CCAMLR

A beach litter survey was carried out on Signy Island, South Orkney Islands during the 1995/96 austral summer. Similar surveys have been conducted during the previous five summers. Debris was cleared from three study beaches, Foca Cove, Cummings Cove and Starfish Cove, in January and February 1996 and items were identified. counted, weighed and any clues regarding their origin noted. No other beach surveys were carried out. This was because of logistical difficulties caused by the late break out of sea-ice and the redevelopment of the British Antarctic Survey (BAS) research station on Signy Island.
At Foca Cove, 26 items were found with a combined weight of 1.20 kg, and at Cummings Cove 81 items (6.23 kg). No items were found at Starfish Cove.
As in previous years, it is clear that almost all debris found on Signy Island originates from accidental or deliberate dumping of rubbish or fishing gear from fishing vessels. Only 2 of the 107 items recovered from the study beaches (~2%) were identified as originating from the research station.
The 1995/96 survey data show a reduction in both the weight of debris and the total number of items found on all three study beaches compared to data from 1994/95 and 1993/94. The results from 1995/96 were the lowest recorded since 1992/93, Comparison of monthly surveys carried out during January 1995/96, 1993/94, 1992/93 suggests that the reduction found in 1995/96 is a real trend rather than an artifact of reduced sampling effort.
The total number of plastic items recovered still remains high (45.8% of all items recovered from the study beaches). The most numerous type of plastic recovered was packaging bands (71.4% of all plastic items recovered). Fortunately, nearly all broads had been cut. No nylon line, as used in tong-line fisheries, was recovered.
Based on the small amount of beach debris recovered it is suggested that the fishing effort during 1995/96 around the South Orkney Islands was probably very low.

This report amalgamates stable isotope analyses of fish (n=476), squid (n=50) and octopod (n=17) samples obtained from long-line fishing vessels from four CCAMLR SSRUs (88.1C, 88.1H, 88.1I and 88.1J) during two fishing seasons 2005/6 and 2006/7. The species sampled were: 6 fish: Antarctic toothfish (Dissostichus mawsoni, n= 100), Patagonian toothfish (Dissostichus eleginoides, n=8), deep sea cod/blue antimora (Antimora rostrata, n=103), icefish (Chionobathyscus dewitti, n=83), moray (or eel) cod (Muraenolepis microps, n=75), and Whitson’s grenadier (Macrourus whitsoni, n=107); 4 squid: Galiteuthis glacialis (Gg, n=3), Kondakovia longimana (Kl, n=20), Psychroteuthis glacialis (Pg, n=20) and the Colossal squid, Mesonychoteuthis hamiltoni (Mh, n=7); and 3 benthic octopods: Octopodid sp. 1 (Oct-1, n=3), Octopodid sp. 2 (Oct-2, n=5) and Cirroctopus glacialis (Cg, n=9). Length and SSRU were the most significant variables in explaining the variation of δ15N and δ13C. Positive relationships between length and δ15N indicate that, very generally, larger fish consume prey of a higher trophic level than smaller fish. There were substantial residual within-species variations in δ15N and δ13C. Dissostichus mawsoni exhibited a range of 7 ‰ (9–16 ‰) in δ15N, which is equivalent to two trophic steps. All fish, except Antimora rostrata (2.7 ‰ range) showed a d15N range greater than 3.4 ‰ spanning more than one trophic step. This implies that the diet of all species sampled was variable, or that individual species were eating a similar diet which itself varied in size and trophic status. Overall, Dissostichus mawsoni and Dissostichus eleginoides occupied a trophic level equivalent to orca (Orcinus orca) and Weddell seals (Leptonychotes weddellii). Antimora rostrata, Muraenolepis microps and Macrourus whitsoni all occupied a trophic level below them. Chionobathyscus dewitti occupied the lowest trophic level of all fish analysed. There was considerable isotopic overlap in both δ15N and δ13C for all four fish prey species. Squids, excluding Mesonychoteuthis hamiltoni were found to be at a lower trophic level than fish species sampled, whereas on average octopods occupied a similar trophic level to the four fish prey species. The squid δ13C signature was more depleted (indicating a pelagic signature) than the octopods, which were all benthic feeders. Large variations in d13C for each species (around 3 ‰ for each species) indicated a variation in source of carbon within individual species. Species with enriched d13C may be feeding further north in warmer waters or may have a stronger benthic compared to pelagic source of carbon. There was no significant difference in Dissostichus mawsoni δ15N and δ13C values between the Northern Area, Ross Sea Slope and Terra Nova Bay Trench. In contrast, all of the four potential prey species caught in the Northern Area had enriched 13C values compared to the Ross Sea Slope, most likely due to warmer temperatures to the north. Since this increased δ13C signature is not picked up by Dissostichus mawsoni, then this suggests that Dissostichus mawsoni either move between and feed equally within the Northern Area and the Ross Sea Slope, or that they predominantly feed on the Ross Sea Slope.

Using a combination of techniques, we examine data from three cruises in 1999, 2000 and 2008 to calculate the biomass and demographic characteristics of Antarctic krill (Euphausia superba) surrounding the South Orkney and South Shetlands Islands. Net tow data show that length frequency distributions of krill between Elephant Island and the South Orkney Islands were similar. The similarity in length frequency distributions suggest that acoustic data collected as part of US AMLR finfish surveys may be useful in deriving biomass estimates for the South Orkney Islands in 1999. We use a simple bootstrap approach to illustrate our ideas. We re-analyze the data from 2000, including some CCAMLR data, and report on the biomass from a survey conducted in 2008. Biomass estimates in 2008 are calculated using the traditional Jolly-Hampton (1991) methodology, and represent the first estimate of biomass in this region. Together the data from these three years suggest that biomass in the South Orkney Islands is similar to the biomass in the South Shetland Islands, especially the Elephant Island region. The results are promising and suggest that where possible future data, derived from ancillary studies, can be used to better resolve the temporal trends in krill biomass in this region. Such data would benefit the future development of management strategies based on small scale units.

Presented research on feeding and the dietary structure by species of minke whales, conducted on board the whaling fleet Sovietskaya Ukraina during the 1982/83 - 1985/86 seasons. Whaling was conducted in all four seasons. There have been no noticeable increase of the population size of large whales over the years after the cessation of whaling. The role of a short and profitable from the energy point of view trophic chain «phytoplankton - krill - baleen whales», which is of main interest due to the potential meaning of its last link for the commercial exploitation, reduced significantly.

The article is based on the data sampled by the authors in the 29th cruise of f/v “Konstruktor Koshkin” (shipowner is the company “Interrybflot”, Sevastopol, Ukraine) in Subarea 48.2 from March till April 2008. The paper has analyzed the distribution of commercial aggregations of krill, their fishable biomass in the different periods of observations, krill biological state, hydro meteorological and ice conditions. Results of fisheries are given. Some ideas about allocation of limits of krill catch between SSMUs in Subarea 48.2.

Weddell seals (Leptonychotes weddellii) have proved to be an important predator of Antarctic toothfish (Dissostichus mawsoni), and currently there is no ecosystem monitoring program (CEMP) in place under CCAMLR with respect to the Ross Sea toothfish fishery. In a previous paper submitted to EMM in 2007 (WG-EMM 07/13), we described procedures whereby aerial photography could be used to monitor Weddell seals along the Victoria Land coast. That area would be important to monitor changes in distribution and abundance, as seals from all the colonies along that coast likely forage in CCAMLR SSRUs 88.1H and 88.1J (WG-EMM 06/29). Herein, we compare air with ground counts made in Erebus Bay, McMurdo Sound, in November 2007, and summarize historical results of aerial surveys made along the coast of Victoria Land. The high correspondence between air and ground counts shows that aerial photography can successfully be used to document changes in distribution and abundance of Weddell seals. Ground counts of Erebus Bay colonies made annually, 1974-2007, demonstrate the sensitivity of count data to environmental variability and the variance that could be expected over a time when the Ross Sea system was without influence from industrial fishing. On the basis of this and the previous paper, a Weddell seals monitoring program can now be put into effect under CEMP, begun with a one-time survey to identify all important haul out locations and the ones that best lend themselves to aerial surveillance.

An uncertainty heretofore has existed over the importance of Antarctic toothfish (Dissostichus mawsoni) as prey of top predators in the Ross Sea. We reviewed the literature to assess the relative weight that should be given to direct, observational evidence of predator diet composition, as opposed to indirect evidence from scat and biochemical analysis. As a result of this assessment, it is evident that toothfish are an important prey of Weddell seals (Leptonychotes weddellii). Recent findings show the seals do not eat toothfish hard parts, thus providing the reason that toothfish have seldom been detected in scat or stomach samples; biochemical samples have been taken only from seal populations where toothfish do not occur. On the basis of data from an under ice observation platform, non-breeding seals in McMurdo Sound take 0.8-1.3 toothfish per day. Seals with video recording equipment were seen to closely encounter toothfish but for unknown reasons did not often pursue for capture. It is estimated that the non-breeding portion of the seal population in McMurdo Sound, during spring and summer, consume about 52 tonnes of toothfish. Too many unknowns exist to estimate what the larger, breeding portion consumes during that and other parts of the year, although it should not be trivial. Much less is known quantitatively about the importance of toothfish to type-C (fish-eating) killer whales (Orcinus orca), but observational evidence indicates toothfish consumption to be common. A decline in the abundance of toothfish in McMurdo Sound appears already to be leading to a decline in the number of foraging killer whales. Care must be taken in managing the Ross Sea toothfish fishery, as the potential is great that, given the high degree of trophic overlap and competition among top predators, likely cascades will lead to dramatic changes in the populations of charismatic megafauna, particularly the seals, should the toothfish, probably the most important predator of fish in the system, become overly depressed.