CCAMLR

Shipboard tracking study of breeding chinstrap penguins (Pygoscelis antarctica) and Antarctic fur seals (Arctocephalus gazella ) at Seal Island were conducted to identify and evaluate their foraging areas in late December 1994 (Leg I) and late January 1995 (Leg II). Leg I and Leg II corresponded to the incubation and guard period, respectively, for chinstrap penguins ; penguins were divided into diurnal and overnight foragers during Leg II. Highest krill (Euphausia superba) densities regularly occurred on the shelf north of Seal Island. However, all predators except diurnal foraging penguins went northward beyond the shelf, and foraged in offshore region during Leg I and on slope during Leg II. The diurnal foraging penguins alone fed on the shelf. The following advantages are considered for feeding in the offshore/slope regions over on the shelf: (1) krill were present near the surface throughout the day so that only shallow diving was required to catch krill even in the day time; (2) krill tend to be larger in size; and (3) Myctophid fish occurred within the predators' maximum diving range at night. Considering that overnight foraging was always made in the offshore/slope regions, (3) is regarded as the most important factor making the predators except diurnal foragers choose the offshore/slope regions (less abundant areas for krill) over the shelf region (more abundant areas for krill).

The diet of Cape petrel was investigated on Mossman Hills, Laurie Island, South Orkney Islands in January-February 1995. Twenty stomach contents were sampled by a water offloading method, during late incubation and chick-rearing period. The analysis of the samples showed that Euphausiids were by far the main prey. Antarctic krill Euphausia superba constituted the bulk of the diet, predominated in mass (97.2%) and in frequency (95% ). Our results reflect broad similitary with other studies conducted during the same period of the life cycle.

A proposal to monitor changes in coastal fish populations is presented in this document. The methodology considered is based in the analysis of regurgitated pellets of the blue-eyed shag Phalacrocorax atriceps. The fundaments of the proposal as well as the methods tested and the steps followed are also provided.

A comparative analysis was carried out on stomach contents and pellets (=regurgitated cast) of the blue-eyed shag or imperial cormorant Phalacrocorax atriceps collected throughout the breeding season at Nelson Island, South Shetland Islands. This allowed to estimate correction factors necessary for the quantification of fish represented in pellets. These factors were obtained for Notothenia coriiceps, Harpagifer antarcticus, Nototheniops nudifrons, Trematomus newnesi, Gobionotothen gibberifrons, Notothenia rossii, Pagothenia bernacchii and Parachaenichthys charcoti whereas Pleuragramma antarcticum, Notolepis coatsi and Electrona antarctica were represented in pellets but not found in the stomach contents. Fish were the main prey and N. coriiceps and H. antarcticus were the dominant species both in mass and number. Observations on behaviour showed that the daily foraging trips per bird increased in number but diminished in duration throughout the breeding season. These trends are related to the increase in the chicks' energetic demands.