A simplified formulation for fish production

Abstract

A new formulation for fish production is presented, one that clearly embodies the balance between aggregate somatic growth and losses due to natural and fishing mortality. The method permits simplified calculation of production over biomass and yield over production ratios; estimates of the latter can be used to investigate the reliability of yield as a proxy for production. Simple applications of the formulation indicate taxonomic variation in the yield to production ratio. Specifically, production is well approximated by yield for many piscivorous species, but yield seriously underestimates production for prey species.