CCAMLR

In the vicinity of the northern tip of Antarctic Peninsula, the Bransfield Straits and South Shetland Islands, cold polar waters from the Weddell Sea meet warmer circumpolar water from the Pacific Ocean. A series of fronts form which collectively are referred to as the Weddell-Scotia Confluence. Within the Confluence region the Weddell Gyre water is separated from the Pacific or Scotia Sea water by a zone of varied width (10 to 100 Km) of water which can best be considered as continental margin water, advected into the region along the extreme western edge of the Weddell Gyre. It is relatively cold and low in salinity through-out the water column and prone to deep reach convective events, even as far north as the Bransfield Straits. Along the northern boundary of the Weddell-Scotia Confluence (the Scotia Front), where the Pacific water is encountered, there are indications of vigorous mixing processes of Bransfield Straits water (derived from the Weddell, with further local modification): an intrusive layer of Pacific derived relatively warm-salty water near 300 meters depth and deeper intrusions (500-1500 meters; e.g. SEIDLECKI stations 217, 226, 231, 235, 236 and 250) of Pacific water, as the Scotia Front protrudes to the south, perhaps associated with meso-scale structures.
The Weddell-Scotia Confluence in the Bransfield Straits is associated with abundant Krill populations. It is speculated that mixing of Weddell and Pacific waters near the tip of Antarctic Peninsula is an important environmental feature related to this abundance.

The report describes the land based ecosystem monitoring studies conducted in three separate areas of the Antarctic Peninsula marine mammal s and birds. In addition, a joint U.S./Chilean cruise to track fu r seals and penguins at sea is described.

As part of the NMFS/AMLR program to provide information for the effective management of Antarctica’s marine living resources, three permanent monitoring sites were established on the western side of the Antarctic Peninsula. Listed from north to south, these were Seal Island (Elephant Island), Admiralty Bay (King George Island) and Palmer Station (Anvers Island). During 1987 - 1988, preliminary data on the breeding success, fledging weights, growth rates and diets of Chinstrap and Adelie Penguins were obtained. Although it is too early to draw conclusions on any aspects of the data, this report provides a current summary of the results of AMLR directed seabird research at the three monitoring sites.

steelon codends used in commercial fishery, with a nominal mesh size A = 80 mm and A = 100 mm, made of double twines with a thickness of 4.2 mm. The studies covered 6 major fish species.
1. It appears from the study that Antarctic icefish and bumphead notothenia are subject to selection during trawling, although the effectiveness of this process - especially in the latter case - is not satisfactory.
2. Scotia Sea icefish, Chaenodraco wilsoni, and Chionodraco rastrospinosus exhibit a lower tendency to pass through meshes of the codend than Antarctic icefish and bumphead notothenia.
3. The solution to the problem of ensuring selectivity of codends at a sufficiently good level seems possible as a result of the application of webbing with permanently open meshes for codend construction.
4. The most difficult matter will be preparing a codend with proper selectivity properties for South Georgia icefish, because this species exhibits the smallest tendency to escape during the trawling among all the species studied.
Conclusions and observations were in some cases based on a relatively small amount of experimental material.
Further investigations of this problem are necessary since producing selective trawl gear for harvesting Antarctic fish seems crucial from the point of view of conservation of living fish resources on those fishing grounds.