(Re)Constructing Food Webs and Managing Fisheries

Abstract

The construction and analysis of a food web is an ecosystem approach that augments classical fisheries management. Food web analysis delineates important ecosystem linkages representing species interactions such as predator-prey relationships; from these linkages emerges a better understanding of ecosystem resiliency, resistance, connectivity, energy transfer efficiency, mass flux, and energy partitioning. In turn, with an understanding of food web dynamics, critical fisheries issues, including the relative importance of fishery and natural mortality, identification of critical life stages, production surplus and partitioning, multispecies yield dynamics, and forecasting, the impact of fishery management scenarios can be more effectively examined. Unfortunately, elucidating a food web is not a trivial task. One of the more parsimonious, cost-effective, and fisheries-amenable methods of reconstructing (at least portions of) a food web is diet analysis. Incorporated as part of standard resource surveys, analysis of stomach composition can not only qualify the linkages of a food web, but can also quantify the magnitude and rate of energy and mass exchange. Examples of statistical analyses from northwest Atlantic diet data demonstrate the utility of this approach in constructing a food web that produces information useful in addressing key fisheries issues.