI = Juvenil eand adul timpi ngementLI= Larvallmpi ngementTable 1.3(cont i nued)Sci ent i fi cNameCommon NameProgramKyphos i daeSea chubshaet odorzoaeUatusSpotfi nbutterflyfi shEphi ppi daeSpadefi shesChaetodipterus JaberAt 1 ant i cspadefi shLabri daeWrassesTautoga orzitisTautogMugil idaeMull etsMugUspp.Uni dent ifi ed mull etMugU cephaL usSt ri redmu 11 etMugi1.curemaWhite mull etSphyraeni daeBa r racudasSphyraerza boreaLisNorthern sennet,.....ranoscop i daeStargazersAstrosoopusUnidentified stargazer......spp.AstrosoopusguttatusNorthern stargazerAstrosoopusgraecumSouthern stargazerB 1enni i daeCombtooth blenniesChasmodes bosquiarzusStri redblennyHypsob1.erzrziushentziFeather b1 ennyHypsob1.ennius ionthasFreckled blennyE 1eat ri daeSleepersDormitatorm::wuLatusFat sleeperGobi i daeGobi esEvorthodus 1.yriousLyre gobyGobiorzeUuss pp.Unidentifiedgobi one 11 usgobyGobiorze1.1.us bo1.eosomaDarter gobyGobiorze1.1.ushastatusSharptai 1gobyGobiorze1.1.usshufeldtiFreshwater gobyL = Larvalfi shD = Di scretedepthN = NektonE = Ent rainmentM = High mars hI = Juveni leand adultimpl ngementLI= Larvalimpl ngementTabl e 1.3(continued)Sci ent ifi cNameCommon NameI--'I--'Gobiosomaspp.Gobiosoma bosciGobiosoma ginsbupgiMicrogobiusspp.Microgobius thaLassinusMi crodesmi daeMicrodesmus Longipinn~sTrichiuridaeTrichiupus LeptupusScombri daeSeomberomopusspp.S eombepomopus macuLatusSt romatei daePeprHusPeprHusPeprHusTri gl i daeppionotusPpionotusPnonotusprionotusPrionotusBothidaeAneyLopsetta quadpoceLLataCithapichthysspp.Citharichthys spiLopterusUnidentified gobiosoma gobyNaked gobySeaboard gobyUni dent ifi edmicrogobi us gobyGreen gobyWormfi shesPink wormfi shCutlassfishesAtlantic cutlassfishMackerel sInidentified mackerelSpani sh mackerelButterfi shesUnidentified butterfishHarvestfi shButterfi shSearobi nsUnidentified searobinNorthern searobiStriped searobinLeopard searobi nBi ghead searobi nLefteye floundersOcellated flounderUni dent ifi ed whi ffBay whispp.aLepidotustpiacarzthusspp.capoHnusevoLanssci tutustpibu LUBL = larval fiE = Entrai nmentLI= Larval lmpingementD = Di scretedepthM = High marshN = NektonI = Juveni1 eand adultlmpi ngementProgramD MTable 1.3(continued)Sc i entifi cNameCommon NameProgramEtpopus apossotusFringed flounderPapaLiehthysspp.Unidentified flounderPapaLiehthys aLbiguttaGulf flounderPapaLiehthys dentatusSummer fl GunderPapaLiehthys LethostigmaSouthern flounderSeophthaLmus aquosus14indowpaneSoleidaeSol esTpineetesrmeu1.atusHogchokerCynogl ass i daeTonguefi shesSymphupusspp.Unidentified tonguefishSymphupusaivitatusOffshore tonguefiSymphupuspLagiusaBl ackcheek tonguefi shf-'Ba 1 ist i daeLeatherjacketsf-'MonacanthushispidusPl anehead fiefi shTetraodontidaePuffersSphoeroidesrmcu1.atusNorthern pufferDi octant i daePorcupi nefi shesChiLomyctepus sehoepfiStriped burrfishSquill idaeSquiUaempusaMantis shrimpPenaei daePenaeid shrimpPenaeussp. (adul t)Penaeus(adult)Penaeussp.(postlarvae)Penaeus(post 1 arvae)Penaeus aztecusBrovin shrimpPenaeus duorapumPink shrimpPenaeus setiferusWhite shrimpTpachypeneus constpietusT -canor hardbacksh ri mpSicyoniaspp.Rock shrimpL = Larvalfi shD = Di scretedepthN = NektonE = EntrainmentM = High marshI = Juvenileand adult impingementLI= Larvalimpl ngementTabl e 1.3(cont i nued)Scientific NameCommon NameP rag ramPa 1 aemonidaePal aemonid shrimpMacpobpachiumspp.Freshwater prawnsPaLaemonetesspp.Grass sh riA 1pIlei daeSnapp i ngsh ri mpALpheusspp.Snappi ng shrimpCrangonidaeSand shrimpCpangon BeptemspinosaSand shrimpUpogebiaspp.andCaLLianassaspp.Mud shri mpsPortuni daeSwimmi ng crabsPortuni dae(meya lops)Swimmi ng crabs(mega lops)OvaUpesspp.Calico crabsPoptunusspp.Unidentified swimmingcrabst--'CaLLinectesspp.Call i nectes crabCaLLinectes sapidusBlue crabt--'CJ1CaLLinectes simiLusLesser blue crabLoLLiguncuLa bpevisBrief squidMaLacLemys teppapinDi amondbackterrapi nL = Larval fiE = Entra i nmentLI= Larvalimpi nyement0 = Di screte depthM = High marshN = NektonI = Juveni1 eand adul t impingement

# o. WATER QUALITY STATIONS' * = RIVER LARVAL FISH STATIONS 

### 0 = DISCRETE DEPTH STATIONS 

### ~ =

ENTRAINMENT STATIONS ...

,,/ 

### ,,/ 

# /~/-

... ,~/

KILOMETERS


### Figure 1.1 River larval f'JSh and 

### water quality sampling locations in the Cape Fear

Estuary during 1984.

### 0 = WATER QUALITY STATIONS * =

RIVER LARVAL FISH STATIONS 

### 0 = DISCRETE DEPTH STATIONS

t::. = ENTRAINMENT STATIONS

Figure 1.1 (continued)HIGH MARSH SAMPLING AREAS NEKTON SAMPLING LOCATIONS ,;

,;,; ,;,; ,;'

,;1' ..,; 

## ...

'1'_.... ,,;

,~I'

KILOMETERS

Figure 1.2 High marsh sampling areas and 

### nekton sampling locations in the

Cape Fear Estuary during 1984.HIGH MARSH SAMPLING AREAS NEKTON SAMPLING LOCATIONS

Figure 1.2 (continued)ACCESS ROADINTAKE CANALI-'Figure 1.3Location ofdiv.ersion structure, sluiceways, and return basin at the Brunswick Steam Electric Plant.WATER QUALITY



### I ntroduct i on

Salinity is a major 

# factor influencing the spatial distribution of 

# estuarine 

# species (Weinstein et 

# ale 1980). Fluctuations in 

# salinity caused by freshwater inflow and variations in tidal stages produce changes in the abundance of speci es in 

### an area. 

## In 1982 the water qual 

## i ty program was initiated to supplement water temperature and salinity data for the river larval fish. high marsh~ and nekton programs in an attempt to better determine periods of freshwater 

## inflow.

The estuary is subject to 

# highly variable and relatively 

## large inflows of freshwater from the Cape Fear drainage 

# basin. The two- 

## layered flow regime typical of coastal plain estuaries is usually present in the portion of the estuary above Sunny Point. Net nontidal drift results in a 

### net upstream flow of 

### more saline water in 

# the lower layer and a 

## net seaward flow of less saline water in the upper 

# layer. These flows resultin a salinity gradient whose position and shape is constantly being modi

# fied. The portion of the estuary seaward of Sunny Point, in which the 

### Brunswick Plant is located. is 

# typical of a marine. well-mixed system. Complex water 

# circulation 

# patterns, vigorous tidal action 

# and high 

### exchange ratios wi th the ocean resu 1 t 

# in th is reach 

# of the estuary act i ng as an extension of the nearby coastal zone.



### Methods

Nine water quality stations 

### (HG) were sampled weekly. Seven of these stations were located in the CFR channel at Buoys 15 , 19, 25, 29, 35. 

### 38. 

### and 42. 

## Station HGll was a shallow-water station west of 

## Southport in Dutchman Creek, and Station HG24 was northwest of the plant site in lower 

### Walden Creek. Water quality data were also collected every three weeks from the high marsh (BH) and nekton (BN) programs (Figure 1. 

## 1).

Surface samples were dipped from the surface with a bucket, and bot

# tom samples were collected 

### with a two- 

# liter Kemmerer water 

## sampler.

### Temperature was measured in 

## degrees Celsius (o C) using a Yellow 

## Springs

Instruments Model 4310 te 

## ethermometer. Sa 1 i 

### nity was measured in 

## parts per thou sand (ppt) wi th an Ameri 

### can Opt i ca 1 Mode 1 10419 

## refractometer.

Bottom salinity 

# and temperature 

# values were plotted for 

## three stations in the CFR channel representative of the various 

# sal inity regimes along with 

## stations which 

# are characteristic of 

# three creek systems: Baldhead, Walden, and Alligator Creeks 

## (Figures 2. 1 and 2. 

## 2).


## Results and- Discussion

A period of high freshwater flow was observed in December 1983 and 

### continued well into May 

# 1984. These increased flows 

# caused salinity va 1 ues 

### to drop in the creeks and upstream nursery areas 

## (Fi gure 2. 

## 1). However , this effect was not observed at Station 15 because this area 

# strongly influenced by the surrounding coastal 

# waters. Historically, freshwater inflows begin to decline around May with this decline 

## lasting 

# into the early winter. This pattern was found to hold true for the most 

# part, with 

# salinity values increasing in the upriver nursery areas and 

### creek systems as the summer 

# progressed. Exceptions occurred during early 

### June and late July when 

# sharp decreases in sal inity were observed as a resul t 

# of unseasonably heavy freshwater i nfl ows from the 

# upper CFR 

# basin. The June decreases were not evident on the creek data because the stations were not sampled during that 

# period. Another deviation from the 

### historical trend occurred in September when Hurricane Diana passed over the CFE. depositing over 40 cm of precipitation on the 

# area. This caused salinity values in the creeks and nursery areas to plummet, but only for a short time, as values were observed to increase the following week.



### maximum bottom temperature of 31. 

# was observed in 

## early September at Station HGll, and a minimum bottom 

## temperature of 3. C was 

### observed in Alligator Creek at 

### Station BH42 in early 

# January. The main 

# factor influencing water temperature in the CFE was 

## seasonal variation 

# (Figure 2. 

# 2). The river 

## channel and 

# creek stations both experienced similar fluctuations in temperature throughout the year.RIVER



### ~ 25
)- 20

...I ,... ..

1983~1 'I( 1984

S1 A TION .........-. H 

### GIS &-&-8- HG29 

# ~+-+

HG42

(DOWNR!VER) (MIDRIVER) (UPRIVER)

CREEK ~g 

# " -



# t;I ,... ,

. , 

# ......" \ ~ '" \ . ' \



# JI. G----EJ 

# "I C1 

# .. /"'

~ 19.._ .a..., 

# ", .

.s.. 

# )A. 

# " ~ \ /

'B" - '. ,'

..



### ..f f'\ tt 

# '. :?-.. 

# / \

.... 

# ~.+*~ 

# ~~~

"'*-~4 .....



# I'" ' 

# " I'" ' .'" '

I'" '.,.., ' 

# .'" '

I'" ' J 25 ~ 20
:i 15 (I) 19



# 1983~1 1984

STATION 

### Be I dhead 

## Creek &-&-8- \.10 I 

### den 

### Creek

+-...-+ A I I I ge tor Cr eek



### Figure 2. 

### Bottom salinity values for selected st;ttions in the Cape Fear



### Estuary from September 1983 through December 1984,RIVER



# ~1983 ..J 

## " I" 

## '" ' .'., ' 

# .'" '

..J ..J

1984


### LEGEND, 5T A TIOH ........ H G 1 5 (DOWNRIVER! &-er-& HG29 (MIDRIVER) +-"-$ HG42 (UPRIVER)

CREEK 

# ;:)

~ 20



# 1~1983 ..J

-o( ..J ..J

1984

D-EJ-e Wa! d~n 

### Cr~ek ST A 

### rION 

### Bal dhead Cre.k +-.....



# Alligator C,.eek

Figure 2. 

### Bottom temperature values for selected stations in the Cape



### Fear Estuary from September 1983 through December 1984.RIVER LARVAL FISH



### I ntroduct i on

Sampling for larvaljpostlarval organisms continued in 1984 to monitor 

# the abundance, species composition 

# spatial distribution, temporal 

# distribution, and size distribution of 

### fish and shellfish in 

# the CFR. 

# This was done to 

# detect and quantify 

# any significant changes in 

## the numbers of larvaljpostlarval organisms which 

# utilize the CFE and are 

## susceptible to being " cropped I' by the operation of the BSEP.



### Results from 1984 were compared with results from previous years to 

### determine if the time periods in which particular species occurred have 

### remained the 

### same, if 

## species were still moving through the estuary and 

### establishing in the same 

### areas, if the same species were occurring most 

# frequently, and if there were 

# any declining trends in the 

## number of organisms in the estuary.



### Behavioral responses which aid the 

### transport of 

# larvaljpostlarval fish from the ocean into the CFE have been addressed by Copeland et 

## ale 

## (1979), Weinstein (1979a), and Weinstein et 

# al. (1979) and are discussed in Section 4. 0 of this report.



### Methods

Samp 1 e Co 11 

## ect i on and Process i 

# The seven sampl ing 

# stat ions used in 

# thi s 

# study have remai ned unchanged since 

# 1981. There were two shallow-water stations: one in Dutchman Creek (Station 

### 11), south of and away from the influence of the plant, and one in Walden Creek (Station 24), north of and bisected by the 

### intake canal. The other five stations were located in the CFR 

## channel between Buoys 15 and 42 (Stations 18, 25, 37 

### , 34, and 

# 41) (Figure 1.1, CP&L 1982).

### Simultaneous replicate 

### samples were collected from the surface and



### bottom at each 

# station with l- m diameter , 505-um mesh nets mounted 

## rectangular frames. An electric winch was 

### used to raise 

## and lower the sled used for collecting samples near the bottom during 

# 1984. Previously 

# the sled had 

# been allowed to free- 

# fall to the bottom before 

## towing; 

# otherwise, no 

# changes were made to 

# the river larval 

# fish sampling procedures, gear, or 

### frequency in 

# 1984. Further description and performance data of this gear were 

### reported by Hodson et 

# ale (1981) and are discussed in Appendix C of this report.

Samples were preserved in approximately a 10% formalin 

# solution. the lab, species were sorted, identified, counted 

### , and 

## standard length recorded. The volume of water filtered by a net was obtained by the use 

### of a 

# flowmeter. Typically 200m 

# 3 of water was filtered 

# during a fiveminute tow. Larval densities were 

### computed by expanding the volume and 

### correspondi ng number of 

## organi sms to obta i n number of organ i sms/1000m 3 . This then was the constant unit used for analysis.



### Sampling trips were scheduled biweekly except during June, July, and 

### August when sampling was 

### conducted once a 

# month. Stations were 

### sampled from the lower 

### estuary to the upper estuary in an attempt to sample 

# all stations during the same 

# tidal stage. Previous studies (Copeland et ale 1979; CP&L 1980) have shown that greater numbers of 

## larval/postlarval fish 

# are collected after 

### sunset and that 

# night samples 

# alone adequately reflected the population.

Data Ana lyses



### For the purpose of analysis, a larval fish year began in September 

## and continued through the following 

# August. The 1984 larval 

## reporting year included data from September 1983 through August 1984.



### For the time-series plots, surface and bottom larval densities were 

### combined to give an average density in the water 

# column. This average 

# water column density 

# predicted from 

# two depths is 

# not significantly different from a mean density predicted from six discrete depths (Appendix

# C). Because sampling trips were not equally 

## spaced, monthly averages of

loge (density + 1) were used (Appendix 

### B).

Results and Discussion

Domi nant 

### Speci es 

# The larval taxa collected in the greatest densities during each of the past six years are, in order of 

## abundance: anchovy, croaker , portunid

megalops, Gobiosoma. 

## spp. , spot, Penaeus spp., menhaden 

### , and 

# silverside. These eight taxa have accounted for approximately 90% of the total density during this time 

## (Table 3. 

# 1). Other recreationallyfcommercially important species collected included seatrout, 

### flounder, and mullet. Mean density 

# fluctuations between years 

# are due primarily 

# to spawning success, transport mechanisms (wind and currents), water temperature and 

# salinity, and other natural factors which affect the survival of 

## larvalfpostlarval 

# organisms. (Norcross and Shaw 1984)

Station Groupi 

### ngs

From 1976 to 1978 the larval fish monitoring program consisted of 28 stations located throughout the 

# estuary. These studies addressed spatial differences in the 

# estuary by averaging data from stations which were 

### within four regions, designated by their distance from the mouth of the 

# river. Data collected by CP&L since 1979 also 

### used this 

## method for grouping stations to describe four areas, although the number of stations 

### was reduced to 

# seven. Using this method caused data from shallow creek 

# stations to be combined and 

### averaged with data from deep river 

## channel stations. A more accurate picture of what was occurring at each station 

# was 

# obtained by 

# using principle component analysis to 

# identify and 

# statistically group 

# stations which showed similarities 

# in species 

## association , temperature, and salinity. A matrix of the seven stations by 

# seven organisms (anchovy, croaker, Gobiosoma 

# spp., portunid megalops spot, shrimp, and 

### menhaden) was constructed using data from 1976 to 

### 1984 

# so that each observation represented the mean for 

# all years. These species were selected because of their abundance and they provide a goodmi x of estuari 

### ne and ocean 

## spawners occurri ng duri ng ei ther the summer or



## winter. 

# A positive relation with downriver shallow-water stations and 

### high (polyhaline) salinity 

### (Principle Component 

### 1) accounted for 73% of 

## the variation in 

# the total data 

# set (Table 3. 

# 2). The second principle component accounted for an additional 17% of the variation and appeared to 

# represent 

# the comparative changes in 

# salinities of stations due
freshwater runoff. This is indicated by the similarity of the downriver 

## shallow- water stations (11 and 24) to the upriver channel stations (34 

### and 41) regarding salinity. During periods of freshwater runoff , salinity at 

# these stations showed the greatest fluctuation (downward) as opposed to the midestuary channel stations which had more stable 

# salinity.

A cluster analysis was performed to indicate which stations were not 

# statistically different. The three- cluster solution, representing 86% of 

# the variation, was overlain on the results of 

# the principle component 

## analysis (Figure 3. 

# 1). The three groups were I-- Stations 11 and 24, the 

### shallow water creek stations which showed large fluctuations in 

# salinity due to freshwater runoff; II-- 

# Stations 

# 18, 25, and 37 , the midestuary 

# river channel stations 

## which show the least amount of 

# fluctuation in 

# salinity; and III-- Stations 34 and 41 

### , the upper estuary river 

### channel stations which 

### , being at the upper 

### boundary of the salt wedge, 

## normally had lower salinity readings and were as sensitive to freshwater runoff as 

## the creek stations.

These three station groupings were used 

# in other analyses in this sect i on 

# of the report 

### except that 

# Stat ions 

# 11 and 24 

# were analyzed 

# individually. This was done to better identify any significant 

## trends in Walden Creek (Station 

# 24). Walden Creek was bisected by the intake 

## canal and it was believed that 

### this area would first show any effect of the 

### operation of 

# the BSEP. Dutchman Creek 

# (Station 11) was chosen as a control area to be compared with Walden Creek. The fact that the cluster 

### analysis grouped these two stations 

# together indicates that the 

## species distributions in these creeks are statistically 

## similar.

## Species-- Station Group Association

Correlation coefficients of water temperature, salinity, and species to Principle Components I and II are listed in Table 3. 

# 2. These analyses show no change in spatial distribution from what Copeland et 

# al. (1979) 

## descri bed: flounder, shrimp, and spot moved out of the channe 

## 1 and into 

# the shallows; croaker utilized 

# the upriver channel 

# areas much more extensively than did other species; menhaden moved 

## upstream (shallow or deep) to 

# the oligohaline (0. 

# ppt salinity) areas; and anchovy preferred areas of stable, higher salinity which are more likely to occur 

### in the summer when 

## they spawn. These results are also consistent with behaviors reported by Weinstein et ale (1980) for juveniles and adults.



### Time- 

### Seri es Ana lys i s 

## Data was subjected to t ime- seri es anayl s is to determi ne if there 

### has been any change in the periods of occurrence of particular species and if 

# the abundance of 

# any species has been declining 

### over the past eight 

# years. The data 

### cons i sted 

# of 12 observa t ions 

### each year 

## where each 

## observation was the mean of 

# all surface and bottom samples collected during a month.

The model 

### , described in Appendix B 

### , fit the data at a 

## high level
(~ 0. 

## 85) (Table 3. 4) indicating a consistent period of occurrence for each 

### species over the 

# years. Periods of recruitment for 

# species of interest were as fo 11 ows:

## Spot Croaker
* Flounder * Mullet 

### Menhaden 

### Shrimp
- brown Late December- Early May Early October- 

## Late Apri
Late December- Late March Late December- Late March Late February- 

### Mid- May

- pink and white * Anchovy
* Seatrout

Gobionellus 

## spp. Mi d- 

## February- Mi d- May Late May- Early October 

## Late Apri l- Late October Early May- 

### Mid- 

## October Mi d- 

### March- Mi d- 

### December Early May- Late October Gobiosoma 

## spp.


## *See Table 1. 2 for species analyzed.

These periods are similar to previous reports (Copeland et al. 1979; CP&L 1982, 1983).



### Plots of mean 

# loge (density + 1) versus time over the past eight 

### years are presented for selected 

### species of interest 

## (Figures 3. 11). Because the 

# analysis was done on species by station group, plots were 

### selected for 

# the station group which was highly associated with a 

## particular species. For instance, croaker was most highly associated with the upriver channel stations; therefore, time-series plots of croaker are shown for station Group III (Stations 34 and 41) 

# only. All other species 

# plots are shown for Walden Creek (Station 

### 24) which was typical of the other station groups. Table 3. 3 summarizes these results for the selected 

### species at each station 

# group. Although there 

## have been year- 

## to- year fluctuations in densities, no declining trends have been observed for any 

# larval 

# species. Time-series analysis 

## indicates an 

# overall increasing trend in the density of total organisms in the past eight 

# years. This increase is 

### primarily due to increases in 

### anchovy in the 

# upper river 

# stations and Gobionellus 

## spp. 

# croaker, 

# and shrimp, throughout the 

# estuary. There has been an increasing trend 

### in densities of larval fish
in Wa 

### 1 den 

### Creek.

### Length- Frequency Ana 1 ys i s



### One way of assessing whether larval organisms were able to move past the influence of the plant, accumulate upriver , and grow is to compare the engths of the organi sms upri ver versus those downri ver. Larger organ 

### isms upriver should affirm this was 

# occurring. Copeland et 

# ale (1979) stated 

# that " 

# in 

# all cases and for 

# all species considered, the 

# larvae and postlarvae upstream were significantly larger than those downstream. 

# To confirm that 

### this was still the 

# case, lengths of 

## postlarval croaker collected from October 

### 1982 to May 

### 1983 were analyzed. 

### Croaker 

## was chosen because of its preference for upriver 

# areas. The analysis period was chosen because it was the latest recruitment period of croaker 

### before the operation of the 

### return system in 

### July 1983 

## (Section 9. 0). This was done to ensure that any effect which might occur in the lengthfrequency distributions after the return system was in operation would not 

## influence the data.

The majori ty 

# of croaker co 11 

# ected ranged from 8 

# to 21 

# mm. Kolmogorov- 

## Smirnov two-sample test 

### was run 

# on 

# the cumulative length distributions for Stations 18 and 25 (downriver) versus Stations 34 and 41 

# (upriver). Analysis results 

# indicate 

# that the two curves are significantly different (P ~ 0. 

# 05). Examination of the distribution plots 

### shows that 

# greater percentages of 

### smaller fish 

# are located downriver 

## (Figure 3. 

# 12). This is consistent with earlier findings and supports the idea of fish accumulating and growing above the influence of the plant.


### Summary

The relative abundance , spatial distribution, and seasonal occurrence 

### of larvae and postlarvae in the CFE have not significantly changed during the past eight years. 

# The decimation of populations in 

## Walden Creek 

## due to the 

## construction and operation of the BSEP 

# has not 

# occurred. This is demonstrated best by the 

### fact that the density of organisms in 

### Walden Creek has been increasing over the past eight years.

### Length- frequency data indicate that larvae are able to move past the



### influence of the intake, accumulate in an area 

### , and grow without risk of exposure to entrainment/impingement

Seasonality, station depth 

### , and salinity appear to be the principle variables controlling larval/postlarval abundance and species distribution
in the CFE.Table 3.Annual mean density (organisms/1O00m) and thepercentage of thetotal mean density for the eightmost abundant species collected in the riverlarval fish program, 1979-1984.Taxa197919801981198219831984Anchoas pp.69143.193763.58134.73335.61441.657847.Croaker17010.23220011.950124.36724.21017.Portunid megalops1.917615325312.114104Gobiosomaspp.36622.35911.842125.197'-DSpot129Penaeusspp.122Menhaden1.01.31.6Silversi des1.5Tota 1 organi sms160292.304696.167992.205292.147590.121891.9

## Table 3. Principle component 

### scores by station 

## and ranked correlations of larvaljpostlarval organisms, water temperature, and salinity for the 1977- 1984 river larval fish data.

Principle Component PCI PC2 

## Score

1.14

1.67 

## 1.43

1.17

73% 17%



### Corre 1 at i 

## Station

% Total variation explained



### Vari ab 1 e


### Temperature Shrimp 

### Spot

Gobiosoma 

## spp. Anchovy Portunid megalops 

## Salinity Menhaden 

### Croaker

See Appendix B for a detailed explanation of principle component analysis.Tab 1 e 3. Results of time- 

### series analysis for river larval fish data by station group (1977- 1984)! indicating significant changes 

# (+ or - ) in de ~sity along with amount of variance explained by the model- 

## (R ).


## Station Group
18 + 25 + 37 34 + 41 

## +/- 

## +/- +/- 

## +/-

Taxon
Anchovy +*** 

### +***



## Croaker +*** 

### +***



## Flounder Gobiosoma 

## spp.

Gobionellus 

### spp. +*** 

### +*** +*** 

### +***

Menhaden 

## Mullet +**



## Seatrout Spot

Penaeus 

### spp. +** +** 

### +***

Total organi sms 

### +** +** 

### +***



### 995 

### +**

NS P 

### )0 0. 

## * 0. 01 ~ P ~ 0. ** 0. 001 ~ P ~ 0.
*** P 

### -:: 0. 

### 001

2 is an adjusted value; see Appendix B.

### Figure 3. PC1 

### Shrjrnp

Gobiosoma 

### spp. 

### Spot Anchovy Portunid mega lops 

### Lower river Shallow water 

### High salinity



### Croaker Upper river



### Deep water Low salinity 

### Fluctuating salinity PC2 

### Menhaden



### Results of principle component ordination on 1977- 1984 river larval fish 

### data. Each axis 

### represents a continuum along an environmental gradient. Solid lines encircle station groups with similiar species distnbutions as 

### determined from cluster analysis. Species listed have strong associations with the gradient. See' 

### Appendix B for more explanation.c.:J ,, ...- , , ",'

t ! I.l . . 

## , , ,.. ,..

T"O" 

### ""."



## TTTLEGEND: 

### Figure 3.

4.-
c.:J ..J

LEGEND:


### Figure 3. "-- '--

0."-- ,.. ,.. ,.. ,..

TRIP DATE- ---n_- PREDICTED 

### ..-.....

YEAR LEVEL OBSERVED

Results of time-series analysis of larval/postla.rval croaker collected 

### Stations 34 and 41 in the Cape Fear Estuary, 1977- 1984.

:.. . , , , . ,

0 , 0 , 

## . 

## . , : - - - , ....... 

## ... --- - ...- . -



## TT".

OBSERVED TRIP DATE

-uu_- fREDICtED 

### .,-..-..

YEAR LEVEL


### Results of time-series analysis of larval/postlarval anchovy collected at 

### Station 24 in the Cape Fear Estuary, 1977- 1984.c:J
...J

LEGEND: Figure 3.4

8--

)- 6-

5--

c:J 9 3

w 2 

# :E

LEGEND: 

### Figure 3. . - .... : ... ~--- -+-. 

## : ;'\ .. :.. : - 

# - ..

TRIP DAfE 

# ----- OBSERVED PREOICfEO .-.-. YERR LEVEL 

### Results of time-series analysis of larvaljpostlarval flounder collected at 

### Station 24 in the Cape Fear Estuary, 1971- 1984. : ' 

## ~ - ......-

--\- -- - - - -. - ..- - - : -... 

## , -

TRIP DATE

OBSERVED PREDICTED .-..-+ YEAR LEVEL

Results of time-series analysis of larval/postlarval Gobiosoma 

### spp. collected 

### at Station 24 in the Cape Fear Estuary, 1977- 1984.)-.

ii5

ell

:l:

L fGENO: 

### Figure 3.

ii5 0 -

:l: TRIP OAfE DBSERVEO PREDICTED .-. -. YER~ LEvEL 

### Results of time-series analysis of larval/postlarval menhaden collected at 

### Station 24 in the Cape Fear Estuary, 1977- 

# 1984. , .

LEGEND: OBSERVED TRIP DAfE ---m- PREDICIED ..-.-. YEAR LEVEL 

### Figure 3. 

### Results of time-series analysis of larval/postlarval mullet collected at



### Station 24 in the Cape Fear Estuary, 1977- 1984....

(!;I ..J
c:(

LEGEND: 

### Figure 3.

"1- ...

CI) (!;I ..J
c:(

LEGEND: 

### Figure 3. .......

+ i

TRIP DATE 

# OBSERVED PREDICTED +-~- ~ YEAR LEVEL Results of time-series analysis of larval/postlarval seatrout collected at 

### Station 24 in the Cape Fear Estuary, 1977. 1984. 

# -"""-

- ~- 

# - - 

# - . - -- - *- 

### ... - 

# - - - .- , 

# - '

TRIP DATE OBSERVED PREDICTED .-~-... YEAR LEVEL 

### Results of time-series analysis of larval/postlarval spot collected at 

### Station 24 in the Cape Fear Estuary, 1977- 1984....

LEGEND:



### Figure 3. ...

..J

LEGEND: 

### Figure 3. ffi . . ... ...

LlJ. ,~

TRIP DATE OBSERVED PREDICTED .-.... YEA LEVEL 

### Results of time-series analysis of postIarval shrimp collected at 

### Station 24 in the Cape Fear Estuary. 1977- 

### 1984.

No Data ..... Available

IOT I "'.. 

### ,."-- ,., .,, ..,

. 7
T RIP OR r E 

# 08SERVED PREDICTED .-.-. YEAR LEVEL 

### Results of time-series analysis of totallarval/postlarval organisms collected 

### at Station 24 in the Cape Fear Estuary, 1977- 1984........10075~1D..;::....J, :)'-:-:--'..'.--"'".~-1 41 51 61 71 81 9LENGTHDOWNRIVER LARVALFISH STATIONSUPR IVEH LA'RV AlFISH STATIONS.LEGEtW:Figure 3.12 Atypical plot of cumulative length distributions showing a greater percentage of smallercroaker in downriver areas than upriver areas in 1983.DISCRETE DEPTH SAMPLING

Introduct ion



### The discrete depth sampling program was established to 

## characterize vertical distributions and movements of larvae in the water column during 

### both tide and 

## photoperi od changes. The discrete depth samp 

### 1 i ng 

### program was first conducted in 1979 and again from 1981 through 

# 1984. The objec

# tive of this study was to assess the effectiveness of the river 

## larvalfish sampling program which collects only nightly surface and bottom sam

# ples. The methods and results of the 1984 discrete depth sampling program are presented be 1 ow.

Discrete depth sampling was not conducted at the identical time that 

### river larval fish samples are taken. To account for potential errors when 

### comparing river 

### larval fish and discrete depth densities resulting from different temporal samp 

# es, a speci a 1 study was conducted that matched 

# river larval fish and 

# discrete depth samples on a temporal, tide, and 

### photoperiod basis. The results of 

# this special study are presented in Append i 

## xC.

Methods

Sample Collection



### Larval depth- 

# density distributions were determined by collecting samples from six specific depths during two 24- 

### hour rounds (trips) 

## Stations 25 and 34 (Figure 1. 

# 1). Sampling was conducted during periods of 

### peak abundance of winter-spawned larvae 

# (primarily spot and croaker) in the estuary.



### In 1984 the two 24- hour sampling rounds were conducted on February 

### 7 and 14- 

### 15 at 

# Station 34 and February' 8- 9 and 16- 

### 17 at Station 25. 

### Each round was divided into five sets corresponding to 

# period and tide 

# direction. Figure 4. 1 graphically illustrates the sequence of these sets 

### and series as they relate to period, tide, and the order of depths sam

## pled.A 11 gear and samp 

### 1 i ng 

## procedures were the same as used in 1982 and



### 1983 (CP&L 1983). Sample preservation and processing and data 

## analyses were unchanged from 

### 1983.


### Data Analysis

The primary emphas 

# i s of the 1984 di screte depth sampling program was 

### to further define the depth distributions of 

### larval fish. 

# A split- plot design was used with period and tide combinations blocked on rounds as the 

### whole- 

# plot units. Each unit was then subdivided into subplots correspond

### ing to 

# the depths 

# sampled. This design was . developed in 

## 1982 (CP&L 

# 1983). This same split-plot design was used in 1983 and 

### 1984. Two 

### wholeplot units occurred at each mean tide direction which were averaged prior 

# to analysis. Each station was analyzed separately. 

# The split- plot design was constructed to effectively isolate (from 

## the other vari ab 1 es in the AN OVA mode 1) and emphas 

# i ze the role of depth in predicting densities of 

# fish. The analysis can 

# be considered as two parts--a whole- 

### plot and a subplot analysis. The whole- plot analysis looks at peri 

### od and tide effects across all 1 eve 1 s of depth 

## , wh il e the subp 

### 1 ot ana lys is 

### focuses on the effect of 

# depth. In keep 

## i ng with the intent and 

### design of the discrete depth sampling program, only the 

## subplot results wi 11 be reported.

Results and Discussion

Water Temperature and Salinity

Water temperature during Round 1 

### ranged from 4. 

## 80 to 8. C at Station 

## 25 and 4. 

# 60 to 8. C at Station 34. Temperatures were generally lowest at 

# night on the 

# surface and highest during the day near the 

## bottom during Round 1. During Round 2, temperatures ranged from 8. 80 to 11. C at Sta

### tion 25 and 8. 00 to 10. 

### C at Station 34. 

## Temperatures were generally lowest at night on the bottom during Round 2 and highest during the day on 

## the surface (Figure 4. 

## 2).

### Salinities ranged from 9 to 33 ppt at Station 25 and 1 to 12 ppt at

Station 34 during Round 

# 1. Round 2 salinities ranged from 11 to 32 ppt at 

## Station 25 and 2. 5 to 20 ppt at 

## Station 34 (Figure 4. 

# 3). The lowest salinities were recorded near the surface around low tide with the highest salinities found near the bottom around high 

# tide.

Analysis of Variance and Duncan s Multiple Range Test Results



### Croaker

Due to the presence of 

## interactions, i nterpretat i 

## on of the sp 1 i t- p 1 

### results is 

### accompl i shed by examination of 

### interaction plots. 

## Data for these plots are presented in Tables 4. 

## 2 and 4.

Plots of croaker densities and a list of cell means show a definite 

### increase with depth at 

## both stations, especially during the day (Figure 

## 4 and Table 4. 

# 2). At night at 

# Station 34, densities increased at all depths but not as much as 

# during the day. The densities increased from 

### the surface 

### (1 m) to the bottom (11 m) with the highest densities at the 

## bottom. At Station 25, however, there was a crossover in the plot (Figure 

# 4) of day/night densities. The daytime densities at the bottom (7 and 9 m) exceeded the nighttime densities at the 

### bottom. 

## A significant tide- by- depth interaction for croaker occurred at Sta

# tion 

# 25. An examination of 

# plots of tide- by- 

## depth means (Figure 4. shows that the depth distribution 

# pattern (5 through 

### 11 m) of 

## croaker became mixed during the low and mean in 

# tidal stages. At the high and mean out tidal stages, a generally linear pattern is 

### shown.

A significant period- 

### by- 

# tide- by- depth interaction for 

# croaker also occurred at 

### Station 25. Plots of period- 

### by- 

# tide- by- 

### depth means (Figure 6) show that during the day the depth distribution pattern looked very much like the overall pattern with mixing at the lower levels (5 m through bottom) during the mean and low tidal stages and all depths mixing at the 

### high tidal 

# stages. At night however, the pattern was different with the 

### l-m depth showing the lowest densities throughout the entire period with the other depths showing a well-mixed pattern throughout all tidal stages.

# A significant tide- by- depth interaction for croaker also occurred at



# Station 

# 34. An examination of plots of tide- 

### by- 

## depth means (Figure 4. show that the depth di 

# stri bution pattern of croaker at 7 and 9 m 

### became mixed during the low 

# tidal stages. At the high and mean tidal stages , a 

### generally linear pattern was 

# shown. There were no significant period- 

### by

# tide- by- 

## depth- interactions for croaker at Station 34 

### , with both day 

### and 

# night data displaying similar patterns.

The plots of depth- 

### by- tide (Figures 4. 

## 5 and 4. 7) effects show that at 

# the surface (1 m) 

## and bottom (11 m), the densities were more 

## closely grouped than the 

# other 

# depths. There was more vari at i 

# on in dens it i es between tides at 3 through 9 m than at the surface and bottom. 

## Figures 4. 4 through 4. 

### 7 also show that the densities at the 

### bottom are always greater than the surface during all tides and 

# period. There 

# was no significant difference between means of 

### densities for all 

## depths and an average of just surface and bottom means (Appendix C); therefore, 

### the river larval fish method is doing an effective job of estimating river larval populations.


### Spot


## An examination of Table 4. 1 shows that although the depth effect always significant, it is not independent of the 

# period. The density of 

### spot at any depth does not vary depending upon the 

# tides. Due to the presence of 

# interactions, interpretation of 

# the split-plot results is accomplished by examination of 

### interaction plots. Data for these 

## plots are presented in Table 4.

Plots of depth- 

### by- period densities of 

# spot (Figure 4. 

# 8) show that 

# densities increase with depth during the 

# day. At night, although the densities at the bottom (11 m) were greater than the surface (1 m), the densi ties 

### at 3 and 5 meters exceeded the 7- 

## and 9-meter dens 

# it i es. with croaker at Station 25, there was a crossover in the plots at both stations, with the densities at the bottom (7 , 9, and 11 m) during the day exceeding the densities at the bottom during the 

# night. This is explainedby the fact that some of the fish are moving upward in the water column at



### night, thereby they are more equally 

### spread out in the 

# column. During both periods however 

# , if depths were averaged, the number would not be significantly different than when averaging only the surface and bottom as the river larval fish program does (Appendix 

### C). 

## Figure 4. 9 also show that densities at the bottom were always greater 

### than at the surface during all tides. When means of densities were aver

### aged over all 

# depths there was no significant difference between that 

# average 

# and 

# the average of 

# just surface 

# and bottom densities (Appendix C). 

# This again shows that the 

# river larval fish 

## program is doing an effective job of estimating river larval populations.



### Summary 

## Discrete depth sampl ing 

### was conducted in 

## both downriver and upriver 

## areas (Stations 25 and 34). Croaker and spot 

## arvae were 

## concentrated near but not on the 

# bottom. Spot deviated from this at night and showed higher densities near but not at the 

# surface. Croaker had maximum densities on or near the bottom and minimum densities near the 

## surface.
Si nce both spot and croaker were more abundant in the bottom half of 

### the water column under almost all conditions, they were carried upstream 

### with the net nontidal drift. In analyzing both period- 

### by- depth and depth

### by- tide effects, the bottom densities were always greater than the surface 

# densities. There was no significant difference between the averages of the means over all depths and the average of the means of just surface and 

# bottom. These results show that the river larval fish program by sampling 

### just surface and 

### bottom at night provides a valid 

### assessment of 

## larval density in the water column.

## Table 4. Results of analysis of variance (split-plot model) for spot 

### and croaker for the 1984 Cape Fear River discrete depth 

### program.



### Source Spot 1



# Station 25 Station 34 

## Croaker



# Station 25 Station 34

Whole plot 

### Round 

## Period *** 

### *** * 

### *** 

### ***



## Tidal

Peri od*Ti da

Subp 1 ot 

### Depth *** 

### *** *** 

### ***



## Period*Depth

Ti da 1 

### *Depth

Peri od*Ti da 

### *Depth


## See Table 4. 

# 2 for cell- means 

### See Table 4. 3 for cell-means Not significant - P 

### ;;. 0.

01 ~ 

### P ~ 0.
O. 05 ~ 

## P ~ 0. 001 

# *** P ~ 0. 001

## Table 4. Analysis of variance cell means for 

# croaker densities collected in the 1984 Cape Fear River discrete depth sampling 

### program.

Source Station 25 

### Stat i on 34 

## Subplot Depth Ce 

## ll-means Loge 

### ~p~h Loge Dep~h



### 1. 76 

### Depth*Period 

## Cell-means Day 

### Night Day 

### Night

Loge 

### Depth Loge 

### Depth Loge 

### Depth Loge 

### Depth



### 1.69 

### 1.56
Depth*Tide 

## Cell- means 

## High Slack High Out 

## High Slack Hi gh Out

Loge 

### Depth Loge 

### Depth Loge 

### Depth Loge 

### Depth



### 1.61 33.

## Table 4. (continued)

Source Station 25 

## Stat i on 34

Mean Out Low Ou t 

### Mean Out 

### Low Out Loge 

### Depth Loge 

### Depth Loge 

### Depth Loge 

### Depth


### 1.42

Low Slack 

### Low In Low Slack 

### Low In Loge 

### Depth Loge 

### Depth Loge 

### Depth Loge 

### Depth



### 1.60

Mean In 

### High In Mean In 

## Hiqh In Loge 

### Depth Loge 

### Depth Loge 

### Depth Loge 

### Depth



### 1.47 

### 1.85

## Table 4. Results of 

### analysis of variance cell means for spot densi

### ties collected in the 1984 Cape Fear River discrete depth 

### samp 1 i ng 

### program.

Source Station 25 Station 34

Subp 1 at 

### Depth Ce 

## ll-means Loge 

### Depth Loge 

### Depth

Depth*Peri ad 

## Cell-means Day 

### Night Day 

### Night Depth Loge 

### Depth Loge 

### Depth Loge 

### Depth

1 1 .1..1.



### 1.34 

## 1.07 Depth*Tide 

### Cell-means 

## High Slack High Out 

## High Slack High Out



### Loge 

### Depth Loge 

### Depth Loge 

### Depth Loge 

### Depth


### 1.97

## Table 4. (cont i nued)



### Source 

## Stat i on 25 Station 34



### Mean Out 

### Low Out Mean Out Low Ou t 

### Loge 

### Loge DeDth 

### Loge 

### Depth Loge 

### Depth



# ---'-

1.92

1 1 .LJ. 

### Low 51 

### Low In Low Slack 

### Low In Loge 

### Depth Loge 

### Depth Loge 

### Depth Loge 

### Depth

Mean In 

### High In Mean In 

## High In Loge 

### Depth Loge 

### Depth Loge 

### Depth Loge 

### DepthDAY NIGHT

MEAN 44% c:-

"1.' Ii' '

LOW 28%
LS.

L.5o L.S.



### Figure 4. 

### Discrete depth sampling tide tabulation graph.DEPTH (m) 13'

Ii!J3

136

, t

LEGEND .

DEPTH 1m)

1 1 

# .. .

LEGEND,


### Figure 4. 5T A 

### T:ION-25 ~ ~



## JI: ..

"jc .

-/. 4 

# . . . . .

. I 9. :3 

### 10. TEMPERATURE :IN C
+-+-+ DAY. ROUND 1 8-S-e NIGHT. ROUND I *-*-~ DAY. ROUND 2 ..--.. NIGHT. ROUND

STAT:ION-34 

# I !

I I
'J(. 

## I I I I 

## I I I I 

# )I: . . I . . . . . I . 

# . . . .

I . . . . . I . . . . . I . . . . . I 

# S 8. 

# 1 8. 

# 7 9. 

# 3 9. 9 la.
TEMPERATURE iN C
+-+-+ DAY. ROUND I 

# e-a-a N:IGHT. ROUND *-*-~ DAY. ROUND 2 ..--.. NIGHT. ROUND 

### Discrete depth sampling temperature prof1les at Stations 25 and 34 

### in the Cape Fear River , February 6- 9 and 14-17 

### , 1984.DEPTH 1m) ST A TJ:ON-2S -.......: ' 

# , ,,~ 

# '" , " "\ '\ 

# \ \ \ , 

# . ~ ,,\

).; 

# \ ' \ \



# '0 rn"'-"' 

### rn...nH ......n nn.

DEPTIi 1m)



### Figure 4. ...

LEGEND . 

### ....... ...n.... Hi! ,.0+ SALJ:NJ:TY J:N PPT
+-+-+ DAY . ROUND I 

## e-s-& NJ:GHT. ROUND I

ST A T:ION-34 

# "'\ 

# ~ ' 

# \\

...n .... .nn' 

## p""'" n.n ... .......

LEGEND. 1121 2121 '26

SALJ:NJ:TV J:N PPT
+-+-+ DAY. ROUND I e-e-e NZGHT. ROUND I *-M-M DAY. ROUND 2



# ~.

NIGHT. RCUNO 2 

### ,..,...... ,......... ,.... 

### .... 

### ,......... .,........

2121

*-M-M DAY . ROUND 2 .-.

N:IGHT. ROUND 2 

### Discrete depth sampling salinity prof1.les at 

### Stations 25 and 34 in the Cape Fear River 

### , February 6-9 and 14-17, 1984....

)- 6

u;

GO 4 

# -' 3 o
~ 21 :ru; 5 D'

GO 4

-' 3



### Figure 4.4 STATION 25

fi.J ... .... .... ... .... ............... """ 

## '" ..

D....... .................. '.",0' c........... ... ....

DEPTH (m)

LEGEND: PER rOD 

# ~DAY o.. 

### o.. Q NIGHf

STATION 34 .,.,. ,........ :..



# ~~9

-c.. .......... 

## ... ~

.c.

0 3 DEPTH (ml

LEGEND: PER IOD 

# ~DAY 0... 0... 

### rnGHT



### Densities of croaker collected by period and depth at Stations 25 and 34 in the Cape Fear River 

### , February 6-9 and 14-17 

### , 1984./ -/-/ ----._,--::::-:-~=-"~--~~--:=~=~~-- ----- -----/ -- ~. -/ /-- /. -- ------ .----z 3' // /"'- // ,....------- -- _--::.:..=-q:"J '/'/ ~-- ,' ~/-'- "- - - - - -'"- c'----- /..-::; /,~~ ~ ~-- -- - - ~-- -- --~ ---- -- ---:;; 2 -~--- c.--- --/ _- - - - 2--"'-'-"--"'~~~-::::,~,--"':::.-- ,- - - -,..,r1 1./~ 76-j1U)w 5-Q) 4c..9 "-.J.....CJ'I1 1DEPTH (m)LEGEND:Figure 4.TIDE----- La---._---- L S--------- H S-------------- L I- - - -Densities of croaker collected by tide and depth at Station 25inthe Cape Fear River, February 6-9 and14-17,1984.PERIOD-DA Y 

# ; :

- r 

# 1: 10--- ~ - \..~.::: '"



# '" g "?t"- ~or 

# \ .::;'..



# Z ... 

# ' - ;

~:~ 

### .. 

# ~ : 

# ' , ~-,.

---e--. .....::::'-



# c - - -'(

'"Y :III: 

# ~ . - ,...



# / ' '

./ \



# ..J 3 / - - 

# --."

z / 

# W 2 , '" ------- 

# . , 

# - \

"\.. .l'



# \ / " ~

.I'

1'10 M.I

LEGEND I DEPTH (m) 

### TIDE



### -+-+-+ 9 ...~. 97 

# ~-e

.......... 1 1 otC-M-M 0:3 

### ..-- 99

PERIOD-NIGHT 

# 8 ~~- )- / -

..:---



# I- , &:" ~



# in ~,.-..;z::-- ~,



## Z S 

# ~- --,,"'-

:;7 -.........,. .... 

# "' ~~~-~-

/F~/ 

# /' - "'-. - 

# ~~ - --=-

... ... 

# " ~ 

# --- '

... 

# "-, - ="

-.,;c - 

# :q ' '-

- - ..;.



# ~o- :---. '- 

# ..... /' - -

..J " ~



### Figure 4. 

# LO 

# LS LX 

# HI

TIDE
LEGEND I DEPTH (m) 

# ~91

...~. a' otC-M-N 93



## .....

- as tr-S-e a6 

# ....--

1 1


### Densities of croaker collected by tide , depth 

### , and period at Station 25 in the Cape Fear River, February 6-9 and 14-17 

### , 1984.

. 4':'16~ 7!:: 6CI)(!)QJ 4...JZ 3~ 2j:::o'-IFigure 4.. /. /~ ~~=:--- ~~;: -;::~.~-:=:::::. ::::::.:::::::::.'-'-- -~ ------/ /. ---- - -/ /./""' ....-;;:;' -- - -/~ /./ ," ,--- ./' /~/ ..--/' /::-/ ........."""" /' -"'" ./ .-r/ .~~~u~=~~:=. ./ /. .LEGEND:1 1DEPTH (m)TIDE----- Lo----_u_-- H S----- M-------- L I. - - - -110Densities of croaker collected by tide and depth at Station 34 in theCape Fear River, February 6-9 and 14-, 1984.STATION 25 ... 

# )-

en 

### ;~ 4 jo.

c:C 0.. ... .... -* .



# 01 

# 03 05 

# 07 

# 89

DEPTH (m) 

### LEGEND: PER roo 

# ~DAY 8... 1J... (;) N I G H T

STATION 34 

# ... ..,

(J)

GO 4...:10. (!1

:IE ....



### ~li- 

# ~~~.

DEPTH (m) 

### LEGEND: PER roo 

# ~DAY (;)... (;)..

IJ ~j IGH T



### Figure 4. Densities of spot collected by period and depth at Stations 25 and 34 in the



### Cape Fear River , February 6-9 and 14-17 

### , 1984.STATION 25

III (:J
...J

0::(

:!E 

# ~~~~~=

~~~~S;~::) 

# '7

DEPTH 1m)


### LEGEND: TIDE L 0 ............... HO .-.-.-.- H S r'r I 

# nmu L I 110

STATION 34

+' 7 :. : 

# ~;~~~~: 

# ~~~=

2 . 

# / /

:!E /

fJ 1 DEPTH 1m)


### LEGUm: HOE 

# -HI -...-...-

.-.---.- H S M I ------_. L I MiJ



### Figure 4. Densities of spot collected by tide and depth at Stations 25 and 34



### in the Cape Fear River , February 6-9 and 14-17 

### , 1984.HIGH MARSH


### Introduct i

The marshes of the CFE provide nursery areas for many fish and shell

# fish. It has been estimated that as much as 93% of the East Coast' s com

## mercial fish , shellfish, and sportfish spend at least a portion of their 

### lives in estuaries 

### (McHugh 1967). Biological monitoring of the fish and 

### shellfish in 

### the CFE 

### marshes is important to determine if the BSEP' 

## removal of estuarine water for cool ing purposes has any adverse effect on 

# their populations and distributions. 

# The high marsh 

## study began in 

# January 1981 wi 

# th the main object i ves to 

## determi ne 

# the seasona 1 

### and spatial distributions of , the influence of physical variables on, and any 

### abnormal trends in populations of selected fish and 

# shellfish. Results from 1981 through 1984 are discussed in this 

## section.

Methods

Station Description



### The study area consisted of four tidal creek 

## systems (Figure 1.2). Baldhead, a polyhaline creek (16- 30 ppt) adjacent to the mouth of the CFR had seven trawl stations 

### and two seine stations. Walden Creek is located adjacent to the BSEP intake canal and is considered to be mesohaline (8- 

# ppt). Nine trawl stations 

## and two seine stations 

## were sampled in this 

# creek. Mott I s Bay, an 01 i goha 1 i ne-mesoha 1 i ne (1- 

# 8 ppt) area, is 

## located upriver from the 

# BSEP. From 1981 to 1983 , Mott' 

### s Bay had one trawl and 

### one seine station. In 1984 a second trawl and a second seine station were 

### added to better 

### sample that area. Alligator Creek is a fresh-oligohaline 

# creek (.:: 1- 

# ppt) located in the upper estuary west of 

### Wilmi ngton and included four trawl stations.



## A 3. 24- hectare return bas 

# i n was constructed in 1983 as part of the 

### modifications made to the BSEP intake 

# system. These modifications were 

### designed to 

# reduce entrainment and to increase survival of 

## organisms imp i nged on the intake screens. The return bas in rece 

### i ves wash water and

### organisms from the screen-wash system via a 1. 

### 37- km sluiceway. A weir on

the north side of the bas 

## i n allows water to flow out of the bas 

## i n on ebb tide and back into the basin on 

### flood tide. Water from the basin flows 

### into Gum Log Branch which joins Nancys Creek and then Walden 

# Creek. this route, surviving organisms were returned to the open estuary (Figure 

# 1.3). One trawl station was sampled 

### in the return basin in 

# 1984. More detailed descriptions of the 

### high marsh stations are presented in CP&L 

### (1982) .

Samp 1 i ng 

### Methods

The 1984 trawl and 

### sei ne samp 1 i ng gear , samp 1 

### i ng methods, 

## and aboratory procedures were identical to those used in previous years (CP&L 

### 1982, 1983, 1984). Discussions of variables 

# affecting the organisms in this 

### study are based on data gathered by the gear types considered the most effective for each species as follows:



### Trawl 

### Spot Bay anchovy 

### Brown shrimp Menhaden 

## Seine Striped mullet Mummi chog 

## White mullet 

# Atlantic silverside Croaker
Blue crab 

## Flounder Pink shrimp White shrimp


## Three sediment samples were collected at each trawl station and two 

### samples were collected at each seine station in September with a 3. 

### 8-cm coring tube. The top 5 cm of sediment was removed for grain-size and per

### cent organics 

### determination. The grain- size analysis was a modified ver

### sion of that used by 

### Ingram (1965). Percent organics was determined by loss of weight after ashing at 550oData Ana ys is



### Recruitment sizes 

## and periods were examined for 

# each species by 

## examining length- frequency distributions 

# fitted to a natural log (loge 

## catch- 

## per- 

# unit-effort (CPUE) scale for 

## each creek. 

## Occasionally the number of individuals collected in a 

## given creek 

## system was low, thus making reliable recruitment size and period estimates 

## impractical.

The blue crabs Callinectes similus and C. sapidus were grouped for time

### series analysis because prior to 1983 these 

## species were only identified to genus. However , 99. 

### 4% of the Callinectes spp. co 11 

### ected in 1983 and

1984 were C. 

### sapidus.

Lower identification cutoff limits were enforced at 20 mm for each of the penae 

## i d shrimp spec i es and 10 mm for 

### blue crabs. 

## Shrimp and blue crabs below the cutoff limits were identified to genus only due to difficulties in identifying these organisms to 

### species. As a result of the identification cutoff limits, 1. 

### 2% and 19. 0% of the respective shrimp and blue crab catches were not included in the analysis.



### Principle component analysis was used to examine the 

## preferences of selected organisms for various abiotic variables and their spatial distri

### butions. A more detailed 

### discription of this 

### analysis is 

## presented in
Append i x B.



### Data collected in the high mars 

### h study from 1981 through 1984 were 

### subjected to a 

# time-series analysis. Catch- 

# per-unit-effort data (by creek) were transformed to natural logs before 

# analysis. Significance of the upward or downward trends was determined at the P ~ 0. 

### 05 level. More 

# detailed explanations of 

# the statistical analysis are 

## presented in Appendix B.Results and Discussion

Sed iment 

## Parameters

Baldhead Creek is 

# characterized by sediments ranging from fine sand 

### in the downstream stations to very 

### fine sand and clay in the 

## upstream 

# areas. The percent organics in Baldhead Creek was greatest in the upper

### most station followed by the midcreek stations and then the downstream stations (Table 5. 

## 1).

The upstream Walden Creek sediments were primarily very 

## fi ne sand, while the middle to downstream sediments were coarse silt and 

# clay. The percent organics was greatest in the middle to downstream stations (Table 

## 1).

The Mott' s Bay sediments were fine 

## sand, coarse 

# silt, and clay. The percent organics ranged from very low on the mainland side of the bay to relatively high on the island side 

## (Table 5. 1).

All Alligator Creek stations contained sediments classified as clay 

### except the downstream station which contained primarily fine 

# sand. The percent organics was higher in Alligator 

### Creek than in any other 

## system. Percent organics was highest in the uppermost station followed by the midstream stations and then the downstream station (Table 5. 

## 1).

Catch by Gear Type



### A total of 138, 359 fish representing 93 species and 85, 

## 569 invertebrates representing 10 species was collected in 

# 1984. A total of 414 trawl samples yielded 101 

### 180 fish (CPUE of 244) and 53, 

## 984 invertebrates (CPUE of 130), while 108 seine samples yielded 37, 

### 179 fish (CPUE of 

### 344) 

## and 31, 

# 585 invertebrates (CPUE of 

# 292). Spot was the most 

## abundant organi sm in 1984 wi th a CPUE of 150 and compri 

### sed 40. 1% of the tota 1 catch 

## (Table 5. 

# 2). Spot was followed in abundance by grass shrimp (CPUE of 96), bay anchovy (CPUE of 35), brown shrimp (CPUE of 20), and menhaden (CPUE of 

# 18). Previous studies by Hodson (1979), Hui 

### sh and Geaghan (1979), and

## Weinstein (1979b) also indicated that catches were generally dominated by



### the same species. Grass shrimp was the most abundant species collected by seines with a CPUE of 281 and 

## comprising 44. 2% of the total catch. 

### Grass shrimp was followed in abundance by spot (CPUE of 128), menhaden (CPUE of 101), striped mullet (CPUE of 27), bay anchovy (CPUE of 24), and mummichog 

### (CPUE of 23). The dominant species collected with seines were similar to 

## those obtained by Weinstein (1979b) using seines in selected tidal creeks.

Relationships with Abiotic Variables



### Seine

Principle component analysis was performed on the 1984 seine data for 

# all i dent if i ed groups of stations based on geograph 

### i ca 1 d 

## is tri but ions of selected species. The first two components were used to examine the rela

### tionships between abiotic 

# variables and 

# species. Component 1 accounted for 62. 

### 4% of the total variation in the data set, while Component 2 accounted for an additional 32. 

### 9% (Table 5. 

## 3).

Weak relationships were indicated between striped mullet, mummichog, 

# white mullet, and 

# the salinity and temperature parameters (Table 5. 

## 3). These three species appeared to be more closely 

### related to mesohal ine 

# areas. Atlantic silverside were strongly correlated to Component 2 which reflects their strong association with polyhaline 

## areas.

Striped mullet, mummichog, and white mullet had weak negative associ

### ations with 

# the sediment organics, while 

# Atlantic silverside were not associated with the percent organics parameter 

## (Table 5. 

## 3).

Principle component analysis appeared to indicate that there was no 

### relationship between striped mullet, 

### mummichog, white 

# mullet, Atlantic silverside, and the size of the particles in the 

## substrate (Table 5. 

## 3). Weinstein et 

# al. (1980) also concluded that 

### sediment size had 

# ittle effect on the distributions of most of these species.

### Trawl

Due to within creek salinity and sediment variability combined with 

# the sal inity and sediment variabil ity 

# within the estuary. PCA was 

## performed on Baldhead and Walden Creeks 

## individually.
The location- by-species matrix of 

## Baldhead Creek trawl data was 

## analyzed by PCA. A total of 64. 5% of the variation was explained by 

### PC1, 

## while PC2 explained another 20. 0% (Table 5. 

# 4). These components were used 

# to determine associations 

### between species 

### and the 

# abiotic variables. 

# Relationships between 

# species and stations 

# will be discussed in 

## the 

## following sect ion.

Moderate relationships were noted between penaeid shrimp, spot , blue crab, and menhaden and low salinity (Table 5. 

# 4). These species were also weakly associated with smaller sediment grain 

# size. No relationship with 

### sediment percent organics and 

## these species was 

# observed. Bay anchovy were weakly associated with low organic sediments and higher salinity. association with sediment grain size was discernible.



### Principle Component 

### Analysis on the 

# location by species matrix of 

## Walden Creek data indicated that 41. 

## 5% of 

# the 

# total variation was 

# explained by 

# PC1. Principle Component 2 explained 31. 

### 0%. while PC3 explained another 14. 

### 7% of the variation in 

### the data set 

## (Table 5. 5). These three components were used to examine the 

# effects of abiotic variables on the distribution of selected 

### . species in Walden Creek.



### The analysis indicated that spot. blue crab, menhaden, brown 

## shrimp, and croaker were most closely related with areas in Walden Creek that were low in salinity and sediment 

# organics. These species were also associated 

### with the more 

# coarse sediment particles. Flounder 

### , white shrimp, pink 

## shrimp. and bay anchovy were not associated with salinity or 

## sediment organics in Walden 

### Creek. A weak relationship was observed between these species and finer sediment particles.Spatial Analysis



### Withi n Creek

The spatial distribution of selected organisms in Baldhead and Walden 

## creeks were determi ned using PCA on 1984 

# trawl data. Seven speci es from Baldhead Creek and nine species from Walden Creek were used for analysis.

In Baldhead Creek , penaeid shrimp, spot, blue crab, and menhaden had 

### moderate to strong associations with the headwaters (Stations 15 , 16 , and 

## 17) (Table 5. 

# 4). Bay anchovy had a weak preference for two of the head

### water stations 

# (Stations 15 and 16) and one of the downstream stations (Station 12).

In Walden Creek , spot , blue crab, menhaden , brown shrimp, and croaker 

### were associated with the uppermost stations 

# (Stations 26 and 

# 27) (Table 

# 5). Flounder, white shrimp, pink 

## shrimp, and bay anchovy were moder

### ately associated with the middle Walden Creek stations (Stations 24 and 29) and the Gum Log Branch station (Station 28).



### These spatial 

# distributions were similiar to 

# those observed by 

## Weinstein (1979b) and CP&L (1982 

### , 1983, 1984). These distributions seemed 

### to be most associated with the upstream/downstream salinity gradients in the two creek systems.

Wi th in the Estuary



### The distribution of most aquatic organisms in the estuary is deter

### mined by sal inity 

### (Copeland and 

### Hodson 1977; Weinstein et 

# ale 1980). Therefore, the 

### selection of a 

# particular area 

# (creek system) by the migrating organisms within the 

### estuary is 

# primarily influenced by the sal inity regime of that area.



### The CPUE 

# by creek was used to determine the 

# creek systems that supported the greatest abundance of 

# each selected 

# species (Table 5. 6). Baldhead Creek 

### which is generally a 

# polyhaline system, yielded the

# highest catches of 

# white mullet and Atlantic 

# silverside. This lower

estuary preference is comparable to previous studies in the CFE (Weinstein

et a 1. 1980; CP&L 1982, 1983, 

### 1984).



## Walden Creek , which is generally a mesohal ine system, 

## had substan

# tially higher CPUEs for spot 

### , brown shrimp, striped mullet, and mummi

# chog. The CPUEs for blue crab and pink shrimp in Walden Creek were only slightly greater than the CPUEs in Mott' s Bay and Baldhead Creek, respect

# ively. These results, except for pink shrimp, are consistent with the findings of CP&L (1982 , 1983, 1984) and Weinstein et al. 

## (1980).

Mott I 

### Bay is an 01 i gha 1 i ne- mesoha 1 i ne 

# area located in the 

### upper estuary well past the influence of 

## the BSEP. This sampling area contained relatively large populations of bay 

### anchovy, menhaden, and croaker. 

### These results were similar to previous years 

### (CP&L 1982, 

### 1983, 1984) except for menhaden which were generally more abundant in Walden Creek in 1981- 

### 1983. 

# Alligator Creek is a 

## fresh-oligohaline area which 

## supported the 

# largest concentrations of 

# flounder. As indicated by Weinstein et 

# al. (1980), this preference for the upper estuary was normal.

Seasonal Distribution 

# The seasonal d 

## i stri but ions 

# of the commerc i a 

### lly and 

### recreat i ona lly 

## important species were associated with the immigration of postlarvae and 

# early juveniles into the 

# marshes. The subsequent decrease in abundances was due to natural mortality and to emigration from the marshes.



### The recruitment of 

### spot in the estuary began during January and 

### coni i nued through March and Apri 1 wi th the majori ty co 11 ected from Walden 

## Creek (Figure 5. 

# 1) The abundance of spot remained relatively high 

## until 

# early summer. Recruitment of croaker began in September and October 1983 

## and continued through January and February 

# 1984. The peak 

## abundance of 

# the 1983 through 1984 year class 

### occurred in 

## March and May 

# 1984. The major part of the 

## croaker catches duri ng peak 

### abundance was from Mott I 

## Bay (Figure 5. 

# 2) The recruitment of 1984 through 1985 year class of croaker began in October 1984 and cont inued through the end of the year.

### The two species of mullet exhibited different 

## seasonal and spatial



# occurrences. Striped mullet y~y were most abundant in April and May with 

### the dominant catch occurring in Walden Creek 

## (Figure 5. 

# 3). This species 

### was fairly common in 

### all months at a variety of 

# sizes. White mullet, however , displayed more distinct seasonal presence in the estuary (Figure 

# 4). Practically all of the white mullet were YOY collected from May to October in Ba 

### dhead Creek. The 

## peak catches of th i s spec 

## i es occurred in July and continued through September and October.



### Flounder were collected 

# in relatively low numbers. except during recruitment, which occurred from January through May with a peak in March 

## (Figure 5. 

# 5). The majority of the flounder were collected from Alligator Creek with a modal length of 20 mm.


### Young-of- year dominated the 

### menhaden catch in the 

## CFE (Figure 5. The abundance of this 

### species peaked in May and was 

## dominated by catches from Walden 

## Creek and Mott' s Bay during recruitment. Bay anchovy were 

# collected practically year round in 

# all study 

# areas with 

# the peak abundance of YOY occurring 

### during July in 

# the lower estuary (Figure 

# 7). The greates t total CPUE of bay anchovy occurred in Mott 

## I s Bay and consisted of individuals from the previous year class.

Mummichog and Atlantic silverside displayed similar seasonal distri

## but ions in that the catches were dominated by adu 1 ts from January through 

# May. During the late spring and summer months, spawning occurred after 

### which the catches were dominated by the YOY 

## (Figures 5. 

## 8 and 5. 

# 9). The peak abundance for YOY Atlantic silverside occurred during July in Baldhead Creek , while the peak for YOY mummichog occurred during September in 

### Walden Creek.

All three species of penaeid shrimp exhibit distinct seasonal distri

## but ions in the 

# CFE. Brown shri mp were abundant from May through Augu 

# with 

# the highest catches occurring in 

### the first 

### month of 

## recruitment 

## (Figure 5. 

# 10). By the 

# time the brown 

## shrimp catches decreased, pink shrimp were abundant and remained so through November (Figure 5. 

# 11). Like brown shrimp, the maximum catch was 

### obtained during the first month of

# recruitment. White shrimp were most abundant from July through October



### with the maximum catch occurring in the first month of 

### recruitment. The maximum recruitment of the three shrimp species occurred in Walden Creek followed by Baldhead Creek.

Blue crab of various sizes were abundant year round in the 

# CFE. The largest catch of 

# blue crabs occurred in May 

# and was dominated by YOY recruits in Walden Creek (Figure 5. 

## 12).

Most of the 

## seasonal and length- frequency distributions in 1984 were similar to previous studies in the Cape Fear and other estuaries (June and 

## Chamberlin 1959; Dudley 

## and Judy 1973; Chao and Musick 1977; Weinstein 1979b; CP&L 1982 , 1983, 1984).



### Time- Series Analysis 

## All i gator Creek

The abundance of flounder in 

## All igator Creek increased significantly 

## over the four- year study period 

## (Table 5. , Figure 5. 

# 13). This increase 

# in All igator Creek is comparable to a general increase of flounder over 

# the entire estuary. An increase in freshwater flow in recent years 

## (pers. comm., C. Gunter 

### , United States 

## Geological Survey) may have resulted in more suitable habitats for flounder throughout the estuary.

The abundance of spot in 

## All igator Creek decreased s igni ficant ly from 

## 1981 through 1984 (Table 5. , Figure 5. 

# 14). This decrease may also be due 

# to the high freshwater flow 

# during recruitment in 

# 1983 

# and 1984. 

## Freshwater flow , as suggested by Copeland et 

# ale (1979), prevents spot from migrating into the upper reaches of the 

### estuary. The increase in the 

### abundance of 

### spot in 

# the lower estuary (i. 

# e., Baldhead 

## Creek) also suggests that the 

# high freshwater flow reduced the recruitment of spot into the upper estuary.


## The abundance of 

### menhaden and bay anchovy in 

## All i gator 

## Creek also decreased significantly 

# over the four- 

# year study 

# period (Table 5.

# Figures 5. 

# 15 and 5. 

# 16). These reductions in abundance are 

## probably

related to freshwater flow or some other environmental factor that pre

### vented menhaden 

# and bay anchovy from uti 1 i zi ng 

## All i gator Creek to 

## the extent of 

### previous years. 

# Since there was no significant decrease in numbers of larval menhaden and bay anchovy 

### in the river channel of the 

## upper estuary, these species may have taken up residence in areas other 

# than Alligator Creek. Crabs, croaker , and pink shrimp showed no signifi

### cant upward or downward trends from 1981 through 1984 , whi le brown and 

# white shrimp 

# were collected in 

# insufficient numbers for 

## analysis

(Tab 1 e 5. 

## 7).

Mott I S Bay

The abundance of flounder in Mott' s Bay increased significantly from 

## 1981 

# through 1984 (Table 5. , Figure 5. 

# 17). This increase, like the 

### increase in 

# Alligator Creek, may 

### have been due to low catches in 1981 which were associated with higher 

### salinities (low freshwater flow). From 

### 1982 through 1984, the high 

# freshwater flow lowered the sal inity in the 

### Mott' s Bay area providing suitable habitat for 

# flounder (Figure 5. 17). Significant decreasing trends were determined for spot. brown shrimp, pink shrimp, and white mullet 

## (Table 5. 7, Figures 5. 

### 18- 

# 21). These decreasing trends appeared to be 

### related to the low freshwater flow in 1981 which 

### allowed these mesohaline species to inhabit the Mott' 

### s Bay area in 

## large 

# numbers. With the onset of the high freshwater flow conditions in the 

### fo 11 owi ng 

# years, 

# the abundance decreased. 

# Further evi dence of th i s phenomenon is the 

# significant increase in most of these species in the 

### lower estuary. 

# No significant 

# trend was evident in Mott' 

## Bay for menhaden, bay anchovy, crabs, croaker , At 

### 1 ant i c s 11 

## vers i de, 

# or s tr i ped 

# mullet (Table 5. 

# 7). The catches of mummichog and white shrimp from 

### 19$1 through 1984 were too low for time-series analysis to be performed.

Wa 1 den Creek



### Analysis on Walden Creek data indicated that 

# significant increases occurred for croaker, striped mullet, and flounder over the study period 

# (Table 5. 

# Figures 5. 22- 

# 24). These increases 

# were mainly due to

### relatively higher catches in 1983 

# and 1984, possibly as a result of the



### high freshwater flow during these years. The abundance of white 

## shrimp, bay anchovy, crabs, spot, brown shrimp, pink shrimp, mummichog, Atlantic silverside, and white mullet remained stable from 1981 through 1984 (Table 

# 7). The menhaden catch, however, decreased significantly over the study 

## period (Figure 5. 

# 25). This downward trend may be part of a natural multiyear cycle, but the short duration of this study does not allow this to be accurate ly determi ned.

Ba 1 d he ad 

### Creek

Menhaden , croaker 

### , spot, crabs, brown 

# shrimp, and 

# pink shrimp had 

### significant increases in abundance in 

## Baldhead Creek (Table 5. 7, Figures 

### 26- 

# 31). These increases, as discussed above, may be due to the high 

### freshwater flow that 

### occurred in 1983 and 

# 1984. The abundance of bay anchovy, mummichog, Atlantic silverside and white mullet in Baldhead Creek 

# did not significantly increase or 

### decrease over the four years of 

# this study (Table 5. 

# 7). The abundances of flounder , striped mullet, and white shrimp were too low for accurate trend determination.

Return Basin Evaluation

Since the return basin was completed , it has been heavily populated 

### with fish and invertebrates from the estuary. These organisms entered the basin by two means: by natural immigration from the estuary and by trans

### portation via the impingement return 

# system. The CPUEs of spot, croaker, 

### blue crab, and pink shrimp were greater in the return basin than in any 

### other creek system 

## (Table 5. 

# 6). The CPUEs of the remaining species were

s imi 1 ar to the other creek systems.



### The seasonal distributions of the 

### populations in the return basin 

### were similar to those in Walden 

# Creek. As in 

# the natural estuary, the 

# peak seasonal occurrences of 

# fish and shellfish were related to
recruitment of the 

## individual species. Spot, croaker , menhaden , flounder, and bay anchovy were most abundant in the 

## winter and spring months. Brown 

## shrimp were most abundant during the summer months while pink shrimp and blue crab were most abundant in the fall.Studies conducted by Pollard (1985) indicated that the populations of



### spot and 

## croaker i 

# n the bas in 

## were res i dents. 

## He tagged and re eased
severa 1 

### thousand spot and 

### croaker and found that the movement from the basin during residency periods was very limited. However , at the end of 

# residency 

# periods, 

# the emigration of 

### these fish coincided with 

## the emigration of the resident fish from the natural 

## habitats.
Cumulative length- frequency distributions were used to determine size 

### differences between two 

## speci es 

# of fi sh in the return bas 

### in and 

### upper Walden Creek. A Kolmogorov- 

### Smirnov two- sample test showed significant 

# differences (P ~ 0. 05) in the cumulative length- frequency distributions 

### for both spot and 

# croaker. These speci 

## es were generally arger in the 

### creek than in the 

# basin (Figures 5. 32 and 5. 

# 33). Two factors may 

### have contributed to the 

### small size of these fish in the 

# return basin. First, smaller individuals usually populate the upper reaches of tidal 

## creeks. Since the return basin is located at the headwaters of a tributary creek 

# it is probably being used similarly. Second, the 

### impingement return system was transporting large numbers of small live spot and croaker from 

## the fi ne- mesh screens to 

# the bas in 

### where they 

### become part of 

## the communi ty.

With the high CPUEs, normal seasonal distributions , evidence of resi

## dence periods, and length- frequency distributions similar to upper 

## tidal creeks, it appears that the 

# return bas; n 

# is bei ng 

## ut il i zed as primary nursery habitat by developing fish and 

## invertebrates.

Summary and Conclusions



### The total 

# trawl and seine catches of fish and invertebrates were 

### slightly greater in 

### 1984 than in 

# 1983. The most abundant species col

### lected in 1984 trawl sampl es 

### was spot, while grass shrimp was the most abundant species in the seine catch.



### Striped mullet, 

### mummichog, and white mullet were weakly related to 

### salinity and 

### appeared to be associated with mesohaline areas within the 

# estuary. Atlantic silverside were 

# strongly associated with polyhaline

# areas. These species were slightly associated with areas within the



### estuary that were 

### lower in 

### sediment organics. There was very 

# little association between the mullet, mummichog, and Atlantic silverside 

### and particle sizes of the substrate.



### Moderate relationships were noted 

### between the penaeid 

## shrimp, spot, blue crab, and menhaden and low 

# salinity. These species were also weakly 

# associated with smaller sediment grain 

# size. No relationship with sedi

### ment percent organics and these species was 

# observed. Bay anchovy were weakly associated with high 

# salinity.

The analysis indicated that spot, blue crab, menhaden, brown 

## shrimp, and croaker were most closely related to areas in Walden Creek that were low in salinity and sediment 

# organics. These species were also associated 

### with the more 

# coarse sediment particles. Flounder 

### , white shrimp, pink 

## shrimp, and bay anchovy were not associated with salinity or 

## sediment organi cs. 

## A weak re at i onsh i p 

## was observed between these 

## speci es and finer sediment particles.


# Penaeid 

# shrimp, spot, bay anchovy, blue 

# crab, and menhaden had strongest preferences for the headwaters of Baldhead 

# Creek. These preferences for the headwater areas also occurred in Walden Creek for spot blue crab 

### , menhaden, brown 

### shrimp, and croaker. Flounder , white shrimp, 

# pink shrimp, and bay anchovy were more closely associated with the midcreek stat ions in Wa 

### 1 den 

### Creek.

White mullet and Atlantic silverside were most abundant in Baldhead 

### Creek, probably as a 

### result of the higher 

# salinity in that 

# area. Spot, brown shrimp, striped mullet, and mummichog, preferring mesohaline areas, were collected in their greatest numbers in 

## Walden Creek. The Matt' s Bay 

## area was selected as 

# preferred habitat by bay anchovy, menhaden, and croaker, whi 

### 1 e flounder were most abundant in the upper estuary. 

## In most cases the peak abundance of the se ected speci 

# es of fi sh and 

## invertebrates occurred 

# during recruitment of 

# the individual species. Spot , menhaden , croaker, blue crab, striped mullet, and flounder were most

### abundant in late winter and 

# spring. Bay anchovy, penaeid shrimp, white

mullet, and Atlantic silverside were more abundant during their respective summer recru i tments. The abundance of YOY mummi 

### chog peaked in May short 1 y after spawni 

### ng.


# The abundance of 

# all selected fish and invertebrates in 

### Baldhead 

## Creek remained constant or increased over the pas t 

# four years. The abundance of all of the selected species, except menhaden in Walden Creek 

# either increased or remained stable 

# over 

# the past four 

# years. The abundance of 

### all of the selected species collected in Mott' s Bay, except 

### for spot, white mullet, and penaeid shrimp, were stable or increased over 

# time. The decreasing trends of menhaden, spot, brown shrimp, and bay anchovy in Alligator Creek were probably due to high freshwater 

### flow. The 

### remaining selected 

# species populations were stable or 

## increased in
abundance over time.



### The return 

# basin was used by many fish 

## and invertebrates during 

# 1984. Because of 

# the similarities between the return basin 

## and the
natura 1 

### estuary, it appears that the 

### construct i on of the bas in produced 

## 24 hectares of primary nursery habitat. 

## Most species exhibited preferences for selected salinity regimes 

### substrate makeup, and exhibited spatial and temporal distributions that 

# were consi stent 

# with 

# past years. These resu lts 

### demonstrate that the operation of the BSEP has had no adverse impact on the primary nurseries of the CFE.Tab 1 e 5. 

### Sediment parameters for the 

### high marsh seine 

# and trawl stations during 1984.



## Station

Baldhead Creek



### Walden Creek

Mott I S Bay

Alligator Creek

Return Bas i n 

## Clay = ~ 0. 016 mm Coarse si lt 

## = 0. 016- 062 mm 

### Gear Type


### Trawl Trawl 

### Seine Trawl Trawl Trawl Trawl 

### Sei ne Trawl Trawl 

### Trawl 

### Sei ne Trawl Trawl Trawl 

### Sei ne Trawl 

### Trawl Trawl Trawl Trawl 

### Sei ne Trawl 

## Seine Trawl Trawl Trawl Trawl Trawl 

### Primary

Grain Size Percent Org an i cs 

### Fi ne sand Fi ne sand Very fi ne sand Fine sand Fine sand Very fi ne sand Very fine sand Fine sand 

### Clay Clay Clay Clay Coarse s i 1 t 

### Clay Very fi ne sand Very fi ne sand 

## Very fi ne sand 

## Very fi ne sand Coarse s i 1 t 

### Clay Clay Coarse s i 1 t 

### Clay Fine sand 

### Clay Clay 

### Clay Fine sand Coarse silt 

## 1.35 1.59



## 1.60 1.60 15. 10. 

### 22.

15.



## 1.18 1.81
12.



### 34. 14. 16.

Very fine sand = 0. 

### 062- 125 mm 

## Fine sand = 0. 125- 250 mmTab 1 e 5. Total catch and percent total of the ten most abundant 

## species collected in the high marsh study during 

### 1984.

Trawl Se i ne Spec i es 

### Catch Speci es 

### Catch


### Spot 62, 182 

### 40. Grass shrimp 

### 30, 396 

### 44. Grass shrimp 

### 39, 632 

### 25. 

### Spot 13, 826 

### 20. Bay anchovy 

### 655 Menhaden 

### 10, 915 15. 

### Brown shrimp 126 Striped mullet 

### 928 Menhaden 564 Bay anchovy 

### 612 

## Croaker 160 Mummi chog 

### 476 Blue crab 

### 174 White mullet 

### 367 

## Flounder 447 

### 1.6 

# Atlantic silverside 225 

## 1.8 

## Stri ped mu 11 et 

### 237 

## 1.4 Croaker 772 

### 1.1 

### Pi nk shrimp 737 

### 1.1 Brown shrimp 567



## Total 147, 914 

### 95. 

## Total 084 

### 97.

## Table 5. Results of the principle component 

### analysis by station for organisms collected by 

### seines in the 

## high marsh study during 1984.

Principle Component



# PC 1 PC2


## Station Score 558 

## 1.284 0 . 504 

### 661 

## 1.254 1.423 1. 046



### 1.140 700 575 

### 273 

### 946


## Percent of tota variation explained 

### 62. 32.

Vari ab 1 es
Mumm i 

### chog Striped mullet White mullet 

### Corre 1 at ions



### % Organi cs 

### 973 

### 862 856 512 

### 275 137 0 . 098 

### ":0. 

### 387 191



### 0. 489 410 776 

### 935 955 119 101 

### Temperature 

## Atl anti c si lverside
Sal inity 

## Grain size

See Appendix B for a detailed explanation of principle component anaysis.Tab 1 e 5. 

### Results of 

# the principle component analysis by 

# station for organisms collected in 

### Baldhead Creek by trawl 

### in the 

### high 

## marsh study duri ng 1984. Principle Component



# PC 1 PC2


## Station Score 403 192 

### 734 307 

### 1.119 189 

### 713 

### 1.191

156 

## 1.020 605 

### 923 126 247


## Percent of tota Variation explained


## Variables Brown shrimp 

### Pi nk shrimp 64. 

### 20.


## Correlations 909 

### 270 0 . 899 

### 270 849 

### 419 839 128 789 

### 546 769 0 . 626 

### 359 

### 887 792 

### 522 494 

### 611 

### 0. 688 

### 374 792 

### 522 White shrimp 

### Spot
Blue crab 

### Menhaden Organi cs 

### Temperature Bay anchovy 

## Grain size 

## Salinity

See Appendix B for a detailed explanation of principle component analysis.Tab 1 e 5. 

### Results of the principle component analysis by 

# station for organisms collected in Walden Creek by trawl in the high marsh 

## study during 1984. 

## Princi le Com 

## onent



# PCl PC2 PC3


## Station 029 

### 1. 379 1. 033 805 792 

### 441 

### 1.499 1.843 256

Percent of total variation explained 41. 5



### Vari ab 1 

### Spot
Blue crab 

### 926 0 . 900 

### 760 O. 708 

### 705 0 . 660 

### 521 161 171 

### 405 714 766 

### 901 Menhaden 

### Brown shrimp 

### Croaker 

## Grain size Flounder White shrimp 

### Pi nk shrimp Bay anchovy Sa 1 i 

## nity
Organi cs 

### Temperature 

## Score 1.670 1. 734 1. 233 

### 920 663 307 

### 328 0 . 289 

### 111



## 31.0


## Correlation 001 214 525 0 . 444 

### 107 

### 563 0 . 694 0 . 845 

### 772 687 281 183 

### 346 012

670 

### 1. 086 259 565 

### 479 775 

### 216 0 . 500



### 14.

356 180 195 0 . 445 

### 524 

### 042 287 

### 452 517 

### 313 

### 494 331 174

See Appendix 8 for a detailed explanation of principle component analysis.Tab 1 e 

## Total 

## catch- per-un it-effort 

## creek system 

## for se 1 

## ected species in the high marsh study 

## during 1984.

Baldhead Wa 1 

### den Matt I 

## Alligator Return 

## Species Creek 

### Creek Bay 

### Creek Bas i n 

### Spot 211 135 

### 650 Bay anchovy 

### 156 111 

### Brown shrimp Menhaden 

### Croaker
Blue crab Striped mullet Mummi chog 

## Flounder Pi nk shrimp

Wh ite mu 11 et 

# Atlantic silverside
* Seine samples were . not co 11 

## ected 

## in Alligator Creek and the return 

## basin.Table 5.Results of the time-series analysis of high marsh data by creek showing trends in abundance from1981 through 1984.Alliator CreekMott I s BaWa 1den CreekBaldhead CreekSpeciesTrendTrendTrendTrendSpot***+**Bay anchovyBrown shrimpMenhadenCroaker+***+***Crabs+***Stri ped mu11 etMummichogFlounder+***+**+***Pink shrimp+**Wh ite mu 11Atlantic silvers ideWhite shrimpP ;. 0.01.:: P.:: 0.001.:: P.:: 0.***.:: 0.0012 is an adjusted value; see Appendix- = decreasi ng trend+ = increas i ng trendID = i nsuffi cent dataNA = analysi~ is not applicable becasue seine hauls were not made18DECEl4DECEl5NOU230CT020CT19SEP21AUG6 3aJUL1 aJULC 21JUNU 29tV1VEl9tV1V18APR27~0Stt:IR14FEB30JANB4JANFigure 5.406080100120140160lElliGTH (mm)Length-frequency distributions ofspot collected in Walden Creek bytrawl in the high marsh study during1984.180EC BB40EC BE!5NOU B230CT 0et2IJCT 0195EP 021AUG 018APR a271'1'1R a05M'1R 014FEB 03BJAN a04JAN Biiil 3BJUL1 BJULe 21JUNP 2sn:1YE a~YFigure100120140160lENGTH (mm)Length-frequency distributions ofcroaker collected in Mott's Bay bytrawl in the high marsh study during1984.LT1+:-18DECB4DECB5NOU e23DCrB2DCr195EP21~UG111B9n:JV B18APR 827t1'1R 8B5tV1R 814FEB3BJAN B04JAN1'131!1JUL11!1JULC 21 JUN29n:JV--lillnFigurerL181'1 1251513 1752813 2252513LENGTH (mm)Length-frequency distributions ofstriped mullet collected in WaldenCreek by seine in the high marshstudy during 1984.1 SDEC EI840EC a23JCr 0B2OCT19SEP 021AUG 0aSffiV a18APR271'1'1R EI05M=IR 0l'!FED30JAN04JAN B85NOU30JUL1 eJUL21JUNeSffiVFigure SA1138 125 150 175200 225250LENGTH (mm)Length-frequency distributions of whiteullet collected in Baldhead Creek byseine in the high marsh study during 1984.1BDEC 3-B4OCC13-B5NOV B230CT 0020CT 0-19SEP 8-21AUG ~-38JUL 818JUL 8-29MW 5B9t1W 5-18APR B271'1'1R 0051'1'1R 014FEB 838JAN e04JAN 521JUNFigure 5.5100125 150175 200225 250LENGTH (mm)Length-frequency distributions offlounder collected in Alligator Creekby trawl in the high marsh study during1984.18DEC BB4DEC BBSNOV 523OCT B02OCT B19SEP 821AUG B1BJUL 829t1W 8B911W 518APR B271'1'1R B051'f1R B14FEB 830JAN 0B4JAN 83BJUL21JUNFigure 5.180125151'1 175 200225 250LENGTH (mmlLength-frequency distributions ofmenhaden collected in Walden Creekby trawl in the high marsh study during1984.U"118DEC1:1B4DEC aB5NOV a230CT1'1El20CT1'119SEP a21AUG1'1891'11Y B18APR1'127~0S~1'114FEB ~3!JJAN 01?J4JAN 030JUL10JULC 21JUNU 2911W-r1I--,1'121'1311141'161'19E1Figure 5.LENGTH (mm)Length-frequency distributions of bayanchovy collected in Walden Creek bytrawl in the high marsh study during1984.11'1018DEC1:184DEC aB5NOU a230CT a020CT a19SEP1'121AUG1'1291'11Y aB9MW 818APR1'127t1'1R aeSt1'IR a14FEB a30JAN 864JAN B1'138JULHIJUL21 JUtlr-r---rll--1r-.,--1-, Ir T -,~ I"1--..--r-r21'131341'161'181'11813Figure 5.LENGTH (mm)Length-frequency distributions ofmummichog collected in WaldenCreek by seine in the high marshstudy during 1984.18DECEl4DECElSNOIJ230CTEJ20CT195EP21AUG30JULe 16JULU"l~ 21JUN29tf1Y'-.JB9tf1'r'18APR27rRR05rRR14FEB3E1JAN04JANlEIFigure 5.-rr-r---,70gelLENGTH (mm)Length-frequency distributions ofAtlantic silverside collected inBaldhead Creek by seine in thehigh marsh study during 1984.11013018DECEl5NOV020CT e195EP ~230CT21AUG3E1JULe IElJULC 21 JUNU 29t1WEl9tf1'r'18APR27/"ARBS/"AR14FEB31'!JANEl4JAN110Figure 5.LENGTH (mm)Length-frequency distributions ofbrown shrimp collected in WaldenCreek by trawl in the high marshstudy during 1984.130U"118DEC 08'1DEC IJB5NOV ij230CT 0B20CT 019SEP 021 AUG 0B9t1\Y B18APR B27t1'1R B05t1'1R B14FEB 030JAN 0IHJAN e3BJUL1 BJUL21JUN29tr1V..rfm""1-108 120140 160188 200Figure 5.LENGTH (mm)Length-frequency distributions ofpink shrimp collected in WaldenCreek by trawl in the high marshstudy during 1984.18DEC 8B4DEC 0ElSNOV e230CT 0020CT 0195EP 821~UG 810JUL 029t1\VB9t1\Y e18APR 827t1'1R 0051'11R 014FEB 030JAN 06"JAtt. 3!1JUL21JUN,..,..,........n--LrTl-1.168 120140 16B180 280Figure 5.LENGTH (mm)Length-frequency distributions ofblue crab collected in Walden Creekby trawl in the high marsh studyduring 1984.::I a..

II.

tHENI/. ::I a..

LEGEND:


### Figure 5.

Figure 5. TR (P DATE OBSERVED h..mm----. PRED IC TED 

## ,.....-..

YEAR LEVEL 

### Results of time-series analysis for flounder collected in Alligator Creek in 

### the high marsh study from 1981 through 1984.



# Lt.

JHIP IJAIE 

## --.--

IIBStHYfIJ ---00.. PHEIIICIEIJ .-0.' YENH lHf.l 

### Results of time-series analysis for spot collected in Alligator Creek in the 

### high marsh study from 1981 through 1984.::)

t:!



### LtGEND: rR IP DATE OBSERVED .....-.

YEAR LEIJEL 

### """""""" PREDICTED 

### Figure 5. Results of time-series analysis for menhaden coUected in Alligator 

### Creek



### in the high marsh study from 1981 through 1984.

J.. ::)

III

EUENDI IRIP DAlE

m_... PREDICTED 

# ---

naSEltVED .-...

TERII LEVU


### Figure 5. 

### Results of time-series analysis for bay anchovy collected in Alligator Creek



### in the high marsh study from 1981 through 1984.TR IP DATE



# LEGEND: OBSERVED ............... PREDICTED



## ..-,*--.

YEAR LEVEL
Figure 17 

### Results of time-series analysis for flounder collected in Matt' 

### s Bay in the



### high marsh study from 1981 through 1984. ::I II.
. 2

...I

:::i:

::I

...I

LEGEND: 

## .-' ~'-



## 77 -. . . ! .

TRIP DATE OBSERVED 

### ...-,*.-.

YEAR LEVEL ............... PRE D I C TED

Figure 18 

### Results of time-series analysis for spot collected in Mott's Bay in the high

marsh study from 1981 through 1984...I 

### ..:.

LEGEND: -. \----

7-:-'-' 7'- 

### '-- .... " 

### ~. .. . \~. 

### ~'---'-'

TR fP DATE
GBS E RVE D .'~-. YEAR LEVEL ............... PRE DIe TE


### Figure 5. 

# 19 Results of time-series analysis for brown shrimp collected in Mott' s Bay



### in the high marsh study from 1981 through 1984.

a... ..:

LEGEND: 

### "" : . ""

.... '-- 

## . ... :"'

TR IP DATE OBSERVED ..~-. YEAR LEVEL ......-........ PREDICTED



### Figure 5. 

# 20 Results of time-series analysis for pink shrimp collected in Mott' s Bay in



### the high marsh study from 1981 through 1984.TR IP DATE OBSERVED 

# .....-

. YEAR LEVEL 

### Results of time-series analysis for white mullet collected in Mott' s Bay 

### in the high marsh study from 1981 through 1984. ::::I

;:5 ::E



### LEGEND: Figure 5.

::::I

..J

::E "-..-......... PRED IC TE D ....

....11-- '--- 

### . r-. -- ,' ...

\..1

TR IP DATE OBSERVED ............... PREDICTED ,..........-;a, YEAR LEVEL LEGEND: 

### Figure 5. 

# 22 Results of time-series analysis for croaker collected in Walden Creek in



### the high marsh study from 1981 through 1984.a..

..I

::t

TRIP DATE OBSERVED -*---*- YEAR LEVEL 

### Results of time-series analysis for striped mullet collected in Walden Creek 

### in the high marsh study from 1981 through 1984. LEGEND: 

### Figure 5.

:; 1.

::J a..

r:J 1. 0 ..I 

# ~ 0. - " 

# ~.. -/ - 

# , , '-.. 

# ' ...

TRIP DATE OBSERVED * YE~R LEVEL LEGEND: ---------------

PREDICTED

--------------- PRED IC TED 

### Figure 5. 

# 24 Results of time-series analysis for flounder collected in Walden Creek in



### the high marsh study from 1981 through 1984.::I .... .

:Ii . :::E

LEGEND: 

### Figure 5.

::I

:::E

LEGEND: TR IP DATE OBSERVED
...-t:.-. YEAR LEVEL 

### Results of time-series analysis for menhaden collected in Walden Creek in

the high marsh 

## study from 1981 through 1984. ............... PREDICTED

. .

TR IP DATE OBSERVED 

## .'-.1.-. YEAR LEVEL .""".""", PRED IC TED 

### Figure 5. 

# 26 Results of time-series analysis for menhaden collected in Baldhead Creek



### in the high marsh study from 1981 through 1984.::)

t:I ..I 

### B, 25

0. B0

TR rp DATE 

# LEGEND: OBSERVED ""'_-..-m.. PREDICTED



# ...,..-.

YEAR LEVEL 

### Figure 5. 27 Results of 

### time-series analysis for croaker collected in Baldhead Creek in



### the high marsh study from 1981 through 1984. 

# . . - -- ~\ .----- 

## ' /-.-.

... :::. ::)

..I

TR (P DATE OBSERVED 

### .-.,.._*-

YEAR LEVEL LEGEND; _......-.......

PREDICTED 

### Figure S. 

## 28 Results of time-series analysis for spot collected in Baldhead Creek in the



### high marsh study from 1981 through 1984.TR IP DATE OBSERVED 

# .--t--. YEAR LEVEL 

### Figure 5. 

# 29 Results of time-series analysis for blue crabs collected in Baldhead Creek



### in the high marsh study from 1981 through 1984. 

# ~ 0.

..I 

### ~~ e. 25

e. fie

LEGEND:

a..

LEGEND: 

### ---- 

## ---.-

TR IP DATE OBSERVED ..~-. YEAR LEVEL - I - -.....--.......

PREDICTED . .

. ""hm--.... PRED IC TED 

### Figure 5. 

# 30 Results of time-series analysis for brown shrimp collected in Baldhead



### Creek in the high marsh study from 1981 through 1984.LEGEND:



### Figure 5.

U 75

513

R 25 ; 2

:tJ OJ
..J 1

TR IP DATE OBSERVED ..---. YEAR LEVEL .........-.... PRED IC TED


### Results of time-series analysis for pink shrimp collected in Baldhead Creek 

### in the high marsh study from 1981 through 1984. Hie ..... ....................

LENGTH 188 128 148 168

LEGEND: RETURN BASIN .....""."."

UPPER WAL.DEN CREEK 

### Figure 5. 

# 32 Cumulative length-frequency analysis of spot collected by trawl in upper



### Walden Creek and the return basin in the high marsh study during 1984.

### HI0 ....

LEGEND: ... ,..........""'"

. . . 

# ,~.

, .. 'T. 

## , . fT ,~ .. ~ I . . . . . 

# 60

L ENG TH 

### 100 120 140

RETURN BASIN---....---..... UPPER WALDEN CREEK

Figure 33. 

### Cumulative length- 

### frequency analysis of croaker collected by trawl in

upper Walden Creek and the return basin in the high marsh study during 1984.NEKTON



### I ntroduct i on

Various species of fish and shellfish spend a portion of their first 

# year in the marshes of the CFE before mi 

## grat i ng to the ocean as juven i 1 e 

### and adult 

### members of the 

## nekton 

## community. Operation of the BSEP 

### and subsequent removal of estuarine water for cooling purposes results in the potential impingement of these nektonic 

## organisms. Biological monitoring of the nekton community is conducted to determine if operation of the BSEP 

# has an adverse effect on these 

## organi sms. The major object i ves of the nekton program were to monitor changes in the relative seasonal and yearly 

# abundances, species composition 

# spatial distribution, 

# and size 

# distribution of the juvenile and adult fish and 

# shellfish in the CFE. 

### Selected stations were also utilized to investigate the effectiveness of 

# the diversion structure. Catch- 

# per-unit-effort (CPUE) and 

## lengthfrequency data were used to 

## provi de a measure of these 

# changes. Resu lts were compared to data collected from 1979 through 1983 to ascertain 

## long

## term trends.

Methods

Fourteen stations in the CFE were sampled with a 6. 

## 4-m semiballoon 

# otter trawl. These stations extended from the freshwater 

### drai nage canal, 

## approximately 3. 4 km west of Southport, to Alligator Creek , approximately 6 km east of the Brunswick River 

## (Figure 1. 

# 2). Detailed descriptions of sampl ing stations and methodology can be found in CP&L 

## (1984).

Principle component analysis was utilized to examine 

# spatial distributions of 

# species groups. Time-series analysis was employed to examine 

## long- term trends in yearly abundance of selected 

# species. Bay anchovy, menhaden , spot , croaker 

### , and weakfish were placed into either the young

# of-year (YOY) or juvenile/adult (J/A) size class by examination of their 

## respective length- frequency distributions 

# (Lagler 1952; Everhart and 

## Youngs 1981; Ambrose 

# 1983). Sizes for 

# blue crab and penaeid shrimp 

## species were 

# lumped. The time- series analysis was performed on Stations

# 1, 4, 7, and 8 combined for the years 1979 through 

# 1984. However, the

analysis for menhaden was performed on Stations 1, 2, 4, 7, 8, and 10 for the years 1981 through 1984 because of higher catches at Station 10 (CP&L 

## 1982, 1983, 

# 1984). Periods of recruitment and abundance were examined by inspection of length- frequency distributions fitted to a natural log CPUE 

### scale instead of a percent scale peymitting direct length and catch comparison between trips.



### An evaluation of the effectiveness of the fish diversion 

# structure, compl eted 

## duri ng November 1982 

## , was based on catches at Stat ions 5 , 6 , and 

## 13 (inside the structure) and the catches of those stations outside 

## (particularly Station 4). Analysis of variance was performed to examine significant spatial variability between Stations 4 , 5, 6 , and 13; and a timeseries analysis was performed on the combined catch of stations inside the 

### diversion structure. Statistical analysis of cumulative length- 

## frequency 

# distributions was employed to investigate size differences of the 

## fish inside and outside of the diversion 

# structure. Stations 1 , 4, 7, and 10 

# are channel stations 

### similar to 

# the intake canal and were 

## considered representative of 

### stations outside 

# the diversion structure. 

## Selected species utilized for the diversion structure evaluation were J/A menhaden spot, and croaker (CP&L 

### 1984).

The loge (CPUE+l) was used in all analyses. 

## 05 significance level. Test were made at the

Results and Discussion

Total Organisms

Bay anchovy, spot, croaker 

### , and menhaden 

### compri sed 81% of the 

## total 

# catch (Table 6. 

# 1). Grass shrimp, brown shrimp, and blue crab ranked next 

### in abundance and 

### comprised 17% of the 

# total 

# catch. These species have hi stori ca lly been the domi 

## nant fi 

## sh and invertebrate speci es co 11 

## ected in 

# the nekton program 

# and 

# by other researchers (Birkhead et 

# al. 1979; 

## Schwartz et a 1. 1979; CP&L 

### 1982, 1983, 1984). Spotted sea trout, stri ped 

### and white mullet, 

# and southern flounder were four 

# other commercially

### important species collected. Since the number of these species collected



### has historically been low due to reduced gear efficiency, these 

## species were not analyzed.

Seasonality, Recruitment, and Time- Series Analysis

Bay Anchovy 

## The bay anchovy was present in the nekton catch throughout most of 

## the year (Figure 6. 

# 1). The abundance of 

## overwinteri ng adults peaked in May and June with most individuals at a size of 40 to 

### 50 mm in 

## length. This peak in 

## abundance may have coincided with peak spawning 

# activity. Kuntz (1914) reported peak spawning activity during July in North Carolina 

# waters. Adults 

# declined 

# rapidly 

# after 

# this time 

# and completely 

## di sappeared by 

# September. The yearly 

### catch of J/A bay anchovi es 

### has significantly increased since 1979 (Table 6. 

## 2 and Figure 6. 

## 2).

Recruits first appeared in the 

### trawl catch during July at 20 mm in 

### length and their 

### number peaked during August 

## and September. The catch increased in 

### 1981 and has remained at that level since 

## (Figure 6. 3). A 

# significant increasing trend was 

# evident from 1979 through 1984 

### (Table 

## 2).
Spot 

# Juvenile and adult spot were abundant in 

# the trawl catch from February through April (Figure 6. 

# 4). The catch of J/A spot was 

## lower in 1984 than previous years but analysis 

# indi~tes a nonsignificant trend in 

## abundance (Table 6. , Figure 6. 

# 5). This reflects the cyclic nature in abundance of J/A spot.


### Young- 

## of- year recruits were first 

### collected in 

### February at a 

### modal 

# length of 20 mm. Recruitment peaked in May and had ceased by the follow

### ing trip. The catch of YOY spot has fluctuated widely from year to year resulting in a nonsignificant trend in catch since 1979 (Table 6. , Figure 

## 6).

### Croaker

Larger croaker (greater than 100 mm) were present in the trawl catch 

### from March through June with 

# peak abundance occurring 

### in May 

## (Figure 

# 7). Th i s peak of abundance may correspond to movements into the lower 

### estuary in spring and a movement out as summer approaches 

## (Haven 1959). Juvenile and adult croaker catches show a nonsignificant trend since 1979 

## (Table 6. 

# 2, Figure 6. 

# 8) peak catch 

# occurred 

# during 1981 with low catches occurring in 1979 and 

### 1983.

Young-of-year croaker 

# were continuously 

# recruited from January through May at 

### lengths of 

### 15 to 20 mm 

## (Figure 6. 

# 7). Recruitment in January was a continuation of recruitment began in the 

### fall of 1983 (CP&L 

# 1984). The maximum period of abundance for the spring recruitment period 

### occurred from May through June. The fall period of recruitment began in 

### September and the magnitude was less than that of the spring recruitment 

# period. Growth of YOY croaker 

### occurred from May 

## through December. Low catches of YOY croaker in 1981 and 1984 resulted in a significant decrease in catch from 1979 through 1984 

## (Table 6. 2, Figure 6. 

## 9).

Menhaden

Juvenile and adult menhaden greater than 50 mm were 

## abundant in the
trawl catch from January through April 

## (Figure 6. 

# 10). These were young 

### adults that 

### overwintered in the 

# estuary and then moved out 

# during late 

# spring (Reintjes 1969). The catch of J/A menhaden did not exhibit a sig

### nificant trend from 

### 1981 to 1984 

## (Table 6. , Figure 6. 

# 11). Peaks in the 

## J/A catch occurred every other year.

Because of their small size and cylindrical shape, YOY recruits were 

### not collected by the 

### trawl until April at 25 to 30 mm in 

# length. Their abundance in the trawl catch peaked in 

# ate May. The catch of YOY menhaden exhibited a nonsignificant trend since 1981 (Table 6. 2, Figure 6. 

## 12).

### Brown Shrimp

Brown shrimp were present in the trawl catch from May unti 1 December 

## (Figure 6. 

# 13). The peak abundance occurred in June 

### and catches 

## subsequently declined, possibly as a result of commercial shrimping which com

### menced north of 

## Southport on June 

# 27, 

# 1984. The catch of 

## brown shrimp exhibited a significant 

### decreasing trend from 

### 1979 to 

## 1984 (Table 6. Figure 6. 14). A slight increase in catch was seen from 1983 to 

### 1984.

Blue Crab



### The blue crab catch 

# consisted of two species, Callinectes sapidus,

and C. similus. The catch of both species was combined for analysis.

Blue crab was present in the trawl catch year round but displayed two 

### periods of 

## abundance (Figure 6. 15). A small peak 

### occurred in May 

### and presumab ly coni nci ded wi th 

### emergence of overwi 

## nteri ng juvenil es 

## from the marsh creek areas as water temperature warmed in the 

# spring (Dudley and 

# Judy 

# 1973). Juveni les 

### and adults were most abundant from July 

## through November. The catch of blue crab in 1984 was the lowest among all years 

## since 1979 (Figure 6. 16). A significant decreasing trend was shown by the 

# analysis (Table 6. 

# 2). Commerical landings of hard blue crab for the Cape 

### Fear River have dropped from 399 

### 600 kg in 1979 to 234 

### 000 kg in 1983 while commercial landings of hard blue crab have increased statewide from 1979 to 1984 however (Street 

### 1985).

Weakfi sh


### Young-of- 

# year weakfi sh recruits first 

### appeared in the trawl catch 

### during June with a peak period of abundance occurring in August 

## (Figure 

# 17). Inspection of the length- frequency data revealed a second recruit

### ment period in 

# September. Merriner (1976) reported that weakfish first 

## spawn in Mayor June with a second spawn occurring in late July and August 

# in North Carolina. A significant decreasing trend in catch of YOY weakfish has occurred since 1979 

## (Table 6. 2, Figure 6. 

### 18). An upswing in the catch occurred in 1984.

### Pi nk Shrimp

Fewer pink shrimp overwintered during the 1983 through 1984 period 

### but recruitment and abundance were relatively greater during late summer 

### and fall than that occurring in 

## 1983 (Figure 6. 19; CP&L 

# 1984). Two periods of recruitment were seen with the September period exhibiting the 

# greatest magnitude. Pink shrimp exhibited a significant decreasing trend 

### in catch from 1979 through 1984 

## (Table 6. , Figure 6. 

# 20). The 1984 pink shrimp catch exhibited an increase from the 1983 catch.

White Shrimp 

## Essentially no white shrimp overwintered from 

### 1983 to 

## 1984 (Figure 

# 21). Temperatures of 4O 

### C or 

# less are detrimental to white 

### shrimp survival (Musick 1979; McKenzie et 

# ale 1981). Water temperatures reached this level in the lower CFE during the latter part of January and may have caused mortal ity 

# or migration of white 

### shrimp from the 

## system (Figure 2). A nonsignificant trend in the 

### catch of white shrimp has occurred 

# since 1979 which is most likely 

# the result of adverse environmental 

## conditions (Table 6. 2, Figure 6. 

## 22).

Tota 1 Orqani sms



### The catch of total organisms remained stable from 1979 through 1982 

### and then decreased during 

### 1983 and 

## 1984 (Figure 6. 

# 23). This led to a significant decrease 

### in catch for the entire study period , 1979 through 

## 1984 (Table 6. 

# 2). All finfish species, except for weakfish , exhibited 

# significantly increasing or nonsignificant trends in 

# abundance. The decrease in catch of total organisms during 

### 1983 and 1984 reflects the 

# widely fluctuating catches of 

# penaeid shrimp and 

# blue crab that 

### has occurred over the past two 

# years. Decreases in abundance of these two 

### groups of organisms may be linked to severe winter conditions during the 

# latter part of 1983 and 

# 1984. An increased local commerical fishing effort for penaeid shrimp and blue crabs would most likely have an effect on the CPUE for these 

# species. Additionally, there is some evidence of a 

### detrimental side effect of 

# the shrimp trawl fishery on young finfish particularly weakfish (Merriner 1973).Spatial Analysis


### Young-of- Year Fi nfi sh

Principle Component Analysis 

### indicates the distribution of YOY 

## finfish was explained by proximity to an inlet and water depth 

## (Table 6. 

## Figure 6. 

# 24). Approximately 89% of the 

# total variation in species was 

### exp 1 a i ned by these two factors.

Spot, croaker , and weakfi 

### sh d i sp 1 ayed greater assoc 

## i at ions wi th 

## Stations 1, 

# 4, 5, 6, 10 

### , 11, 13, and 

# 14. All of these stations are deep channel stations near inlets which are avenues of entry for larvae spawned 

# offshore. Station 11 near Mott' s Bay is relatively 

## shallow; however, its proximity to the 

# river channel and to Snow 

# Cut, immediately to the 

### south , probably produced the association of spot, croaker, and weakfish 

### with this 

# station. During the period of abundance of 

# weakfish, salinity 

# regimes ranged from 

## mesohaline (8- 

# 16 ppt) to polyhaline (16- 

# 30 ppt) 

# (Figure 2. 

# 1). These stations 

# exhibited oligohaline (0. ppt) to mesohal ine (8- 

# 16 ppt) sal inity regimes during the periods of abundance of YOY spot and croaker (Figure 2. 

## 1).

lack of associations of 

### croaker and spot with 

# the upriver areas, Stations 12 

### , 15, and 16, was probably due to sustained high current flow 

### and displacement of the salt wedge downriver during their respective re

## cruitment periods 

## (Figure 2. 

# 1). Similiar events were reported for the 

## Ogeechee River- Ossabaw Sound Estuary in Georgia (Rogers et al. 1984).



### Stations 2 and 8, located in the lower river , are broad, flat, sandy 

# stat ions subject to heavy currents 

## duri ng most of the t i da 1 cyc 1 e wh i ch 

### would tend to push YOY spot , croaker 

### , and 

# weakfish from these areas. Weinstein et 

# al. (1980) reported a similar effect for 

### his Spoil 

## Island 

## Station.
Young-of - year bay 

## anchovy, croaker , weakfi sh 

### , and spot were high ly 

### associated with the intake canal due to the 

### combination of a 

## continuous incoming current and the 

### ability of the YOY 

# fish to pass through the mm mesh screening 

### of the diversion structure 

### (CP&L 1980, 1984).

# appears that they took up res i dence in 

# the intake canal for a 

## peri od of



# time. Copeland et ale 0979) made reference to the ability of spot and croaker to ma 

## i nta in themse ves by tak i ng a pos 

### i t i on near the bot tom of the 

### intake canal. Th 

## i s abi 1 i ty wou 

### 1 d increase as the spot and croaker became 

# larger. Higher catches were more strongly associated with Stations 5 and 

### 13 as opposed to 6. Th is was probab ly due to the sha 

### 11 ow 

## depth of Stat i on 

# 6. As incoming flow is restricted vertically by the shallow depth , the 

### flow velocity increases. Flow velocity then decreases at Stations 13 and



### Young-of- year bay anchovy and menhaden displayed greater associations 

### with Stations 

### 1, 8, 11, 

# 15. and 

# 16. All of these stations, with the ex

### ception of 

### Station 1, are shallow 

# shoal 

# areas. Station 1 

## was on the 

## average 10 to 2O 

### C warmer than 

### all other 

## stat ions duri ng the wi nter 

### and spring, possibly due to the dark 

# tannin stained water at this 

# station. This may have led to the 

# similarity of Station 1 and the shallower stations which 

### would warm more quickly 

### during the 

### spring. A 

## moderately positive association of 

### temperature with the shallower stations was evi

# dent (Table 6. 

# 3). Salinity ranged from oligohaline to mesohaline during 

### the period of abundance of yay menhaden 

## (Figure 2. 

# 1). Weinstein et 

# al. (1980) reported menhaden as being transitional between oligohaline and 

### mesohaline areas. Salinity regimes at these stations during the period of abundance of yay bay anchovy ranged from 01 i goha 1 i ne to pol yha 

### 1 i ne (F i gure 

### 1) .

Juvenile/Adult Finfish and Invertebrate Catch

Juvenile/adult fish and invertebrate distributions were explained by 

# water depth and a downriver to 

# upriver gradient (Table 6. Figure 

# 25). These two factors accounted for 72% of the variation in 

## the distributions of J/A fish and 

### shellfish. An additional 15% of the variation was accounted for by the distribution of blue crab which did not exhibit a downri ver to upri ver 

## preference.

Spot, croaker 

### brown shrimp, 

### and pink 

## shrimp were most closely associated with Stations 

# 1. 4, 5, 10, 13. and 

# 14. All of these are deep

### channel stations 

### located in 

# the lower and midriver 

### areas of 

# the CFE.

These stations exhibited mesohaline to polyhaline salinity regimes of 8 to 

### 23 ppt during the periods of abundance of 

### these four 

# species (Figure 

# 1). Juvenile/adult menhaden were most closely associated with Stations 

## 10 and 

# 14. Both of these are midriver deep stations in the vicinity of Snow 

# l s Cut. Sal inity regimes during the period of abundance of J/A menha

### den ranged from 4 to 16 ppt indicating a preference for the 01 igohal ine 

### and mesohaline areas of the 

## CFE (Figure 2. 

# 1). Schwartz et 

# ale (1979) reported similar trends for spot, croaker , and menhaden.

Blue crab was associated with Stations 5 , 10 , 12 , 13 , and 14. these are deeper stations ranging from the lower to the upper CFE. All of

Lack of a strong association by bay anchovy to either water depth orthe downriver to upriver gradient indicates that J/A bay anchovy was widespread in its distribution.

Diversion Structure Evaluation 

# Significantly higher catches of 

# J/A spot, croaker 

# and menhaden occurred outside the diversion structure as compared to the inside 

## (Table 

# 5). Prior to 1983 

### , catches of these species inside the intake canal exceeded catches outside (Schwartz et ale 1979; CP&L 

# 1982). These trends in the small trawl catch reversed themselves during 1983 with the diversion structure becoming 

### operational during November of 

### 1982 (CP&L 1984). In addition 

### , results of the time- series analysis 

## (Figures 6. 26 through 

### 28) indicate a highly significant decreasing trend in the catch of J/A spot, croaker, and menhaden at the intake canal stations since 

# 1981. This decreasing trend can be attributed to 

### the diversion 

# structure. Spot 

# catches increased from 1982 to 1983 at 

# the CFE river stations but 

### decreased in the intake canal during 1983 and steadily declined through 

# 1984. The J/A croaker catches were relatively 

### stable at the river 

## stations whi 

### le they decreased at the intake stations. The menhaden catch at 

# the intake stations mirrored the 

### fluctuations of the river station but were significantly reduced over previous years.Spot of approximately 40 mm or below were capable of passing through



### the diversion 

## structure (Figure 6. 29). A Kolmogorov- Smirnov two-sample 

# test showed that 

# the cumulative length- frequency distribution of 

## spot 

# inside the 

# intake 

# canal was significantly different from that of 

## spot 

## outside (P = 0. 

# 05). The greatest difference in cumulative percent between 

# the two distributions occurred at approximately 60 to 70 

# mm. At this 

# point. 

# less than approximately 2% of 

# the spot inside the diversion structure were greater than 60- 

### 70 mm, whereas 10% of the spot outside of the diversion structure were greater than 70 mm. 

# The cumulative length- frequency distributions of 

# croaker between 

# inside and outside of 

# the diversion structure were also significantly 

# different (P = 0. 

# 05). Croaker of approximately 45 mm or less were not excluded from the intake 

# canal (Figure 6. 30). A greater percentage of 25 

### to 35 mm croaker were present 

### outs i de 

# of the intake canal. Fi ne- mesh impingement and entrainment of the smaller size 

### classes of croaker 

### (-:: 45 mm) entering the intake canal may have resulted in this 

# difference. The 

# diversion 

# structure became effective at excluding larger 

# croaker at lengths greater than 45 mm. For example, approximately 13% of the croaker outside of the intake canal were greater than 80 mm , whereas approximately 3% of the croaker ins 

# i de of the intake cana 1 were greater than 80 mm. 

# The cumulative length- frequency distributions of 

### menhaden present outside and inside of the diversion structure began to diverge at approxi

### mately 80 to 90 mm 

## (Figure 6. 

# 31). The greatest difference in cumulative 

### percent of the two 

### 1 ength- 

## frequency di stri butions occurred at around 95 

### mm; however, the 

# two distributions 

# were not significantly different. 

# These cumulative 

# length distributions were 

# the result of problems associated with the maintenance of the diversion structure during the week 

# of January 14- 

# 20, 

# 1984. Strong winter storms piled 

### much debris and detrital material on the diversion screen panels caused damage and blown

## out screens. Although the catch of menhaden was still greater outs 

## i de, a arge number of menhaden moved into the 

# intake canal that week 

## thereby influencing the length- 

### frequency distribution of menhaden present in the 

## intake canal (Figure 6. 32).Summary and Conclusions



# Nekton 

# monitoring 

# during 1984 showed 

# little difference in seasonality, abundance, and distribution from 

### previous years. 

### The dominant species collected have remained as such since 

### 1979. Any changes were 

### minor and were due to gear differences and to the cyclic nature of most 

# populations. The bay anchovy exhibited a significant increase over the 

# years 1979 through 1984, while 

### YOY croaker , blue crab, brown 

## shrimp, 

## weakfish , and pink shrimp exhibited a significant downward trend. 

## This is most likely related to a combination of the cyclic nature of these species 

### coupled with severe winter 

# conditions. Brown shrimp, weakfish, and pink 

### shrimp showed an 

## increase from 1983 to 

# 1984. Spatial distributions for
the dominant species were consistent with past data which 

# indicated that operation of the BSEP 

### has not imited movement of 

## fi sh and shell fi sh to and from nursery areas. High springtime freshwater flows seems to have limited movement of YOY croaker and spot into the upriver areas sampled by 

### the nekton program, particularly the Alligator Creek 

### area. A 

### change in 

# spatial distribution of J/A spot, croaker, and menhaden has 

## occurred in one respect. 

# Historically, the catches of these three species in the 

### intake canal were among the 

### highest in the 

# CFE. Since operation of the 

### diversion structure began in 

### 1982, the catch of these 

# species in the intake has been relatively 

### low.

Operation of the BSEP has not adversely affected the population of 

### nektonic organisms residing in the 

# CFE. Trends in seasonality, distri

### bution, and relative abundance from year to year of most 

## species exhibit 

# no changes associated with 

### operation of 

# the BSEP. Further, the fish
diversion structure has been successful at excluding larger organisms from the intake canal.Tab 1 e 6. 1 Tota 1 number 

### , percent total number 

### , and 

## annual catch- 

## per-



# unit-effort (CPUE) of 

# the 

# ten most abundant species

co 11 ected in the nekton study 

## duri ng 1984.



## Percent Total Spec; es 

### Number 

## Total CPUE

Bay anchovy 

### 46. 838 

### 33. 

### 98. Spot 788 

### 24. 73. 

### Croaker 20 , 

### 600 

### 14. 

### 43. Menhaden 

### 10. 752 

### 22. Grass shrimp 

### 805 18. 50 

### Brown shrimp 

### 015 

### 10. Blue crab 

### 551 

### 1.82 Weakfi sh 193 

### 1.57 Pink shrimp 2 , 

### 061 

### 1.47 Hogchoker 1, 104



## Total 134 707 

### 96.

## Table 6. Results of time-series analysis of nekton river data 

## indicating significant increase (+) or decrease (- ) in CPUE for 1979 through 1984.



## Species Trend

Bay anchovy 

### JjA yay +**



### Spot 

### JjA
YOY 

### Croaker JjA
YOY


### Menhaden 

### JjA
YOY 

### Brown shrimp Blue crab Weakfi sh Pink shrimp White shrimp Total organisms 

### ***

p;:. 0.

.( P 

## .( 0. 001 ~ P ~ 0. 

# *** p

~ 0. 001
Time-series analysis for menhaden was run for 1981 through 

### 1984. is an adjusted value; see Appendix
JjA = Junvenile and Adult
YOY = Young of YearTab 1 e 6. 

### Results of the principle component analysis by station for 

## young-or- 

# year finfish collected in the nekton study, years 1983 and 1984 comb 

### i ned.



## Princi Com 

## onent 

## Pel PC2



### Score
1. 53 

## 1.96 1. 52 

## 1.26

1. 33



### 1.64 

### 1.21 

## 1.43 1.04 1. 70



### 57. 

## 31.3
Corre 1 at 

## ions 

## Station 5 (i ntake cana 1 ) 

## 13 (i ntake cana 1 )


## 6 (i ntake cana 1 )



## Percent tota variation explained 

### Vari ab 1 es 

## Croaker Weakfi sh 

## Spot Bay anchovy 

### Sa 1 i ni ty 

### Menhaden 

### Temperature 

# See Appendix B for a more detailed explanation of 

# principle exponent 

## analysis.Tab 1 e 6. 

### Results of the principle component analysis by station for 

### juveniles/adults collected in the nekton 

## study, years 1983 and 1984 comb 

### i ned. 

# Principle Component 

# PC1 

# PC2
PC3


## Station Score 

## 5 (i ntake canal) 1.47 1. 25 

### 1.38 1.15 

## (i ntake cana 1 ) 1 1 

### 1. 60 .L. .L.L 

## (i ntake cana 1 ) 

### 0. 58



### 1.03 1.06

Percent of total 

### vari at i on exp 1 a i ned 

### 49. 

### 22. 15. Vari ab 1 es 

### Corre 1 at 

## ions
Pink shrimp 

### Croaker Brown shrimp 

### Spot White shrimp 0. 18 Sal inity Bay anchovy 

### Menhaden Blue crab 

### Temperature

See Appendix B for a more detailed explanation of principle exponent 

## analysis.Table 6.Results ofanalysis of variance and Duncans multiple range test forselected speciesutilized in the evaluation of the BSEP diversion structure during1984.Spot(juveni 1 ejadul t)SourceValueTrip82 NSStat ion30.50***Trip*station1. 64Trip1.21 NSStation12 . 17***Tripstation64 NSTrip20.35***Stat ion22.30***Trip*station1.81 NSDuncans MultipleRange TestSpeciesANOVA R5 13 6Croaker(juveni 1 ejadul t)Menhaden0'\t-'0'\(juveni 1 ejadul t)5 6 13Station 4 islocated outside of the diversion structure and Stations5, 6, and 13 are locatedinsideof the diversi on structure.Underscores indicate similarity and values decrease from left to right.NSP ~ 0.0 .01 ~ P ~ O.** 0.001 ~ P ~ 0.***P ~ 0.00121IfN

Ff1lI1V

!7UCT

I s.uJi 

# 0 2~

a2.Q.

11alII

lIMY

atltAy

29fEB

11..rAH 

## 15 18 21 24 1:1 38 33 38 39 ~ 

### 4S 48 51 54 fU 68 63 ee 6U it 1S 76 LENGTH (mm)



### Figure 6. Length- frequency distributions of bay anchovy collected in nekton trawls

during 1984.::::I II..

III

LEGUID : 

### Figure 6.

::::I a..

III

..J



### Figure 6. , ' -., 

### -*~ , --

.:Ie . - . -

--11 . -- . -

TR IP DATE
OBSERVED .......-....... PREDICTED *---*--;jI- YE A LEVEL

Results of time-series analysis for juvenile/adult bay anc.llovy collected in 

### nekton small trawls at Stations 1, 4, 7 

### , and 8 combined for 1979 through 1984. ' : \ !



# : I 

# . , : -

....-1 - 

# - -- ---..: ---- , 

## ---- " ---- :---

... ...- 

# \ /\

0- ::

TRIP DATE LEGEND: OBSERVED 

### -------

PREOICTED .-.-. YEAR LEVEL 

### Results of time-series analysis for young-of- 

### year bay anchovy collected in nekton small trawls at Stations I, 4 

### , 7 

### , and 8 combined for 1979 through 1984.mJV

2SSEP .

84SEP

! s.w;

Z 4dl.



### 82JI.

12J1f

liMY

81/IAY

18AfR

2SIUR

2Sf'E8

86FEB

17dM1



### Figure 6.4 

### .-rrT""r-.

TI....... 

### .,....,..,

188 IZ8 148 lea 188 288 LENGTH Imm)



### Length-frequency distributions of spot collected in nekton trawls during 1984.CL.
II 2 :!: 

## -;- -*. .

TR IP DATE OBSERIJED ............... PRED Ie TED ...-....._,"*-

YEAR LEVEL LEGEND:

Figure Results of time-series analysis for juvenile/adult spot 

### collected in nekton

small trawls at Stations 1, 4, 7 

### , and 8 combined for 1979 through 1984. :!: , . ; -

. ....

..J

LEGEND. OBSERVED ....:'



## I -

TRIP DATE -------

PREOlcrEO .-.-. YEAR LEVEL 

### Figure 6. Results of time-series analysis for young-or- 

### year spot collected in nekton

small trawls at Stations 1 4, 7 

### , and 8 combined for 1979 through 1984.Z-w..

Ill.....

12d11

Z1NY

9!!!AY

!9APR



### 3NR

Figure !800:

Z7lfJV

87!IJV

r'-'l.1

2SSa'

IHSEP

Z9FEB

II6fEB

17JIII 

# ~._

"" ""OU I' .._m' .'..... "'

1""" "' 1"'" "" 1""""' ." ,.... "

1"'" 

## 189 12.8 1-18 168 168 

### 28B 2Z8 248 LENGTH (mm!



### Length- frequency distn'butions of croaker collected in nekton trawls during 1984,TR IP DATE LEGEND: OBSERVED ,.... -*"- 

# ,.

YEAR LEVEL LEGEND: 

### Figure 6.

::;)

::E



### Figure 6.

::;)

TR IP DATE OBSERVED 

### ..-'f;._,. YEAR LElJEL 

### Results of time-series analysis for juvenile/adult croaker collected 

### in nekton small trawls at Stations 1 

### 4, 7, and 8 combined for 1979 through 1984. ............... PREDICTED

I - 

# I , 

# - I

"'...".""" PRED IC TED


### Results of time-series analysis for young-of- 

### year croaker collected in nekton small trawls at Stations I 

### , 4, 7 

### , and 8 combined for 1979 through 1984.tIlDE!:

'i8 

## 188 128 1.. 

## 168 188 

## 288 22B Z'i8 ZS8 LENGTH (mml 27MJY

I1lIIY ::



### Figure 6. 10 Length- 

### frequency distributions of menhaden collected in nekton trawls

during 1984. 

### IUL

IZ....

Z1MY

81"1"1

28IAR

Z9f'EB

8IIfEB

17.JA11c:J

LEGEND: I:)



### Figure 6. 11 Results of 

### time-series analysis for juvenile/adult 

### menhaden collected in nekton

small trawls at Stations 1 4, 7 

### , 8, and 10 combined for 1981 through 1984. .

+ 1. 00-

Q,.

c:J 

### Z 0. ....-~.-.

TR I P DATE
OBSERUED YEAR LEIJEL .....-......... PRE DIe TED



### Figure 6. 12 . Results of time-series analysis for young-of- 

### year menhaden collected in nekton

small trawls at Stations 1 

### , and 10 combined for 1981 through 1984. 50-

25-

25-

LEGEND I TRIP DAlE 

### OBSERVED ---_h- PREDICIED .-. -. rEAR LEVEL

### g Zw.

~ 9W. 1800:

Z7H)V

17(X:1'

IZJ.It

ZINY

alMAY

1-


### 2JJWl -



### 29ftB ..

96FtJ :.

17JA1f - 

# 18 

# 28 38 48 58 

# 68 78 88 118 1118 118 IZO 138 1-48 158 1fJ! 178 188 LENGTH (mm)



### Figure 6. 13 Length- 

### frequency distributions of brown shrimp collected in nekton trawls

during 1984.0"10"15 1;:;- 4 ~I:J -Q. 3-CII(!) -.:(1~1~ n" ...JTRIP DATEOBSERVED~-.YEAR LEUELLEGEND:PREDICTEDFigure 6.14Results of tillIe-series analysis for brown shrimp collected innekton ('malltrawls at Stations 14, 7, and 8 combined for1979. through 1984.24d1. 

### e - Z7JIJV

rnm 

# ~ .

J"\..r1

I~ 

# h - 

# ' =

1-

112.11.

12d11

2'f8.AY

IWR

2SIIAR

Z9F9

86fEB

17.w1 .. .. 

### ... 

### .'..

-18 

# 88 188 128

LENGTH (mm) 1-18 168 168



### Figure 6. 

# 15 Length-frequency distributions of blue crab collected in nekton trawls

during 1984.0"\....~ 2.(!J1.0LEGEND:11"\TRIP DATEOBSERVED--_u--PREDICTED.-+-...YEAR LEVELFigure 6. I 6Results of time-series analysis for blue crab collected in nekton small trawls at Stations 1,4, 7, and 8combined for 1979 through 1984.

### ISU

G Z4.JI.

P 82.0.

IZdlt 2NJV

I7tf1t

170:1"

ZUlU

8111AY

IWR

2I!W1

29fIB

86ftB

17.JA11 

### .-.. ......... ,....... ,.. .....

,........ "I 188 118 

# ' III 138 I" 158 LENGTH (mm)



### Figure 6. 17 Length- 

### frequency distributions of weakf"lSh collected in 

### nekton trawls

during 1984.0'\(:)I""ic:(~iLEGEND:(\ \! (\lilt:~ -'----1',--TRIP DATEOBSERlJED.-~-. YEAR LEVELPREDICTEDFigure 6.18Results of time-series analysis for young-or-year weakfish coUected innekton small trawls at Stations4, 7, and 8 combined for 1979 through1984.?:- ,.:

2'MN
z.:

8'MN
z.: 

### meT t

z.: ,.:

2SSEP .

z.: ,.:



## am .
z.: 

### , s.u;

~ 2.a 

# ro

BlJ.l. ! E ' !2J.!1 

### --.



### 'Wi ZIMY

II HAY ,.:

Z9FEB .

z.: 88FEB &

z.: ,.:

'7JA11 "

185 lIS IZS LENGTH tmm)



### Figure 6. 

# 19 Length-frequency distributions of pink shrimp collected in nekton trawls

during 1984......c..--;, 2...Jc:(LEGEND:*--11:r-',~.I ""- ---"::r nTRIP DRTEOBSERUEO*---*--* YEH RL E IJE LPRED IC TEDFigure 6.20Results of time-series analysis for pinkshrimp. collectedin nekton smalltrawls at Stations 14, 7, and 8 combined for 1979 through 1984.I SMJ&

G 21d1. 

### p et.u.

12dIt ZM1t

81lfN

11U:T

2SSEP

84SEP

21&'

eUfAY

IWR

2IJW!

2SfEII

8IIFEB

17 .IAN 

## 189 118 128 138 I" 158 LENGTH (mm)



### Figure 6. 

# 21 Length-frequency distributions of white shrimp collected in nekton trawls

during 1984.;:)

III

TR IP DATE OBSERVED 

# .-~-

. YEAR LEUEL 

### Results of time-series analysis for white shrimp collected in nekton small 

### trawls at Stations I, 4, 

### , and 8 combined for 1979 through 1984. LEGEND: 

### Figure 6. --...........-.

PREDICTED

;:)

III 2

TR IP DATE OBSERVED 

### ..-t--- . YEAR LEIJEL LEGEND: -----..........

PREDICTED


### Figure 6. 

# 23 Results of time-series analysis for total organisms collected in nekton small

trawls at Stations 1 

### , 7 

### , and 8 combined for' 1979 through 1984.Deep



### Figur~ 6. PC1 

### Croaker Proximity to Weakfish 

### an inlet 

### Spot

I PC2

Shallow



### Principle component ordination of the nekton young-or- year f"milSh data 

### for 1983 and 1984 comQined. Each axis represents a continuum along an environmental gradient. Solid lines encircle station groups with similiar 

### species distributions as detennined from cluster analysis. Species listed have str~ng associations with the gradient See 

### Appendix B for more explanation.

### Brown Shrimp Pink Shrimp 

### PC, 

### Spot Croaker jDeepl



### Menhaden

Downriver



### Figure 6. Upriver



### I Shallowl



### Principle component ordination of the nektonjuvenilefadult data for 1983 and 1984 combined. Each axis represents a continuum along an environmental gradient. Solid lines encircle station groups with similiar 

### species distributions as detennined from cluster analysis. Species listed have strong associations with the gradient. 

### See Appendix B for more 

### explanation.:::E

LEGEND;

, Figure 6. Diversion Structure Completed , '

TR I P 0 A TE ""'..m_-... PREDICTED 

### Results of tim~series analysis for 

### juvenile/adultspot collected in the intake canal (Stations 5, 6, and 13), by the nekton trawl for 1981 through 1984.

:::E

LEGEND:


### Figure 6. OBSERVED 

### .,...--.t- YEAR LEVEL

Diwrsion Structure Completed

TR IP DATE

08 S E R lJE D 

### .-....-.t- YEAR LEVEL nm_"nn_-- PRE 0 leT

Results of tim~series analysis for juvenile/adult croaker collected in the intake
canal (Stations 6, 

### and 13), by the nekton trawl for 1981 through 1984.LEGEND: DivenJon Structure Completed '+ 3 ;:)

CI.
CI 2

of(. :ii

TR fP DATE OBSERVED ..~-. YE~R LEVEL 

### """"""'" PREDICTED 

### Figure 6. 

# 28 Results of time-series analysis for juvenile/adult 

### menhaden collected in the

intake canal (Stations 5, 

### 6, and 13), by the nekton trawl for 1981 through 

### 1984.

M 75

. L 

## I sa

~ 25 HHJ .... ...... .... .... ... --.......

n-- " ._m ........---..............



## 80 100 120 

### LENGTH (mm)
INSIDE 140 1 6 EI 18 EI 

### 200

LEGEND: 

### ............... OUTSIDE 

### Figure 6. 

# 29 Cumulative length-frequency analysis of spot collected by the 

### nekton

trawl inside (Stations 5 , 6 , and 13) and outside (Stations 1 

### , 4, 7 , and 10) 

### the diversion structure during 1984.HHI ... ..,



### M 75 """



## "nn .."".. ",~



# 100 125 151:) 

### LENGTH (mm) INSIDE LEGEND: - -=- """"-"""-"'.............,....,.. 

# """" """"

175 2 !':Jfj 

### 225 

### 250

""-m..m.. 

### OUTSIDE 

### Figure 6. 

# 30 Cumulative length- 

### frequency analysis of croaker collected by the nekton

trawl inside (Stations 6, 

### and 13) and outside (Stations 1 4, 7 

### , and 10) 

## the dive~ion structure during 1984.

100 ... ---

~- 25 ",...., 

## ".""' "..""' ......" "",,, .. '"



### " I

LEGEND: 

# HJ0 

# 125 150



### LENGTH (mm)
INSIDE



### Figure 6. "".............m......................-----------------..... 

### , ".. , ' ".. ..,,'

175 20B 

### 225 2SEI 

### 275

"""-nm... 

### OUTSIDE



### Cumulative length- 

### frequency analysis of menhaden collected by the nekton trawl inside (Stations 5 , 6, and 13) and outside (Stations 1, 4, 7, and 10) 

### the diversion structure during 1984.0"\+:0L I~g WlL82JIl12JlII21mY81mY100"2!.HIHBmillINSIDE1mE(2i'IIIJJ8ml))170n2SSEP845EPOUTSIDE18Of(2i'111JJa8i'IIIJJ170(112SSEP 884SEPl$AlIi24JlL 482JIL12JIIE limY 8almYI00Pl/2!HBeifElml'fl.....,188128118 Iii188 28B 2(8218 268LENGTH (mm) .Figure 6.32 Length-frequency distributions of menhaden collected by the nekton trawl inside (Stations 5, 6, and 13)and outside (Stations 1, 4, 7, and 10) the diversion structure during 1984.28486888'188 128148 Iii188 288228 218268LENGTH (mm)ENTRAINMENT



### I ntroduct i on

Studies to determine the 

# species composition, seasonality, 

### and abundance of entrained larval and postlarval fish, penaeid shrimp, and 

### portunid crabs at the BSEP have been conducted by CP&L as part of 

# its long- 

## term monitoring program since 

## September 

# 1978. Prior to that entrainment studies were conducted by NCSU from May 1974 through August 

## 1978. In addition , the results of studies conducted since July 1983 are 

### used to determine the effectiveness of flow minimization and fine- 

### mesh 

### screens on reduci ng entra i 

### nment.

To determine reductions in entrainment due to fine Jmesh screens, a 

### speci a 1 study was imp 1 emented whereby samp 

### 1 es 

## were co 11 ected from the 

# two types of intake screens (9. 4- and 1- mm mesh) during comparable time 

# periods. Three such comparative studies were 

## completed; one each in November 1984, December 1984, and January 

### 1985.

Methods

The collection gear, sampling methods, and sample processing have 

### remained unchanged since 

# 1982. For further 

## discussion, . 

## refer to . CP&L 

## (1983).

The ideal conditions under which to measure reduction in 

## entrain

# ment due to fine- mesh screens would be to have each unit operating a 

### different screen type 

### simultaneously. However , due to plant operating 

### restrictions, this was accomplished only 

### during the 

## December study. During the November and January studies, the samples were collected from the two types of screens in two consecutive 24- 

## hour periods.

In all three studies, the samples were collected according to ap

# proved entrainment samp 1 i ng 

# procedures. The November and 

### December 

# studies had 

# additional samples collected at 

# 0600 

# and 1800 hours. Because of an overlap in operation of screen type, the 0300 samples were
de 1 eted from the ana lys is for the Janu ary study.

### ANOVAs were performed testing 

### week, period, and tide effects as



### well as all two- 

# factor interactions. All ANOVAs and DMR tests were 

## performed on loge 

## transformed numbers and 

# densities. Results are presented at the P ~ 0. 

## 05 significance level.

Results and Discussion

Domi nant 

### Speci es

In 1984 the dominant organism entrained was Gobiosoma spp. which 

### comprised 24% of the mean density of all organisms 

# entrained. Croaker 

## ranked second with 16% 

### , while spot and Anchoa 

### spp. ranked third 

### and fourth, respectively, at 15% 

# each. The other 

## top-ranked species, in 

## decreas i ng order of abundance, were bay 

## anchovy, portun 

# i d mega lops

Penaeus 

# spp. postlarvae, 

# silversides, blennies, Microgobius 

## spp.,

menhaden, and Gobionellus spp. (Table 7. 

## 1).

Seasona 1 i ty and Abundance

The seasonal ity 

# or periods of abundance for the selected species 

### analyzed remained the same as 

### in previous years 

## (Table 7. 

# 2; Figures 11).

Croaker reached a peak density of approximately 1896/1000m 3 in mid

# January. Flounder achieved a peak density of 12/1000m 

# in late 

# February. Menhaden peaked at 151/1O00m 

### in early 

# April, mullet at 26/1000m 3 in late February, spot at 1857/1000m 3 in mid- 

### March , anchovies at 1179/1000m 3 in late June, Gobionellus spp. at 163/l000m 3 in mid- 

### March

Gobiosoma spp. at 2028/l000m 3 in late May, and seatrout at 13/1000m 

## 3 in 

# early June. Of the shrimp, pink and white shrimp had a peak abundance of 186/1000m 3 in mid- September and brown shrimp peaked at 108/1000m 

## 3 in
late June (Table 7. 

## 2).

Number Entrained

Entrainment rates were computed by multiplying the mean density per 

### day by the mean flow per 

# day. The mean daily flow of cooling waterthrough the BSEP ranged from 1. 5 x 10 6 m 3 in April to 4. 

### 5 x 10 6 m 

## 3 in
September and early October (Table 7. 

## 3).

The rate of total fish entrained ranged from 6. 6 x 10 /day in mid

# January to 2. 2 x 1O /day in mid- 

## November. For the species 

## analyzed, 

# croaker were entrained at a maximum rate of 5. 

### 8 x 1O /day in 

### mid

# January, flounder at 3. 7 x 10 

### /day in late February, menhaden at 3. 1 x /day in mid- March, mullet at 7. 7 x 10 /day in late February, spot at 

### 5 x 1O6 /day in mid- March, anchovies at 2. 

### 6 x 1O 

### /day in late 

## June,

Gobionellus spp. at 3. 9 x lO /day in mid- March, and Gobiosoma spp. at 4. x lO6 

# /day in early June. Pink and white shrimp had a maximum 

## entrainment rate of 5. 1 x lO /day in late September and brown shrimp of 2. 4 x /day in late June (Table 7. 

## 3).

Diel Patterns



### ANOVAs performed on 

### all species analyzed showed that entrainment 

### densities were significantly different between day and 

# night. In allcases, DMR tests ranked nighttime densities greater than daytime densi

# ties. This was consi stent with previous years I data (CP&L 

### 1983) (Figure 

## 12).

Entrainment Special Study



### When all data 

### from the three study 

# periods were combined, only anchovi es, croaker , spot, Gobionellus 

### spp., and 

# total fi sh appeared in sufficient numbers to be analyzed accurately. 

# All species, except spot, were entrained in larger numbers and 

### densities at night. The ANOVA for spot numbers and densities showed no significant difference between periods. 

# All species, except Gobionellus 

### spp., were entrained in 

## larger numbers and dens 

# i ties through the standard-mesh (9. 4-mm) screens. 

### The

ANOVA and DMR test for Gobionellus 

### spp. densities showed no 

## significant difference between screen 

# types. However, Gobionellus spp. numbers were significantly higher through the standard- 

### mesh screens.

### For the three study 

# periods combined, a 

# total of 153 fish was



# entrained through fine- 

# mesh (l- mm) screens for 

# mean density of 99/1000m 

# A total of 973 fish was entrained through standard- 

### mesh

screens for a mean density of 

### 543/1000m These figures represent an 84% reduct ion 

# in total number 

### and an 

### 82% reduct i 

# on in mean dens ity entrained organisms due to fine- 

### mesh screens. For the species analyzed, 

## anchovy dens it i es 

# were reduced 69%, croaker 

### dens it i es 88% 

## spot

densities 58%, and Gobionellus spp. densities 70% (Table 7. 

## 4).

Flow Minimization

In June 1981 , plant operations enacted a partial flow minimization 

### regime whereby the 

### amount of 

# water withdrawn from the 

## estuary for 

# cooling purposes was reduced (Figure 7. 

# 13). In July 1983, a more drastic flow-reduction schedule was 

## employed. This schedule called for a maximum flow of 915 cubic feet per second (cfs) (25. 9 cubic meters per 

## second 

## (cmsJ) during three- pump operation and a maximum 

## allowable flow 

# of 605 cfs (17. cms) during two- 

### pump operation. 

## The delineation between two- pump and three- 

### pump operat i on was dependent on intake water 

# temperature. 

# At water temperatures 65O 

# F (18. 

# C) and above (approximately the end of April), three- 

### pump operation was allowedn below that (approxmiately the end of November) only two- pump operation 

### was used. A further restriction required that two of the three traveling screens on each unit must be equipped with fine mesh.

To determine reductions in entrainment due to flow minimization , acomparison using observed entrainment numbers was made between historical flows (pre- January 1981; Hogarth and Nichols 1981) and the observed 

## flows. For the peri od from January 1981 through June 1983, the mean number of total fish entrained per day was 3. 6 x 10 6 and the average plant flow 

## was 843 cfs (23. 

# cms). Using the historical 

### mean flow of 

## 1149 cfs (32. 5 cms), the mean number would 

### have been 4. 9 x 10 

## The percent reduction in number entrained per day was 26. 5% (Table 7. 

## 5).

### During the 

### period from July 1983 through November 21, 1983 , the

mean number of total fish entrained was 1. 3 x 10 6 with an average plant flow of 818 cfs (23. 

# 2 cms). The mean number using the historical flow 

## of 1185 cfs (33. 6 cms) would have been 1. 8 x 10 The percent reduction between the historical and observed numbers was 27. 

### 8% (Table 7. 

## 5).

From November 22, 1983, through April 1984 , intake water tempera

## tures were be 1 ow 65 o f (18. 3 a C); therefore on 

## 1 y two- pump opera t i on was permited and the corresponding traveling screens 

### had to be fine 

### mesh. 

## However, 

## some samples were collected 

# during times of 

# debris filter cleaning when a third pump (standard mesh) was activated as allowed by 

### the permit. The number reported has been adjusted to reflect only fine

### mesh entrainment. 

# These periods of three- pump operation are also the 

### reason that the observed plant mean flow is 

### h i gher than the perm 

## it ted 605 cfs. The estimated hi storical 

### mean number for 1105 cfs (31. 3 cms) 

### was 9. 7 x 10 , and the observed mean number for 610 cfs (17. 3 cms) was 4 x 105 This represents a 44. 3% decrease in entrainment due to flow 

### minimization. By applying the 82% decrease in density due to fine- 

### mesh screens calculated from the entrainment special study 

## (Table 7. 4), the 

### estimated historical number for 1105 cfs through standard mesh screens is 5. 4 x 10 

## The difference between th i s and the observed mean number of 5. 

### 4 x 10 5 for 610 

# cfs through fine- mesh screens represents a 90% decrease due to both mod 

### i f i cat ions (Tab 1 e 7. 

## 5). For the peri od from May 1984 through October 29, 1984 , the observed 

### number was a 28. 6% reduction from the estimated historical number. 

# The period from October 

# 30, 1984, through April 

# 18, 1985, was another time of two- 

## pump, fine- mesh screens only 

# operation. Again, we see a 90% decrease in number entrained due to both flow minimization and 

## fi ne-mesh screens.

Summary and Conclusions

In 1984 

### , studies were conducted to determine the species composi

## tion 

# seasonality, and abundance of entrained larval 

## and postlarvalfish, penaeid shrimp, and portunid crabs. The results were also used to



### determine the effectiveness of flow 

## minimization and fine- mesh screens on reducing entrainment.


## The domi nant 

### organ i 

### sm entra i ned in 1984 was Gobiosoma 

# spp. It
compri sed 24% of the mean dens 

# i ty of all organi sms 

# entrained. The other 

## top- 

# ranked speci es, in decreas 

# i ng order of abundance, were croaker

spot, Anchoa 

# spp., bay anchovy, portunid megalops, Penaeus 

## spp. 

# postlarvae, 

# silversides, blennies, Microgobius 

# spp., menhaden, and

Gobionellus 

### spp.

The periods of peak abundance for all species analyzed remained the 

### same as in previous years. The pattern of diel variation also remained 

# the same--night densities were 

# significantly greater than day densi

# ties. For all species, the greatest daily average of numbers of organisms entrained occurred during the period of peak abundance.


### speci a 

# study was conducted on 

# three occas ions 

# to compare entrainment densities 

# and numbers between standard- mesh screens and 

## fi ne- mesh screens.. 

### For all 

## speci es 

## analyzed, except spot, the die vari at i on was the same as for 

# entrainment. Except for Gobionellus 

## spp. significantly higher densities of entrained organisms occurred through 

# the standard-mesh screens. 

# Overall, there was an 82% 

## reduction in
densities and an 84% reduction in numbers due to fine-mesh screens.

Estimates of the historical mean number entrained per day based on observed values were used to determine the reduction in entrainment due 

### to flow minimization. The percent reduction ranged from 26. 5% to 47. 4%. 

## There was 

# also 

# an estimated 90% 

# reduction between historical 

### and observed estimates 

### due to 

# the combined effectiveness of fine- mesh screens and flow minimization.Tab 1 e 7. 1 

### Mean density and percent total of fish, penaeid 

## shrimp, and portunid crabs entrained, September 1978- August 1984.



### Speci es

Gobiosoma 

## spp. Croaker Spot

Anchoa 

### spp. Bay anchovy Portunid megalops

Penaeus 

### post 1 arvae 

### Si lversides 

## Blennies

Microgobius 

## spp. Menhaden

Gobionellus 

## spp. September 1978 - August 1983 

## Dens ity Percent September 1983 - August 1984 

### Dens i ty 

## Percent

373 170 

### 164 191 177 

### 235 145 

### 22.

10. 10. 

### 11.0 10. 

### 14. 143 

### 24. 16. 15. 15.



## 1.0 1.0 1.0 

## 1.0

7 -Table 7.Entrainment densities(mean per day) at the BSEP from September 1983 through ApriI 1985.Samp I eTotalGob i 0-Gob i 0-DateFishCroakerFlounderMenhadenMu IletShr I mpSpotAnchovynellussomaSeatrout06SEP83398.52,77 .190.13SEP83241 .185.26.22.75.20SEP83170.43.39.66.27SEP83148.113.50.60.040CT8369.17.31.20.IlOCT8399.11.44.32.18.180CT8327 .23.14.250CT8392.30.17.30.01NOV8362.13.21.23.13.08NOV8385.17.19.55.15NOV8319.10.10 .22NOV8329NOV8321.17.00 '06DEC8334.j 4 .-.J13DEC8377 .52.15.20DEC83240.134.15.27DEC83191.129.50.04JAN84283.249.20.10JAN8433227733.18JAN84172.895.185,46.24JAN84046.882.161,31 JAN84235.176.44.07FEB84583.120.11.422,14.14FEB84137.14.105.21FEB84372 .46.10.15.271.10.28FEBB4485.15.12.26,373.26.06MAR8458142.434.13MARB420120.13110.19.20MAR84281.55.128.24.856.23.163.27MARB4465.32.59.331.22.03APRB4221 .23.26.133.15.10APR84629.52.151.366.13.17APRB4398.152.33.121.33.25APRB4302.153.BO.13.29.Table 7.2 (continued)Samp I eTotalGobio-Gob i 0-DateFishCroakerFlounderMenhadenMulletShrimpSpotAnchovynell ussomaSeatrout01 MAY84521222.10.62.17 .16.08MAY84591.139.47.58.24.55.15MAY84654.50.12.358.65.22MAY84066.10.471.11.300.29MAY84098.762.026.05JUN84919.11.494.24.282.13 .12JUN84181.399736.19JUN84707.22.809.787.26JUN84308.108., I 78 .04402JUL84671.24.274.265.IOJUL84745.14.292.376.17JUL84161.42.47.60.24JUL84423.60.319.67.'-I31 JUL84335.63.261 .33.07AUG84140.35.98.21.I.D14AUG8466.29.49.21 AUG84278.40.189.60.28AUG84222.90.137.34.04SEP8484.50.44.24.18SEP8490.14.17.23.25.25SEP8414139.25.13.020CT84193.31.36.89.090CT84261.104.99,53.160CT84335.288.27 .18.230CT84198.1 54 .11.34.300CT8478.65.06NOV8468.56.13NOV8429.19.19NOV8419.27NOV8452.33.14.04DEC8429.19.11 DEC84213.040.11.65,19DEC8426.16.26DEC8425.15.Table 7.2 (continued)Samp I eTotalGob i 0-Gob i 0-DateFishCroakerFlounderMenhadenMulletShr impSpotAnchovynell ussomaSeatrout02JAN8538.33.09JAN85210.118.39.34.10.16JAN85104.63.29.24JAN85256.175.69.31 JAN85257.106.127.06FEB85190.57.125.13FEB85328.95.22720FEB85271.93.166.27FEB8573.12.51.05MAR85310.39.246.13MAR85696.28.11.25.623.20MAR85344.49.71.278.27MAR85436.34.25.46.343.--..J03APR85129.15.10.44.47.IOAPR85478.20.15134.162.f-'17APR85485.35.61.Table 7Entrainment rates(mi II ion number per day)at the BSEP from September 1983 through ApriI 1985.SampleDateMean f low(Mi II ioncubicmFlounderMenhadenTotalFishCroaker'-J......I-'06SEP83 4.478 1.785 0.000 0.000 0.00013SEP83 4.478 1.083 0.000 0.000 0.00020SEP83 4.478 0.763 0.000 0.000 000027SEP83 4.478 0.666 0.006 0.000 0.000o4o~l8r---.r:418-----(r~311 0~OOO 0~OOO 0.000110CT83 4.478 0.446 0.051 0.000 0.000180CT83 3.719 0.104 0.005 0.000 0.000250CT83 3.719 0.344 0.115 0.000 0.0006lNOV83..480- 0.092 0.019O~OOO -- 0.00008NOV83 2.929 0.249 0.052 0.000 0.00015NOV83 3.156 0.060 0.032 0.000 0.00022NOV83 2.398 0.022 0.008 0.000 0.00029NOV83 2.398 0.051 0.042 0.000 0.000(y6DFC1n-----39r-~-O~OB.)---O~ozr-- cf:ooo - 0.00513DEC83 2.398 0.186 0126 0.000 0.00020DEC83 2.796 0.672 0.375 0000 0.00027DEC83 2.398 0.460 0.310 0.000 0.00004JA~2.38--- -- D~()8 r- ----599-()OO---O~.(roo10JAN84 2.961 0.985 0.822 0.000 0.00018JAN84 3.037 6.598 5.758 0.000 .01524JAN84 2.961 3.099 2.613 0.007 0.00031JAN84 2.961 0.696 0.522 0.000 0.00007Fm84----L.9or-T~12~- 0.358:oT6-m".-O:OO814FEB84 2.961 0.408 0.044 0.000 0.00021FEB84 2.961 1.102 0.137 0030 0.00028FEB84 2.961 1.437 0.045 0.037 0.01406MAR84 -2~2~----1~28if----o~69-- -004 -----o:oli13MAR84 2.398 0.484 0.050 0.012 0.01320MAR84 2.398 5.470 0.134 0.020 0.30827MAR841 .556 0.725050002 0.09303APR84~~--()-:328- 0.0350-----0-;040---10APR84 1.480 0.932 0.078 0.003 0.22417APR84 1.480 0.590 0.226 0.000 0.050Mullet0000000000000 :000000000000000000000000000000000000005O~(JOo0000060000070:0340130450776:054006059000---0-:066--000000ShrimpGob i oneil usGob i 0-soma Seat routSpotAnchovy237 0.000 0.349 0.035 0.851 0.024833 0.000 0.121 0.100 0.337 0.018196 0.000 0.177 0.039 0.299 0.000509 0.000 0.224 0.034 0.270 0000078 0.000 0.141---;029----"92----0:000 -200 0.000 0.144 0.084 0.028 0.000088 0.000 0.020 0.054 0.000 0.000128 0.000 0064 _().~15 - 0.000 0.000032 0.000 0.034 0.019 0.000 0.000058 0.000 0.163 0.023 0.000 0.000032 0.000 0.009 0.009 0.000 0.000000 0.000 0.005 0.009 0.000 0.000005 0.000 0.005 _JJ.Oo.~n- ().D.QO_---_JJ_OOQ.000 0.000 0.034 0.013 0.000 0.000000 0.000 0.038 0.000 0.000 0.000000 0.000 0.244 0.042 0000 0000000 0.010 0.122 0.005 0.000 0.000- - -Cf-:-()()O----0~O()5-----o.04-r--()-:-0()0~-- -D:(JOlr~~OOO000 0.044 0.099 0.000 0.000 0.000000 0.564 0.141 0.000 0.000 0.000000 0.478 0000 0000 0000 0.000000 0.133 0.006 0.000 0.000 0.000000 1252 0.043- 0:000-----0:000--0:000-000 0.311 0.005 0.000 0.000 0.000000 0.804 0.032 0.000 0.000 0.000000 1.105 0.079 0.021 0.000 0.000000962004- ---0:006---0:660- ---0:000----000 0.315 0.024 0.046 0.000 0.000028 4.452 0.057 0.391 0.000 0.000010 0.516 0.004 0.035 0.000 0.000~Oi2---ir:198-0:o66----0:02:fobd 0.000000 0.542 0.020 0.014 0.000 0000005 0.180 0.050 0.012 0.000 0.000Table 73 (continued)SampleDateMean flow(Mi II ioncub i c m.yc;",v-1Jc.ktl'1~C;$rr.C'tY'o,c""","(Ii'TotalFishi\tlt.L"It;'c...Croakerf\tlc..1~'c..FlounderMenhaden'-.J......25APR841 .480___448__~_Q.l~__9QP__~_Q._QQ_01MAY84 2,239 1168 0.498 0,000 0.01308MAY84 2.239 1.325 0.311 0,000 0.00015MAY84 2.239 1.466 0.114 0,000 0.00022MAY84 2.239 2.387 0.013 0.000 0.00029MAY84480 4.585 0.004 OO~Q_Q,-~QQ-05JUN84 -239-------8- 0.003 0.000 000012JUN84 1.480 1749 0.000 0.000 0.00019JUN84 2.268 6.140 0.000 0,000 0.00026JUN84 2.239 5.168 0.000 0.000 000002JUI84 2.239~O4 -:000--- O~OOO 0.00010JUL84 2.239 1668 0.000 0.000 0.00017JUL84 2.355 0.379 0,000 0,000 0.00024JUL84 2.239 0.948 0.000 0000 0.00031JUL84 2.239 0.751 0.000 0000 0.000--- -n____--- u_-- -u_-------07AUG84 2.239 0.314 0.000 0000 000014AUG84 2.239 0.149 0.000 0000 0.00021AUG84 2.239 0.624 0.000 0.000 0.000~~UG~"---____~~- 0.000..o_Q~-.o..!.OOQ--D4SEP84 2.239 0.189 0.000 0000 000018SEP84 2.588 0.233 0036 0.000 0.00025SEP84 -156__-- 0.447 0._126 - 0.000 0.000020CT84 3.719 0.719 0.117 0.000 0.000090CT84 3.719 0.973 0.389 0.000 0.000160CT84 3.532 1.186 1020 0000 0.000230CT84 3.719 0.738 0.575 0.000 0.000300CT84579 0124 0104- OOQQQ...QQa.06NOV841 .480 0.102 0.083 0.000 0.00013NOV84 2.398 0.122 0.072 0.000 0.00019NOV84 1635 0036 0013 0.000 0.00027NOV84 2.961 0.156 0.100 0.000 0.000040EC84 - -~~--07------O~O48-----o-=6ob--- -0 :006 -110EC84 2.961 3.592 3.081 0.033 0,000190EC84 2.961 0.080 0.050 0.000 0.005(YIv'(;" ~-Mullet000000000000000..9_C&...._-000000000000004000000000000- ------~000000000000OOC000000000000000000OOC)000000000000- -6~ooo000000Y-h-rf mp007 0,119023 0.139009 0.106010 0,027023 0.007Q...OQCL-- O.QQG - -025 0000005 0,000050 0.000242 0.000055 0.000031 0.000100 0.000136 0.0000 . 14 .3.._-o.~OO() u079 0,000067 0.000091 0000202 0.000' 12 0,000045 0.000079 0.000.135 0.000017 0,000011 0000043 0.000009 0000 -010 0000083 0.000005 0.000000 0.000cf.0606;600000 0000000 0.000P'M;".-..~ f-Gob i oneil usr -Gob i 0-SpotAnchovysoma Seatrout020 0.043 0.000 0.000039 0.036 0.000 0.000131 0.055 0124 0.003802 0.013 0.190 0.004055 0.026 0.673 0.000- _J, 115L- -- - 0_.QOJL____QQ2-___-.Q9_106 0.056 0633 0,031591 0.002 1090 0005837 0.000 4,053 0.007..2....6.39_____0...o.Ol.--- 2 .338---0....00.0615 0.003 0.595 0.003654 0.000 0.842 0.017113 0006 0142 0.013714 0.010 0,151 0.0\6- 05~6 0.042- 0()76- 0.003220 0.007 0.048 0.003111 0.010 0.017 0,000425 0.003 0,136 0013306 0.019 0,078 0.009ci:099-O03------0 :OS4- -- 0:000060 0,065 0.014 0004236 0.-04.1 D._ODD 0.010333 0.186 0.011 0.000370 0.197 0.011 0.000096 0.065 0.000 0.000127 0029 0000 0.000003 001.4 0000- 0.000009 0,003 0.000 0.000005 0.046 0.000 0.000009 0.009 0.000 0.000013 0044 0000 0000---- -_____n_n______-005 0.012 0.000 0.000221 0.193 0.000 0.000005 0.015 0.000 0.000Table 7.3 (continued)SampleDateMean flow(Mi II ioncubic m.CroakerFlounder MenhadenAnchovyTotalFishMulletGob i oneil usGob i 0-soma Seat routShr impSpot-...J......26DEC84 2.961 0.077 0.046---------- _--_02JAN85 2.961 0.114 0.09909JAN85 2.961 0.623 0.35216JAN85 2.961 0.310 0.18824JAN85 2.961 0.760 0.51931 JAN85003 0.773 0.31906FEBB5 2 .61--563-Tid13FEB85 2.961 0.974 0.28320FEB85 2.961 0.804 0.27627FEBB5961 0.217 0.022MAR85----2--:96 r-------O:-gnro:TT1----13MARB5 2.454 1.708 0.06920MAR85 2.961 1021 0.14727MAR85961294 0.10303APRB5----835 -~237-----02910APR85 2.398 1.147 0.05017APR85 2.398 3.561 0.0130006~o60005005005000606- -0000000060:010 -022000028- 6.006 - -000000000 0.000 0.005Q.QQ.----!.!_n_SJ..Q------C!PO----Q..._--0:000:00-6------0;605-----0:000 -011 0.000 0.000 0.000000 0118 0.000 0.102 0.030 0.006 0.000 0.000000 0.005 0.000 0.087 0.019 0.005 0.000 0.000000 0.026 0.000 0.204 0.005 0.000 0.000 0.000008- 0024 0.000 0.383 0.015 0.000 0.000 0000000 0.005 - 0.000-- - - 0~371(j~Or6 -- ---()-~odoM6 - ---0:000000 0.006 0.000 0674 0.012 0000 0.000 0.000000 0.006 0.000 0.492 0018 0000 0000 0.000000 0.037 0.000 0.152 0.000 0.000 0.000 0.000----O:OT6--o:6T5-- --o:ciTs-- - --0:729 - ---01'6---00-000--------0;-6-028 0.000 0.062 1.531 0.017 0.006 0.000 0.000014 0014 0.210 0.825 0.000 0.007 0.000 0.000076 0.000 0.139 1.018 0.000 0.051 0.008 0.000020 00060:OB0:0Bo- - -0:005-- - -o:oatr-o:m)O~OOO363 0.004 0.083 0390 0.010 0.005 0000 0.000084 0.005 0.148 0.036 0009 0.005 0.005 0.000Tab 1 e 

## Reduct i on 

# in entrainment by 

## number 

# and mean dens ity 

### (#/lOOOm 

### ) for selected species for the three special study 

## periods.

Gobionellus 

## Total Anchovies 

### Croaker Spot 

### spp. Fi sh

Number 

### 9. 4-mm screens 

### 690 125 

### 973
1-mm screens 

### 153 Reduct i on 68% 90% 71% 67% 84%

Dens ity 

### 9. 4-mm screens 387 

### 543 1-mm screens 

### Reduct i on 69% 88% 58% 70% 82%Table 7.Comparative reductions in entrainment of total organisms due to flow minimization.ObservedHistoricalTime PeriodDens i tyFlowNumber/DayFlowNumber/DayPercent Reduction(#/1000 m(cf s)January 1981-June 198317598433 . 6x 1011494 .9 x 1026.July 1983-November 21, 19836328181. 3 x 1011851.8 x 1027.November 22, 1983-Apri 1 19843596104 x 1011059.7 x 1044.November 22, 1983-Apri 1 198419946100 x 1011054 x 1044.May 1984-0ctober 29, 19847058841.5 x 1012051 x 1028.-..JOctober 30, 1984-Apri 1 18, 19852895801 x 1011058 x 1047.c 16063 x 104 . 3 x 10October 30, 1984-Apri 1 18,1985580110546.Adjusted for fine mesh only.Estimated number of total organisms entrained/day.Calculated increase in entrainment without fine-mesh screens based on results ofspecial study(Table 12).Calculated number that would have been entrained without fine mesh or flow minimization.NOTE:Difference between band d is a 90% reduction inentrainment because of flow minimization andfine-mesh screens.I R. 8~ S.c:J--J........~ 2.DATEFigure 7.Density of total fish entrained at the BSEP fromMay 1974 through August 1984.'-J'-JCI)11).....I::iii:Figure 7.OAT(Density of croaker entrained at the BSEP from May 1974 through August, 1984." 2inCIOt:J--..J,.....c( ,w '::!:DRHFigure 7.Density of flounder entrained at theBSEP from May 1974 through August 1984.3-;Ci)aJ..J-...J....DA J(Figure 7.4Density of menhaden entrained at the BSEP from May 1974 through August 1984........ii)II)t.:J..Jon J(Figure 7.Density of mullet entrained at the BSEP fromMay 1974 through August 1984....J"-JI-~I IORaFigure 7.Density of shrimp entrained lit the BSEP from May 1974 through August 1984............!:::..J.c:(. 3OAT(Figure 7.Density of spot entrained at the BSEP from May 1974 through AugustJ 984.18.--..Jii)ffi 5..:( 2.OArrFigure 7.Density of anchovy entrained at the BSEP from May) 974 through August 1984....-.J..J1':-OAf(Figure 7.Density ofGob;one/lusspp. entrained at the BSEP from May 1974 through August 1984.18.8'"7. 5-....Jffi 5.~ 2.OAf(Figure 7.10Density ofGob;osomaspp. entrained at the BSEP from May 1974 through August 1984........r'0...1. I. DnaFigure 7.11Density of seatrout entrained at the BSEP from May 1974 through August 1984.J0"" "11 200B--I1100010ee090130.......1')aEIO"";::;.I;; 713138::J.E 6000~ seee1.1140ee3eee2131301 B0E1, ). ,I' ,, IIIr I ,III' IJ I ,, I'III .~I( I II'I..\J\-J\..YEARDAY----- NIGHTFigure 7.12Entrainment day/night mean densities for total fish, September 1974 through August 1984.-...JCXJJANUARY1981I ~Figure 7.JUNE1981~.(91 5 cIsJUI Y NOVEMBER19831983MAY1984OCTOBER1984APRIL1985~ IFINE MESHIe "nd "1915 cisI FINEMESH I915 cIsFINE MESHI'" and "605 cisI FINE MESH I605 cisTime line depicting initiation dates of the Brunswick Steam Electric Plant modifications and maximumflow lunit from June 198t through April 1985.SURVIVAL STUDIES


## Introduction

Survival studies were initiated in early 1984 to determine what per

### centage of 

### organi sms impi 

## nged on the travel i 

# ng screens and transported
down the return flume are returned to the CFE 

# alive. Specifically, these 

### studies examined 

### survival by species and size class in addition to 

### speed and mesh size of the 

# traveling 

# screens. Emphasis was directed 

## towards 

# those species that 

# are consistently dominant in 

# either the larval or juvenile/adult impingement programs.



### Methods

The logistics of 

# collecting organisms from the 

# intake traveling screens during plant operation produced many unexpected variables in the 

### data set. 

# Percent survival was examined for as many 

## species and size classes as time, laboratory space! and species availability allowed.

Co 11 

### ect i on


### Imp i nged 

## organ isms were washed off the screens into the two- 

## trough 

# fiberglass return 

# sluiceways. Collections were made at 

### the end of 

## the 37- km flume where it emptied into the 3. 

### 24- hectare return basin (Figure 

# 1.3). At first an 

## oversized " plankton bucket" was used to collect the 

## smaller organisms. The bucket, similar in shape to the cup on a 

## larval net, measured 1.5 m tall by 27. 

### 9 cm in diameter , with 1- 

### mm mesh 

## screen

# ing. Several 15-second samples were usually 

# taken. Beginning in May, a larval table similar to one used by McGroddy and Wyman (1977) was utilized 

### that allowed for a longer sampling duration while 

## decreasing mortality associated with collection. Water from the return flume flowed through a 

### lO. 2-cm diameter PVC 

### intake pipe onto the table where it spread out and 

### reduced velocity. 

## The organisms were then 

### funneled into a 

# relatively undisturbed collection basket. The table was used for the duration needed (usually 3 to 10 minutes) to obtain statistically sufficient 

### numbers. The larger juvenile and adult organisms were collected with a 9. mm bar- 

### mesh

# net fitted on a frame that conformed to the shape of 

## the return fl ume.

Sampling duration was limited to approximately three 

## minutes.
Contro 1 organi sms were co 11 

### ected from the 

## intake canal us i ng several 

# different gear 

# types. Initially for collection of 

# the smaller size classes, a 1- m diameter 505- 

### )..Im mesh 

# net with 

# the oversized II 

## plankton bucket 

## II was used. After June 10, 1984 , a similar net with 1- mm mesh was 

# utilized. Smaller juveniles were 

# collected with a 3. 2-m two-seam trawl 

# with a body of 

### 4-mm bar mesh 

### and a cod end of 

### 2-mm knitted 

### mesh. Occasionally when control 

### organisms were scarce or larger size classes 

## were needed, a 6. m semiballoon otter trawl with a 18. 1-mm bar-mesh web

## bing and a 6. mm bar- 

### mesh cod end was used. To keep mortality associated with collection at a minimum, all tows were as short as possible, usually 

### between one and three mi nutes (McCoy and Brown 

# 1967). After each co 11 

## ection, organisms were transported to the laboratory for sorting and stocking into holding tanks.

Holding Facilities



### The survival 

## laboratory was located at the end of the return flume 

### adjacent to the 

# return 

# basin. Water from the intake canal was 

### pumped through an aeration 

### tank to 

## various size flow- through tanks to maintain water quality as close to ambient as possible.

Housed in the laboratory were ten 92. liter round black tanks equip

### ped with overflow valves and modified bottoms which allowed for flushing 

### of dead organisms and removal of 

# poor quality water. Eight l1S.4- 

# liter glass aquaria were used for shellfish and those organisms such as flounder and young- 

## of- the- year mullet not requiring the round tanks (person. comm., 

### W. F. Hettler, National Marine Fisheries Service). Four 769- liter tanks 

### were used for larger juvenile and adult 

# organisms. Small portunid megalops and postlarval penaeid shrimp were held in 3. liter plastic buckets, whi le juveni le 

### crabs were held in individual SOO-ml cups to prevent cannibal ism.Stocking and Monitoring



### At the laboratory, organisms were placed on a lighted sorting table and the targeted organisms sorted by species and size 

# class. Efforts were 

### made to stock at 

## least 30 1 ive organi sms per repl icate which were held for a minimum of 96 hours to determine 

### latent mortality. Live 

### and dead organisms were then 

# sorted and 

# counted. During the 96- hour holding period tanks were monitored hourly and any dead organisms were removed and meas

# ured. Water quality 

## parameters (temperature and salinity) were checked 

### initially and at the end of 

# 1, 3, 6, 9, 12, 18, 24, 36, 48, 60, 72, 84, and 96 hours (Taft et 

# ale 1981). The tanks were drained and all live and 

### any dead organi sms were counted and measured after 96 hours.

Definitions, Calculations, and Analyses

Initial mortality refers to those organisms that died before reaching 

# the laboratory. Latent mortality 

### describes those 

### organisms that 

## died 

# after stocking. The summation of 

### the two results in the total mor

# tality. For reporting purposes, a percent total 

### mortality and 

## percent. survival were calculated using the following formulae:
Initial Mortality + Latent Mortality 

## Percent Total Mortal 

## i ty x 100 

### Number of Organ isms Co 11 

## ected

Percent Survival = 100 - Percent Total Mortality

Occasionally more live organi!ms were collected than could be 

## stocked. In 

# these cases, the 

# atent mortality percentages were app 

### 1 i ed to all 1 i ve organisms prior to calculation of percent total mortality.

12.. 

### f+I~ ;'"



## The intake travel ing screens rotate approximatel ~ 75 cm per 

### slow-screen operation and 

### between 2. 5 and 4 times faster 

## during fast

# screen operation. To examine the 

# effect of screen speed on survival analysis of variance (ANOVA) was performed on two size classes of croaker 

### and one size class of spot using the general linear models procedure of the Statistical Analysis 

# System. The model examined date, screen speed 

### and their 

## interaction as factors with 

# replicate nested in screen 

## speed.

### For all statistical analysis, a 

### significance level of 5% 

# (P ~ 0. 05) was



# used. Prior to any analysis, an arcsine square root transformation was mad~ to achieve uniform variance of the percentage 

## data.

Results and Discuision 

# In assessing any stress- 

# related effects on larval and 

## postlarval organisms, special handling methods and/or acclimation periods are usually 

# required (Hoss et a1. 1974 

### . 1977). The organisms sensitivity to handling and holding often results in a reduced survival prior to any experimental 

# test i ng. To ascertain that fact, 

### contro 1 organi sms were collected and 

### held. The survival percentages obtained from those controls are presented 

### along with the 

## experimental percentages. No 

## adjustments were made for this mortality associated with collection or holding; therefore, the survival rates reported are conservative.

Total Organisms



### Forty 96- 

# hour survival studies were 

### conducted from early 

## February 1984 through the middle of April 1985; however , techniques for collection 

### handling, and holding were not standardized until late March 

# 1984. From 

### the remaining 34 sampling dates, 15 taxa and over 21, 000 organisms were 

### collected and used in obtaining the survival percentages presented 

### (Table 8. 

# 1). Included among the 15 taxa collected are members of the com

# mercially 

# and/or recreationally important families 

### found in 

# the CFE: 

### drum , flounder mullet, herring, penaeid shrimp, and portunid 

# crab. Other taxa examined included members of the anchovy, sole, and 

## searobin fami

# lies.

Survival studies conducted during fast-screen operation resulted in 

### the collection of over 6600 organisms comprised of 14 

# taxa. Croaker and 

### striped mullet were placed in two groups for calculation of percent sur

# vival. Croaker 25 mm or greater in length were considered Group 2, while striped mullet were grouped by young-of- 

## the- year and juveni le/adult 

## cate

# gories. During slow-screen operation, only 9 taxa but over 6200 organisms


## were co 11 

# ected. Again. both croaker and spot were separated by size group

## (Table 8. 

# 2). Almost 8800 organisms, including 14 taxa, were collected as



### contro 1 s with every taxa represented except for 

### menhaden (Tab 

### 1 e 8. 

## 3). Croaker , spot, and striped mullet were again grouped to obtain more real

### istic and 

# accurate estimates of the survival for each 

# respective size class.

Species Accounts



### Croaker

Croaker were collected on 24 different dates including 21 occasions 

# during fast-screen operation and 18 times during slow- 

## screen operation. On a 11 but two dates, control 

### organi sms were co 11 

### ected. Altogether , over 6000 croaker were collected for analysis, and almost 3000 were stocked and examined for survivability at 96 

## hours.

Croaker exemplify the problems encountered in obtaining a particular 

### survival figure for any 

# species. Results indicated poor survival of the 

## smaller sizes (9- 13 mm) during slow-screen operation but good 

## survival of
these same 

## sizes collected during fast- screen operation (Table 8. 

# 4). the organisms increased in 

# size, survival also increased (Figure 8. 1).The younger organisms collected from late October through December consis

### tently showed 

## less than 10% survival during slow-screen operation , while 

# those collected during fast-screen operation (12- 

### mm fish) showed a 

## sur

# vival ranging from approximately 10% on 

### November 13 to almost 57% on 

### December 4. The effect of screen speed was less evident with the larger size classes.



### Controls consistently showed a mean 

## survival over 90%. However on October 15 

### , November 5, and January 

### 23, unusually low mean survival per

## cents were observed i nd i cat i ng a phys i ca 

## 1 response by the fi sh to certa 

# conditions. The low survival experienced by experimental organisms from the first two dates does not reflect plant- induced mortal ity but mortal 

# ity from either " outside environmental conditions 

### (fish stressed prior to impingement) or from poor water quality during 

# holding. The poor results 

# on January 23, 1985, reflects the 

## extremely cold temperatures (3. experienced during that week of collection.

### Two additional dates showed low 

### survival. On June 17 and 24 , 1984



# the larger size classes (41- 

### 45 mm) collected 

### during both screen speeds 

### displayed low survival. The possibility of exposure of these organisms to 

## ch lori ne in the spray wash water was thought to be the cause of the low 

### survival. It has been documented that three- minute exposure to chlorine 

### concentrations as low as 0. 

### 13 ppm causes high 

# mortality (Hoss et 

# al. 1977) .

The results of ANOVA indicated that smaller organisms (~ 25 mm) col

### lected during fast-screen operation 

### showed significantly higher 

## survival than those collected during slow-screen operation. No significant differ

### ence in survi va 

### 1 was seen between screen 

### speeds for the arger organi 

### sms 

## (:: 25 mm).



## Overall 

## during fast-screen 

# operation, approximately 29% of 

## all smaller croaker survived the impingement process, while at least 36% of the large croaker were returned 

# alive. During slow-screen operation, only 

### 10% of the smaller sizes 

### survived, while 36% of Group 2 

# survived. Controls exhibited approximately 20% mortality for the smaller sizes but only 2% for the arger croaker. 

### Spot

Spot were analyzed on 14 dates involving 12 trials during slow- 

## screen operation and 8 trials during fast 

### operation. Over 3500 experimental spot 

### were co 11 ected wi th 

### an add i t i 

## ona 1 2300 contro 1 s co 11 

## ected. 

# Results indicated that as 

# size increased so did 

# survival (Figure 8. 

# 2). Mean survival ranged from ~ 1. 0% on March 4 with 18- mm fish to 

### almost 77% on 88-mm 

## fi sh on January 17, 1985 (Tab 

### 1 e 8. 

# 5). Survi va 

## 1 of spot collected during fast- screen operation was consistently higher than those collected during slow-screen operation. The low survival on June 17 again reflects the possibility of exposure to chlorine in the screen wash 

## water.

### Results of the ANOVA indicated that small spot 

### (0:: 25 mm) collected



# during fast-screen operation showed significantly higher survival than those collected during slow-screen 

# operation. The mean survival computed 

### for all dates during fast-speed operation was 31% compared to only 8% 

# during slow-screen operation 

## (Table 8. 

# 2). Small control organisms displayed an average mortality of 20% compared to 2% for the larger 

## sizes.

Penaeid Postlarvae

Postlarval penaeid shrimp (9- 

### 14 mm) exhibited high survival off the 

### fine-mesh screens. Survival averaged 80% during slow-screen operation and 

### over 90% 

## during fast-screen 

# operation (Table 8. 

# 6). Controls indicated approximately 10% of the mortality was associated with the handling and holding of the organisms.

Pink and White Shrim



### Due to the difficulty in 

## identifYing young penaeid shrimp at 

## the species level 

# without 

# additional handling, pink and white shrimp were 

### combined during 

# collection and analyzed as 

# one group. Overall , they showed excellent survival regardless of size class or screen 

# speed. Sur- vival ranged from a low of 81. 2% with 51-mm shrimp collected during slowScreen operation to a high of 100% on two dates in October with shrimp of 

### approximately the 

# same length collected during fast-screen operations 

## (Table 8. 

# 6). Control data indicated high survival with approximately 8% mortality associated with collection and holding.



### Brown Shrim


## Survival data on the brown shrimp were obtained only on the 

## larger size cl asses wi th mean 

### engths rangi 

## ng between 72 and 143 mm. Three stud- ies were conducted during slow 

### operation and two during fast 

## operation 

## (Table 8. 6). Overall , survival was slightly better during 

## slow-screen operation than during fast (approximately 90% to 

### 70%). However , two fac- tors influenced the percent survival on those collected during fast-screen 

# operation. First, during the middle of August 

### , molting occurred andresulted in impingement of soft- 

### bodied shrimp. This probably caused more

physical damage and a resultant lower 

# survival. In addition , chlorine was 

### detected in the 

### screen wash water on August 19, possibly causing some stress to organi 

### sms and lowered survi va 1 even more.

CoDtrol organisms showed a lower percent survival on the average than 

## the experimental organisms. This was, however, an artifact of the collec

# tion gear. The trawl 

### used in collecting larger shrimp from the 

## intake 

# canal occasionally became filled with silt, consequently 

## clogging the gills of the shrimp and causing some 

### latent effects. When this was compounded with molting, organisms became stressed and an even lower 

## survival 

# resulted. Survival percentages ranged from approximately 63% in August to 

### over 83% 

### in June 

## (Table 8. 

# 6). It appeared that plant impingement had little effect on the survival of brown shrimp.

Blue Crab

Callinectes sapidus and C. similis were combined as Callinectes spp. during 

### collection, holding 

### and, for 

# analysis. These abundant and commercially important species were held during nine dates. Experimental data for 

## all 

# cases indicated excellent survival regardless of 

# ife stage or 

## screen speed (Table 8. 

# 7). Survival ranged from over 82% to 100% for experimental organisms with control survival ranging from 77% to 100%.



### The survival of the 

### megalop life 

### stage of the blue crab 

## collected
from the fine- mesh screens was examined on four different occasions (twice at each screen speed) during October and November 

# 1984. During these four studies, 159 megalops were 

## collected during fast-screen operation, 203 

### during slow operation, and 363 were 

### collected as controls. 

## A mean survival of 86% was obtained for 

### all three groups indicating that 

## neither screen speed nor impingement had any effect on survival of blue crab mega

## lops.

Juvenile blue 

# crab consistently showed a mean survival over 85% 

## (Table 8. 

# 7) Five studies were conducted during September and October on 

## blue crab that averaged 22 mm. The average survival for those trials was

## approximately 92%. Screen speed showed no effect on 

# survival. Control

organisms displayed similar results with mean survival ranging from 85% to 

## 100%. Again, the observed mortality may be associated with collection and holding of the organisms rather than the actual impingement process.



### Weakfish

In addition to croaker and spot of the drum family, weakfish was also 

### collected and held during four survival studies. All experimental organisms were collected during fast-screen 

# operation. Survival was extremely poor during the two dates in August and September; however, controls also 

# displayed low 

# survival indicating a possibility of stressed organisms 

### prior to impingement or just confirming the delicate nature of weakfish 

## (Table 8. 

# 8). An improvement in survival (35%- 37%) was seen in October as 

# the organisms increased in 

# size. Likewise, control 

## organisms also improved dramatically with over 94% of 

# the individuals collected living
the full 96 hours. However , the few numbers collected prevent any conclusive statement of survival for weakfish.

Bay Anchovy 

## Bay anchovy showed no survival 

### from the 

## intake travel 

# ing screens during either fast- or 

### slow-screen operation. 

### A total of 845 

## anchovies was collected from the return flume representing two size classes (20- and 

### 33-mm mean 

# length). Both groups showed no 

# survival. Bay anchovies col

### lected for 

# control purposes also 

### showed poor survival documenting the inabil ity 

### to collect 1 ive 

## anchovies. Of 60 control anchovies collected only 29% survived the 96- hour holding period which confirmed the statement 

## Stickney (1983) made concerning the mere removal of the bay anchovy from the water which caused " almost instant mortality.

Striped Mullet

The survival of two different age classes of striped mullet was exam

# ined. Postlarval mullet (25 mm) showed a mean survival of 67. 6% collected during fast- screen operation, while control mullet of this size exhibited

# excellent survival of over 

# 95%. Juvenile/adult striped mullet (150 mm)

showed excellent survival for experimental (91. 

### 9%) as well as for 

## control organ isms (100%).



### Flounder

Results from the only survival study 

## conducted on flounder indicated 

# that postlarvae survived the 

### impingement process extremely well. 

### Collected during 

# fast-screen operation, 13- 

### mm flounder exhibited over 90% 

### mean survival. Control flounder 

### indicated 5% of this can be 

## contributed

to co 11 

### ect i on and ho 1 

## ding.

Menhaden



### Few large menhaden were available for 

# collection during survival 

## stud i es. Of the 32 

### menhaden co 11 

### ected with a mean 

### ength of 95 

### mm, a 15. 6% mean survival 

### was seen. No controls were collected, thus no deter

### mination of the 

# percent mortality associated with collection and holding
was made.

Miscellaneous Species

Blackcheek tonguefish, searobin 

### , and hardback shrimp were also collected in sufficient numbers for analyses.



### Collectively, a total of 110 

## blackcheek tonguefish was collectedduring fast-screen operation on three separate dates resulting in an over

### all mean survival of 83% 

## (Table 8. 

# 9). Of 116 control organisms , 113 

## (97. 6%) remained alive at the end of the 96- 

### hour studies. Mean 

## lengths of experimental and control organisms were 62 and 50 

### rom, 

## respectively.

Four 96- 

### hour survival 

## studies were conducted on searobin from Sep

### tember 24, 1984, through October 19 

### , 1984. A total of 132 

## experimental 

## organisms with mean lengths between 21 

### and 27 mm 

# was collected during 

# fast-screen 

# operation. Searobin exhibited excellent survival with over 

## 89. 0% survival. Control organisms indicate approximately 4% of this mortality is associated with collection and holding (Table 8. 

## 9).On October 29, 1984 , 123 hardback shrimp were collected during slow

### screen operation. Survival for the two replicates averaged only 22. 

## (Table 8. 

# 9). No data from organisms exposed to the fast-screen operation 

## were obtai ned. Contra 1 s, as expected , showed exce 11 

## ent survi va 1. Th is poor experimental survival is 

## unexplainable considering the high survival
of the related Penaeus 

# spp. Additional data are needed to conclusively state survival percentages for hardback shrimp.



### Throughout the 

# study 

# period, additional species not reported were 

# collected. These incidental 

# species included mummichog, skilletfish 

## black drum, 

## blenny, stargazer , and pipefish. Occasionally these species 

### were held for 96 hours, even though sufficient numbers were not collected to statistically substantiate the high survival percentages obtained.

Summary and Conclusions

Intensive efforts were made to obtain accurate estimates of the per

# cent survival for 

# selected commercially and recreationally 

## important species and size classes of fish and shellfish that were commonly impinged 

# or entrained by 

# the BSEP. Overall, 15 different taxa were 

### examined including over 21, 

### 000 organisms of which 10 

### 700 were held for 96 

## hours. Approximately 6200 organisms were collected during 

## slow-screen operation, 6600 during fast- screen operation , and almost 8800 for controls. 

## Thirty- four dates from April 1984 through April 

## 1985 provided sufficient information to conclude that most shellfish survived the 

### impingement process 

### extremely well. 

## Penaeid shrimp survival was consistently
over 80% , while megalop and juvenile stages of blue crab constantly exhib

### ited over 85% 

# survival. Experimental percentages were equal to or 

## exceeded control 

### percentages for these organisms indicating little or no 

# plant effect on 

# survival. In addition, the commercially important flounder and striped mullet showed excellent survival , while the abundant 

## sole and searobin indicated good survival.

Croaker and spot showed varying 

### degrees of 

# survival with survival usually increasing with size. The smaller size classes for both 

## species showed a higher percent survival collected during fast-screen operation.Weakfish and hardback shrimp, along with numerous other species, were



### collected in 

# too few numbers to conclusively state any 

# trend of 

# survival. Menhaden showed poor survival , while the bay anchovy showed no
survi val. 

## Survival studies indic~te that 

# the intake modifications return a 

# considerably 

# high percentage of 

# organisms impinged back to 

# the CFE 

# alive. Numerous commercially important 

## species, including most shellfish species, were shown to be 

### minimally, if at all, affected by 

### impingement and their subsequent return.Table 8.Mean lengths of organisms examined during 96-hour survivalstudies at the BSEP during 1984 and1985.Pink/WhiteBrown.Penae i dBluePortun i dSea-BayTongue-HardbackDateCroakerSpotShr i mpShrimpPost larvaeCrabWeakfishMega lopsrobi nAnchovyfishFlounderMulletShr i mpMenhaden01 APR 8408 APR 8430 APR 8406 MAY 8410 JUN 8417 JUN 8424 JUN 8408 JUL 8422 JUL 8405 AUG 8413 AUG 8413219 AUG 8414127 AUG 8417 SEP 8424 SEP 8401 OCT 8408 OCT 84........1 5 OCT 8429 OCT 8405 NOV 841 3 NOV 8426 NOV 8404 DEC 8410 DEC 8412-27**17 DEC 8407 JAN 8513-29**17 JAN 8523 JAN 8517604 FEB 8518 FEB 8504 MAR 8518 MAR 8501 APR 8515 APR 85numberof tr ia I s*Blue crab megalops were not measured**Two size cI asses were heI d on these dates.Table 8.Survival percentages for organisms coilected during fast- and slow-screen operation atthe BSE? during 1984 and 1985.PercentTaKonScreenNumberNumbern II aCollectedSpeedTr i alsCollectedStockedMarta I i tyMorta I i tySurvivalCroaker--Group2903128539.52.28.--Group 258433836.43.36.Spot--Group134962019.61.Pink and whi teshrimp26421992.Brown shr imp25.69.Penae i dpost larvae18812090.Blue crab17092.Blue crab megalops15911.88.Weakf I sh28219119.82.12.Sea rob i n13212489.Blackcheek tonguef ish11015.79.Bay anchovy24911454.100.Str i pedmu II et--Group19.67.--Group 291.1--&4'0Flounder90.Menhaden83.15.Croaker--Group210577260.77.--Group 259742015.57.35.Spot--Group180676739.87.Group 233321927.61.28.Pink and whiteshrimp81.Brown shr i24924189.Penaeid postlarvae13111915.Blue crab92.Blue crab megalops20313511.86.Bay anchovy59690.100.Hardback shr imp12366.34.22.= Fast-screenoperat i on.S = Slow-screenoperat i on.N umberorgan ismsthat werefounddeadin collection gearf number collectedNumber oforgan ismsthat diedafterbe i ng stockedin tanks f number stockedlOO -((a) (Number collected) +(b) (Number stocked) +(b) !Other live organisms collected but notstocked)) '"number co I I ect edTable 8.Survivalpercentagesfor controlorganismscall ectedforsurvi vastudiestheBSEP during 1984 and 1985.NumberPercentTaxonNumberNumberInitialLatentTota 1CollectedTrialsCollectedStockedMarta 1 i tyMorta 1 i tySurvi va1 cCroaker--Group 11392109514.77.Group 225506111.897.Spot--Group 1136189512.80.Group 297321398.Pi nk and whiteshrimp56134792.())Brown shri32330423.72.,....Penaeid postlarvae11511289.Blue crab23810094.Blue crab megalops36223186.Weakfi sh15511640.51.0Searobin1041.91.096.B 1ackcheektonguefish44411697.Bay anchovy20.56.29.Striped mullet--Group 195.Group 2100.Flounder95.Hardback shrimp90.~Number of organisms that were found dead in co11ect i on gearf number co11ected.Number of organisms that died after bei ng stocked in tanksf number stocked.100 - ((a) (number collected) +(b) (number stocked) +(b) (other live organismscollectedbut not stocked)) f number collected.Tab 1 e 8. Mean percent 96- hour unadjusted 

## survival va 1 ues 

## for croaker held during survival studies at the BSEP during 1984 and 1985.

Mean Percent Survival 

# Size (SL) 

### Experimenta Date 

## Range (mm) Mean (mm) 

### Slow 

## Fast Control

08 APR 84 

### 11- 

## 23. 66. 

## 86.
30 APR 84 

### 13- 

### 39. 

## 98.
06 MAY 84 

### 14- 

### 33. 54.
10 JUN 84 

### 22- 

### 43. 

## 97.
17 JUN 84 

### 31- 

### 10. 9* 

## 93.
24 JUN 84 

### 32- 

### 20. 10. 

## 97.
08 JUL 84 

### 39- 

### 70. 33. 

## 95.
22 JUL 84 

### . 46- 

### 76. 50. 

### 100.
05 AUG 84 

### 53- 62. 100 . 15 OCT 84 

### 18. 

### 52.
29 OCT 84 

## 81.8
05 NOV 84 

### 17. 

## 48.
13 NOV 84 26 NOV 84 

## 21.4 80~ 3 04 DEC 84 

### 57. 

## 90.
10 DEC 84 

### 17. 

### 26. 

## 87.

20- 

## 96.
17 DEC 84 41. 7 

## 87.
07 JAN 85 

### 12. 56. 

## 87.

20- 

### 51.1 100.
23 JAN 85 

### 37. 

### 38.
04 FEB 85 

### 10- 

### 33. 

## 87.
18 FEB 85 

### 37. 

## 84.

04 MAR 85 

### 15. 52. 

## 98.
18 MAR 85 

### 24. 

## 88.
15 APR 85 

### 22. 100 .

*Results possibly reflects chlorine present in screen wash water.

## Table 8. Mean percent 96- hour unadjusted 

## survival val ues 

## for spot held during survival studies at the BSEP during 1984 and 

### 1985.

Mean Percent Survival Size (SL) 

### Experimenta Date 

## Range (mm) 

### Mean (mm) 

### Slow 

## Fast Contro 1

01 APR 84 

### 15- 15. 

### 68. 89. 08 APR 84 

### 15- 

### 84.
30 APR 84 

### 12- 11. 5 

## 91.0 06 MAY 84 

### 14- 

### 19. 

### 33.
10 JUN 84 27 - 

### 37. 

### 97. 17 JUN 84 

### 28- 

### 98.
17 JAN 85 

### 74- 124 

### 76. 100. 23 JAN 85 

### 11- 

### 14. 

### 47.
04 FEB 85 

### 11- 13. 

### 86. 18 FEB 85 

### 12- 

### 26. 48. 04 MAR 85 

### 14- 

### 94. 18 MAR 85 

### 14- 

### 12. 

## 41.2 83. 01 APR 85 

### 15- 

### 34. 

## 91.2 15 APR 85 

### 12- 18. 

### 82.

*Resu 1 possibly reflects chlorine 

## present in screen wash water.

## Table 8. Mean 

## percent 96- hour 

## unadjusted 

## survival values 

## for penae i d 

## shrimp held during survival stud i es at the 

### BSEP dur i ng 1984 and 

### 1985.

Mean Percent Survival Size (TL) 

### Exper i menta Speci es 

### Date Range (mm) 

### Mean (mm) 

### Slow 

## Fast Contra

Pink and
Wh i 13 AUG 84 

### 34- 

## 97. 96. Shrimp 19 AUG 84 

### 31- 

## 83. 75.

17 SEP 84 

### 19- 

## 81.2 98.
24 SEP 84 

### 27- 

## 91.2 94.
01 OCT 84 

### 23- 100. 

### 97.
08 OCT 84 

### 22- 100. 

## 91.6
15 OCT 84 

### 23- 

## 91.7 93.

Brown 10 JUN 84 

### 42- 107 

### 93. 83.
Shri mp 17 JUN 84 

### 44- 118 

## 81.0 79.

24 JUN 84, 

### 46- 13 5 

### 94. 68.
13 AUG 84 

### 69- 175 132 

### 76. 69. 19 AUG 84 

### 115- 185 141 

## 61.4 63.

Penaei d 01 APR 85 

### 10- 

### 60. 

## 89. 84. 

## postlarvae 15 APR 85 

### 100. 

## 91.8 94.

## Table 8. Mean percent 96- 

### hour unadjusted survival for 

## blue crab held during survival studies at the BSEP during 1984 and 

### 1985.

Life Stage Mean Percent 

## Survival Experimenta Date Slow 

## Fast Control

01 OCT 84 

## 81.8 96.
08 OCT 84 

## 88. 94.
29 OCT 84 

### 86. 78.
05 NOV 84 

### 85. 77.
17 SEP 84 

### 92. 

## 95.
24 SEP 84 

## 94. 89.
01 OCT 84 

## 85. 100.
08 OCT 84 

### 100. 100 . 15 OCT 84 

## 87. 85. Megalops



## Juveniles

Table ~. Mean percent 96- 

# hour unadjusted survival for 

# weakfish held

, during survival studies at the BSEP during 1984 and 

### 1985.

Mean Percent 

### Su rv i val Size (SL) 

### Exper i menta 

### Date Range (mm) Mean (mm) 

## Fast Contro

05 AUG 84 

### 15- 

### 37. 24 SEP 84 

### 16- 21. 3 01 OCT 84 

### 18- 

### 37. 

## 94. 08 OCT 84 

### 25- 

### 35.

## Table 8. Mean percent 96- 

# hour unadjusted survival for 

## miscellaneous 

# species held during survival studies at the BSEP during 1984 and 1985.



### Speci es 

### Date Size 

## Range 

## (mm) Mean (mm)

B 1 

### ackcheek 

## tonguefish 27 AUG 84

08 OCT 84 15 OCT 84

Searob i n 24 SEP 84

01 OCT 84 08 OCT 84 15 OCT 84



### Hardback 

### shrimp 29 OCT 84 

### 18- 

### 22-

22 -



### 13- 12- 

### 15- 14-

18- Mean Percent Survival



## erimenta 

# Fast Control

79. 

### 80. 89. 

## 95.

99. 97.

84. 90. 

### 90. 

## 91.9 100.



## 95. 100 . a 

## 93.

22. 

## 90.

*Hardback shrlmp collected during slow-screen operation.,......Xa20Xa661 BB-JX a 36 X 5 45X ~ 77X=56X a813 ,x - 15513x = 12x = 12413....\ /\ /A./ \,/ ..f\\';'/. . 12X - 12X . 11x = 14II' \/ \x-1~1, , l'I X~x--'IlI XI :k-. /~ X- - - - -+X'"1\.... ;of--- -..-....-1+ ++"APR84MAY84JUN84JUL84AUG84SEP84OCT84NOU84DEC84JAN85FEB85NARB5APR85NAY8SDATEX-x-X FASTLEGEND: SPEEDCONTROL++-+SLOWX = MEAN STANDARD LENGTHFigure 8.Mean percent survival of croaker during survival studies conducted at the BSEP during 1984 and 1985.1 1210--+ttttJIlIlIlIlIlI-t*----+------+JT~+- --*It!\/: :/IIt+4-\i1\ IlilifI 1II11I-4-II1I1I1 \ Itt4.8121!i/ \'1111III!\ I1. / 1111'II li/ \111 IIII /III1* ,I. / ,. J",1 /II\ iIIIE=I. I1\ ilII 1I,1/ \~I I11212121100120LE-:NQ TH(MM)LEGEND:STUDY-I--+---f-CONTROL0 0 0FAST""*-*--*SLOWFigure 8.Survival/mortality comparisons of spot by size class collected during fast and slow screen operation atthe BSEPduring 1984-1985 survival studies.IMPINGEMENT (Larval)


## Introduction 

# With the initiation of fine- mesh screen operation , many of 

## the 

# larval and postlarval organisms that 

# would 

# previously 

# have been 

## entrained were impinged and returned to the CFE. A larval impingement 

### program was begun in January 1984 to provide an estimate of the total 

### number of larvae and postlarvae being 

# impinged. Survival percentages applied to these estimated numbers gave an assessment of the success of 

## fine-mesh screens.

Methods

Samp 1 e Co 11 

### ect i on

To collect the 

## impinged larval - and postlarval organisms, a 505-um 

### mesh plankton net, 

### 1 m in diameter, was placed in the 

## nekton return flume such that 

# the entire water column was 

### filtered. Five- 

## minute samples were collected on mid and slack tides over one 24- hour period 

## per ca endar week.

Samp 1 e Ana lys is

Due to the 

### arge number of organi sms co 

### 11 ected , many of the samp 1 es were subsampled; however 

### , at least 25% of the total sample weight was 

# retained for processing. Samples were processed in the same manner as 

### entrainment samples except that only minimum and maximum lengths were recorded for each species (CP&L 

### 1983).

Incidental collection of 

### organisms large enough to be 

## considered juveniles or adults required the 

### enforcement of 

### length limits. 

### Only fish 2 40 mm were identified with the exception of eels, pipefish , and 

### leptocephalus larvae which were kept only if they were 2 

## 100 mm. The portunid crab cutoff imit was set at 2 24 mm.

### Processing of larval impingement samples was very time- 

## intensive.



# All collections made 

### in January were 

# processed and analyzed. After January at 

# east two samp 1 i ng 

# tri ps 

# per month were 

# processed and 

# analyzed. Three-way analyses of variance and Duncan s multiple range test were performed to examine month , period, and tidal factors. ANOVAs 

### were performed on loge transformed numbers, and 

## . results are presented at
the P ~ 0. 

## 05 significance level.

Results and Discussion

Domi nant Spec i es



### A total of 5. 

# 7 x 108 organisms representing 99 taxa was 

### impinged 

# during 

# 1984. Croaker and spot were the dominant species 

## comprising 22. 9% and 20. , respectively, of the 

### total catch. Of the other com

### mercially and/or 

# recreationally important species, portunid megalops 

### ranked third (20. 4%), Anchoa 

### spp. fourth (10. 

# 0%), bay anchovy fifth 

## (6. 9%), Penaeus 

## postlarvae sixth (5. 6%), Gobiosoma 

## spp. seventh (3. 0%), and menhaden eighth (2. 

# 9%). Portunid crabs and Gobionellus 

# spp. ranked ninth and tenth, respectively, with a combined percentage of 

## approx

## imately 3. 0% (Table 9. 

## 1).

Seasona 1 i ty and Abundance 

## The typi ca 1 wi nter 

# and summer peaks 

# ; n abundance observed in entra i nment were also observed in arva 1 imp 

## i ngement. The wi nter peak 

### consisted of menhaden 

# spot, croaker, 

# mullet, flounder, and brown 

## shrimp-- all ocean- 

### spawned species. Portunid megalops is an early 1 ife stage of the blue crab which spawns near the mouth of the river in the 

### higher saline areas during the 

# summer. Its period of peak 

### abundance occurred during the 

### late summer and fall months and is considered a 

### winter species. The summer peak consisted of such ocean- 

### spawned species 

# as seatrout and pink and white 

### shrimp and of 

# the estuarine-spawned

species of anchovies, Gobionellus 

## spp. , and Gobiosoma 

## spp.

### Menhaden were present in 

### impi ngement from January through May and



### were impi nged in greatest 

### numbers from 

## ate March to mi d- 

# April. Spot and croaker were impinged from January through mid- June with spot being 

### impinged in greatest 

### numbers in late March and croaker 

## during mid to 

# late January. Mullet and flounder were impinged from January through 

### April and they both achieved greatest impingement during late January 

## through early March. Brown shrimp were present in impingement from mid

### February to 

# late 

# June, had their 

# greatest impingement during 

## late March, 

# and reached a second peak in 

# ate 

# June. Portun i d mega lops appeared in impingement from early April through December and had their highest impingement from late August to late November.

Of the summer species, seatrout were impinged from mid- May to early 

## October and had their greatest impingement during early to mid- 

## June. 

# Pink and white shrimp were present in 

## impingement from mid- August through early November with their greatest impingement occurring from 

## late August to early October. Anchovies and both genera of gobies were 

### present throughout the year. 

### Anchovies reached peak impingement during

June as did Gobiosoma spp. Gobionellus 

### spp. had two periods of 

### high impingement--one during late March to 

# early April and the other from late September through early October (Table 9. 

## 2). 

# All seasonality and peak abundance patterns 

### observed in arva 1 impingement closely follow the patterns seen in both the entrainment and river larval fish programs.

Diel Patterns



## ANOVA and 

## DMR test 

# results showed that 

# for 

# all species 

# significantly 

# greater numbers were impinged at 

# night. This is consistent with the pattern seen in entrainment.Tidal Patterns



### Except for seatrout, penaeid shrimp, Gobionellus spp., and portunid 

### megalops, ANOVA 

### results showed no significant difference among 

# tidal stages for numbers imp 

### i nged.



### According to 

# the DMR 

# test rankings, the 

# most 

# penaeid shrimp,

GobioneZlus 

### spp., and portunid megalops were impinged during high slack tides and the most seatrout were impinged during low slack tides.

Survival Estimates

In most cases, survival studies were conducted with organisms collected from two different intake screen rotation 

### speeds. To obtain an 

### overall percent 

### survival of impinged larval and postlarval organisms 

### returned to the 

### estuary, all survival tests from slow screen rotation for size classes whose mean length was ~ 40 mm were 

# used. The same was done for corresponding size classes from fast screen 

# rotations. These percentages are presented in Table 9. 

## 3 by speci es and screen speed.

month ly 

# est imate of 

# total number imp i nged 

# for each speci es studied was calculated by expanding the known number collected for the hours sampled by the total hours in that 

# month. These monthly estimates 

### were then combined and are presented as the total number 

## impinged in

Tab 1 e 9.


## In 1984 an estimated 1. 3 x 10 

## 8 croaker were impinged. If they had 

# been impinged on slow- 

# rotating screens, 1. 6 x 10 

## would 

# have been returned to the 

### estuary alive. If they 

# had been impinged on fast

# rotating screens, 3. 8 x 10 7 would have been returned 

# alive. Total spot 

## impingement was 1. 2 x 10 If these were impinged during slow rotation, 

### 1.1 x 10 would have returned to 

### the estuary alive. If they were impinged during fast rotation, 3. 7 x 10 

### 7 would have survived. 

## Similar 

# fast/slow survival estimates were calculated for the 

# other species 

## studied and are presented in 

## Table 9. 

# 3. The eight 

# taxa tested for

### survival represent 79% of the total impingement 

# catch. Of these, 49% would have been returned 

## al ive to the estuary if the screens had been on 

# fast rotation. This corresponds to 39% of the total larval organisms impinged being returned to the estuary.

Summary and Conclusions



### In 1984 a 

# larval impingement program was initiated to provide an 

### estimate of 

### the total 

# larvae and postlarvae being impinged by the BSEP. A total of 5. 7 x 10 

## 8 organ isms represent i ng 99 taxa was imp i nged 

### with croaker and spot dominating the catch. The seasonalities of those 

## commerciallyjrecreationally important species were much the 

## same as those observed in the entrainment and river larval fish programs. 

# All species were impinged in greater 

### numbers at 

# night. Penaeid

shrimp, Gobionellus 

# spp., and portunid megalops showed 

# significantly higher impingement catches during high slack tides and seatrout 

### showed 

# significantly higher catches during low 

# slack tides. . For all other 

# species analyzed, there was no significant 

### difference in 

### impingement catches among tidal stages.



## Overall , percent survival estimates for slow- intake screen speeds 

## ranged from 8. 9% for spot to 86. 

### 3% for 

## portunid megalops. Survival estimates from fast screen rotation ranged from 12. 

### 6% for weakfish to 

## 90. 2% for Penaeus 

### postlarvae. Bay anchovy showed no survival at either 

# speed. The eight taxa tested for 

### survi va 1 represented 79% of the 

## total impingement catch. 

# At fast screen rotation , 49% of 

# these organisms would have been returned alive to the estuary which corresponds to 39% of the total larval organisms impinged being returned to the estuary.Tab 1 e 9. 

### Ranking by percent of total impingement of 

## species collected in the BSEP larval impingement program during 1984.

Rank Spec i es Percent of Total Imp i ngement



### Croaker 22. 

### Spot 20. Portunid megalops 

### 20.

Anchoa 

## spp. 10. Bay anchovy

Penaeus 

## postl arvae

Gobiosoma 

## spp. Menhaden Portunid crabs 

## 1.6

Gobionellus 

## spp. 1. 5Table 9.Total number of selected species collected by tripin larvalimpingement during 1984.PenaeusGobionell usGob j osomaPortun i dTripDateAnchovyMenhadenSeatroutSpotCroakerMulletFlounderSPP.SPP.SPP.Mega lops12 JAN 848359338842471 7 JAN 8431075189914815924 JAN 8493250593,64419899931 JAN 8447058160273633607 FEB 8403212634578079783121 FEB 8433242127 ,35649540569225006 MAR 8401626729447686282014821320 MAR 8446060326408313339380736403 APR 8415288850198715136933310APR 8464991934183811487770801 MAY 8495517657410476544315 MAY 8498210770514517660530912 JUN 84581809354295121'-019 JUN 84701360650142518'-.J26 JUN 8498114717220510JUL 8452031145813924 JUL 8453118443634563107 AUG 848947171052141911 4 AUG 8415056715674921 AUG 8471814417471932728 AUG 8417610354524614350818 SEP 8452613928269748828526225 SEP 8453628742350513083102 OCT 8469910899732508730283009 OCT 8499931777611029213416 OCT 8468275169561810067306 NOY 8432822088637772327Nay31938319384889104 DEC 8445101724901020 DEC 84860683114306130Table 9.Overall percent survival and number of larval impinged organisms returned alive to the Cape FearEstuary.Speci esTotalNumber Imp ingedveraII Percent ~urV1va~ lScreenScreenSpeedSpeederurned All veasScreenScreenSpeedSpeed'-0CroakerSpotBay anchovyPenaeus postl arvaeFlounderMulletPortuni d mega lopsWeakfishAnchoa spp.MenhadenOther organisms (89 taxa)1.3 X 101.2 x 109 x 102 x 107 x 101.6 x 101.2 x 105 x 107 x 101.6 x 100 x 1029.30.90.90.67.88.12.12.77 .86.8 x 107 x 109 x 102 .4 x 101.1 x 101.1 x 101.1 x 101.6 x 101.1 x 105 x 101.0 x 107 x5 x 108 (79%)a1 x 108 (72%)bTota 1 organi smsTota 1 organi sms testedTota 1 organi sms tested(excluding bay anchovy)Not testeda Percent of total organlsms implnged that were tested.b Percent of total organlsms imp1nged that were tested excluding bay anchovy.c Percent of a that were returned a1 i ve.d Percent of b that were returnedal ive.2 x 108 (49%)c2 x 108 (54%)d

### 10. IMPINGEMENT (Juvenile and Adult)



### 10. 

### I ntroduct i

Impingement studies have been conducted at the BSEP since January 

### 19, 1974, when water was first pumped through the 

# plant. Objectives of the past and present studies addressed the determination of 

## numbers, weights, 

## species composition, and length frequency of 

## organisms impinged at the BSEP.


# The 1984 juvenil e and adu 

# It (J/A) imp 

## i ngement study was conducted with the permanent fish diversion structure 

### in operation. The 

## diversion structure, as descr 

# i bed in Append i x 

### A and the 

## 1981 annua 

# 1 report (CP&L 

## 1982), prevented arger organi 

## sms from enteri ng the intake canal except 

### when screen panels failed 

## as a 

# result of biofouling 

# and/or debris 

# buildup. During the repair of failed screens, sections of the diversion 

### structure were opened 

### all owi ng access of organ 

### isms to the intake cana 1 . Except for these short 

## periods, most J/A fi 

## sh and she 11 fi sh 

### were excl uded from possible impingement during 

### 1984.



### 10. Methods

Samples were collected for one 24- hour period each week during 1984 

### with only two 

# exceptions. The data for the first week in January were omitted due to the use of an experimental sampling procedure which was not comparab 1 

# e with 

# the subsequent samp 1 i ng scheme and the 

## second week in September was not sampled because of 

### Hurricane Diana. During these two months, data were expanded based on three week s of 

### samp 1 i ng instead of the normal four or five weeks. 

# The 1984 samples were taken by 

# placing a steel- framed collection basket in each 

# sluice. The baskets were fitted with a 9. 4-mm plastic 

### webbing similar to the screens on the original intake traveling 

## screens. Contro 1 

# valves were opened so screen wash water flowed freely 

## i n both sluiceways. As a basket filled with organisms and debris, a third basket was set in the flume to guarantee continuous filtration of the screen wash



### 10-

## water while the basket was emptied. A sample was completed at sunrise or

sunset to be day/night 

# specific. Samples were returned to the laboratory 

# for sorting, identifying, enumerating, 

# measuring, 

# and weighing of organisms. Up to 50 individuals of the 13 selected 

## species (Table 1.2)
were measured from each samp 

# le. Monthly estimates and expans ion factor 

### calculations were identical to those 

### described in the 1982 

## annual report (CP&L 1983). This report uses 1977- 

### 1982 as comparable past 

# data. The data for 1983 was only recorded for the first six months 

## , whi le the second six months was used to develop the new J/A impingement 

# program. Data are reported in both numbers and 

# densities. Total numbers refer to the 1984 

### data set, while 

## densities are used when 

## comparing 1984 to past years. Converting all years of data to densities enables comparisons, regardless 

# of plant operation 

# (flows). The 1984 data reported in densities can 

# objectively compare the 

### effects of 

# the fine- mesh screens, diversion structure, and most importantly flow minimization to past J/A impingement 

## data.

. Organisms 

## ;;: 25 nun were considered 

### incidental catches and were not 

### recorded in the J/A program, while larval impingement (Section 9. 

### 0) did 

### not record 

### organisms ~ 40 

# mm. To resolve this 16-mm overlap between programs, the 1977- 

### 1982 J/A impingement data were examined for catches 

## below 40 mm. Historically, 2. 

### 0% of the 1977- 

### 1982 catch was ;;: 40 mm 

### whereas 60. 3% of the 1984 J/A impingement was 

## ;;: 40 mm (Table 10. 

# 1). The addition of fine-mesh screens, the effect of the diversion structure, plus 

### the change in 

# the sampling gear in 1984 dramatically skewed the catch 

## towards smaller organisms. An adjustment of the data set was 

## needed for 

# two 

# reasons: (1) the 25- 

# 40 mm organisms 

# were being expanded and documented in both 

### larval and J/A impingement and (2) the data set would have to be comparable to past years so trends could be 

# determined. Thus,

organisms ~ 40 mm are considered part of JjA 

### impingement.

Fish ~ 41 mm, shrimp ~ 41 mm, crabs ~ 25 mm, and eels and pipefish ~ 101 mm were included as the JjA impingement 

# catch. Occasionally groups of 

## organisms were 

## recorded below 

# and above the 

# cutoff 

# limits. On such occasions the values remained in the J/A analysis and 

# reportings. Lengthfrequency plots 

### include data with no cutoff 

# limit to show the 

# entire

10-

### length frequency ~ 25 

## mm. A reference line was included in all 

## lengthfrequency plots at 40 mm to divide larval versus JjA impingement.



### 10. Results and Discussion



### 10. Species Composition



### The total JjA impingement during 1984 

## included 5, 128 817 organisms 

# representing 116 

# taxa and weighing 16 

# 890 

# kg (Table 10. 

# 1). Total impingement density was reduced in number by 43% and in weight by 67% when compared to the 1977- 

### 1982 mean catch (Table 10. 

# 2) Bay anchovy were the most abundant species totaling 59. 0% of the catch. Menhaden (12. 

## 8%), blue crab (5. 

# 6%), Atlantic silverside (4. 0%), blackcheek tonguefish (2. 6%), and 

## croaker (2. 1%) were second, 

### third, fourth, and fifth, respectively. 

### Pink shrimp (1.8%), spot (1.7%), brown shrimp 

## (1.6%), and white shrimp (1.0%) rounded out the top ten species (Table 10. 

# 3). Each of the remaining 106 taxa was represented by ~ 1% of the total expanded catch.



### 10. Oiel Patterns



### The catch at night comprised 78% of the 

### total J/A 

### impingement. The lowest night impingement rate (47%) was recorded during May, while the 

# highest 

# night catch 92% 

# was recorded during 

# October (Figure 10. 

## 1). Percentages of day 

### versus night impingement calculated by weight were similar to the numerical 

# percentages. Both number and weight percentages are consistent with data reported in the 1982 annual report (CP&L 

### 1983).

10. 

## Flow Rates

Flow rates in 1984 were below the mean flow of previous years 

### (1977- 

# 1982). Mean monthly intake flow rates in 

## 1984 ranged from 45. 4 x 10 jmonth in April to 110. 

### 0 x 10 6 m 

## jmonth during October. Mean monthly flow rates for previous years ranged from 85. 9 x 10 6 m 

## jmonth in June to 117. 6 x 10 6 m 

### jmonth during January (Figure 10. 

# 2). The lower flow rates during 1984 are attributed to the flow-minimization program which in turn 

### reduced impi 

### ngement.

10-

### 10. 4 Length- 

### Frequency D 

### is tr i but ions

Length- frequency data was collected to examine the size distribution 

# of certain species from 

# the impingement catch. Seatrout , mullet , and 

# flounder were 

# not impinged in 

# sufficient numbers for length- frequency 

# distribution 

# analysis. All length- 

### frequency plots 

# include organisms between 25 and 40 mm, even though that size group is not being reported as JjA impingement.



### The modal length of bay anchovy decreased from previous years by up 

### to 25 mm, especially in the 

### first six months. 

### The reduced modal length may be 

# attri buted to the fi ne-mesh screen 

### and new 

### samp 1 i ng 

## procedure (Figure 10. 

## 3).

Menhaden 

# spot, and croaker 

# length distributions for 

## juvenile organi sms were s imil ar 

### to previous 

# years, although numbers were 

### reduced (CP&L 1982 , 1983). Unlike previous years, adult menhaden were essentially absent except in January and February when catches were attributed to the failure of the diversion screens in mid- January (Figure 10. 

# 3). Catches of
adu It 

# spot al'1d croaker did not 

## increase duri ng those months and rem 

### a i ned low throughout the year (Figure 10. 

## 4).

Length data for penaeid shrimp are similar to past years (CP&L 

### 1982, 1983) . 

## Brown shri mp peaked in 

## numbers duri 

## ng Ju ly and in 

### s i ze duri ng 

# August. White shrimp peaked in number during September and in size during 

## November. Pink shrimp 

# had scattered distributions throughout the year 

### peak i ng 

## in abundance duri ng October.



### 10. Estimated Survival Adjustments



### The JjA survival studies tested ten of the most 

# frequently impinged 

## species (Section 8. 

# 0). Bay anchovy was tested but showed practically no 

# survival. The remaining nine 

# species and estimated survival of 

## the remaining nine species are presented in Table 10.



### 10-

### The application of the survival study results to the J/A impingement

data documents a probability of survival for organisms which were impinged (Table 10. 

# 4). An estimated total of 813, 

## 372 organisms weighing 7, 174 kg 

# were impinged and returned to the 

### estuary alive in 

## 1984 (Table 10. 

## 4). When the survival estimates are subtracted from the J/A 

## impingement, only 220 kg of spot, 197 kg of croaker, 266 kg of blue crab, and 158 kg of 

# all penaeid shrimp were actually 

### lost to the estuary because of 

### impingement 

## during 1984 (Table 10. 

## 4).

The application of 

# the survival study results 

### to the 

### impingement totals reduces the 

### loss to 

### impingement in number by 15. 9% and weight by 

### 42. 5% of the 

### 1984 expanded J/A imp i ngement catch. 

## Casual observat ions of the survival studies and impingement sampling showed many live individuals 

# of additional species initially 

### survived the 

# return 

# system. Those additional species have yet to be tested, thus the reduced percentages are a documented minimum and future studies should show 

## additional survival.

10. Summary and Conclusions 

# The 1984 J/A impingement catch 

### consisted of 5 

### 128, 

# 817 organisms 

## weighing 16, 890 kg. 

## Bay anchovy (59%) was the most 

### abundant species, while menhaden was the 

## second most abundant species. 

# Total impingement density was reduced in number by 43% and in weight by 67% when compared to the 1977- 

### 1982 mean catch. The diversion structure probably excluded most 

# of the J/A menhaden 

### spot, and croaker, which historically 

### dominated impingement catches at the BSEP 

### (CP&L 1982, 1983). 

## Bay anc.hovy was not excluded by the diversion structure 

# and 

# thus dominated the 

## 1984 J/A impingement. Three out of four organisms were impinged at night.


### Length- frequency plots generally showed typical distribution of YOY 

### organisms but 

# with 

# the substantial reduction of 

# year and older 

# individuals. The smaller organisms ~ 40 

### mm could 

# pass through the diversion screens and populate the intake canal , while larger individuals 

### were generally 

# excluded. The smaller organisms freely entered the 

## canal and possibly establish residence until the time of their natural migration 

### out of the estuary. Their size would limit them from exiting through the



### 10-

# diversion screens and their only 

## departure route then would be through

impingement and the nekton return 

### system. However , survival studies show that essentially all of the penaid shrimp and blue crab can be returned to 

## the open estuary a 1 i 

## ve.

An estimated total of 813, 

## 372 organisms (15. 

## 9%) weighing 7, 174 kg 

## (42. 5%) were returned alive to the 

### estuary. The tested survivability was appl ied to J/A impingement 

## total s resulting in the loss of only 266 kg of blue crab, 158 kg of penaeid shrimp, 220 kg of spot, and 197 kg of croaker 

## during 

# 1984. The southern district of North Carolina reported prel 

## iminary landings of 446 

### 265 kg of blue crab , 1 

### 211 

### 731 kg of 

# penaeid shrimp, 133, 871 kg of spot, and 164 

### 167 kg of croaker during 1984 (Street 

## 1985). 

## Additionally, private individuals harvest unknown quantities of blue crab 

### and penaeid shrimp for personal 

# usage. When J/A impingement is compared 

# to such 1 and i 

## ngs, one can see that 

## what was cropped by the BSEP was 

### ins i gn if i 

## cant.

10-

## Table 10. A summary of expanded juvenile/adult impingement at the BSEP 

## duri ng 1984.

Number of organi sms 

### Weight (kg) Number of shellfish Weight of shellfish 

### (kg) Number of finfish Weight of finfish 

### (kg) Number of mi sce 11 aneou s Weight of miscellaneous Total number of taxa 

# Total taxa of finfish speci es 

### species (kg) 128, 817 

### 16, 890 587 

### 048 5, 689 

### 531, 733 

### 11, 161 

### 10, 036
116 102

Tab 1 e 10. 

### A summary of expanded 

## juvenile/adult imp 1 ngement by year at

the BSEP. 

### Imp i nged Number 

## Impinged Weight (kg)

of Organisms per of Organisms per 

## Total Million Cubic 

## Total Million Cubic 

### Number Meters of Water 

### Weight (kg) Meters of Water 

### Year 

### Impinged Entra i ned Imp i nged 

### Entra i ned



### 1977 

### 16, 

### 355, 569 

### 124 

### 593 

## 98, 730 743 

### 1978 

### 18, 859 331 

### 124 

### 289 131 

### 570 

### 865 1979 

### 11, 147 

### 099 

## 91, 060 

### 61, 374 

### 464 1980 697 879 

### 79, 647 

### 67, 701 

### 523 

### 1981 9 , 736 , 795 

### 74, 286 270 514 1982 

### 810 886 

### 204. 162 

### 76. 494 709 

### 1984 

## 926, 485 

### 167, 346 20 , 

### 628 

### 256 1984 

### ;:. 40 

### 128, 817 

### 66, 398 

### 16, 890 210 

### 1977- 1982 116 

### 341 

### 636 mean 

### 1984 % reduct i



### 10-Tab 1 e 

### 10. summary of 

### juven 11 e/ adu 1 mp; 

### ngement 

## spec; es 

## the BSEP during 

### 1984. 

## Total Tota 1 

### Rank 

### Speci es % of catch 

### Number 

### Weight (kg)

Bay anchovy 

### 59. 

### 023, 433 

### 950 Menhaden 

### 12. 

### 653, 960 186 Blue crab 

### 286, 626 227 

# Atlantic silverside 203, 697 

### 585 B 1 

## ackcheek tonguefi sh 131, 575 192 

### Croaker 110 

### 199 

### 445 Pink shrimp 

## 1.8 92, 551 172 

### Spot 

### 1.7 89, 252 544 

### Brown shrimp 

## 1.6 83 , 

### 662 

### 878 White shrimp 

### 1.0 52, 529 327



### 10-Table 10.Estimated survival of juvenile and adult organisms impinged during1984.Number ofEstimatedEstimatedPercent**Survi valNumberWeight (kg)NumberWeight (kg)SpeciesSurvi vaTestsImpi ngedImpi ngedSurv; vedSurvivedPenaeus spp. (pink and whi te)92.145,08049913376446081 uecrab93.286,626227268,569961Stri ped mull et92.19,69147518,116437Brown shrimp86.662878368759Blackcheek tonguefish79.131,57519296,774153Spot59.89,252544105324Croaker55.110,19944561,381248(:)35.277Weakfi sh20,790Menhaden15.653960186102018809Bay anchovy023,433950At 1ant ic si 1 verside203,697585Other species (104 taxa)370,852842Total128,81716,890813 ,372174% Survival15.42.Exc 1 ud i ngbay anchovy105,38438.Excluding bay anchovy and others not tested530,83553.*Not tested.**Percent survival calculated using only juvenile and adult-sizeclasses.100~.....(:)......DAYillNIGHTFigure 10.MONTHDay Inight comparisonof juvenile/adult impingement at the BSEP during 1984.1401201 0 0 i""----- -......1977-1982\ /---t"\ //----JonDeeFigure 10.FebMarRprMayJunJuRugSepDe\:,No\)MONTHMean monthly rates of water entrained at the BSEP, January-December, 1977-1982 and 1984.BA Y ANCHOVYJItrEB.........N = 274 760N = 389 675N = 128 620N = 73953N = 19732N - 30 668N =4.422.N =N '" 9067N = 28561N = 31931N = 269,8698 5un,," 1m)N = Number SampledMENHADEN58.42110746N =23 95747361N =1655N =384N =174N =N -784N =336N =.N =JlR822IIlIt1lIfIBIIIII'fItCIIIIII141U~1H (ltI)Figure 10.3 Length-frequency distributions of bay anchovy and menhaden impinged at the BSEP, January-December, 1984.Organisms greater than 40mm are considered juvenile and adult.........AI 8c-arug 8tI1/ 8c-aIQ) A'illmY 8RJII8UL 8roi 8ocr 8/OJ 8IIC 8SPOTCROAKERN = Number SampledN = 1430339= 9647438N = 2229N =147N =609N = 5,510N = 1,381N '" 9984N = 4.445R 11" J1N = 7332N '" 4332N = 8.443N = 5741N =836N =590282198286N =6821111128141lIB188281W'II/Im,N = ,.37388 II13)lOtllll (1ft)1181(1IIIFigure 10.4 Length-frequency distributions of spot and croaker impinged at the BSEP, January-December, 1984.Organisms greater than 40mm are considered juvenile and adult.

### 11.0 REFERENCES



## Allen, 

# G. H., A. C. Delacy, and D. W. 

# Gotshall. 1959. Quantitative sam

### pling of marine 

### fishes: A problem in fish behavior and 

## fishing 

# gear. Pages 448- 509. in 

# E. A. Pearson (eds. ). Proc. 1st 

## International Conference on 

### Waste Disposal in the 

## Marine Environment. Pergamon Press, New York. 

### Ambrose, J., Jr. 

## 1983. Age 

# determination. Pages 301- 324 in L. A. Niel

### son and D. L. Johnson 

# (eds). Fisheries techniques. American Fisheries Society, Blacksburg, VA. 

### Birkhead, W. S. , B. J. Copeland 

### , and 

# R. G. Hodson. 

# 1979. Ecological

monitoring in the lower Cape Fear River estuary, 1971- 

# 1976. North Carolina State University, Raleigh , NC. 

### Bousfield, E. L. 

# 1955. Ecological control of the occurrence of barnacles

in the Miramichi Estuary. Natl. Mus. Can. Bull. 137:1- 

### 69.
CP&L. 1980. 1979 monitoring 

# program. BSEP Cape Fear studies, Supplement 

# I. Carolina Power & Light Company, New Hill , NC. 

# 1982. Brunswick Steam 

# Electric 

# Plant, annual biological monitoring report, 

# 1981. Carolina Power & Light Co., New Hill NC. 

# 1983. Brunswick Steam Electric 

# Plant, annual biological monitoring report, 

# 1982. Carolina Power & Light Co. , New Hill 

### Nc. 

# 1984. Brunswick Steam Electric 

# Plant, annual biological monitoring report, 

# 1983. Carolina Power & Light Co. , New Hill NC.


### Chao, L. N.. and 

# J. A. Musick. 

# 1977. Life history, feeding habits , and



### functional morphology of 

# juvenile sciaenid fishes in the York 

### River estuary, Virginia. Fishery Bulletin 75:657- 

### 702.
Copeland, B. J., and 

# R. G. Hodson. 

# 1977. Larvae and postlarvae in the



### Cape Fear Estuary, 

## NC, 1976- 

# 1977. Report No. 77- 

### 5 to 

## Carolina Power & Light 

## Company. North Carolina State University, Raleigh, NC. 

### Copeland, B. J., R. G. Hodson 

### , and R. J. Monroe. 

## 1979. Larvae and postlarvae in the Cape Fear River estuary, NC, during operation of the Brunswick Electric Plant, 1974- 

# 1978. North Carolina State University, Raleigh, NC. 

## Dudley, D. L., and M. H. Judy. 

# 1973. Seasonal abundance and distribution

of juvenile blue crabs in Core 

### Sound. NC. 1965- 

# 1968. Chesapeake Sci. 14: 51- 

### 55.

11-

### Everhart, H. W., and W. 

## D. Youngs. 

# 1981. Principles of Fishery Science 

### 2nd ed. Cornell University Press, Ithaca , NY. 

### Geaghan, J. 

### P., and M. 

# T. Huish. 

# 1980. Distribution and diversity of



### fish and crustacean communities in the Cape Fear 

## River estuary, 

# North Carolina, 1977- 

# 1979. North Carolina State 

## University, Raleigh, NC.


### Haven 

# D. 

# S. 1959. 

### Copeia 1:25- 

### 30. Migration of the croaker 

## Micropogon undulatus.

Hodson 

### , R. 

# G. 1979. Utilization of marsh habitats as primary nursery



### areas by young fish and 

## shrimp, Cape Fear Estuary, NC. BSEP Cape 

# Fear Studies, Volume 

# VIII. North Carolina State 

## University, Raleigh, NC.


### Hodson , R. G., 

# C. R. Bennett, and 

# R. J. Monroe. 

# 1981. Ichthyoplankton

sampler for simultaneous replicate 

### samples at 

## surface and bot

# tom. Estuaries 4(3): 176- 184. 

### Hogarth , W. T. 

# , and K. L. Nichols. 

# 1981. Brunswick Steam Electric Plant 

# intake modifications to 

# reduce entrainment 

# and impingement 1 os 

# ses. Caro 1 i na 

## Power & Light Company, New Hi 11 , NC. 

### Hoss, O. E., 

## W. F. Hettler , Jr., 

### and L. 

# C. Coston. 

# 1974. Effects of



### thermal shock on larval 

# fish: Ecological implications with respect to entrainment in power plant cooling 

# systems. Pages 357-

371 in 

### J. H. S. 

## Blaxter (ed. 

# ).

The early life history of 

# fish. Springer Verlog, Berlin, West Germany.


### Hoss D. E., L. E. Clements, and 

# D. R. Colby. 

# 1977. Synergistic effects

of exposure to temperature and chlorine on survival of young- 

## of

## the- year estuarine fishes. 

### Pages 345- 355 in 

### F. J. Vernberg, A. Calabrese, F. P. Thurberg, and 

## W. B. Vernberg (eds. 

# ).

Physiological repsonses of marine biota 

# to pollutants. Academic Press, New 

### York.
Huish , M. 1., and J. 

### P. Geaghan. 

### 1979. A study of adult and 

## juvenile

fishes of the lower Cape Fear River near the 

## Brunswick Steam Electric Plant, 1975- 

# 1976. North Carolina State University, Raleigh NC.


### Ingram, R. L. 

# 1965. Facies maps based on the megascopic 

## examination of

modern sediments. J. Sed. Petrol. 35(3):619- 

### 625.
June, F. C., and 

### J. L. 

## Chamberlin. 

# 1959. The role of the estuary in the

life history and biology of Atlantic 

## menhaden. Pages 41- 45 in 

# P. Idyll 

# (ed). Proceedings of the Gulf and 

## Caribbean Fisheries Institute, 11th Annual Session. Miami Beach , FL. 

### Kuntz, A. 

# 1914. The embryology and larval development of Bairdella chrysura and Anchoviamitchilli. 

### Fish. Bull. 33:1- 

### 19.



### 11-

## Lagler 

# , K. F. 1952. Freshwater fishery 

## biology.



# lishers, Dubuque, IA. Wm. C. Brown Co. Pub
## Lawler, J. P., 

# H. Y. Chen, T. L. Englert, and T. B. Vanderbeek.

Mathematical modeling of biological impact on the Cape Fear ary due to operation of the Brunswick Steam Electric Plant. 

### Cape Fear Studies, 

## Volume 

# XX. Lawler, Matusky, & Skelly neers, Pear 1 River, NY. 

### 1980.

## EstuBSEP
E ng i -

McCoy, E. G., and J. T. 

# Brown. 

# 1967. Migration and growth of 

### commercial 

# penaeid shrimps in 

### North Carolina. N. 

# C. Dept. of 

# Natural and Economic Resources, Division of Commercial and Sports 

## Fisheries. Raleigh , Nc. 

### McGroddy, P. M., and 

# R. L. Wyman. 

# 1977. Efficiency of nets and a new

device for sampling 

# living fish larvae. J. Fish. Res. Board 

### Can. 

## 34:571- 574. McHugh 

### , J. 

# L. 1967. Estuarine nekton. Pages 581- 620 in 

# G. H. Lauff 

## (ed). Estuaries. Am. Assoc. Ad. Sci. 

### No. 83. Washington, DC. McKensie, M. D., J. Whitaker , C. Bearden, D. Theiling, D. Ligo, R. Rhodes,

E. Schroeder 

### , and 

# K. Swanson. 

# 1981. Profile of the penaeid ~hrimp fishery in 

### the South 

# Atlantic. South Atlantic 

## Fishery Management Council , Charleston , SC. 

## Merriner , J. V. 

# 1973. Assessment of the weakfish 

### resource, a 

## suggested

management plan and 

### aspects of 

# life history in 

## North Carolina. Doctorate thesis. 

## North Carolina State University, Raleigh, Nt. 

# 1976. Aspects of the reproductive biology of the weakfish
Cynocion regalis (Sciaenidae), in North 

# Carolina. Fish. Bull. 74: 

### 18- 

### 26.
Musick 

# , J. L. 1979 Assessment of Georgia 

### shrimp and crab 

## resources.

Georgia Department of Natural Resources, Contributing Serial No. 

### 30.
Norcross, L. B., and R. 

# F. Shaw. 

# 1984. Oceanic and. estuarine 

## transport

of fish eggs and 

### larvae: A 

# review. Am. Fish. Soc. 113:153- 

### 165. 

# Pollard, 

# L. W. 1985. Brunswick Steam Electric Plant, movement of fish



### from the 

## nekton return bas 

# in. Caro 1 i na Power & Light 

### Company. New Hi 11 , NC. 

# Reintjes, J. W. 1969. Synopsis of biological data on the Atlantic menhaden, Brevoortia tyrannus. S. Fish and Wildl. Serv. , Circ. 320.
Rogers, S. G. , T. E. Targett, and S. 

### B. Van Santo 

# 1984. Fish nursery use



### in Georgia salt- 

### marsh estuaries: The influence of 

## springtime freshwater conditions. Trans. Am. Fish. Soc. 113:595- 

### 606.

11-

# Schwartz, F. J., P. Perschbacher 

### L. Davidson 

### K. Sandov 

# J. Tate, M. McAdams, C. Simpson , J. Duncan 

## , and D. Mason. 1979. An 

## ecological study of fishes and invertebrate macrofauna utilizing the 

## Cape Fear River estuary, Carol ina Beach Inlet, and adjacent Atlan

### tic Ocean, 

# 1978. BSEP Cape Fear Studies, Volume 

# XV. Report to Carolina Power & 

### Light Company. Institute of 

## Marine Sciences. 

## University of North Carolina, Morehead City, NC. 

### Stickney, R. 

# R. 

# 1983. Care and handling of 

### live fish. 

### Pages 85- 94 

# L. A. Nielson and 

# D. L. Johnson 

# (eds). Fisheries techniques. American Fisheries Society, Blacksburg, VA. 

# Street, M. 1985. Status of North Carolina 

### commerical catch. Tar Heel 

# Coast. Vol. 20, No. 

# 1. North Carolina Division of Marine Fisher- 

# i es. Department of Natural Resources and Community 

### Development, Morehead City, NC. 

# Taft III , E. P., T. J. Horst, and J. K. 

## Downing. 

# 1981. Biological evalu- 

# ation of a fine- mesh traveling screen for protecting 

## organisms. Pages 159- 168 in 

### P. B. Dorn and J. T. Johnson 

# (eds). Proceedings of the workshop of advanced intake 

### technology. San Diego, CA.

Wang, J. C. 5., 

## and R. J. Kernehan. 

# 1979. Fishes of the Delaware estuar

### ies: A guide to the early life 

# histories. Ecological Analysts, 

## Inc. , Towson , MD. 

### Weinstein, M. P. 

# 1979a. Larval retention study, Cape Fear River , 1978.



### BSEP Cape Fear Studies, Volume 

### X. Lawler , Matusky & Skelly Engineers, Pear 1 River , NY. 

# 1979b. Shallow marsh habitats 

### as primary 

## nurseries for 

# fishes and shellfish, Cape Fear River , North 

# Carolina. Fish. Bull. 77:339- 

### 357. Weinstein, M. P., 

# S. L. Weiss, 

# R. G. Hodson, and L. 

# R. 

# Gerry. 1979.

Retention of 

### three taxa of 

# postlarval fishes in 

## an intensively flushed tidal 

### estuary, Cape Fear 

# River, North Carolina. 

## Fish. Bull. 78:419- 

### 436. 

## Weinstein , M. P., S. 

### L. Weiss, and M. F. Walters. 

# 1980. Multiple deter

### minants of community structure 

### in shallow marsh habitats, Cape 

## Fear Estuary, NC. Mar. Biol. 58:227- 

### 243.

11-APPEND IX A

BRUNSWICK STEAM ELECTRIC PLANT
INTAKE MODIFICATIONS AND FLOW MINIMIZATION

DIVERSION STRUCTURE


## The 4. km intake canal intersects Walden Creek in the area of Snow ' 

# Marsh. In the fall of 1982, a diversion structure was installed at the 

### mouth of the intake canal where it intersects Walden Creek (Figure A- 

## 1). 

# This structure was intended to prevent juvenile 

### and adult fish 

### from entering the canal and thus reduce 

### impingement.

The diversion structure consists of concrete pilings driven into the bottom across the mouth of the 

# canal. The entire device was constructed 

# in a V-shape with the 

### apex pointing away from the plant so 

# that tidal flushing would 

### keep the screening relatively 

# clean. In the event 

## that trash became impinged on the 

### screens, it would wash off at the 

## change of 

# the tide.

Panels are 

## constructed of 9. 4-mm mesh copper-nickel screens mounted
on copper- 

# nickel 

# frames. Sheet metal pilings with 

## cathodic protection
extend the full length of the diversion structure and provide relief from 

# underwashing. Vertical guideways that 

### allow the installation of two 

### screens, one directly 

### behind the other, extend upward 

### from the 

## sheet piling to a walkway that 

### extends the full 

### length of the structure. 

### The walkway allows 

### access to each screen and facilitates their removal for 

### cleaning or 

# replacement. Because impingement of 

## organisms and trash
aga i nst the screens presents a prob 

### 1 em, the daub 

## e-screen system is u sefu 1 as it allows one panel to always be in place while the other is pulled up for cleaning or maintenance.

### FINE- MESH SCREENS



### In June of 

## 1983, fine-mesh (1-mm) polyester screens were placed over two of the four 9. 

### mm intake traveling screens on each 

# unit. The NPDES 

# permit requires that 

# these screens be 

### run at all 

# times. Except for periods when detritus loading, drive chain, or pump problems prevented the operation of these screens, this was the case.


## The flow- minimization regime resulted in only fine- mesh screens being 

### run during those periods when the intake water temperature was less than 65O 

## F as a five- day average. When the water temperature was greater than 65O F, two fine-mesh and one 9. mm screens were operated.

The effectiveness of fine- mesh traveling screens in reducing entrain

## ment is discussed in Section 7.

FLOW MINIMIZATION



### Tables A- 

### and A- 

# present 

# the flow-minimization regime from June 1, 1981, through the permit expiration date. Prior to this time, the 

### cooling-water flow was approximately 1105 cfsjunit except the period May through October when the flow was 1205 cfsjunit.Cool ing 

### water flow (cubic feet per second)/unit for the BSEP from June 1, 1981 through June 30, 1983.



### Flow 

## Intake water temperature 1 es s 

## than
65O F as a 5- day average 

### Reactor power 1 eve 1 40% or greater Reactor power level less than 40% for 48 hours or more 

### 915

605

Intake water temperature between 65O F and 85O as a 5- day average 

### Reactor power 1 eve 1 40% or greater 

### Reactor power 1 eve 1 1 es s than 40% for 48 hours or more 

### 915

605

Intake water temperature 85O F or greater 

### Reactor power evel 40% or greater 

### Reactor power 1 eve 1 1 es s than 40% for 48 hours or more 

### 1105



### 835

### Cooling water flow (cubic feet per second)/unit for the BSEP from



## July 1, 1983 through the permit expiration date.



### Flow 

## Intake water temperature ess than 

### 6so F as a 5- day average 

### 605

Reactor power 

### 1 eve 1 40% or greater Reactor power level less than 40% for 48 hours or more 

### 605

400

Intake water temperature between 65O F and 85O
as a 5- day average

Reactor power level 40% or greater Reactor power level less than 40% for 48 hours or more 

### 915

605

Intake water temperature 8so F or greater

Reactor power evel 40% or greater Reactor power level less than 40% for 48 hours or more 

### 1105



### 835ACCESS ROAD:PFigure A-Location of diversion structure, sluiceways, and return basin at the Brunswick Steam Electric Plant.APPENDIX B

STATISTICAL EXPLANATION OF TIME- SERIES AND

MULTIVARIATE ANALYSES

DATA TRANSFORMATIONS 

# Fisheries and environmental data can be considered as collected on several levels: sample, replication, space, and 

# time. For many statisti

## ca 1 ana lyses , the data were accumu 1 ated 

### over one or more of the above 

## levels and a " mean 

# 'l calculated to represent the distribution of values. 

# The distribution of 

### numbers at any collection 

### level tends to be 

### skewed toward the lower ranges of 

# values. Application of 

# the In(X+1) transformation to individual samples 

### helps to normalize the base 

## data. This transformation was applied to the 

## lowest collection level , the sam

### ple, to ensure that distributional parameters calculated at higher 

## levels would still maintain the assumptions of normality (means of normally di~- 

# tributed data will be normal). Calculation of means across 

## several levels of collection will further stabilize the normality 

### assumptions. The 

### above procedure was applied to all data before time- series or multivariate analyses were performed.


# II. TIME- SERIES MODEL

Form of the Mode

The concept of 

## independent error terms inherent in typ i ca 1 

### regres s ion techniques are often violated in the analysis of 

### environmental data. 

### Most general linear models (GLM) assume that the observations within a singledata series measured at fixed intervals of time are statistically indepen

# dent. Time correlations of data occur when an observation at some present time can be predicted from past values of the same 

# series. Application of strictly linear models to this data will typically violate the assumptionsof independence and can lead to an 

## invalid predictive model. Data exhibiting consistent 

### measurable cycles 

# over time are 

## considered periodic. Trigometric functions are easily used to approximate periodic behavior. 

## function obeying sine- cosine type periodicity is specified as follows:

f(t) = A sin (At +



### where: = amp 

## itude

= frequency, the number of times the function repeats itself in a period of length 2n

= time = phase angle, determines the points (- ~ plus integer values of ~) where the function is 

## zero.

Using standard trigonometric identities, a more useful paramaterization is written:

f(t) = B 1 cos At + B 2 sin At


### where: 

## 1 = A siM

2 = A cos~ 

# Based 

# on 

# the above 

## developed as follows: 

## relationship, GLM time-series model was 

# ' = y, + r ' COS (2~t/P ) + B 

## Sin (2~t/P, ) + E 

# j=l 'J

= 1 to the number of years of data (N) 

### where:



### k = the number of periodicities selected to fit all years 

# P = periodicity (= 2~/A)

### The total number of terms in 

### the model is 

## N+(N*k)+1. 

# The model

requires a data series measured at equally spaced intervals of time with a 

## constant number of observat ions per year. Res i dua 1 s 

## from the correct selected model will be independent and normally distributed , exhibiting no 

## testable periodicity.
The time-series model paramaterization does not allow the 

## inclusion of an 

# intercept term. Therefore, the correlation of determination (R 

### reported in this report has been 

### reformulated. The model and total sums 

### of squares (reported R 

### 2 numerator and denominator, respectively) are not 

### adjusted for 

### the mean of the 

### dependent variable. The result is an R 

### which is 

# slightly inflated over 

# the standard formulation of R 

### comparison of 

# the two formulations of R 

### resulted in 

### an R 

### 2 of 0.
(standard value) and 0. 

## 88 (reported value).
Model Advantages



### The funct i ona 1 form 

### of the above mode 1 allows for ana lys is 

### of the 

## following: 

# Statistical testing of selected periodicities within each 

## year.

Comparisons of s~lected periodicity effects between years.

Comparisons of year level terms (Y i) between years.



### Abundance measurements of most fish species under study in this report vary in number or density and distribution between 

### years. Therefore calculation of a mean value based on a yearly sampling protocol is highly 

### dependent upon distributional 

# constraints imposed by changing spawning times, year-class abundance, and temperature and salinity differences over 

# time. Comparisons of these means between years may not be good indicators 

# of fish abundance or year-class 

# strength. The year- level terms in 

## the 

# time-series model serve as a 

# yearly indication of abundance after adjusting for environmental effects which impose selective periodicities on

### the distribution of fish. Year- level terms in the 

### model are 

### comparable

with each other but are not comparable to yearly mean densities reported 

# in the 

# text. Sta tis t i ca 

## test i ng 

# of the presence or 

## absence of 

# significant periodicty between years 

### provides a 

# testable means for biological or environmental interpretation.

Ana lys i s 

## Steps

Development and 

### evaluation of any time-series model proceeded with 

## the following steps:

Spectral analysis of the In(X+1) data including statistical tests for periodicity.



### Selection of dominant or " 

## most explainable " periodicities based on the results of (1) above.

Fitting the time- series model.

Fitting the time~ series model without the year- level terms 

## (but including an intercept).

Spectral analysis of the residuals from (3) 

## above, including statistical tests for periodicity, to evaluate model fit and residual assumptions.

Linear regression on the residuals of (4) above to test for significant linear trends over time. 

# Most species of 

# fish were initially 

# fit with 

# 1- and 6- month 

# periodicities. In most cases, this model fit well and met the assumptions 

# of independent and random mode 

### 1 errors. However, in those cases when other periodicities were dominant and explainable or the error assumptions were violated, the model was rerun using a second set of selected period

# icities.Spectra 1 Ana 1 ys

Spectral analysis techniques are used to define the periodicities for model formulation as well as testing 

### model residuals. In spectral analy

### sis! the fourier 

### transform is used to decompose the data into sine and cosine waves of different ampl itudes and wavelengths:



## X(t) = (a 

# /2) + E (a k COS w t + b k Sin w



### k=l 

### where: X(t) = data at time t (t = 1 

# . .

. N)



## = N/2 (even N) or (N- l)/2 (odd N) = number of periodicities 

### which are determi ned

2X (set to zero for analyses in this report)


## = cosine coefficients
= sine coefficients

21T kIN

The periodogram ordinate is defined 

## as:

k = N (a 2 + b 

## )/2

and represents the sums of squares for each of m frequenc 

# i es. Select i on of those frequencies with the greatest periodogram ordinates for inclusion into the model will result in the best 

### model fits. The larger periodogram 

## ordinates also represent the most important biological and 

## environmental 

# frequencies. The distribution of periodogram ordinates for data or resid

# uals with no periodicity will be 

### relatively flat. Fisher s Kappa and 

## Bartlett' s Kolmogorov- Smirnov statistics were used for statistically testing the presence or absence of periodicities in both the data and resid

# uals. Application of these tests to model residuals was used to test for the assumption of residual independence.Linear Trends



### After application of the properly constructed time-series model, the 

### model residuals 

# will generally show 

# no significant 

# periodicities (as tested by Fisher s Kappa and Kolmogorov- 

### Smirnov statistics). 

## Linear regression can then be applie~ to these residuals without violation of the 

### standard error 

# assumptions. The year- level terms are 

## removed from the standard model to allow for trends over time (otherwise, the slopes would 

### always be 

# flat). The regression results 

### provide a statistical test for significant linear increases or decreases across all years. 

# III. MULTIVARIATE ANALYSES

Overvi ew

The multivariate analyses presented in this report are a composite of principal component 

# analysis, correlation analysis, cluster analysis, and 

# graphical techniques coupled with comprehensive biological 

## interpreta

# tion. Principal component analysis (PCA) is a multivariate technique for examining the relationship among quantitative 

# variables. The effect of a 

### PCA analysis 

### is to take a 

# location by species matrix of mean 

### In(X+1) values and reduce it into a location by component matrix where the number of components is smaller than the number of spec 

# i es. Each component has 

# an associated eigenvalue giving the 

### amount of 

# variation 

# in species accounted for by the component and an eigenvector giving the weighting of 

### each species on the 

## component. The eigenvectors are orthogonal , so the 

### principal components 

### represent jointly perpendicular directions through 

### space of 

# the original 

# variables. Successive components 

## account for 

# unique, progressively 

# smaller portions of 

# the 

# total variation in speci es. Ideally, 2 or 3 components wi 

## 11 account for the majori ty of the 

### variation in species 

### contained in the 

# original data matrix. Correlation 

## analysis can be used to measure the amount of association of a 

## species with a component. Those species that vary widely over locations can have 

### high positive or negative correlations with the 

# components. Note that 

# high correlations are dependent upon geographic distribution 

# and not magnitude of 

# abundance. Principal components can be 

## computed from a

### variety of matrix transformations including the sum of square and cross



# products, covariance, and correlation 

# matrices. In this report, the 

## correlation matrix was uti 

# ized. The effect was to adjust each species by 

### its mean and 

## standard deviation , thus eliminating species magnitude and variance as a measure of importance. 

# The multivariate analyses proceeded as indicated in the 

## following outl i ne:

Development of a 

# location by species matrix where the number of speci es is 

### 1 ess than or 

### equal to the 

## number of 

## locations.

Development of a 

## " location by environmental indicator 

### (temperature, sal inity, grain size) matrix.

PCA of (1) above, producing a location by component matrix.



### Correlation of individual species from (1) above with each 

### component.

Correlation of individual environmental indicators from 

### (2) above with each component.

Cluster analysis of (1) 

### above.

Bivariate plot of component scores plotting locations with 

### species and environmental indicators as axis labels; also on the plot is an overlay of the cluster results.

Interpretat ion

Interrelations of locations as defined by multivariate distributions 

# of species can be examined by 

# bivariate plots of each location on the scores of the first two principal 

### components. The score of a location on 

### a component 

### is the sum of the products of the transformed abundance of

### each species times its 

### corresponding eigenvector. Locations with similar



## species associations wi 11 form a cluster on this 

# graph. Cluster analysis 

### of the original location by 

## species matrix , with squared euclidean dis

### tance as a measure of 

# interlocation similarity, was also used to help 

# identify location groupings. Although cluster and PCA analysis are very different techni 

### ques, concordance among the resu ts strengthens the 

## i nterpretation of the 

# data. Biological and environmental gradients along the 

### components were exami ned with Spearman 

### s rank 

### corre 1 at 

## i on coeffi ci ents. Variation along the component is related to those species and environmental indicators with high positive or negative correlations with that com

# ponent. Environmental indicators were 

# standardized to mean 

# zero and 

# standard deviation one before correlation 

### analysis. It is important to 

### note that the correlations test linear relationships between 

## variables. The assumption of linearity between biological and environmental variables 

### is usually 

### not met which affects significance testing of the 

## correlation. However , the relative level of the correlation is an indication of variable relationship and creates a basis for further 

# biological interpre

# tation.

The final 

### step in 

# the multivariate analysis is 

# the comprehensive biological interpretation. PCA, correlation, and cluster analysis serve 

### to define the geographical 

### gradients of species and 

## environmental variables. However , the biological and 

## ecological evaluation of these relationships is left to the 

## individual analyst.APPENDIX C

RIVER LARVAL FISH AND TUCKER TRAWL
GEAR COMPARISON STUDY

INTRODUCTION



### The river larval fish (RLF) program utilized only surface and bottom 

## samples (Section 3. 0) to assess river 

### larvae densities. 

## The discrete 

# depth (DO) sampling program (Section 4. 

# 0) utilizes a Tucker trawl and 

### bottom sled to 

### sample the 6 or 7 different depths over the water column 

### , 3, 5 

### , 7, 9, and 11 

# m). In order to determine which method 

## provided the best estimate of 

# larval densities, a special study was conducted to 

### compare larval 

### fish densities using RLF gear 

### and DD trawl gear 

## simultaneou s ly.

METHODS

Sample Collection



### The samples were taken at 

### Tucker trawl Station 34 for one 

### complete 

# tide (approximately 12. 

# hours) on two separate nights (April 7- 

### and April 9- 

### , 1984). At the start of each tidal stage , surface and bottom larval fish samples were taken, followed immediately by a complete set 

## (1, 

# 3, 5, 7, 9, and 11 m) of DO trawl samples, followed by another set of 

### surface and bottom larval 

# fish sample. This same sample scheme was re

### peated through each of 

# the 8 tidal 

# stages: high slack, high out, mean 

## out , low out, low slack, low in , mean in, and high 

## in.

The collection gear and sample preservation was the same used in the 

### regular RLF and DO 

## sampling programs. For further discussion , see CP&L 

### (1983) .

### Data Analysis

Since the objective was to determine if there was a significant difference in the densities estimated by the two gear 

# types, a paired t- 

# test was conducted to 

### see if the two 

### means (determi ned by each gear) were 

# equal. The t- tests were performed on loge 

### transformed densities. Results 

# are presented at the P 2 0. 05 significance level.

RESULTS AND DISCUSS ION 

# Paired t- test results by round and with rounds combined (Table C

### showed mixed results. Salinities may have had some effect on the results as they were lower during Round 1 than Round 2 (Figure C- 

## 13).
Clupeidae

Clupeidae in Round 

### 1 showed a significant difference between gears 

# with RLF catching 

### higher densities. RLF surface nets 

# caught higher densities than DO trawls, and both bottom nets caught similar 

## densities 

# with the 3- , 5- 

### , and 7-m depths falling far 

### below the 

# straight line between surface and bottom (Figure C- 

# 2). Comparisons by tidal stages also 

### followed the same pattern throughout the 

### eight tidal 

# stages (Figure 

# 3). Past studies have shown that 

## clupei ds tend to move to the surface 

# at night, so the curve for the DO 

### trawl is quite representative of the larval distribution of Clupeidae for 

### all depths except the 

# surface. The 

### RLF gear actually samp 1 ed 

# the surf ace, whereas the 

### DD trawl samp 1 ed 

### 1 meter below the 

# surface; therefore, the DO 

# trawl gear showed lower 

# densities. Round 2 data showed no significant difference between gear 

### types but an examination of the density plots (Figure C- 

### 2) show much the 

### same pattern as Round 1 for the upper half of the water column , but the lower half of the water column was a different pattern. The OD trawl gear 

## caught more larvae in 

# the bottom half of the water column , thereby ba 1 

## anci ng out the compari son.When results of both rounds were combined. the data showed a signifi

## cant difference between gears, with 

### the pattern the 

### same as 

## shown for Round 1. Mean densities of RLF were similar for both rounds, but DO trawl mean densities were lower in Round 1 than Round



### Croaker

Croaker in 

## Round showed no 

# significant difference between gear types but an examination of the plots by tide and round show the DO 

## trawl gear caught more larvae at most depths (Table C- , Figures C- 5 and C- 

## 6).

Round 2 croaker data 

### showed a significant difference between gear types with the DO trawl gear again having higher densities, although both gear types caught higher mean densities than in Round 1 (Figure C- 

# 5).
examining the comparisons by 

### tidal stage (Figure C- 6). they followed the same pattern as the 

# overall round. With salinity at zero, there were no 

### croaker present but as the sal inities 

### increased (at the 

# bottom of the water column) densities increased, thereby weighting the bottom densities 

### of DD 

# trawl gear. The same was true in Round 2 to a greater degree as salinities were slightly higher . so densities at the bottom portion of the water column increased proportionally.



### When both rounds were combined 

### , the data 

### showed a 

# significant dif-:- Ference between gear types (Figure C- 

### 4) with DO 

### trawl gear showing much higher densities at the bottom of the water column (7 , 9 and 11 m) during both rounds.


### Spot

Spot showed no significant difference between gear types in either Round 1 . Round 2 

### , or combined rounds (Table C- 

# 1). The density by tidal stage and round show the larval fish gear collected higher 

# densities at
the surface and the DO trawl gear collected higher densities at the bottom (Figures C- , C- 8, and C- 

## 9).Total Fish



### Total fish 

### in Round 1 showed a significant difference between gear 

### types with RLF catching higher densities (Table C- , Figure 11). 

## This was explained by the fact that clupeids were the most 

## abundant species caught, so total fish results were 

## heavily weighted by Clupeidae (Table 

# 1). Plots by round and tidal 

### stages of total fish (Figures C- ll and 

### 12) and Clupeidae (Figures and C- 

### 3) showed the same patterns for 

# both. Combined round results were again like 

## Clupeidae, showing no significant difference between gear types (Table Figure C- 

## 10).

SUMMARY



### Allen et ale (1959) summarized many other studies in which efficiencies of various gears were 

## compared. The overall conclusions to be drawn 

## from their rev; ew are:

Most gears do not capture all fish exposed to them.



### The proportion of the vulne;,rable fish 

### captured by the gear may not be consistent and certainly varies by species.



### As a consequence, absolute 

### abundance data cannot be obtained from monitoring surveys with most sampl ing gear.

In looking at the overall results of the t- test, it is apparent that 

### the RLF sampling technique, of 

### sampling just 

# surface and bottom, did an 

### adequate job of gathering information for estimating densities of 

## larval fish in the water 

### column. It is also apparent that the RLF surface nets 

### were more efficient at sampl ing 

### the surface than the DO 

# trawl. On the 

# other hand, it appears that the DD 

# trawl sled was more efficient at sampling the 

### bottom; but when the results are 

### averaged over all 

## species and rounds, there was no significant difference in gear 

## types.Table C- Results of paired t- 

### test on 

## larval 

## densities co 11 

## ected in the gear comparison study conducted during 

### 1984. 

### Standard Error Taxon Round Mean of Mean 

### PR 

## )0 It! 

## Difference Clupeids 1.174 270 

### 003 

## Clupeids 079 O. 301 O. 80 1 

### Croaker 546 

### 334 

### 1.63 146 

### Croaker 1.023 323 

### 016 

### Spot . 1 

### 229 

### 352 535 

### Spot 141 

### 351 O. 699 

## Total 878 252 

### 010 

## Total 0 . 004 

### 323 

### 992 

## Clupeids 1 & 2 

### 627 

### 241 

### 020 

### Croaker 1 & 2 

### 784 

### 233 

### 004 +**



### Spot 1 & 2 

### 044 

### 245 

### 860 

## Total 1 & 2 

### 437 

### 228 

## 1.92 075

Not significant -
01 " " 0. 0 . 00 1 " P " 0.
P " 0. 

### 001 Indicates discrete depth mean ln (density + Indicates discrete depth mean ln (density + 

## P ;. 0. ***

mean In(density + 

### 1) " river larval fish



### mean In(density + 

# 1) )0 river larval fishDEPTH 1m)Figure CoLARVAL FISH GEAR~ /4 4.6 4.8 5.MEAN LOGe (DENSITY +1)Clupeid density profiles for the gear comparison stud ywithrounds combined, April 7-, 1984.DEPTH (m)
ra!

133

137

DEPTH (m) 

### rat J 

## 93 1

rae; ~ 

### " t

1 1

Figure CROUND '" 1

LARVAL FISH GEAR



# -4

e; MEAN LOG e (DENSITY +1)

ROUND '" 2

LARVAL FISH GEAR

lJ



# I" "'" 0""'"'"' 

# "" ",..

I""'"'" 0""""""" 

### 0"" . .. . .. I"'" ."".



# -4

MEAN LOG e (DENSITY +1)



### Clupeid density profiles for the gear comparison study showing rounds 1 and 2 

### , April 7- 

# 10, 1984.3 ~-------::. .B 11,...B 11B 11811DEPTH 1m)Tidal StageLO = LowoutMI c MidLS = LowSlack MO = MidoutLI = LowClupeid density profiles for the gear comparison study by tidal stage, April 7-, 1984.+:0+:::0 '+ - - += TUCKER TRAWLx - - x= LARVALFISH GEAR. MEAN OF REPS0 = LARVALFISH GEAR. INDIVIDUAL REPFigure CLO',...! 0"t0 '+,.- 0: ~f.+.-o"-'---oto 0---0 0j.-fe'"'to oMEAN LOGe (DENSITY +1)HO =High outHS =High slackHI =High In\,0DEPTH (m)e 1LARVAL FISH GEARTUCKER TRAWL11, S, ', "." ',',. '." "'" "'" "'" ,."" "" ,6. BFigure C1.91. 52. B~. 04. SMEAN LOGe (DENSITY +11Croaker density profiles for the gear comparison study with rounds combined, April 7-, 1984.ROUND = 1 DEPTH 1m)

9:3

137

1 1 

# ;3 

# ...

MEAN LOG e (DENSITY +11

ROUND = 2
DEPTH 1m)

1211 

# ~ "'" "'"

1213

1215 TUCKER TRAWL

LARVAL FISH GEAR ""' 

### "'" "'"

1217

1219 

## ..... ,.. .... ... 

# ,......... ,......... 

# ,.........



# :3 

# ...

MEAN LOG e (DENSITY +1)

Figure C- 

### Croaker density proIt1es for the gear comparison study showing rounds

1 and 2, April 7- 10, 1984.DEPTH 1m)LS .B 11HSHO ~/-. -- *'--:1--- ---+B 11'+-+x 0......B 11:T '-..:-+"+ ""1-.0 "B 11I .I .I .I .I '+ - - += TUCKER TRAWLMEAN LOGe (DENSITY +1)Tidal Stagex- - x =LARVAL FISH GEAR - MEAN OF REPSLO = LowoutMI = MidHO =High out0 = LARVALFISH GEAR - INDIVIDUAL REPLS = LowslackMO = Mid outHS =High slack= LowHI =High inFigureCroaker density profiles for the gear comparison study by tidal stage, April 7-, ) 984.DEPTH 1m)f--'f13f1STUCKER TRAWL2. (1Figure Ci;:LARVAL FISH GEAR6 4.MEAN LOGe (DENSITY +11Spot density profiles for the gear comparison study with rounds combined, April 7-, 1984.DEPTH Iml

ge;

Ii!JS

1 1

DEPTH 1m)

a 1

Figure CROUND'" 1

i LARVAL FISH GEAR 

## ,... .. ,." .... 

# ,....,.... "..... "' 

# "."....",'"."., ....... ,.'

MEAN LOG " (DENSITY +11

ROUND = 2

TUCKER TRAWL

MEAN LOG (DENSITY +1)



### Spot density prof'tles for the gear comparison study showing rounds 1 and 2 

### , April 7- 10, 1984.DEPTH (m)LS ILIB 11:'\t\1 HO-- /---- -- + ,"""",,+8 110 o"i-00"iLO . ~LS '......-:::- +..,..:+,~:t"1-B 110 '+HS r0 .B 11c0J.Tidal StagLO = LowoutMI '"Mid inLS = Lowslack MO =Mid outLI = LQWSpot density profiles for the gear comparison study by tidal stage, April 7-, 1984.+- -... =TUCKER TRAWLx - - x= LARVAL FISH GEAR - MEAN OF REPS0 = LARVALFISH GEAR - INDIVIDUAL REPMEAN LOGe (DENSITY +11HO =High outHS =High slackHI =High inFigure C-.......U"1DEPTH 1m!1J9LARVAL FISH GEARl..-/1'155. GMEAN LOGe (DENSITY +1)Figure C-IO. Total fishdensity profiles for the gear comparison study with rounds combined, April 7-10, 1984.DEPTH (m)



### ,!t

1 I LARVAL FISH GEAR



# IS

MEAN LOG e (DENSITY +1)

DEPTH 1m)

137

1 I TUCKER TRAWL 

# .",..., .'"., 

# ""...,.."



# I;

MEAN LOG e (DENSITY +1)

Figure C- 

### 11. Total fISh 

### density pror1les for the gear comparison study showing rounds

1 and 2, April 7- 

### , 1984.I--'-....JDEPTH 1m)B 11B 11B 11 .B 11--------:+: 0-1----:~0-.."+........Z\+-- + = TUCKERTRAWL)( --)( =LARVAL FISH GEAR - MEAN OF REPS0 = LARVAL, FISHGEAR - INDIVIDUAL REP0 o"""0 '++.......-it1o-+0""""f-.o~o~'-..-f--11 2Tidal StageLO = LowoutLS = LowslackLI = LowMEAN LOGe (DENSITY +1)()MI = MidMO"Mid outFigure C-12. Total fishdensity profiles for the gear comparison study by tidal stage, April 7-10, 1984.HO =High outHS =High slackHI =HighinDEPTH 1m)LO .LS .B 11 -1 -5 -I '+7 -! \B 1'......+ ":,-.......B 11. ~-..........-..":,-B 111 Ii)1 (i)3 EJ(i)113213413Tidal StageLO "" Low outMI = MidinHO =High outLS = LowslackMO = Mid outHS =High slackLI = LowInHI =High inFigure C-13. Salinityprofiles by tidal stage during the gear comparison study, April 7-, 1984.MEAN LOGe (DENSITY +1)