A CRITICAL-APPRAISAL OF POPULATION APPROACHES IN ASSESSING FISH COMMUNITY-HEALTH

The characteristics of a fish population that is healthy from the standpoint of human exploitation include its ability to produce numerous healthy, fecund, and normal-sized adults and to resist or rebound from short-term stresses. These characteristics generally can be expressed in terms of the population staying within a certain range of values in abundance, age structure, length and weight structure, condition factor, and sex ratio. Some of the traditional approaches used in studying fish populations are reviewed and it is shown that, at best, only some of the above population characteristics can be evaluated using these traditional approaches. The individual-based modeling approach is an alternative to traditional models that permits explicit representation of the feedback between the differing physiological states of individual members of the population and their ability to feed, grow, reproduce, and avoid disease and predation. It may be superior for describing and predicting population health. An example of the use of this approach is presented.