General response patterns of fish populations to stress: an evaluation using an individual-based simulation model

General response patterns of fish populations tostress, originally proposed by Colby for fisheriesrehabilitation and later adapted by Munkittrick forcontaminants, were evaluated using an individual-basedsimulation model. General response patterns relatechanges in population-level variables to the type ofstress. The model follows the daily growth,mortality, and spawning of individual yellow perch andwalleye through their lifetime, and was corroboratedusing Oneida Lake data. Two versions of the model wereused: population (yellow perch only) and community(dynamic predation on yellow perch by walleye). Eightstresses were imposed on the population and communityversions of the model and 100-year simulations wereperformed. Response patterns were defined by changesin predicted yellow perch mean population abundance,mean age of adults, and mean adult growth (representedby mean length at age-7). Proposed response patternswere similar to those predicted using the populationversion of the model. Simulations using the communityversion of the model distorted the response patterns,either causing amplification, dampening, or reversalof many of the patterns. Predicted response patternsbecame unique when additional variables were included.Our model results suggest that caution is appropriatein interpreting general response patterns based onmean age, or when the population of interest plays amajor role in a relatively simple food web. The responsepattern approach may be better at identifying the lifestage impacted rather than the mechanism of the stress.