Behavioural and electrophysiological responses to F‐prostaglandins, putative spawning pheromones, in three salmonid fishes

Abstract

Behavioural and electro‐olfactogram (EOG) responses to synthetic F‐prostaglandins (PGFs) were recorded in the three salmonids: brown trout Salmo trutta, lake whitefish Coregonus clupeaformis and rainbow trout Oncorhynchus mykiss. Exposure to 10−8 M PGF2α and 13, 14‐dihydro‐PGF2α increased swimming activity in individually exposed brown trout in a flow‐through tank. Digging and nest probing behaviours were further observed in brown trout females exposed to PGF2α. Lake whitefish exposed to 10−8 M PGF2α and 15‐keto‐PGF2α also increased their locomotion. In rainbow trout, the absence of behavioural responses to PGFs correlates with a lack of olfactory sensitivity to these chemicals. PGFs triggered behavioural responses distinct from the feeding stimulant in brown trout. EOG measurements demonstrated that brown trout were most sensitive to PGF2α, with a threshold concentration of 10−11 M. Lake whitefish were most sensitive to both 15‐keto‐PGF2α and 13, 14‐dihydro‐PGF2α. Cross‐adaptation and binary mixture experiments suggest that only one olfactory receptive mechanism is involved in PGFs detection. The behavioural and olfactory responses observed with exposure to PGF2α and its metabolites suggest these compounds function as reproductive pheromones in brown trout and lake whitefish.