Reproduction of deep-water hydrocorals (family Stylasteridae) from the Aleutian Islands, Alaska

Previous studies in the Aleutian Islands have found dense coral "gardens" dominated by hydrocorals, gorgonians, and sponges between 117 and 338 m depth. These structurally complex habitats supported a high taxonomic diversity of corals and associated fauna, but disturbance from fishing activities was observed at many of the sites. In 2003 and 2004, the submersible Delta was used to collect samples of 11 different species of hydrocorals from deep-water sites along the Aleutian Island Archipelago. Samples of three species were also collected from shallow water (< 27 m) in 2003 using SCUBA. All samples were processed according to standard histological techniques and used to describe the reproductive traits of each species. All species studied were gonochoristic brooders with the majority of gonophores containing mature embryos or planulae. The developmental stage of gametes within a single specimen was not highly synchronized; females contained eggs as well as planulae, and males exhibited a range of gamete development. These reproductive traits indicate that hydrocorals have limited potential to recolonize disturbed areas in the Aleutian Islands.