The induction of maturation and ovulation in American eels, Anguilla rostrata (LeSueur), and the relevance of chemical and visual cues to male spawning behaviour

Female American eels, Anguilla rostrata (LeSueur), were artificially matured with injections of salmon and carp pituitary and human chorionic gonadotropin. In vivo ovulation was induced with 4‐pregnene‐17α,20β‐diol‐3‐one and eggs were spontaneously released. Eggs were fertilized in vitro and survived to the gastrula stage. Males were matured with injections of human chorionic gonadotropin. They were attracted by the sight and odour of maturing and mature females. Ovulated females released a sex pheromone which was especially attractive to mature males and triggered the release of sperm.