PHOTOPERIOD CONTROL OF PUBERTY IN FARMED FISH: DEVELOPMENT OF NEW TECHNIQUES AND RESEARCH INTO UNDERLYING PHYSIOLOGICAL MECHANISMS

摘要

A major constraint in farming of fish is the timing of initial sexual maturation or puberty. Farmed Atlantic salmon can show high rate of parr maturation and grilse (maturing after 1 sea-winter) levels can be 70% or higher in some stocks. Early maturation also represents a major constraint in producing larger rainbow trout for the market. Most male flatfish and a high proportion of male sea bass mature prior to reaching desired harvest size, while 100% maturation rates at an age of two years are common in farmed Atlantic cod. Sexual maturation results in reduced growth, regressive changes in harvest quality, increased susceptibility to diseases, and reduced feed conversion efficiency, and ultimately increased production costs.