Photo-identification of humpback whales, Megaptera novaeangliae, off the Antarctic peninsula: 1997/98 to 1999/2000

Abstract

During three Summer seasons (1997/98-1999/00), photographic sampling of humpback whales was conducted by Projeto Baleia/Brazilian Antartic Programme in Waters of the Antartic Peninsula. Whales photographed totalled: 63 (1997/1998), 70 (1998/1999) and 21 (1999/2000). Of these, 74,6% (n=47), 87,1% (n=61) and 100% (n=21), respectively, were represented by photographs categorised as quality 1 (excellent) or 2 (moderate). Inter-annual comparisons showed two matches: a whale photographed on 27 January 1998 in the Gerlache Strait was resighted on 11 January 1999 in the same region; the second on 3 February 1998 in the Gerlache Strait was resighted on 25 January 1999 at almost the same coordinates. These matches indicate that humpback whales may show fidelity to feeding grounds off the Antartic Peninsula. Intra-annual comparisons showed two matches: a whale photographed on 22 January 1998 close to the King George Island and another on 27 January 1998 in the Bismarck Strait were resighted together on 7 March 1998 in the Gerlache Strait. Average índices of fluke colouration obtained for 1997/1998 and 1998/1999 were 2.39 (n=44) and 2.60 (n=53), respectively. Total average índex, including photographs from the three period, resulted in 2.54 (n=116). All values are significantly different from those obtained by Rosenbaum ET AL. (1995) for western and eastern Australia (p<0.001) and similar to that found for Colombia (p>0.05) (non-parametric test of Kolmogorov-Smirnov). These results reinforce the view that humpback whales feeding in the western side of the Antartic Peninsula probably originate from eastern South Pacific breeding grounds.