CCAMLR

Labelled water methodology was used to quantify energy expenditure during lactation and energy gain during the post-breeding aquatic phase in Southern elephant seal females at Stranger Point, King George Island (25 de Mayo). During lactation females spent a mean of 6021±1365 Mj, which resulted in a loss of 35% of the initial mass, comprising 63% of initial body fat and 20% of initial body protein. During the 58±5.4 d post-breeding foraging period, females gained 135±39 Kg, which allowed them to recover an average of 55% of the mass, including 46% of the fat, 71% of the protein and 47% of the energy lost during lactation. Neither the mass nor the energy lost during lactation were related to those gained while at sea. However, protein loss expressed in absolute terms or as a proportion of that present at the beginning of lactation explained about 50% of the variation in the protein gained during the post-breeding phase. This might indicate the presence of a mechanism favouring an increase in lean tissue during post-breeding.
Daily energy requirements for an average sized female during the post-breeding aquatic phase were estimated at 96 Mj. Estimation of prey consumption varies according to assumptions about diet composition. On a basis of 450 females, the total biomass of fish and squid consumed by the breeding group, assuming a diet composed of 75% cephalopods and 25% fish, was estimated at 521 t and 174 t respectively for the period examined.

Many international conservation treaties, non-binding agreements and other instruments that have relevance to marine protected area (MPA) development provide for action to be taken globally, and thus include Antarctica within the scope of a worldwide system of marine protected areas. However, depending on their specific provisions, full application in Antarctic waters may be difficult, inappropriate or even impossible because of the area’s unique political situation and existing regimes. It is concluded that although direct application of other international conservation agreements is in most cases unlikely to be feasible, efforts should be made to apply within the Antarctic Treaty System (ATS) certain principles and requirements agreed under instruments with global purview. These include the formulation of guidelines and criteria for MPA establishment, the consideration of marine protection as a separate, but linked issue to protection of other environments, and the development of more specific guidelines on the timeframe in which these should take place. In addition, the consideration of Antarctic waters in parallel with global work to develop high seas protected areas should be undertaken to achieve the goal of a global, representative system of MPAs, of which Antarctic MPAs should be an important component.

Observers on krill vessels fishing around South Georgia in the 2003 fishing season recorded fur seal captures by some krill fishing vessels. These captures can be attributed to the absence of effective mitigation measures (escape panels in the nets) and lack of experience of crews new to the fishery. Experienced vessels, employing effective mitigation measures, caught no seals. Although these levels of seal mortality are unlikely to impact significantly on fur seal populations, it is clearly important to have observers on krill vessels monitor the effectiveness of mitigation measures as well as to collect other biological data.

The USSR has fished in the Atlantic Sector of the Antarctic for three living marine resources: whales, krill and fish. In order to provide the fisheries with rational database the AtlantNIRO vessels conducted fishery and scientific studies. Investigations on whales were commenced in 1960. There were collected a big set of statistical and biological data on embryos growth rate of sperm whales, pigmy blue whales, southern baleen whales, physiological structure of the females share in the aggregations of various whale species, migrations etc. which is widely used for correct stocks evaluation and population dynamics. Using information collected by whalers, the world krill fishery was commenced by the AtlantNIRO vessel “Muxun” in 1961. From 1961 to 1970 eight scientific research and fishery voyages to the ASA were undertaken, from 1971 to 1980 – 25 voyages, from 1981 to 1989 – 22 voyages. For all the period of studies in the ASA an enormous primary database was collected by AtlantNIRO and VNIRO. Investigations of Antarctic fish were started by RV "Academik Knipovitch" in 1967. The main purpose of the researches was ecology of the commercially important species, stock and recruitment assessment and search for the new resources. Since 1960 AtlantNIRO’s contributions in the study of all three resources: whales, krill and fish, were very important, unique and may be used for oceanic ecosystem better understanding and protection and for planning and development of sustainable fisheries as well.

Numbers of gentoo penguins Pygoscelis papua, macaroni penguins Eudyptes chrysolophus, eastern rockhopper penguins E. chrysocome filholi and Crozet shags Phalacrocorax [atriceps] melanogenis continued to decrease at Marion Island in 2003/04. The decreases are thought to be due to a reduced availability of prey to birds foraging near island. Numbers of wandering albatrosses Diomedea exulans, grey-headed albatrosses Thalassarche chrysostoma, light-mantled sooty albatrosses Phoebetria palpebrata, northern giant petrels Macronectes halli, Antarctic terns Sterna vittata and Kerguelen terns S. virgata appear stable at the island, but often with large fluctuations in numbers breeding. Numbers of dark-mantled sooty albatrosses P. fusca, southern giant petrels M. giganteus and kelp gulls Larus dominicanus have shown a long-term decrease, although the count for dark-mantled sooty albatrosses was higher in 2003/04 than for several seasons.

In South Africa, four seabirds that feed mainly on sardine Sardinops sagax and anchovy Engraulis encrasicolus all have an unfavourable conservation status or a small population: African penguin Spheniscus demersus, Cape gannet Morus capensis, Cape cormorant Phalacrocorax capensis and swift tern Sterna bergii. Availability of prey is thought to influence the populations of these species, but their food requirements have not been accounted for in management of the purse-seine fishery on sardine and anchovy. Means of identifying and attaining target populations of predators that are dependent on forage fish prey are discussed. It is suggested that criteria used by The World Conservation Union to assess the conservation status of a species may prove useful in determining minimum viable populations, and that the use of functional relationships in coupled models of predators and their prey may enable quantification of levels of escapement of prey that are necessary to maintain or rebuild populations of predators.

Three basic length groupings of krill were identified with the clustering analysis on the basis of the data of two complex surveys carried out in the western Atlantic sector of Antarctic in summer 1984 and 1988. The large-length grouping is biotopically associated with the waters of the southern branch of the Antarctic Circumpolar Current (ACC). The middle-length grouping and the small-length grouping are associated with the Weddell Sea waters. Besides, the additional fourth grouping with bimodal length structure was revealed in the survey 1988. It is assumed that the first grouping is transported into the area from the Pacific sector, while the second and the third groupings are of local origin and the forth one is formed as a result of mixing of the groupings inhabiting different biotopes under the impact of the secondary frontal zone dynamic conditions. Hydrometeorological conditions in summer 1988 complied with the climatic norm and seemed to stipulate the typical pattern of krill spatial distribution. The different distribution pattern observed during the survey 1984 was related to intensification of ACC and reduction of the Weddell waters intrusion into the eastern Scotia Sea. The comparative analysis of the survey results in 1984, 1988 and CCMLR-2000 showed that krill population structure in the western Atlantic sector of Antarctic has not actually changed.

The Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR) is currently considering plausible models of the Southern Ocean ecosystem within the Working Group on Ecosystem Monitoring and Management (WG-EMM). While recognised to be an important component of this ecosystem, particularly with regard to food-web structure and function, squid have rarely been included in previous ecosystem models except perhaps to assess their potential impact as predators of Antarctic krill. This paper describes properties for three groups of squid that may be included in future ecosystem models of the Southern Ocean: onychoteuthids, ommastrephids and small – medium nektonic squids. Important ecological differences are considered to exist among these three groups (e.g. spatial and depth distribution, ontogenetic and vertical migrations). Furthermore, this paper reiterates findings from previous studies that squid should no longer be modelled as specialist predators on Antarctic krill.

This paper reports on the intersessional activities of the Steering Committee of the “Workshop on plausible ecosystem models for testing approaches to krill management” in preparation for the workshop at WG-EMM 2004. The overarching Terms of Reference are (i) to review the approaches used to model marine ecosystems, (ii) to consider plausible operating models for the Antarctic marine ecosystem, and to advance a program of work to develop and implement operating models to investigate the robustness of different management approaches to underlying uncertainties in the ecological, fishery, monitoring and assessment systems. As agreed at WG-EMM in 2003, intersessional activities have included (i) provision of advice on the potential contributions from experts in preparation for the workshop and in participating in the development of models at the workshop, (ii) a review of relevant literature and information on the development of ecosystem models elsewhere as per the first term of reference, (iii) compilation of a catalogue of available software and other simulation environments for ecosystem modelling, (iv) preliminary consideration of the requirements for datasets, estimates of parameters and other aspects related to the second term of reference, and (v) preliminary outline of the aims and specifications for ecosystem modelling as it relates to the development of management procedures for krill. The results of this work are outlined. Also provided in this report is a draft agenda for the workshop.

CCAMLR requires an assessment method for recommending a subdivision of the krill catch limit in Area 48 that will be highly likely to achieve the objectives of the convention despite the uncertainties in knowledge. This will be part of the management procedure governing the krill fishery. The agreed workplan for developing a management procedure includes the evaluation of candidate management procedures in a simulation framework, using plausible models of the Antarctic marine ecosystem. This paper develops a framework for erecting such models. It is divided into three main parts, addressing different aspects of model development. Part 1 outlines the issues to consider in assessing the requirements of plausible models. Part 2 discusses the general model requirements while Part 3 presents a possible framework for developing ecosystem models to evaluate krill management procedures. The first section of this part outlines a conceptual approach to the taxonomic/biological elements of a model and the manner in which linkages between those elements might be considered. The second section details a model framework for characterising (i) the different taxa depending on the status of knowledge and their importance for understanding the ecosystem effects of fishing, (ii) important physical processes that will influence the system and (iii) the fisheries. In developing these parts, the paper highlights areas that may be necessary to be considered by WG-EMM in the development of plausible models.