Mixed-Species Yield-per-Recruitment Analyses Accounting for Technological Interactions

Multipecies fishery assessment models may be divided into two general categories: those involving analyses of the trophic interdependence of species (biological interactions) and those addressing the question of co-occurrence in fishing gear (technological interactions). Certainly, both categories of interactions may occur simultaneously. Nevertheless, the latter class of models is probably adequate if major species of interest exhibit a high degree of mutually exclusive food resource partitioning, and interspecific competition for food is low. In this study, multispecies analogs of the Thompson–Bell yield-per-recruit model are developed for alternative situations in which species groups (assemblages) are exploited solely by one fishery, and when several fisheries (defined by gear type, seasonal changes in species mix, etc), exploit the same species concurrently and/or sequentially. Species included in the analyses are assumed to have negligible trophic dependence. Equilibrium fishery yields (in aggregate...