Reproductive pattern in the brooding and broadcasting sea star Pteraster militaris

Abstract

Pteraster militaris (O. F. Müller, 1776) broods young in an aboral chamber and broadcasts gametes and offspring as well. The reproductive cycle of a population of P. militaris from the northwest Atlantic Ocean was examined over a 23 mo period from September 1985 to July 1987. The species is gonochoric (sex ratio 1:1), with only one incidence of hermaphroditism observed (n=261). Gonad indices were lower in females than in males, possibly an adaptation to the limited space available in the brood chamber. Body component and maturity indices, gonad histology and response to 1-methyladenine indicate that females in the population have a continuous breeding season, with a slight decrease in intensity in the spring. Males have a more pronounced decrease in the intensity of reproduction in the spring. Gonad development in males in synchronous both within and between individuals. Gonad development in females is asynchronous. © 1989 Springer-Verlag.