CCAMLR

The suggestion that sex of Adélie penguins, Pygoscelis adeliae, might be assigned by observing which member of the pair (the male) takes the first long incubation shift (Anon. 1991) was examined for each of the 1990–91, 1991–92 and 1992–93 breeding seasons. There was an 8- or 9-day period when more than 90% of the incubating birds were male and a 6- or 7-day period when more than 90% of the birds were female. The dates of these peak periods of male or female presence overlapped by only 2–5 days between the three seasons but were constant to within 2 days relative to the commencement of egg laying. Peak presence of males occurred 15–21 days after the appearance of the first egg in the colony and peak presence of females after 33–36 days from this date. In all three seasons male birds could be identified with 91∙8–98∙6% accuracy within 15–21 days after the first sighting of an egg. The method provides, therefore, a means of identifying the sex of Adélie penguins with an accuracy greater than 90% and is applicable to whole colonies containing several hundred pairs without recourse to continuous observations or capturing the birds.

Corrected ships heading data were used to calculate drift data for the shelf area to the west of South Georgia. The data were collected over a six-week period during 1986. A distance weighted interpolation was used to obtain tracer trajectories in this irregular data grid. The vector field is complex with no simple flow field. These data include a lot of complex process interactions. Particles getting onto the shelf become retained with little escape after a run of 100 days. Some of the trajectories are extremely complex. Particles to the north of the shelf can get up onto the shelf. Only those particles released very close to the shelf break in the south move up onto the shelf. Further south particles move to the west along the shelf.

A single time realisation of the FRAM model has been used to obtain trajectories of passive tracers. This note presents some of the analyses to provide background information on the potential transfers of krill in the Scotia Sea. More detailed presentation of the stream lines in the South Georgia region are also reported.