Blackbelly rosefish, Bluemouth rockfish, Bluemouth seaperch
Helicolenus dactylopterus, blackbelly rosefish, bluemouth rockfish, and bluemouth seaperch, is a species of marine ray-finned fish belonging to the subfamily Sebastinae which is classified within the family Scorpaenidae. This Atlantic species is a typical sit-and-wait predator with a highly cryptic coloration.
Helicolenus dactylopterus is widely distributed in the Atlantic Ocean. In the west, it ranges from Nova Scotia to Venezuela. In the east, it ranges from Iceland and Norway to South Africa, including the Azores, Madeira and Canary Islands, and the entire Mediterranean Sea.
The blackbelly rosefish is a bathydemersal scorpionfish, found in soft bottom areas of the continental shelf and upper slope. They have been recorded at depths between 50 and 1,100 m (160 and 3,610 ft), but usually from 150 to 600 m (490 to 1,970 ft). They feed on both benthic and pelagic organisms including decapod crustaceans, fishes, cephalopods and sometimes pyrosomes, polychaetes and echinoderms. The proportions of these prey types in their diet vary according to the size of the fish.
Blackbelly rosefish have intraovarian gestation. Fertilization is internal, as free spermatozoa were found primarily in resting ovaries from July through early December, with peak occurrence in September through November in the Western Atlantic. There was a delay of 1–3 months before fertilization, as oocyte development did not begin until December. Occurrence during January through April of early-celled embryos, the most advanced stage observed, and postovulatory follicles indicated that oocyte development was rapid. The females can store sperm within their ovaries that allows them to spawn multiple batches of embryos, which are enclosed within a gelatinous matrix secreted into the ovarian cavity. This species has a zygoparous form of oviparity, which occupies an intermediate position between oviparity and viviparity. Larvae and juveniles are pelagic.
