CHARACTERIZATION OF VIBRATIONAL AND VISUAL SIGNALS WHICH ELICIT SPAWNING BEHAVIOR IN THE MALE HIME SALMON (LANDLOCKED RED SALMON, ONCORHYNCHUS-NERKA)

Hime salmon (landlocked red salmon, Oncorhynchus nerka) have an elabor ate communication system, which ensures synchronous spawning by both s exes and successful fertilization. Both the vibrational and visual sig nals have been suggested to be involved in this communication system. To characterize these signals, vibrating or stationary three-dimension al models of various types were presented to the male, and male behavi or elicited was examined. The results showed that the vibrating model mimicking certain aspects of the female behavior ('prespawning act') e licits the spawning in the male (Figs. 2, 3, 5). Furthermore, it was f ound that (1) the presence of both the vibrational and visual cues (Fi gs. 6, 7), and (2) spatial coincidence of these two cues (Fig. 8) are necessary for eliciting this behavior. Based on these results it was s upposed that the vibrational and visual informations converge at the c entral nervous system where they are integrated to elicit the spawning .