A PRELIMINARY-STUDY ON THE RELATIONSHIPS BETWEEN OTOLITH INCREMENT WIDTH, METABOLIC-RATE AND GROWTH IN JUVENILE WHITEFISH (COREGONUS-LAVARETUS L.)

The effects of growth and metabolic rate on otolith increment width we re studied in juvenile whitefish (Coregonus lavaretus L.). Daily incre ments were deposited on the otoliths of both starving and growing fish . The increment width was practically constant in non-growing or slowl y-growing fi:jh (up to specific growth rate of +1.2 % d(-1)) and start ed to increase with growth rate only in faster growing fish. A similar relationship was observed between increment width and total metabolic rate. When total metabolic rate was further divided into components o f standard metabolic rate (SMR) and feeding-induced thermogenesis (FIT ), increment width showed no clear relationship with SMR, but a positi ve trend was observed in the case of FIT. These results suggest that t he mechanism behind otolith growth includes both a growth-independent component which is governed by basic physiological maintenance process es, and a growth-dependent component which is possibly induced by FIT.