Assessment of American Assessment of American Shad Shad
((Alosa sapidissimaAlosa sapidissima) in the ) in the Cape Fear River at Cape Fear River at
Lock & Dam #1Lock & Dam #1
Theresa CeliaTheresa Celia
Picture by Robert Michelson
Introduction
Range: Range: St Lawrence River, Canada to the St. Johns River, FloridaSt Lawrence River, Canada to the St. Johns River, Florida
Size: Size: Largest Atlantic coast ClupeidLargest Atlantic coast Clupeid 20-24 inches20-24 inches Largest at ~30 inchesLargest at ~30 inches
Sexual maturity: Sexual maturity: Males – 3-4 yearsMales – 3-4 years Females – 4-6 yearsFemales – 4-6 years
NCDMF
AnadromousAnadromous Begin migration at temperatures between 10 Begin migration at temperatures between 10 ooC C
and 15 and 15 ooCC High, stable, high quality flow of waterHigh, stable, high quality flow of water Latitudinal cline in post spawning survivalLatitudinal cline in post spawning survival
South of NC – semelparous – spawns onceSouth of NC – semelparous – spawns once North of NC – iteroparous – spawns two or North of NC – iteroparous – spawns two or
more timesmore times
Spawning Migration
Shad Fishery
Historically the most valuable fishery in NC in Historically the most valuable fishery in NC in the 19the 19thth & 20 & 20thth centuries centuries
Since 1800’s, NC consistently ranked highest Since 1800’s, NC consistently ranked highest of commercial landings along the east coastof commercial landings along the east coast
Declined by early 1900’sDeclined by early 1900’s OverfishingOverfishing Construction of damsConstruction of dams Habitat degradation in spawning areasHabitat degradation in spawning areas pollutionpollution
Commercial landingsCommercial landings 468,484 lbs ($111,609) in 1972 – 131,621 lbs 468,484 lbs ($111,609) in 1972 – 131,621 lbs
(108,142) in 1999(108,142) in 1999 Cape Fear River – 66,968 lbs in 1972 – 6,804 in Cape Fear River – 66,968 lbs in 1972 – 6,804 in
19991999
Dams
Obstruct migrationObstruct migration Limit access to a diversity of habitatsLimit access to a diversity of habitats Fragment habitatFragment habitat
Quaker Neck Dam
Located on the Neuse River, NCLocated on the Neuse River, NC Prior to its removalPrior to its removal Beasley and Hightower, 2000Beasley and Hightower, 2000 Implanted sonic transmitters in American Implanted sonic transmitters in American
shad and striped bassshad and striped bass Of 13 striped bass and 8 American shad, Of 13 striped bass and 8 American shad,
only 3 striped bass passed over the dam only 3 striped bass passed over the dam while submergedwhile submerged
Quaker Neck Dam
After its removalAfter its removal Bowman and Hightower, 2001Bowman and Hightower, 2001
12 of 22 American shad and 15 of 23 12 of 22 American shad and 15 of 23 striped bass with transmitters migrated striped bass with transmitters migrated upstream of former dam siteupstream of former dam site
Quaker Neck Dam After its removalAfter its removal Burdick and Hightower, 2006Burdick and Hightower, 2006 Sampled eggs and larvae Sampled eggs and larvae
American shadAmerican shadhickory shad hickory shad striped bassstriped bass
Increase in the distribution of spawning activity Increase in the distribution of spawning activity Substantial upstream expansion for American Substantial upstream expansion for American
shad spawning activity relative to the spawning shad spawning activity relative to the spawning area before the dam was removedarea before the dam was removed
Management Plan
ASMFC (1999)ASMFC (1999) Fishery management planFishery management plan
American shadAmerican shadRiver herringRiver herring
Five-year phase-out of ocean fisheryFive-year phase-out of ocean fishery Each state required to develop a recovery Each state required to develop a recovery
plan for each stock under restorationplan for each stock under restoration
Management Plan
NCDMF (2005)NCDMF (2005) Eliminated fishing of American shad in Eliminated fishing of American shad in
the Atlantic Oceanthe Atlantic Ocean In 1995, a closed season was established In 1995, a closed season was established
for American shad for American shad April 15 through January 1April 15 through January 1
Study AreaLock and Dam #1
Location:Location: Cape Fear River in Bladen County, North CarolinaCape Fear River in Bladen County, North Carolina
Built:Built: 19151915 Aid waterborne navigation from Navassa to Fayetteville, NCAid waterborne navigation from Navassa to Fayetteville, NC
Lock & Dam #1
Picture by Theresa Celia
Modifications to Lock and Dam #1
March 1997 (Moser & March 1997 (Moser & Hall, 1996)Hall, 1996) Fish locking Fish locking
procedure modifiedprocedure modified Lower lock gatesLower lock gates Retain fish longerRetain fish longer
April 8, 1996, a April 8, 1996, a Steeppass Denil fishway Steeppass Denil fishway installedinstalled Ineffective in getting Ineffective in getting
fish past the damfish past the damPicture by Theresa Celia
Picture by Theresa Celia
Field Methods
March 6 – April 10, 2007March 6 – April 10, 2007 Measured (mm)Measured (mm)
Fork & total lengthFork & total length
Picture by Theresa Celia
Field Methods Cont’
Weighed (kg)Weighed (kg) Homs, model 10 Homs, model 10
scalescale
Picture by Theresa Celia
Field Methods Cont’
Sex determinationSex determination Removal of scalesRemoval of scales
Age determinationAge determination
• Individually labeled envelopsIndividually labeled envelops
• Not analyzed in this studyNot analyzed in this study
Statistical Methods Sex ratioSex ratio
calculated by dividing # calculated by dividing # males by # femalesmales by # females
Tested using a chi-square Tested using a chi-square testtest
CPUECPUE Net Net
# shad / # drifts# shad / # drifts H&LH&L
# shad / hrs fished x # # shad / hrs fished x # anglersanglers
Regression analysis (Proc Regression analysis (Proc GLM)GLM) Evidence of linear trend in CPUEEvidence of linear trend in CPUE
Z transformation Z transformation Standardize CPUE’sStandardize CPUE’s Z = [x-mean (survey)]/ std Z = [x-mean (survey)]/ std
(survey)(survey) Technique used to standardize Technique used to standardize
data sets to zero with a standard data sets to zero with a standard deviation of 1deviation of 1
Dependent data was modeled Dependent data was modeled using a Proc GLM to determine if using a Proc GLM to determine if a linear trend was presenta linear trend was present
Assumption of normalityAssumption of normality
Statistical Methods Cont’
Kolmogorov-Smirnov test (SAS Prox Capability) used to Kolmogorov-Smirnov test (SAS Prox Capability) used to test normalitytest normality Normality was violated for the SEAMAP indexNormality was violated for the SEAMAP index
Often inaccurate at low samplesOften inaccurate at low samples CPUE’s transformed using log (CPUE + 1)CPUE’s transformed using log (CPUE + 1) All indices met criteria for normalityAll indices met criteria for normality
Mean scores analyzed for differences using NPAR1WAY Mean scores analyzed for differences using NPAR1WAY procedureprocedure
Statistical Methods Cont’
Length-weight relationshipLength-weight relationship Determined by the following parameters Determined by the following parameters
a (proportionality constant or intercept)a (proportionality constant or intercept)b (exponent) of the length-weight relationship of b (exponent) of the length-weight relationship of
the form: the form: • W = aLW = aLbb
Logarithmic transformation as follows:Logarithmic transformation as follows: lnW = ln a + b lnLlnW = ln a + b lnL
• a and b are estimated as least squares a and b are estimated as least squares regressionregression
Results & Discussion # females > # males# females > # males Peak commercial fishery Peak commercial fishery
catchcatch Mid MarchMid March
Majority caught in Majority caught in MarchMarch
Peak recreational fishery Peak recreational fishery catchcatch Early March and Early March and
AprilApril Majority caught in Majority caught in
AprilApril
0
10
20
30
40
50
60
70
March April
Year
Nu
mb
er
Commercial Fishery
Recreational Fishery
Sex Ratio Greater # of females caughtGreater # of females caught Significant difference in Significant difference in
gear type and yeargear type and year Commercial – majority Commercial – majority
femalesfemales Recreational – majority Recreational – majority
malesmales Greatest # of shad Greatest # of shad
caught (n = 248) were caught (n = 248) were males in the recreational males in the recreational fishery in 1995fishery in 1995
Lowest # of shad caught Lowest # of shad caught (n = 0) were both males (n = 0) were both males and females in the and females in the recreational fishery in recreational fishery in 20052005
0
50
100
150
200
250
300
1995 1997 1999 2000 2001 2002 2004 2005 2007
Year
Num
ber
Recreation Fishery Males Recreation Fishery Females
Commercial Fishery Males Commercial Fishery Females
Sex Ratio MarchMarch
Low water clarityLow water clarity Some fishermen Some fishermen
threw back males, threw back males, keeping only femaleskeeping only females
Size of nets (5.5” Size of nets (5.5” stretched mesh)stretched mesh)
Females larger than Females larger than malesmales Females more Females more
susceptible to susceptible to capturecapture
Picture by Theresa Celia
Catch Per Unit Effort
20072007 Commercial Commercial
44thth highest highest
Recreational Recreational 33rdrd lowest lowest
Factors contributing to Factors contributing to low CPUE for recreational low CPUE for recreational fishermenfishermen TemperatureTemperature Water level - MarchWater level - March Water clarityWater clarity
Good for commercialGood for commercial Bad for recreationalBad for recreational
• 0 catches - 0 catches - lowered CPUElowered CPUE
InterviewsInterviews March > AprilMarch > April
Catch Per Unit Effort
Commercial fishermen had Commercial fishermen had greater # of years with higher greater # of years with higher CPUE than recreationalCPUE than recreational
2004 - highest CPUE 2004 - highest CPUE Commercial Commercial
(n = 19.70) (n = 19.70) Recreational Recreational
(n = 7.00)(n = 7.00)
2005 – lowest CPUE2005 – lowest CPUE Commercial Commercial
(n = 2.30)(n = 2.30) Recreational Recreational
(n = 0)(n = 0)
Picture by Theresa Celia
Trip Ticket Data of the Commercial Fishery From 1994 - 2006
CPUE – linear CPUE – linear regressionregression Drift gill netsDrift gill nets
Highest in 2003Highest in 2003 Lowest in 1999Lowest in 1999
Set netsSet nets Highest in 2003Highest in 2003 Lowest in 1999Lowest in 1999
Non-parametric TestIndicates No Significant Trend Present in Abundance
RecreationalRecreational Highest (n = 1.00) in 2007Highest (n = 1.00) in 2007
RecreationalRecreational Lowest (n = 0.14) in 1995 and 1997Lowest (n = 0.14) in 1995 and 1997
CommercialCommercial Highest (n = 0.88) in 1996Highest (n = 0.88) in 1996
Commercial Commercial Lowest (n = 0) in 2007Lowest (n = 0) in 2007
# Fish Mean CPUE Mean CPUE Standard Mean Score Mean ScoreYear Measured H&L Net Deviation H&L Net
1995 395 4.88 2.67 1.56 0.14 0.801996 162 4.56 2.85 1.21 0.33 0.881997 154 1.97 3.36 0.98 0.14 0.801999 221 3.60 2.61 0.70 0.39 0.702000 461 5.46 13.28 5.53 0.46 0.612001 174 4.09 4.76 0.47 0.40 0.802002 241 4.33 3.29 0.74 0.30 0.552004 195 7.00 19.70 8.982005 35 2.302007 297 2.25 4.20 1.38 1.00 0.00
Trends In Abundances
Data not documented long enough to see any Data not documented long enough to see any changes in abundanceschanges in abundances
3 – 6 years to mature and migrate back to natal 3 – 6 years to mature and migrate back to natal freshwater rivers to spawnfreshwater rivers to spawn
3 – 6 years for 23 – 6 years for 2ndnd generation to mature and generation to mature and migrate back to natal freshwater rivers to spawnmigrate back to natal freshwater rivers to spawn
Can take 12 years (2 generations) of solid data to Can take 12 years (2 generations) of solid data to sufficiently analyzed and document population sufficiently analyzed and document population abundancesabundances
Mean Length And Weight In 2007
Males Mean LengthMales Mean Length RangeRange
325 mm – 470 mm325 mm – 470 mmMode = 370 mmMode = 370 mm
Males WeightMales Weight RangeRange
0.55 kg – 1.70 kg0.55 kg – 1.70 kgmode = 0.75 kgmode = 0.75 kg
Females Mean LengthFemales Mean Length RangeRange
367 mm – 500 mm367 mm – 500 mmMode = 460 mmMode = 460 mm
Females Mean WeightFemales Mean Weight RangeRange
0.65 – 2.50 kg0.65 – 2.50 kgMode = 1.4 kgMode = 1.4 kg
Length-Weight Relationship Analysis of Covariance Analysis of Covariance
(ANCOVA)(ANCOVA) Significant difference Significant difference
t-test (P < 0.0001)t-test (P < 0.0001) Significant for both Significant for both
regression intercept and regression intercept and regression sloperegression slope
Means:Means:• Some years had Some years had
differences in the differences in the rate of change and rate of change and in other years, shad in other years, shad either started off either started off heavier or lighterheavier or lighter
Y ear; LS M eans
Current effec t: F (7, 1682)= 87.624, p= 0.0000
(Com puted for c ovariates at their m eans )
V ert ic al bars denote 0.95 c onfidenc e intervals
1995 1997 1999 2000 2001 2002 2004 2007
Y ear
-0.1
0.0
0.1
0.2
0.3
0.4
lnW
t
Covariate m eans :lnLen: 6.050822
Y ear; LS M eans
Current effec t: F (7, 1675)= 31.006, p= 0.0000
(Com puted for c ovariates at their m eans )
V ert ic al bars denote 0.95 c onfidenc e intervals
1995 1997 1999 2000 2001 2002 2004 2007
Y ear
-0.1
0.0
0.1
0.2
0.3
0.4
lnW
t
Covariate m eans :lnLen: 6.050822
Water Temperature
Primary factor that triggers migration and Primary factor that triggers migration and spawningspawning
Other factors include:Other factors include: TurbidityTurbidity water velocitywater velocity photoperiodphotoperiod
Enter rivers at temperatures between 10 Enter rivers at temperatures between 10 ooC and C and 15 15 ooCC
Peak spawning at 20 Peak spawning at 20 ooC in NCC in NC
Temperature RangeRange
11.67 11.67 ooC to 20 C to 20 ooCC Commercial Commercial
greatest # shad greatest # shad caught at 12.2 caught at 12.2 ooCC
Recreational Recreational greatest # greatest #
shad shad caught at 20 caught at 20 ooCC
0
20
40
60
80
100
120
140
0 5 10 15 20 25
Temperature
Nu
mb
er
Recreational
Commercial
Trends In Temperature & Catch #
# of shad dropped during days of rough # of shad dropped during days of rough turbulent waterturbulent water
March 18March 18thth – zero catch – zero catch Water temp dropped from 14.4 Water temp dropped from 14.4 ooC to C to
11.67 11.67 ooCC Season started with water temperature at Season started with water temperature at
11.7 11.7 ooC with 42 catchesC with 42 catches
Trends In Temperature & Catch #
This study indicates that there is no trend with # of This study indicates that there is no trend with # of shad caught and temperatureshad caught and temperature
Regardless of temperature, some days the catch Regardless of temperature, some days the catch was high with a low # of interviews, and other was high with a low # of interviews, and other days the catch was low with a low number of days the catch was low with a low number of interviewsinterviews
Correlation did occur with the # of shad caught Correlation did occur with the # of shad caught and other environmental factors such as rough, and other environmental factors such as rough, murky and turbulent watermurky and turbulent water
Trends with temperature and catch # may require a Trends with temperature and catch # may require a longer period of time to accurately analyzelonger period of time to accurately analyze
I would like to thank Fritz Rohde, Biologist Supervisor of the North Carolina Division of Marine Fisheries for his guidance, assistance, and editorial comments; Dr. Jeffery M. Hill Graduate Program Coordinator of Environmental Studies at UNCW for his guidance and support; Chip Collier, Fisheries Biologist of the North Carolina Division of Marine Fisheries for his assistance with statistical data; Robin Hall, Lock Master at lock and dam # 1 of the Army Corps of Engineers for the valuable information on the lock and dams and operating procedures; The commercial and recreational fishermen for their cooperation throughout this study.
Acknowledgements
Picture by Theresa Celia
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Picture by Theresa Celia
Literature Cited
Moser, M.L. and S.W. Ross. 1993. Distribution and movements of anadromous fishes of the Lower Cape Fear River, North Carolina. Final Report. US Army Corps of Engineers, Wilmington,
North Carolina. 155 p.Nichols, P.R., and D.E. Louder. 1970. Upstream passage of anadromous fish through navigation
locks and use of the stream for spawning and nursery habitat, Cape Fear River, NC, 1962-1966. 11 p.NCDMF, in press. Kingfish Fishery Management Plan. North Carolina Division of Marine Fisheries, Morehead City, NC 241 p.NCDMF. 2000. Required state shad and river herring report. North Carolina Marine Fisheries Management Rep.
42 p.Parker, J.A. 1992. Migratory patterns and exploitation of American shad in the nearshore ocean
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QUESTIONS ?
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