The currents and circulation in Saldanha Bay after 1975 deduced from historical measurements of drogues

In 1975, major harbour works modified the physiography of Saldanha Bay, dividing it into two bodies of water, Big Bay and Small Bay. This study uses historical drogue data to investigate the relative importance of physical forcing mechanisms (wind and tides) in Saldanha Bay after 1975. It is concluded that wind-forcing is the dominant factor in determining current direction and magnitude in both Small Bay and Big Bay. The dominance of the wind is in the surface layer which, in summer, is above the thermocline and, in winter, extends throughout the water column.     

Nest Densities of the Wandering Albatross Diomedea Exulans at the Prince Edward Islands,Estimated Using Gps

Hand-held Global Positioning System (GPS) receivers provide opportunities for detailed and rapid mapping of features, including biological ones, further enhanced by the removal during 2000 of "selective availability". GPS was used to map, describe and compare nest densities within wandering albatross Diomedea exulans colonies at subantarctic Marion and Prince Edward islands. On Prince Edward Island, the coordinates of 1 061 wandering albatross nests were determined and, on Marion Island, 1 779 nests. For describing nest densities of wandering albatrosses, a 50-m grid is recommended, at which scale, the densest area of Prince Edward Island was in Albatross Valley, where the area of the colony was 46 ha and nest density was 22.3 nests ha^?1. For Marion Island, the total area of the wandering albatross colonies was 306 ha and the nest density was 5.8 nests ha^?1. In the three study colonies there (Macaroni Bay, 28 nests; Sealer's Beach, 117 nests; Goney Plain, 140 nests), the density statistics did not differ greatly from the overall densities on the island, with overall mean densities of 4.9, 5.7 and 8.0 birds ha^?1 respectively. Although comparisons with nest densities at other breeding colonies are uncertain because of differing methods of computing them, the nest densities in Albatross Valley lie within the reported ranges for other colonies of great albatrosses.