Optimize photoperiod to maximixe spawning performance

摘要

A Canadian restocking hatchery maximizes rainbow trout production with three successive spawning seasons over 18 months. Two of the most popular programmes offered by the Freshwater Fisheries Society of British Columbia, Canada (FFSBC) are Learn to Fish and Fishing in the City. These programmes involve stocking urban lakes with catchable rainbow trout from March to October. This means a constant supply of225-250g trout over an extended period. Complicating matters is that the five FFSBC hatcheries that stock out the fish are located in different regions of the province and they each have distinct thermal profiles to their water supplies. This means holding fish back or accelerating growth to meet the stocking demands, which is not cost effective. The solution seemed to be in moving the spawning season.