South Atlantic Right Whale

South Atlantic Right Whale (Eubalaena australis)

The southern right whales, Eubalaena australis (figure 1), were intensely exploited in the Southern Hemisphere between the 18th and 20th centuries. Although the species has been protected internationally from commercial whaling since 1935, some populations were further depleted by illegal catches until the early 1970’s.

Current estimates suggest that there are approximately 7,000 southern right whales, which is thought to represent a small fraction (about 5%) of its population size prior to commerical whaling.

Although some populations have shown signs of recovery, the species is still vulnerable and cited under “Appendix I” of the International Trade of Endangered Species Fauna and Flora (CITES) and on the IUCN red list of endangered species at risk of extinction (IUCN 2000).

The largest populations of the species are currently distributed in
the South Atlantic Ocean (Figure 2). Although a number of provisional stocks have been described for the species based on historically whaling records and geographic distribution of the wintering grounds, the rates of migratory interchange or degree of isolation among these populations are still poorly known.

This is especially true for the right whales that aggregate along the Brazilian coast during the winter, for which relatively little biological information is available.

[Figure 1]
Aerial photograph of
a southern right whale.
(Photo: Rodrigo Baleia).

[Figure 3]
Biopsy dart with a skin sample
of a southern right whale.
(Photo: Rodrigo Baleia).

[Figure 3]
In order to determine the stock identity of this population, a biopsy sampling program was started in southern Brazil in 1998 in collaboration with the Brazilian Right Whale Project (IWC/Brasil). Skin samples from free-ranging right whales have been collected for genetic analyses using a crossbow and a small biopsy dart
(Figure 3).

Current genetic analyses, involving
the use of mithocondrial and nuclear markers (e.g. microsatellites), has focused on the existent levels of genetic variability and extent of gene flow with other wintering grounds (e.g. Peninsula Valdes, Argentina).

These genetic analyses, in conjunction with the undergoing photo-identification and behavioral studies attempts to achieve a better understanding of both the present-day and historical relationships among different stocks
of right whales in the South Atlantic Ocean.

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