A preliminary study on the relationships between otolith increment width, metabolic rate and growth in juvenile whitefish (Coregonus lavaretus L.)

Abstract

The effects of growth and metabolic rate on otolith increment width were studied in juvenile whitefish (Coregonus lavaretus L.). Daily increments were deposited on the otoliths of both starving and growing fish. The increment width was practically constant in non-growing or slowly-growing fish (up to specific growth rate of +1.2%d -1 ) and started 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 of standard metabolic rate (SMR) and feeding-induced thermogenesis (FIT), increment width showed no clear relationship with SMR, but a positive trend was observed in the case of FIT. These results suggest that the mechanism behind otolith growth includes both a growth-independent component which is governed by basic physiological maintenance processes, and a growth-dependent component which is possibly induced by FIT.