[MARMAM] New publication on balaenopterid whales off Mauritania in winter
mickbaines at gmail.com
Sun Jul 5 23:40:26 PDT 2015
We are pleased to announce the publication of the following paper:
Mick Baines & Maren Reichelt*. Upwellings, canyons and whales: An important
winter habitat for balaenopterid whales off Mauritania, northwest
of Cetacean Research and Management, 14: 57–67, 2014.
The aim of this study was to identify critical habitats for baleen whales
in the Mauritanian upwelling zone using data collected from a platform of
opportunity: a 60 day geophysical survey approximately 100km southwest of
Cap Blanc, Mauritania in winter (2012/13). The bathymetry of the 5,500km2
study area was complex, including parts of the Cap Timiris Canyon system.
Large whales, including sei and blue whales, accounted for 70% of the 238
cetacean sightings. Species identification was often problematic,
especially in the case of balaenopterid whales, so data for all whales of
this genus were pooled for the estimation of abundance and distribution.
Spatial modelling was applied to estimate abundance and to plot a predicted
density map of balaenopterid whales. Depth and the chlorophyll-a
concentration when at its peak (in the previous September) were significant
predictors of whale density. Point abundance in the study area was
estimated at 272 whales (95% CI 265–279) and density was highest in the
depth range 500–2,250m near to the canyon system (6.18 whales/100km2 , 95%
CI 6.03–6.51). Steep seabed topography created by canyons running off the
shelf edge, together with the strong upwelling system, probably create
optimal habitats for the euphausiid prey of sei and blue whales. Sei whales
were observed skim-feeding at dawn or dusk on seven occasions; in one
sighting an aggregation of 18 skim-feeding sei whales were observed. The
high density of these baleen whale species in such a highly productive area
and direct observation of feeding behaviour in sei whales, provides
evidence of feeding during the winter breeding season, when they have
previously been presumed to feed less. This study demonstrates the
potential value of collecting further data on seismic survey vessels and
would improve understanding of cetacean ecology in remote and
JCRM is a free access online journal and papers may be downloaded from the
following link: https://iwc.int/jcrm-documents.
Alternatively, a pdf of the paper and the supplementary data file may be
downloaded from the authors' website at: http://wildscope.com/publications/.
Mick Baines & Maren Reichelt
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