“Movements of southern rockhopper penguins from Staten Island during the winter dispersion in relation with oceanographic features two year study.”

A RAYA REY; K PÜTZ; A SCHIAVINI

Ushuaia, Tierra del Fuego, Argentina

Congreso; V International Penguin Conference; 2004

CADIC-CONICET

Seabirds show a strong association with oceanographic features expressed as fronts, sea surface height anomalies and water mass boundaries during their foraging movements while at sea. We characterized the movements and oceanographic habitats of southern rockhopper penguins from Staten Island during the winter dispersion. Ten birds were fitted with platform terminal transmitters in March 2002 and 15 in March 2003. Analyses of satellite telemetry data in conjunction with remotely sensed sea surface temperature (SST) and bathymetry revealed two main foraging areas: one situated to the north of Staten Island off the coast of Tierra del Fuego and the other one to the south of Staten Island in the vicinity of the Antarctic Polar Front. Sixteen out of 25 birds commuted between the two zones. In the area to the north of Staten Island birds used shallow coastal waters characterized by tidal fronts, which are well-known highly productive features. Moreover, penguins spent 47% of their time at sea in those areas. By contrast, the area to the south included pelagic waters (> 3000m) and penguins spent 43% of their time in those waters. This area, in the region of the Drake Passage, included the Polar Frontal Zone (PFZ), an important water mass with high phytoplankton concentration, especially in its southern and northern limits (polar front PF and sub-Antarctic front SAF, respectively). During March and April birds preferred water masses warmer than 8ºC SST (along the Atlantic coast of Tierra del Fuego), although during April some birds also foraged in Antarctic waters (-2ºC). From May to July penguins spent more than 50% of time in water masses between 4-6ºC (PFZ based on the published and widely used locations of water masses and fronts). The individual movements were analysed together with SST, sea surface height anomalies and chlorophyll a images to identify the oceanographic features that penguins follow during their movements. Implications for the status and present conservation of this species in the southwest Atlantic Ocean are also discussed.