This note presented the first comprehensive summary of confirmed records of Bryde’s whales in Chilean waters. Genetic analysis confirmed these animals as B. brydei according Wada et al. (2003)’s classification. As reported for other oceans, Bryde’s whales in the Eastern South Pacific do not occur in waters south of 38°S. For Chilean waters, whales were reported mainly in spring and summer, however, it should be noted that limited survey effort has been spent in other months.
Genetically Bryde’s whales from Chile and Peru were closely related as no statistically significant mtDNA differences were found. Samples sizes used in the comparative genetic analysis between Peru and Chile’s Bryde’s whales, were small, 24 ad 10 samples, respectively. However, such sample sizes were large enough to detect significant genetic differences with Bryde’s whales from other oceanic regions.
These results therefore are not inconsistent with the hypothesis of a north (Peru)-south (till latitude 38ºS) movement of Bryde’s whales in the eastern South Pacific in spring-summer. This hypothesis should be further examined through the analysis of former ‘sei’ whale catches in Chile (such analyses are underway), and larger number of genetic samples.
Sightings of Bryde’s whales were related to a coastal upwelling ecosystem in central Chile (Gallardo et al., 1983). As the stomach contents of whales examined in central Chile were composed of pelagic fishes (Table 3), the north-south migration in spring/ summer could be related to food availability. As suggested by Gallardo et al. (1983), Bryde’s whale appears to show more correlation with the presence of food of the right kind and in the adequate quantities, than with a given range of temperature