Medusae, siphonophores and ctenophores of the Magellan region

Medusae, siphonophores and ctenophores were conspicuous and relatively abun dant organisms in the Magellan Straits, Beagle Channel and adjacent waters during the "Victor Hensen" campaign in 1994. Hydromedusae were the most abu ndant component of this assemblage (mainly Bougainvillia macloviana, Clytia simplex and Obelia spp.) and showed the highest number of species (29). Si phonophores were second in species number (8) and mainly occurred outside t he Magellan Straits (mainly Muggiaea atlantica, Dimophyes arctica, Lensia c onoidea and Pyrostephos vanhoeffeni). Callianira antarctica was the only me sozooplanktonic ctenophore and showed a widespread distribution throughout the region. Aggregations of large Beroe cucumis and Desmonema gaudichaudi w ere observed at some stations. The abundance and depth distribution is give n for the most important species and some patterns in the species distribut ion are postulated.