Seasonal Occurrence of sei (Balaenoptera borealis) and other whale species in Punta Marqués (Chubut Province, Argentina).

RIERA, MARINA G.; COSCARELLA, M. A.

Cambridge - Virtual

Congreso; 68°C Annual Meeting of the International Whaling Commission; 2021

International Whaling Commission

In the past few years, different rorqual species have been increasingly observed in Golfo San Jorge. In Chubut province, Argentina, occurrence of these whales may attract the attention of the local community as a potential resource for tourism-related activities, since the region has a long history on whale watching targeting the southern right whale. Systematic visual surveys have been conducted from April 2019 to May 2020. The observations were made from the top of a 160 m high cliff to assess the seasonal occurrence and relative abundance of these species, following a scan method with the aid of a spotting scope. A total of 104 scans were performed in which 96 sei whales, 1 minke whale, 4 humpback whales and 247 rorquals registered as indetermined were spotted. It is discussed that the unidentified rorquals might be sei whales. The Sighting per Unit Effort indicates that during the summer and autumn months the frequency of sightings increase. Sei whales were spotted while feeding on squat lobster, being one of the main observed behavioural states. For humpback whales the main behavioural state recorded was socializing. Golfo San Jorge could be regarded as a previously unreported feeding summer ground for sei whales. The continuation of this study will provide a better understanding of the habitat use and the factors that influence seasonal patterns of rorquals in the area and generate baseline knowledge to contribute to the conservation and assist in developing management actions.