Dear colleagues,
My co-authors and I are pleased to share our new publication: Virgili,
A., Araújo, H., Diaz, A. A., Doremus, G., Garcıa-Baron, I., Eira, C.,
... & Ridoux, V. (2024). Seasonal distribution of cetaceans in the
European Atlantic and Mediterranean waters. Frontiers in Marine Science,
11, 1319791.
The article is available here (open access):
https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2024.1319791/full.
Abstract:
As apex predators, cetaceans play an essential ecological role in marine
ecosystems. Fluctuations in the abundance of these top predators linked
to human activities can have detrimental consequences for the entire
ecosystem. Cetaceans face numerous anthropogenic threats that can have
both short and long-term effects. To ensure their conservation, it is
necessary to identify changes in seasonal distributions at small and
large scales. We aimed to model the seasonal distribution of the most
abundant cetacean species in the European Atlantic waters and the
Mediterranean Sea by assembling datasets collected over 16 years of
surveys using a standardised line-transect protocol. Data were
homogenised, detection functions fitted and effective strip widths
estimated. We extracted environmental variables integrated over the
water column, which we transformed using a principal component analysis
(PCA). The dimensions of the PCA were then integrated as explanatory
variables in a generalised additive model, taking seasonal and spatial
effects into account to predict the seasonal cetacean distribution. We
were able to highlight changes in the spatial distribution and/or
density of cetaceans throughout the year at a large scale, considering
environmental extrapolation areas to predict where environmental
variables were sampled during the surveys. For minke (Balaenoptera
acutorostrata) and fin (B. physalus) whales, densities varied over the
seasons but not the distribution, suggesting a seasonal migration
outside the survey areas. For common dolphins (Delphinus delphis),
bottlenose dolphins (Tursiops truncatus) and harbour porpoises (Phocoena
phocoena), densities varied little but distributions did over the
seasons. Finally, pilot whales (Globicephala spp), Risso’s (Grampus
griseus) and striped (Stenella coeruleoalba) dolphins showed little
seasonal variation in their distribution. Using monthly dynamic
environmental variables at depth and PCA dimensions in habitat models,
we produced maps of the seasonal distribution of cetaceans in the
Mediterranean Sea and the European Atlantic waters to help fill gaps in
our knowledge of cetacean distribution.
If you have any questions, please feel free to contact me at
auriane@sharetheocean.earth.
Best wishes,
Auriane
--
Dr Auriane VIRGILI
Ingénieure de recherche / Research engineer
Share the Ocean consortium,
14 place de l'Eglise, 56870 Larmor-Baden, France
E-mail : auriane@sharetheocean.earth
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