Abstracts (first author)
Fine-scale population structure of humpback whales in South Africa coast
Humpback whales (Megaptera novaeangliae) undertake extensive seasonal migrations from polar feeding grounds in the summer to tropical breeding grounds in winter, displaying high fidelity to the same breeding and foraging areas. En route between these areas, some humpback whales utilize the coastal waters of southern hemisphere continents as migratory corridors. On South African coast two distinct migratory corridors of humpback whales are present. One takes humpback whales past the west coast of South Africa in autumn, en route to breeding grounds off Gabon, Congo, Angola and coastal and offshore areas in Gulf of Guinea. And the other takes them past the east coast of South Africa, en route to coastal waters of Mozambique and Madagascar. The aim of the present work was to assess a fine-scale population structure of humpback whales on the two migratory paths in the South African coast, combining mitochondrial DNA and microsatellites markers in order to characterize individual and population levels of genetic structure variation in this region. It was amplified, sexed, genotyped and sequenced a total of 484 samples from west and east coast. The results revealed population differentiation and restricted connectivity of humpback whales from west and east coast of South Africa. Differences on fidelity and seasonality to each region were also found, with humpback whales from west coast showing high levels of long term fidelity to the area, with identified animals returning to the same area in multiple years and between long periods of time and broader seasonality with several animals been sighted and resighted in summer months suggesting that this region besides functioning as a migratory corridor serve as an important feeding ground to some animals of the population. A better understanding of the scale of this behaviour off the west coast of South Africa and the importance of this area for the breeding ground of Gulf of Guinea should be achieved in the future.