CCAMLR

Results of the February-March 1998 exploratory and experimental fishing operations using pots are described. This research took place during the New Fisheries Project carried out by Chile, with the purpose of determining the presence of Dissostichus spp. in Subareas 48.1, 48.2 and 88.3. In each location where industrial bottom longlines were used, six pots were lowered, three at each end of the fishing gear, with a distance of approximately 90 m between them. The pots were lowered at a depth of 290-1 920 m. A total of 300 pots of four different designs were used. Approximately 1 kg of either whole salted sardines (Sardinops sagax) or squid (Illex argentinus) were used. According to total weight obtained with pots, the main resources were Antarctic crab (Paralomis anemerae) (28%), striped-eyed rockcod (Lepidonotothen kempi) (1 7%), eel pout (Lycenchelys bellingshauseni) (1 3%) and smalleye moray cod (Muraenolepis microps) (11%). Regarding the number of individuals caught, most were amphipods (55%), Antarctic crab (P. anemerae) with 110.7 g/pot, striped-eye rockcod (L. kempi) with 67.4 g/pot and eelpout (L. bellingshauseni) with 51.2 g/pot. In general, P. anemerae was captured in all researched subareas, with a higher yield in Subarea 48.2 (548.8 g/pot).

A 43-day cruise on FV Tierra del Fuego took place in February and March 1997, as part of the New Fisheries Project developed by Chile in Statistical Subareas 88.3, 48.1 and 48.2. During this research study every measure currently in force was used to prevent incidental seabird mortality, carrying out bird observations in each one of the 52 castings with the Spanish-designed longlines as well. The streamer line suggested by the CCAMLR was not appropriate during wind conditions, so an alternate design was tried out using loophole sacks as secondary elements, which proved more efficient due to their simpler construction and increased visibility. Neither bird capture nor mortality was reported during the fishing activities. During the entire cruise a total of 436 birds were observed. The most abundant was Diomedea melanophrys, with 204 sightings, followed by Oceanities oceanicus, with 77; Catharacta lonnbergi, with 40; and Diomedea chrysostoma, with 37. The highest relative abundance was found in Subarea 48.1 with I1 .I birds/haul, followed by Subareas 48.2 and 88.3 with 7.6 and 5.0 birds/haul, respectively. The highest number of species was found in Subarea 48.1 with 19 species observed and the least in Subarea 48.2 with the presence of only 4 species.

The United States Antarctic Marine Living Resources (U.S. AMLR) program conducted bottom trawl surveys in March, 1998 of the two major regions of the South Shetland Islands: Elephant Island and the lower South Shetland Islands from King George Island to Livingston Island. Estimates of total stock biomass and spawning stock biomass were computed for six species: Champsocephalus gunnari, Gobionotothen gibberifrons, Notothenia coriiceps, Chaenocephalus aceratus, Chionodraco rastrospinosus, and Lepidonotothen squamifrons. Estimates of total stock biomass only were computed for two additional species: Lepidonotothen larseni and Notothenia rossii. Biomass was estimated for both regions separately, and combined as one system using previous and updated estimates of seabed areas for Elephant Island and the lower South Shetland Islands.

Maturity data information obtained by the scientific observers on board the ships Argos Helena and Cisne Verde during August of 1997 -and utilized by the WG-FSA-97 to build the maturity ogives- were age transformed applying the age-size relationship obtained from the specific equations for each sex in samples coming from South Georgia Islands. The results show that the differences are due to maturity at age and not due to the growth rate. Based on this sample of 434 females and 398 males, it is concluded that the males mature for the first time at 4 years age and females at 10 years age, reaching 100% maturity at 12 years age the males and 21 years age the females.

Bottom trawl surveys were conducted by the United States Antarctic Marine Living Resources program in two major regions of the South Shetland Islands: Elephant Island and the lower South Shetland Islands from King George Island to Livingston Island. Information on species composition, catch levels, size composition, and condition are described and compared between the two regions. Maturity ogives were constructed for five species of finfish: Champsocephalus gunnari, Gobionotothen gibberifrons, Chaenocephalus aceratus, Chionodraco rastrospinosus, and Lepidonotothen squamifrons. Estimates of length at sexual maturity and length at first spawning are computed and compared with previous estimates and other populations.

Bathymetric maps of two major areas within the South Shetland Islands were generated using several integrated bathymetric databases. These areas comprise the lower South Shetland Island chain from King George Island to Smith Island, and the region around Elephant Island. From the integrated data sets, areas of seabed within the 500 m isobath for six levels of depth strata (0-50 m, 51 - 100 m, 101-200 m, 201 -300 m, 301-400m, 401-500 m) were computed. Areas were calculated based on true surface area of seabed incorporating seafloor slope

The absolute and relative fecundity of Patagonian toothfish inhabiting areas of South Georgia Island and Shag Rocks were studied. The absolute individual fecundity of toothfish in relation to the size of specimens ranged from 56,3 to 567.5 thousands of eggs, averaging 152,9 thousands of eggs. Values of relative individual fecundity of toothfish varied from 4,1 to 13,0 thousands of eggs (averaging 8.19 ± 1,73 thousands of eggs ) per 1 kg of fish body weight. Our studies and the analysis of data published previously indicate, that Patagonian toothfish similar to the most of Notothenioids characterized by large eggs can be included in the fish group having a level of absolute fecundity and a low value of relative fecundity.