WILLIAM T. COBB, Antarctic Ecosystem Research Group, Southwest Fisheries Science Center, La Jolla, California 92038
During the 1996-1997 austral summer, researchers from the Antarctic Marine Living Resources (AMLR) program at the Southwest Fisheries Science Center conducted research on antarctic pinnipeds and seabirds in support of the Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR) Ecosystem Monitoring Program (CEMP). Studies were conducted at Seal Island (60°59'14"S 55°23'04"W) and Cape Shirreff at Livingston Island (62°28'07"S 60°46'10"W), Antarctica, during the austral summer (January to March).
Long-term data collection at CEMP sites includes census surveys, capture, and handling of animals and general observations (including weather, tag resights, and animal entanglements). The protocols and methods used for study design and data collection are those described in the CEMP Standard Methods manual (CCAMLR 1995). The objectives for the studies were the following:
Over the past decade, predator studies have focused on animals at the Seal Island location. Because Seal Island was found to be unsafe due to landslide hazards, however, studies at the island have been curtailed. The AMLR program hopes to continue to monitor the site intermittently over the next decade. To continue a comprehensive research program on antarctic predators, the AMLR program established a new campsite at Cape Shirreff this season. Preliminary results from information collected at each site are presented below. AMLR scientists at Seal Island and Cape Shirreff did not observe pinniped entanglements this season. A summary of the animals taken this season, by site, is provided in the table.
AMLR program researchers occupied Seal Island between 11 February and 16 March 1997. Limited research studies focused on antarctic fur seals and chinstrap penguins. Census surveys for antarctic fur seal pups were conducted at four study sites on Seal Island: Beaker Bay Beach, Big Boote, North Annex, and North Cove. Surveys were conducted by walking the perimeter of a colony, causing minimal or no disturbance to animals. In total, 212 pups were counted during these surveys. Because of limited time at the site, it was difficult to determine maximum pup numbers on the island. It is interesting to note, however, that the pup count for the North Cove/North Annex sites is the second highest count recorded since the 1993-1994 count during the same seasonal period (14-19 February). Counts for North Annex and Big Boote were comparable to those recorded during the 1995-1996 austral summer. Information describing animals with tags (from previous seasons or from other sites) was also recorded; these data can provide estimates of first reproduction as well as cohort and age-specific mortality. Sixteen known-aged individuals were sighted, including one female who was seen with a pup.
Weights were recorded for 217 chinstrap fledglings on Beaker Bay Beach at Seal Island. Fledglings were captured, weighed, marked (with small dye spot on a feather, thereby avoiding recapturing the same individual), and then released on the beach as close to the place of capture as possible. The timing of the start of fledging was normal compared to past seasons (Trivelpiece et al. 1997). Average fledging weight was 3.22 kilograms (±0.32 standard deviation), slightly higher than means recorded over the past seven seasons at Seal Island. Because time was limited, adult penguins, cape petrels, and macaroni penguins were not included in any study this season. Resight data (animals with tags from previous seasons or other sites) were recorded for 71 chinstrap penguins, 6 macaroni penguins, and 1 sheathbill ( Chionis alba ).
At the new Cape Shirreff camp, AMLR program researchers and two carpenters constructed a campsite consisting of four semipermanent structures. The site was occupied between 24 January and 8 March. Again, because of time constraints, the AMLR program did not conduct any pinniped studies this season. Daniel Torres from the Instituto Antarctico Chileno (INACH), however, conducts studies of antarctic fur seals at Cape Shirreff, including periodic censuses. On two occasions, to promote future cooperation and collaboration, AMLR scientists observed research activities (pup weighing) conducted by Torres' group. During observation, AMLR researchers did not record any data.
Limited studies on seabirds were conducted at Cape Shirreff this season. Breeding colonies were identified at the site, including 19 chinstrap, 6 gentoo, and 5 mixed gentoo-chinstrap colonies. Colonies were marked and plotted for future studies. Chinstrap penguin chicks (1,000 birds) were captured and banded; these individuals will be used for demographic studies. Chinstrap penguin fledglings (sample size of 214) were captured, weighed, and then released on the beach as close to the site of capture as possible. Of these fledglings, roughly 50 animals were weighed intermittently over a week; average weight for these individuals was 3.27 kilograms (±0.31 standard deviation). Adult chinstrap penguins were not censused this season. In addition, 12 nesting sites of brown skuas ( Catharacta lönnbergi ), including 16 chicks and 3 adults, were observed. The skuas (adults and chicks) were captured and banded. Because of time constraints, gentoo penguins, cape petrels, giant petrels ( Macronectes giganteus ), south polar skuas ( Catharacta maccormicki ), sheathbills, kelp gulls ( Larus dominicanus ), and blue-eyed shags ( Phalacrocorax atriceps ) were not included in any studies.
The author would like to thank the officers and crew of the R/V Yuzhmorgeologiya for their significant logistical support. This research is funded by the National Oceanic and Atmospheric Administration's National Marine Fisheries Service as part of the AMLR program.
CCAMLR. 1995. CCAMLR ecosystem monitoring program standard methods manual. Hobart, Tasmania: Convention for the Conservation of Antarctic Marine Living Resources.
Trivelpiece, W.Z., W.T. Cobb, R.S. Holt, D. Marks, J. Sterling, M. Stiehr, and T. Stiehr. 1997. Seabird and pinniped research at Seal Island, and Cape Shirreff, Livingston Island, Antarctica, 1997. In J. Martin (Ed.), AMLR 1996/97 field season report: Objectives, accomplishments and tentative conclusions (NOAA/NMFS/SWFSC admininstrative report LJ-97-09). La Jolla, California: Southwest Fisheries Science Center.