Distribution, reproductive and energetic conditions of decapod crustaceans along the Scotia Arc (Southern Ocean)

LOVRICH G.A.,; ROMERO M.C,; TAPELLA F.; THATJE S.

SCIENTIA MARINA

INST CIENCIAS MAR BARCELONA

Año: 2005 vol. 69 p. 183 - 193

0214-8358

Studies on decapod distribution patterns and reproductive and energetic conditions were carried out along the islands and shallows of the Scotia Arc (Southern Ocean) during the RV “Polarstern” LAMPOS expedition (PS XIX/5) between April and May 2002.  A clear biogeographic zonation was found. The subantarctic Magellan-South Atlantic decapod fauna consisting of both “natant” (caridean) and “reptant” (astacidean, anomuran, and brachyuran) decapods were along the northern branch of the Scotia Arc to South Georgia, where Subantarctic and Antarctic faunas were found overlapping. An impoverished caridean shrimp fauna occurred along the islands of the southern branch, from the South Sandwich Islands to the Antarctic Peninsula. Differences in the reproductive traits of the two most abundant species were detected. The reproductive cycle of Notocrangon antarcticus at South Georgia was advanced in comparison with that at the South Orkney Islands, probably due to temperature differences between both locations. Although the oogenesis and the reproductive cycle of Munida subrugosa seem to be in phase at Burdwood Bank and in the Beagle Channel, oocyte number is probably lower in the former location. A new index to measure the energy devoted to reproduction was used, which relates the energy contents of the egg mass/ovary plus hepatopancreas and the energy contents of the whole body. This index revealed that the energy investment in reproduction was (1) independent on the sampling location, (2) species-specific, and (3) larger in caridean shrimps than in galatheid crabs.