Modeling the growth of larval cod on Georges Bank: a synthesis of observations and model results for

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Modeling the growth of larval cod on Georges
Bank a synthesis of observations and model
results for Spring 1995C. Werner, G. Lough, J.
Quinlan, L. Buckley, P. Berrien, E. Caldarone,
E. Durbin, C. Flagg, J. Green, L. Incze, D.
Lynch, J. Manning, D. McGillicuddy, D. Mountain,
C. Naimie and J. Runge
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Objectives - with the recently completed BSS on
Georges Bank explore larval cod growth...

• as a function of feeding and physical
  environments
• and its inter-seasonal and inter-annual
  variability

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Physical Environment(March-May)- Temperature
and turbulence bi-monthly
climatological fields (Naimie, 1997)- Light
latitude dependent duration and
intensity,vertical extinction coefficient
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March - 6mm larvae Colder, less stratified
Shorter days, lower light intensityApril
- 8mm larvaeMay - 10mm larvae Warmer,
increased stratification Longer days,
stronger light intensity
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Feeding Environment(March-May)- Observed
fields from 1995 BSS - OAXed (4-D) onto Georges
Bank Pseudocalanus all stages Oithona all
stages Calanus fin. N1-N6
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24-hour growth rates computed at fixed points as
functions of Temperature, light and ?
Pseudocal., Oithona Calanus - no advection
- no prey field evolution
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Modeled versus Observed
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Preliminary conclusions

• In 1995 Pseudocalanus provides the largest signal
  for 6-10mm cod larvae
• Oithona Calanus fin. negative gwth rts
• Modeled and observed larval cod growth rates
  comparable when prey combined

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Next steps include...

• Compute flow fields (data assimilation)
• Dynamic prey fields (inverse methods)
• Advection of larvae and behavior
• Synthesis

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Broadscale Sampling ProtocolNETS MOCNESS
153 mm mesh (all stns) PUMP 1995 50
mm mesh 1996-99 35 mm
meshDEPTH INTERVALS 0-15 m 15-40
m 40-100 or bottom 100-bottom (MOCNESS
only)
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