Environmental effects on recruitment of northern shrimp in the gulf of maine
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Environmental Effects on Recruitment of Northern Shrimp in the Gulf of Maine. Anne Richards Michael Fogarty David Mountain NOAA National Marine Fisheries Service Woods Hole, MA. Outline. stock-recruit-environment relations mechanisms for recruit-env’t relation.

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Environmental effects on recruitment of northern shrimp in the gulf of maine

Environmental Effects on Recruitment of Northern Shrimp in the Gulf of Maine

Anne Richards

Michael Fogarty

David Mountain

NOAA National Marine Fisheries Service

Woods Hole, MA


Outline the Gulf of Maine

  • stock-recruit-environment relations

  • mechanisms for recruit-env’t relation


Northern shrimp pandalus borealis
Northern Shrimp the Gulf of MainePandalus borealis

  • Boreal distribution

  • Gulf of Maine=southern limit

  • Locally important fishery

from Shumway et al. 1985

Life history

Fishery


Impetus
Impetus the Gulf of Maine

  • Conventional wisdom: temperature = primary regulating factor

  • will “…not respond well to attempts to control exploitation”

    (Apollonio et al. 1986)


Stock recruitment series 1968 2002
Stock-Recruitment Series the Gulf of Maine1968-2002


Environmental variables
Environmental Variables the Gulf of Maine

  • Temperature anomalies (W Gulf of Maine)

    • fall bottom: developmental rates, egg parasitism

    • spring bottom: developmental rates, hatch timing

    • spring surface: larval development

  • NAO winter index


Analysis
Analysis the Gulf of Maine

  • Box-Jenkins TSA to ID factors affecting recruitment

  • S-R with environmental inputs


Results tsa significant crosscorrelations with recruitment

SSB the Gulf of Maine

2

+

Spring Surface TA

-

Spring Bottom TA

4

-

NAO

1

-

Results – TSASignificant crosscorrelations with recruitment

Lag

Sign

1

Planktonic larvae

Male maturation, gender transition

without 2002


Stock recruitment models
Stock-Recruitment Models the Gulf of Maine


Stock recruit temperature
Stock-Recruit-Temperature the Gulf of Maine


Conclusion
Conclusion the Gulf of Maine

  • Shrimp recruitment dependent on SSB and spring temperatures (surface and bottom)


Mechanisms spring sst
Mechanisms: Spring SST the Gulf of Maine

  • Spring surface temperature effect (larvae):

    • Appears intuitively correct

    • But counters laboratory studies: better growth and survival at warmer temperatures.

    • Indirect effect, e.g. match-mismatch?


Match mismatch hypothesis
Match-Mismatch Hypothesis the Gulf of Maine

  • Coastal Gulf of Maine: Bloom timing determined by solar insolation (Townsend and coauthors)

  • Shrimp development: temperature-dependent


Match mismatch hypothesis1
Match-Mismatch Hypothesis the Gulf of Maine

  • Bloom timing

  • Hatch timing

  • Survival rates


Bloom timing
Bloom Timing the Gulf of Maine

  • Townsend and Cammen (1988): 1971-1980

  • CZCS and SeaWifs

    ’78-’86, ’98-’03


Hatch dates
Hatch Dates the Gulf of Maine

  • Maine DMR fishery sampling, 1980-1983 and 1989-1993

  • Probit analysis: 50% hatch, duration of hatch


Hatch timing
Hatch Timing the Gulf of Maine


Shrimp development
Shrimp Development the Gulf of Maine

  • temperature-dependent


Bloom onset and hatch timing
Bloom Onset and Hatch Timing the Gulf of Maine


Survival
Survival the Gulf of Maine


Larval shrimp diet
Larval Shrimp Diet the Gulf of Maine

  • Zooplankton bloom ~ one month later (Townsend 1984)

Stage I larvae

Stickney and Perkins (1980)


Implications
Implications the Gulf of Maine


Application
Application the Gulf of Maine

  • Management:

    Adjust fishing effort to allow higher egg deposition in warmer years


Stephen h clark

Summary the Gulf of Maine

Stephen H. Clark

1) SSB and spring temperatures affect GoM shrimp rcrt

2) Spring SST effect may be mediated through match-mismatch


Ongoing work
Ongoing Work the Gulf of Maine

  • Bloom timing

    • Solar insolation, 1982-1999

    • CZCS / SeaWiFS, ‘83-’91, ‘97-’03

  • Hatch timing


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