DEMERSAL FISH

K. MINTENBECK; R. ALARCÓN; E. BRODTE; F. VANELLA; R. KNUST

Berichte zur Polar- und Meeresforschung / Reports on Polar and Marine Research. Expeditions Antarktis XIX/5

Alfred-Wegener-Institut

Lugar: Bremerhaven; Año: 2003 vol. 462 p. 55 - 58

1618-3193

 The aim of our studies was to investigate the distribution of species in the area between South America and de Antarctic Peninsula. Since some species, such as Chaenocephalus aceratus or Gobionotothen gibberifrons are known to be widely distributed along the Scotia Arc, these islands have served as stepstones during the dispersion process. Genetic analysis will show to what extent local stocks of one species are isolated from each other. Material was collected from 14 Agassiz trawls (AGT) and 8 bottom trawls (GSN). Fishes were identified using appropriate literature, measured and weighed. Sex and maturity stages were determined. Otoliths were taken for age determinations and stomachs were removed for diet analyses. Tissue samples from white muscle for stable isotope analyses were frozen at - 30 °C. For population genetic studies in abundant species gill and muscle samples were stored at -30 °C as well as in 90 % ethanol. For this first evaluation only the shallow water (<400m) bottom trawls (GSN) were considered. Numbers per catch were converted to numbers per 15 min trawling. The Antarctic suborder Notothenioidei is remarkably dominant in the whole area. Only southwest of Elephant Island, a few more non-notothenioids were found, mainly Paradiplospinus gracilis (Gempylidae, Others) and Bathyraja sp. (“Rajids”). The fish communities in the northern part of the Scotia Arc around Burdwood Bank and northwest of South Georgia were dominated by the small notothenioid species Patagonotothen guntheri. Trematomus lepidorhinus, a species that is common on the north eastern Weddell Sea Shelf, was found in high numbers only southeast of South Georgia. The fauna around the South Sandwich Islands is obviously dominated by Lepidonotothen kempi, whereas Gobionotothen gibberifrons was the most common species at the South Orkneys. On the shelf of the Antarctic Peninsula several icefish species (Channichthyidae) were often dominating the communities, while Lepidonotothen larseni and Gobionotothen gibberifrons were also common species.