Aspects of the spawning of western Atlantic butterflyfishes (Pisces: Chaetodontidae)

Synopsis

The status of knowledge of spawning among the five shallow water Chaetodon species in the western Atlantic is reviewed. Spawning has been observed for three species in Puerto Rico, St. Croix and the Bahamas, with possible courtship in a fourth. Chaetodon aculeatus spawned near the time of sunset over objects on the reef as single female/male pairs or as two females and one male, with pair spawning in rapid succession. Spawning occurred during much of the lunar month from February to April and it is uncertain whether any lunar periodicity to spawning exists. Male-male aggression was noted. Spawning sites (coral heads) were alternated daily and it is likely that females spawn only once every two days. A single female produced as many as 2090 eggs in a single spawning. Chaetodon capistratus spawned during much of the lunar month from February to April. It spawned about 5 min after C. aculeatus, occasionally using the same sites, and alternated sites daily. A female produced as many as 3710 eggs in one spawning. Chaetodon striatus spawned from February to April but it is unknown if it has any lunar spawning cycle. No predation attempts by piscivores on spawning adults were seen. Predation by Melichthys niger on eggs of C. striatus occurred. No egg predation was observed for C. aculeatus and C. capistratus. With an assumed four month reproductive season, alternate day spawning and observed egg production values, C. aculeatus and C. capistratus produce respectively about 100000 and 200000 eggs per large female per year. The reproductive strategy of smaller species may be to produce moderate numbers of eggs per day over a spawning season of at least a few months while larger species may produce more eggs per day for a shorter period.