Scientia Marina, Vol 65, No S1 (2001)

Larval trophodynamics, turbulence, and drift on Georges Bank: A sensitivity analysis of Cod and Haddock


https://doi.org/10.3989/scimar.2001.65s199

Francisco E. Werner
Marine Sciences Department, University of North Carolina, United States

Brian R. MacKenzie
Danish Institute for Fisheries & Marine Research, Denmark

R. Ian Perry
Pacific Biological Station, Department of Fisheries and Oceans, Canada

R. Gregory Lough
National Marine Fisheries Center, Northeast Fisheries Science Center, United States

Christopher E. Naimie
Dartmouth College, United States

Brian O. Blaton
Marine Sciences Department, University of North Carolina, United States

John A. Quinlan
Marine Sciences Department, University of North Carolina - National Marine Fisheries Center, Northeast Fisheries Science Center, United States

Abstract


Using an individual-based model approach we consider trophodynamic effects on the growth and survival of larval cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) on Georges Bank during late winter/early spring. These studies represent an extension of results described in Werner et al. (1996; Deep-Sea Res. II), wherein the effect of turbulence-enhanced larval-prey contact rates increased the effective prey concentration resulting in growth of cod larvae consistent with observed rates in the field. We reformulated the feeding of the larvae to include existing relationships between maximum prey-length and larval-length and we examined: (i) larval search behaviour and its effect on encounter with prey, (ii) the ability of larvae to pursue and capture prey in a turbulent environment, and (iii) the effect of turbulence on the dispersion of larvae in the vertical. We find that search behaviour, the effect of turbulence on pursuit and capture, and vertical dispersion decrease the predicted larval growth rates compared to those observed in the earlier study. These results suggest that larval feeding behaviour, and especially the ability of larvae to pursue encountered prey, could be an important input to larval growth and survival models. The inclusion of turbulence in determining the position of passive larvae in the water column allows the larvae to sample the entire water column, contributing to a decrease in the variance of the size of the larvae over time. The ability of larvae to swim and aggregate in the vertical will be necessary to reproduce distributions observed in the field.

Keywords


larval trophodynamics; turbulence; modelling; cod; haddock; Georges Bank

Full Text:


PDF


Copyright (c) 2001 Consejo Superior de Investigaciones Científicas (CSIC)

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.


Contact us scimar@icm.csic.es

Technical support soporte.tecnico.revistas@csic.es