Response of the Crayfish Orconectes virilis to Exploitation

Life tables can aid in assessing the impact of exploitation of the crayfish Orconectes virilis by fish, invertebrates, and man. The major response of the population to exploitation comes through an adjustment of both the mx column (egg production) and lx (survivorship). Fish and invertebrate predation were directed towards modification of the early portion of the lx column. Survivorship did not change appreciably.Exploitation by man was directed toward males rather than females. An indirect result was an increase in the lx values for females. However, this was counteracted by a decrease in mx values leading to population stability as indicated by the Ro values. Both the exploitive strategies of fish and man failed to extract the maximum available biomass from the production of a given year-class.