(Table 1) Reproductive performance of brown skua pairs with and without feeding territories at Potter Peninsula/King George Island from 1998/1999 to 2000/2001

In the maritime Antarctic, brown skuas (Catharacta antarctica lonnbergi) show two foraging strategies: some pairs occupy feeding territories in penguin colonies, while others can only feed in unoccupied areas of a penguin colony without defending a feeding territory. One-third of the studied breeding skua population in the South Shetlands occupied territories of varying size (48 to >3,000 penguin nests) and monopolised 93% of all penguin nests in sub-colonies. Skuas without feeding territories foraged in only 7% of penguin sub-colonies and in part of the main colony. Females owning feeding territories were larger in body size than females without feeding territories; no differences in size were found in males. Territory holders permanently controlled their resources but defence power diminished towards the end of the reproductive season. Territory ownership guaranteed sufficient food supply and led to a 5.5 days earlier egg-laying and chick-hatching. Short distances between nest and foraging site allowed territorial pairs a higher nest-attendance rate such that their chicks survived better (71%) than chicks from skua pairs without feeding territories (45%). Due to lower hatching success in territorial pairs, no difference in breeding success of pairs with and without feeding territories was found in 3 years. We conclude that skuas owning feeding territories in penguin colonies benefit from the predictable and stable food resource by an earlier termination of the annual breeding cycle and higher offspring survivorship.

The CoastColour Round Robin datasets: a database to evaluate the performance of algorithms for the retrieval of water quality parameters in coastal waters

The CoastColour project Round Robin (CCRR) project (http://www.coastcolour.org) funded by the European Space Agency (ESA) was designed to bring together a variety of reference datasets and to use these to test algorithms and assess their accuracy for retrieving water quality parameters. This information was then developed to help end-users of remote sensing products to select the most accurate algorithms for their coastal region. To facilitate this, an inter-comparison of the performance of algorithms for the retrieval of in-water properties over coastal waters was carried out. The comparison used three types of datasets on which ocean colour algorithms were tested. The description and comparison of the three datasets are the focus of this paper, and include the Medium Resolution Imaging Spectrometer (MERIS) Level 2 match-ups, in situ reflectance measurements and data generated by a radiative transfer model (HydroLight). The datasets mainly consisted of 6,484 marine reflectance associated with various geometrical (sensor viewing and solar angles) and sky conditions and water constituents: Total Suspended Matter (TSM) and Chlorophyll-a (CHL) concentrations, and the absorption of Coloured Dissolved Organic Matter (CDOM). Inherent optical properties were also provided in the simulated datasets (5,000 simulations) and from 3,054 match-up locations. The distributions of reflectance at selected MERIS bands and band ratios, CHL and TSM as a function of reflectance, from the three datasets are compared. Match-up and in situ sites where deviations occur are identified. The distribution of the three reflectance datasets are also compared to the simulated and in situ reflectances used previously by the International Ocean Colour Coordinating Group (IOCCG, 2006) for algorithm testing, showing a clear extension of the CCRR data which covers more turbid waters.