Fifty-eight species of planktonic Cnidaria and Ctenophora were observed and collected in the Alborán Sea (western Mediterranean) during a cruise in April 1991 on the RV Seward Johnson. Eleven stations were sampled 10 to 21 nautical miles off the north coast of Morocco between the Strait of Gibraltar and the Cap de Trois Fourches: 26 dives using the manned submersible Johnson-Sea-Link I were made to bottom depths of 370-850 m, and at 5 of the same stations 7 bluewater SCUBA dives were made from the surface to about 15 m. Twelve species of hydroidomedusae, 18 species of siphonophores, 6 species of scyphomedusae, and 22 species of ctenophores were collected. The most numerous species seen from the submersible in deep water included Solmissus albescens, Haliscera conica, Forskalia (?)Formosa, Lensia conoidea, Abylopsis tetragona, Paraphyllina ransoni, Periphylla periphylla, Euplokamis stationis, Bathocyroe fosteri, Bolinopsis infundibulum, an undescribed cydippid ctenophore, and an undescribed lobate ctenophore. Species that were most numerous near the surface were Pandea conica, Solmaris leucostyla, Nanomia bijuga, Haeckelia beehleri, Pleurobrachia rhodopis, Bolinopsis vitrea, 0cyropsis maculata immaculuta, Beroe ovata, and an undescribed cydippid ctenophore. Advantages of using a submersible for this study included the ability to collect in perfect condition fragile forms like siphonophores and ctenophores that fa11 apart when collected in nets, the possibility of obtaining a realistic image of small-scale distribution throughout the water column, and to sample plankton close to the sea floor. |
Keywords: Hydromedusae, Hydroidomedusae, Scyphomedusae, Siphonophora, Ctenophora, gelatinous zooplankton. Mediterranean, community structure, distribution. |