Document: STU-3-56-23

Relationship between consumption and growth in selected fishes of the NW Atlantic: Insight from a long-term bottom-trawl database.

WHIPPLE, S.J., J.S.LINK and L.P.GARRISON

National Marine Fisheries Service, Woods Hole, MA 02543 USA ¹

Abstract:
An ecological simulation model of the fish community of selected regions of the NW Atlantic continental shelf system was developed to provide insight into the functioning of the fishery ecosystem under different fishery removal regimes. The model consists of sub-models that portray the processes of consumption, growth, reproduction, migration, and fishery removals. One of the main submodels describes a relationship between fish consumption and growth. We investigated the nature of an empirical relationship between food consumption and growth to provide a basis for a mathematical representation in the simulation model. The amount and selection of food types consumed and the relationship of ingestion to growth must be addressed in the consumption-growth sub-model. These relationships were derived by using NEFSC data. Growth increments for age cohorts were calculated from length-at-age data. By utilizing the parameters of stomach content weight and bottom temperature data, a gastric evacuation model calculated consumption for age categories. For fish are that are not routinely aged by NEFSC, ages were calculated by using von Bertalanffy growth equations. Preliminary results indicated a strong relationship between consumption and growth for some species in the system, whereas the relationship was indeterminate for other fishes. We explored factors that might contribute to this pattern, including differential fishing removals, inter- and intra-specific competition (density dependence, depensation), and changes in abiotic factors. These results suggest that food consumption estimates derived from stomach contents data may be valuable in developing algorithmic relationships between fish food consumption and individual growth. Algorithms such as these furnish a valuable component in multispecies trophic dynamic models of fisheries ecosystems.

Keywords: consumption-growth algorithm marine fish

This abstract is being presented at: 10:30 AM in session:
Oral Session #57: Ocean-Going Fish and Mammals.