Humpback whales (Megaptera novaeangliae) in the surrounding waters of Isabel Island in western-central Mexico: unveiling a little-known wintering area

Abstract

AbstractThe humpback whales which breed in the Mexican Pacific represent an important fraction (~38%) of the estimated population of the North Pacific. Despite the importance of Mexican waters for the reproductive habits of this species, little is known about the ecology of these whales, along the continental coast of Mexico. We analysed the temporal variation of abundance, group types, and inter- and intra-annual recapture rates in the waters adjacent to Isabel Island National Park as well as intra- and inter-seasonal movements with Banderas Bay breeding areas. Inter- and intra-annual recapture rates in Isabel Island National Park were low (1.8%); while 34% of 222 individuals photo-identified in Isabel Island National Park were also recaptured in Banderas Bay. Groups with calves were uncommon (9.5%), while pairs (33.5%) and competitive groups (29.5%) were more common. Intense singing activity was detected in the waters adjacent to Isabel Island. These waters seem to function as a reproductive corridor for the so-called ‘coastal stock’ of humpback whales in the waters adjacent to the continental coast of the Mexican Pacific. Therefore, mid- and long-term studies are needed to understand the dynamics of these displacements. Our findings suggest that Isabel Island National Park is an important area for the mating ecology of the humpback whales of the continental waters of the Mexican coast, and support the initiative to incorporate a Marine Protected Area within the Isabel Island National Park.