Changes in biomass of eight species of finfish around the South Orkney Islands (Subarea 48.2) from three bottom trawl surveys

Stocks of finfish around the South Orkney Islands (Subarea 48.2) suffered substantial declines during the period the fishery was open from split year 1977/78 through 1989/90. Scientific bottom trawl surveys of finfish biomass within the 500 m isobath of the South Orkney Islands have been conducted by the Federal Republic of Germany in 1985, Spain in 1991, and the United States in 1999. Estimates of total stock biomass were computed for eight species that comprised 98% of survey nominal catch. Biomass levels in March 1999 were compared to previous trawl surveys conducted in Feb. 1985, and Jan-Feb 1991. Species examined were Gobionotothen gibberifrons, Lepidonotothen squamifrons, Pseudochaenichthys georgianus, Champsocephalus gunnari, Chaenocephalus aceratus, Chionodraco rastrospinosus, Notothenia rossii and Lepidonotothen larseni. Although there is substantial variability in point estimates, biomass levels of most species appear to be unchanged or may have declined slightly since 1991. The stock of C. gunnari is currently extremely low, while there appears to be a strong signal of recovery for N. rossii. However, overall levels of biomass indicate very little potential for commercial exploitation at this time.