Ecosystem Models of Fishing Effects: Present Status and a Suggested Future Paradigm

Quantitative modeling methods applied to anthropomorphic effects of harvesting on aquatic ecosystems have become increasingly utilized tools in the management of fisheries. However, to date traditional modeling approaches have not been found to be very useful as “surrogate experimental systems” in applied ecology, such as fishing effects on entire ecosystems. A review is made of several dynamic ecosystem models, and an effort is made to assess their utility to fisheries management. Both theoretical and simulation models, as well as individual-based models are shown to be of limited utility for various reasons. A new paradigm based on the premise that dynamic behavior of models, which includes fishing effects on the entire aquatic ecosystem, emerges from low-level interactions of independent agents. This concept is illustrated with simple artificial life models of fish schooling and predator-prey relations. These models describe each individual fish, including its interaction with others and the environment. There is no overall controlling program. Thus, the overall behavior of the school and predator—prey relations emerge from local interactions among many individuals. A brief description of the premise on which artificial life is based is included. Examples of other artificial life models at ecological scales are provided and some specifics on artificial life models in a fisheries context are suggested.