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  • 1
    In: Royal Society Open Science, The Royal Society, Vol. 6, No. 8 ( 2019-08), p. 181800-
    Abstract: Knowing the migratory movements and behaviour of baleen whales is fundamental to understanding their ecology. We compared δ 15 N and δ 13 C values in the skin of blue ( Balaenoptera musculus ), fin ( Balaenoptera physalus ) and sei ( Balaenoptera borealis ) whales sighted in the Azores in spring with the values of potential prey from different regions within the North Atlantic using Bayesian mixing models to investigate their trophic ecology and migration patterns. Fin whale δ 15 N values were higher than those recorded in blue and sei whales, reflecting feeding at higher trophic levels. Whales' skin δ 15 N and δ 13 C values did not reflect prey from high-latitude summer foraging grounds; instead mixing models identified tropical or subtropical regions as the most likely feeding areas for all species during winter and spring. Yet, differences in δ 13 C values among whale species suggest use of different regions within this range. Blue and sei whales primarily used resources from the Northwest African upwelling and pelagic tropical/subtropical regions, while fin whales fed off Iberia. However, determining feeding habitats from stable isotope values remains difficult. In conclusion, winter feeding appears common among North Atlantic blue, fin and sei whales, and may play a crucial role in determining their winter distribution. A better understanding of winter feeding behaviour is therefore fundamental for the effective conservation of these species.
    Type of Medium: Online Resource
    ISSN: 2054-5703
    Language: English
    Publisher: The Royal Society
    Publication Date: 2019
    detail.hit.zdb_id: 2787755-3
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  • 2
    In: Proceedings of the Royal Society B: Biological Sciences, The Royal Society, Vol. 289, No. 1981 ( 2022-08-31)
    Abstract: Disentangling the impact of Late Quaternary climate change from human activities can have crucial implications on the conservation of endangered species. We investigated the population genetics and demography of the Mediterranean monk seal ( Monachus monachus ), one of the world's most endangered marine mammals, through an unprecedented dataset encompassing historical (extinct) and extant populations from the eastern North Atlantic to the entire Mediterranean Basin. We show that Cabo Blanco (Western Sahara/Mauritania), Madeira, Western Mediterranean (historical range) and Eastern Mediterranean regions segregate into four populations. This structure is probably the consequence of recent drift, combined with long-term isolation by distance ( R 2 = 0.7), resulting from prevailing short-distance (less than 500 km) and infrequent long-distance dispersal (less than 1500 km). All populations (Madeira especially), show high levels of inbreeding and low levels of genetic diversity, seemingly declining since historical time, but surprisingly not being impacted by the 1997 massive die-off in Cabo Blanco. Approximate Bayesian Computation analyses support scenarios combining local extinctions and a major effective population size decline in all populations during Antiquity. Our results suggest that the early densification of human populations around the Mediterranean Basin coupled with the development of seafaring techniques were the main drivers of the decline of Mediterranean monk seals.
    Type of Medium: Online Resource
    ISSN: 0962-8452 , 1471-2954
    Language: English
    Publisher: The Royal Society
    Publication Date: 2022
    detail.hit.zdb_id: 1460975-7
    SSG: 12
    SSG: 25
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