Abstract

Population models have been used to describe and predict changes in population structures through time. In fishery applications these models (utilizing such factors as growth, recruitment, fishing mortality and natural mortality) are used to manage and regulate fishing activities. As our waters are increasingly impacted by both point and non-point source pollution the parameter of “natural mortality” must be examined in greater detail. Toxicological studies based on both commercially important species and proxy species have shown a variety of physiological effects that have not been addressed in practical applications of modeling. Stage specific mortality, altered rates of development and reduced growth have been reported. These effects were documented in a xanthid crab exposed to sub-lethal concentrations of the mosquito larvicide, methoprene, and have been incorporated into a crustacean fishery model. Impacts on survival and fecundity produce a much different picture for long term population growth that needs to be considered in the application of population models. Multi-species tropical fisheries will tend to magnify the effects demonstrated on prey species through complex tropho-dynamic linkages. Design and placement of marine protected areas o r attempts to rehabilitate degraded habitats must consider the effects of xenobiotics in the aquatic habitat and provide for restrictions of terrestrial inputs as part of their overall management strategy.

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