Spatial and seasonal variability in cetacean distribution in the fjords of northern Patagonia, Chile

Abstract

Viddi, F. A., Hucke-Gaete, R., Torres-Florez, J. P., and Ribeiro, S. 2010. Spatial and seasonal variability in cetacean distribution in the fjords of northern Patagonia, Chile. – ICES Journal of Marine Science, 67: 959–970. Compared with other Chilean coastal areas, little is known about the diversity and distribution of cetaceans in northern Patagonian fjords. Between December 2000 and November 2001, surveys on platforms of opportunity were undertaken in southern Chile to evaluate species richness and the spatial and seasonal distribution of cetaceans. Nine species were recorded, blue, humpback, and minke whales, Peale's dolphin, Chilean dolphin, killer whale, false killer whale, bottlenose dolphin, and Cuvier's beaked whale. The pattern of cetacean distribution displayed significant seasonal differences, with most baleen whales (mysticetes) observed during late summer and autumn, and toothed cetaceans (odontocetes) mostly during spring. Generalized additive models, used to assess the spatial distribution of cetaceans, showed that mysticetes were distributed disproportionately along a north–south gradient, in open gulfs with oceanic influence, and close to shore. In contrast, odontocetes were observed mainly within narrow channels, areas with complex coastal morphology, peaking at different water depths. These findings, although from a single year of data, increase our understanding of habitat determinants of cetacean distribution in southern Chile. The results have the potential to be applied to coastal conservation and management in the region.

Diversity and Summer Distribution of Cetaceans in Inlet Waters of Northern Aisén, Chile

“…Our results confirmed that Peale's dolphin and Chilean dolphin are the most frequent small cetacean species (65.5% and 20.2% of the sightings respectively) that inhabit in most of the sheltered areas of southern Chile as it has been documented in the region (Goodall et al 1988, 1997, Goodall 1994, Viddi et al 2010). An exception is the eastern Strait of Magellan where Commerson's dolphin is the most common one (Lescrauwet et al 2000).…”

“…In this last area a summer aggregation of humpback whales has been reported as well (Galletti et al 20062 , 20083 , Hucke-Gaete et al 2006 ), and photographic identification has confirmed movements and interchange of humpback whales individuals within the Strait of Magellan near Carlos III Island (Capella et al 2008 (Viddi et al 2010). Mysticetes were distributed along a north -south gradient with preferences for open gulfs with oceanic influence, and close to shore.…”

“…The near shore habits of the small cetaceans species have been documented by Goodall et al (1988Goodall et al ( , 1995Goodall et al ( , 1997, Gibbons et al (2001), Ribeiro et al (2005), Viddi & Lescrauwaet (2007) and Viddi et al (2010).…”

“…Mysticetes were distributed along a north -south gradient with preferences for open gulfs with oceanic influence, and close to shore. In contrast, odontocetes were observed mainly within narrow channels, areas with complex coastal morphology, peaking at different water depths (Viddi et al 2010).…”

“…In Guaitecas archipelago, Viddi (2010) found Peale's dolphin, Chilean dolphin, killer whale Orcinus orca (Linnaeus, 1758), bottlenose dolphin and Burmeister`s porpoise. In Chiloé Island, Chilean dolphins occurred mainly in several southern selected bays and channels (Heinrich et al 2008).…”