CCAMLR

Counts of Adélie penguin populations are most conveniently and most often undertaken at breeding sites during the breeding season. The objective of this paper is to identify and describe the aspects of Adélie penguin population structure, dynamics and demography that are relevant to the interpretation of counts made at breeding sites and the estimation of overall population abundance derived from such counts. To appreciate what counts conducted at different times within a breeding season represent, it is important to understand the population dynamics of the different components of the population throughout the breeding season. The conceptual model described here is specifically based on data obtained from the Adélie penguin population at Béchervaise Island, East Antarctica. While the various life stages described here are also likely to represent other Adélie penguin populations, details in the proportion of each category either at the breeding site or at sea may potentially differ.

The size of two of the inaccessible (non-breeding) components of the Adélie penguin population associated with the Béchervaise Island breeding population is estimated over the past decade using a series of mark-recapture analyses and some simple population modelling techniques.

Broad-scale surveys of penguin breeding abundance generally rely on on-off counts of adults, nests or chicks across several or many breeding sites, and the timing of these counts is often outside the control of researchers. Time series counts of Adelie penguin breeding population attributes (adults, nest and chicks) within the breeding period show considerable variability across space and time (between years). Given this variability, there will be substantial uncertainty in correcting one-off counts with date-specific correction factors to estimate the population attempting to breed at the beginning of the breeding season.

This paper presents spatial modelling based abundance and density estimates of pack-ice seals, crabeater, Weddell and leopard seals, based on aerial survey line transect data collected in January 1999 under the Antarctic Pack-Ice Seal (APIS) programme. Estimates are reported for the Antarctic Peninsula and the western Weddell Sea region (90º to 30º W and 60º to 80º S).

More white-chinned petrels (Procellaria aequinoctialis) are accidentally killed in fisheries than probably any other seabird in the world, but the population impact of this mortality is poorly understood, partly because there have been no estimates of the species’ abundance in recent decades. The largest breeding aggregation, comprising the majority of the worldwide total, is believed to be on the sub-Antarctic island of South Georgia. We estimated the size of this population by calculating the area of suitable habitat and the density of occupied burrows within it. Just less than one million pairs of white-chinned petrels laid on South Georgia in the survey seasons (2005/06 and 06/07). This is 50% of the previous estimate, but still represents around two-thirds of the global population. If the population is declining due to fishery bycatch off S America, as is likely, the scale of annual mortality in this population alone is at least in the high tens of thousands, and plausibly hundreds of thousands.

This paper describes methods and results from a recent aerial survey of the macaroni penguin population at South Georgia.

We investigate the influence of krill (principally Euphausia superba) patchiness on the foraging distributions of seabirds to understand how variation in krill influences patch dynamics between krill and birds. At sea surveys were conducted near Elephant Island, Antarctica for three years (2004-2006) during the annual U.S. Antarctic Marine Living Resources (AMLR) program. Standardized strip-transect surveys were used to map seabirds, and a combination of acoustic and net surveys was used to map krill. We measured patch size of krill and seabirds and elucidated how krill patch dynamics influence foraging seabirds. The spatial association between krill and predators was influenced by the size and arrangement of krill patches. We found a negative relationship between abundance and patchiness of krill and predators, indicating that when krill is less abundant, krill and its predators are less abundant and concentrated. We conclude that annual patch dynamics of krill strongly influences the local abundance and distribution of seabirds. Such information should be used to interpret potential interactions between seabirds and krill fisheries operating near Elephant Island.