Determining Annual Production Capabilities for Sequential Rearing Programs through the Use of Routine Fish Culture Data

Abstract

Routine fish culture data, such as growth rates, feed conversion, length−weight relationships, and mortality rates from empirical studies of rainbow trout Oncorhynchus mykiss, are used to model sequential rearing strategies in order to demonstrate their impact on production. Increasing the frequency of cohort introductions into the rearing cycle improves output but at a diminishing rate. Moving from a single-cohort, batch culture strategy to one that involves two cohorts per rearing cycle increases production by as much as 60%. For the same number of cohort introductions per rearing cycle and similar feed conversions, slow-growing fish realize the same annual output as fast-growing fish, but a greater number of fish (i.e., greater biomass) must be maintained with the former. Five different rearing strategies are presented, namely, those involving 1, 2, 4, 6, and 12 cohorts. Two to six cohorts per rearing cycle appear to be optimal for nonmixed production programs.