Feasibility of rearing brook char fingerlings in an intensive recirculating hatchery as a complementary species to rainbow trout

Abstract

Aquaculture, as the fastest growing agriculture sector, is currently focused on exploring the development of effective intensive recirculating systems (RAS). The use of intensive RAS requires a stable supply of fingerlings throughout the year. Salmonids are a highly important aquaculture species, with rainbow trout Oncorhynchus mykiss often reared in freshwater RASs. The dominant position of rainbow trout has triggered the investigation of a wider diversification of species, including brook char Salvelinus fontinalis. Brook char has the potential to be reared in facilities similar to those used for rainbow trout, but it is not known if brook char is suitable for hatching in an intensive recirculating hatchery system (RHS) to provide a consistent supply of fingerlings to an associated RAS roughly every three months. The present study evaluated the feasibility of producing brook char fingerlings in an RHS and compared results to those obtained with rainbow trout. A production cycle from eyed egg to fingerling was completed separately for rainbow trout, brook char, and parallel rearing of both species for the comparison of growth rate, feed conversion ratio, and the time to reach individual fingerling weight of 2 g. The results showed slower growth rate of brook char compared to rainbow trout reared under the same conditions and a significantly longer production cycle (∼108 days), compared to rainbow trout (∼74 days). Results suggest that brook char is not suitable for parallel rearing in facilities with primary rainbow trout production. The main practical problem is disruption of the production cycle which requires fingerling stocking at 3-month intervals.