Standing stock, spatial distribution and biological features of demersal finfish from the 2006 US AMLR bottom trawl survey of the northern Antarctic Peninsula and Joinville–D’Urville Islands (Subarea 48.1)

During February-March 2006, the United Station Antarctic Marine Living Resources (U.S. AMLR) Program in collaboration with the German Federal Research Centre for Fisheries conducted a bottom trawl survey of the northern Antarctic Peninsula (southern Bransfield Strait) and Joinville/D’Urville Islands. This area included the likely historical fishing grounds of a trawl fishery for the spiny icefish (Chaenodraco wilsoni) conducted from the late 1970’s to the mid-1980’s, as well as rarely sampled shelf areas to the south. Estimates of seabed area by strata between 50-500 m for the region surveyed are computed. Information on demersal finfish biomass, spatial distribution, size and maturity composition, and dietary patterns from the survey is presented. Most biomass of finfish in this region occurs around the likely historical fishing grounds, north of Joinville Island. In addition to the inventory of species encountered, estimates of total stock biomass were computed for the eight most abundant demersal species: Chaeonodraco wilsoni, Chionodraco rastrospinosus, Cryodraco antarcticus, Gobionotothen gibberifrons, Lepidonotothen larseni, Lepidonotothen squamifrons, Notothenia coriiceps, and Trematomous eulepidotus. The species with the highest biomass was G. gibberifrons. Observations on benthic bycatch, and differences in finfish species composition and abundance between this surveyed region and the adjacent South Shetland Islands region of Subarea 48.1 are given. High–Antarctic finfish fauna are considerably more prominent on the Antarctic Peninsula shelf region relative to the South Shetland Islands shelf region, and overall abundance of finfish is considerably lower. This is likely due to the influence of colder water from Weddell outflow, lower productivity, and lower prey availability along the Antarctic Peninsula region. Biomass for all species of demersal finfish in this region is currently not at a level for which commercial exploitation would be advisable.