CCAMLR

During three summer surveys at Prince Edward Island (PEI), southern Indian Ocean (2001, 2004 and 2008), 416 southern elephant seals Mirounga leonina were inspected for identification tags. In all, 42 seals that had been tagged as weaned pups at their natal site were found on Marion Island (MI), 38 of which could be individually identified by resighting their tag numbers. The majority of the MI-tagged seals were yearlings or subadults, and all but one were hauled out at PEI for the annual moult. The attendance rate of the known individuals at their natal island during the annual moult was only 40%, based on their resighting histories. This was significantly lower than the 77 ± 6% moult attendance rate estimated for a random MI population sample drawn from the same cohorts (based on 10 000 replications). Annual resight probabilities (considering all haulout phases) was 58% per annum for the MI seals seen at PEI, and 80 ± 4% for the simulation. Seasonal and annual absences of seals from MI violate the ‘homogeneity of capture’ assumption of mark–recapture models. When multiple sightings during any year are treated as a single sighting, resights during other haulouts (e.g. breeding) compensate only partially for absences during the moult. Therefore, mark–recapture studies undertaken in archipelagos should ideally include both marking and resighting of individuals on all islands which will allow discrimination between mortality and local migration.

The onshore distributions and the abundances of Antarctic fur seals Arctocephalus gazella and Subantarctic fur seals A. tropicalis were determined at Prince Edward Island during 16–20 December 2008. This repeats a survey conducted in December 2001 and extends the area surveyed to include the entire south-west coast of Prince Edward Island. Of the two colonies of Antarctic fur seals, the colony among Subantarctic fur seals north of Boggel Beach remained small, with increased numbers of Subantarctic fur seals and putative hybrids. The other Antarctic fur seal breeding colony at Penguin Beach remained free of Subantarctic fur seals and had expanded at a mean intrinsic rate of natural increase of 11.4% per year from 2001. With an estimated 810 pups, the Antarctic fur seal is still in the rapid recolonisation phase of population growth. The distribution of the more widespread and abundant Subantarctic fur seals also had increased, with several new breeding colonies along the east coast and one at Kent Crater on the west coast. The annual pup production was conservatively estimated at 14 130 pups. The mean intrinsic rate of natural increase has declined to –0.3% per year over the last seven years, compared to the 9.3% per year between 1987/1988 and 2001/2002, and the population is in the mature phase of population growth.

Breeding numbers of Laridae and other surface-nesting seabirds have been monitored at subantarctic Marion Island since 1996/97 and counts of breeding birds were made at nearby Prince Edward Island in December 2001 and December 2008. Four species are regular breeders at the islands: subantarctic skua Catharacta antarctica, kelp gull Larus dominicanus, Antarctic tern Sterna vittata and Kerguelen tern S. virgata. The latter three species currently each have populations of below 150 breeding pairs at the islands. Kelp gull numbers appear to be relatively stable though they may have decreased since the 1980s. Kerguelen tern numbers decreased and then recovered at Marion Island but numbers of the species have declined at Prince Edward Island and it maintains a tenuous foothold there. The small Antarctic tern population appears to be stable.

The second mid-summer survey of surface-nesting seabirds at the Prince Edward Island group (Marion and Prince Edward islands) was conducted during December 2008, seven years after the initial midsummer survey. Wandering albatrosses Diomedea exulans may have decreased slightly at Prince Edward Island, mirroring a decrease of roughly 2% per year at Marion Island from 1998 to 2005, a decline that has since reversed. Numbers of grey-headed albatrosses Thalassarche chrysostoma on Marion Island have remained stable, whereas the population on Prince Edward Island decreased by 20% from 2001 to 2008 (3% per year). The estimate of Indian yellow-nosed albatrosses T. carteri at Prince Edward Island was similar in 2001 and 2008. Counts of both sooty albatrosses Phoebetria spp. were substantially higher at Prince Edward Island in 2008, possibly as a result of better coverage compared to 2001. Dark-mantled sooty albatrosses P. fusca on Marion Island have decreased by almost 2% per year since 1996, continuing a negative trend from the early 1980s, whereas lightmantled sooty albatrosses P. palpebrata have increased by almost 6% per year at Marion Island since 1996. Counts of both giant petrels increased at Prince Edward Island (northern Macronectes halli by 44%; southern M. giganteus by 28%), whereas their numbers have remained stable at Marion Island. Current best estimates for annual breeding populations (pairs) at the two islands are 3 650 wandering albatrosses, 9 500 grey-headed albatrosses, 7 000 Indian yellow-nosed albatrosses, 2 900 dark-mantled sooty albatrosses, 800 lightmantled sooty albatrosses, 750 northern giant petrels and 2 800 southern giant petrels, confirming the global importance of the Prince Edward Islands for these seven species. Apart from the dark-mantled sooty albatross, their populations are reasonably healthy despite fishing mortality.

Subantarctic skuas Catharacta antarctica are key predators of burrowing petrels at sub-Antarctic islands, and can be used to monitor the health of burrowing petrel populations. A survey of skuas at the Prince Edward Islands was conducted during December 2008, repeating a previous survey in December 2001. Prince Edward Island (46 km2) remains free of introduced mammals, whereas Marion Island (290 km2) had a feral population of cats from the 1950s to 1980s, and still supports a large population of introduced house mice Mus musculus. Breeding skuas were more widespread, occurred at greater densities and extended to higher elevations at Prince Edward Island than Marion Island. Prince Edward also supported twice as many non-breeding birds. Burrowing petrels comprised 96% of prey in skua middens at Prince Edward Island compared to only 22% on Marion Island where penguins are more important. The numbers of breeding pairs at Prince Edward Island increased from 2001 to 2008, probably as a result of better coverage in 2008, whereas the number of skua nests on Marion Island was barely half that counted in 2001, continuing an apparent decrease in this species at Marion Island since the 1980s. There is no evidence that removal of cats from Marion Island in the early 1990s has benefited the major native predator of burrowing petrels.

Numbers of Crozet shags Phalacrocorax [atriceps] melanogenis breeding at Marion Island decreased by more than 70% from 840 pairs in 1994/95 to 220 pairs in 2003/04 and then increased to some 500 pairs in 2008/09. The trends are thought to have been influenced by breeding success, which averaged 0.30 and 0.66 chicks per pair per year from 1998/99– 2002/03 and 2003/04–2008/09, respectively. There were similar trends in numbers breeding and breeding success of gentoo penguins Pygoscelis papua, which at Marion Island have a similar diet to Crozet shags, suggesting that both species may have been influenced by food availability. Numbers of Crozet shags breeding at Prince Edward Island approximately doubled between the summers of 2001/02 and 2008/09. In 2008/09, some 600 pairs of Crozet shags were breeding at the Prince Edward Islands.

Four species of penguin breed regularly at South Africa’s Prince Edward Islands: king penguin Aptenodytes patagonicus, gentoo penguin Pygoscelis papua, macaroni penguin Eudyptes chrysolophus and southern rockhopper penguin E. chrysocome. In December 2008 it was estimated that some 65 000 pairs of king penguins were incubating eggs at Marion Island, the larger of the two islands in the group, and 2000 pairs at Prince Edward Island. At Marion Island from 1987–2008, there was no long-term trend in numbers of king penguin chicks that survived to the end of the winter period, but there was considerable fluctuation in chick production in the 1990s. It was roughly estimated that on average 88% of king penguin chicks survived the winter period (from April to September/October). Numbers of gentoo penguins at Marion Island decreased from more than 1300 pairs in the mid 1990s to fewer than 800 pairs in 2003, and then increased to almost 1100 pairs in 2008 as breeding success improved. Between 1994/95 and 2008/09 numbers of macaroni and southern rockhopper penguins at Marion Island decreased by about 30% and 70%, respectively. In 2008/09, some 290 000 pairs of macaroni penguins bred at this island, mostly in two large colonies where there was a progressive decrease in the density of nests. At both these colonies decreases in numbers breeding followed outbreaks of disease. Inadequate breeding success has influenced the decreases of macaroni and rockhopper penguins. In 2008/09, some 42 000 pairs of southern rockhopper penguins bred at Marion Island and 12 000 pairs of macaroni penguins and 38 000 pairs of southern rockhopper penguins at Prince Edward Island.

The data of krill fishery in Subarea 48 for 1986 – 2008 presented to CAMLR database by haul-by-haul data were used. Standardizing CPUE was performed by applying the generalized linear model with random effects (GLMM). The analysis of diagnostics of GLMM tuning indicated that the model with Tweedie’s distribution satisfactorily describes the set of data collected in Subareas 48.1, 48.2 and 48.3. However, there were many hauls to be interpreted as “outliers”, i.e. the points from the sample where residuals significantly deviated from the normal distribution. The number of krill hauls, where Pearson’s residuals corresponded to quintiles of normal distribution more then 2, constituted 2.3% of the total number of krill hauls in the CAMLR database for 1986 – 2008. It was shown that extremely high CPUE values are results from converting high catch values obtained for a short time haul (5-10-15 min) into catches per hour. Such high CPUE values constituted 100 – 600t/hour and more (up to 1000 t/hour). The» outliers by different fleets (countries) in the Subareas 48.1-48.3 were analyzed. The procedures of CPUE indices estimation for krill fishery description claim special attention. The authors discussed several approaches to improve diagnostics of GLMM tuning for krill fishery analysis.

At CCAMLR-XXIX, the Commission recommended that a staffing and salary strategy be included in the review of the Secretariat’s Strategic Plan and that SCAF consider the outcomes of that review at its meeting in 2011 (CCAMLR-XXIX, paragraph 3.5 and 3.10). In addition, following consideration at last year’s meetings of WG-SAM and WG-FSA the Commission adopted a recommendation from the Scientific Committee (SC-CAMLR-XXIX, paragraph 14.2) that a review of the Secretariat’s data management systems be undertaken (CCAMLR-XXIX, paragraph 3.7).

This paper provides the 2011 meetings of WG-SAM and WG-EMM with a brief description of the process that has been supported since CCAMLR-XXIX to address these tasks and the principal outcomes of relevance to the Scientific Committee and its working groups.