Species distribution modelling of Bryde’s whales, humpback whales, southern right whales, and sperm whales in the Southern African region to inform their conservation in expanding economies
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Date
Authors
Purdon, Jean
Shabangu, Fannie Welcome
Yemane, Dawit
Pienaar, Marc
Somers, Michael J.
Findlay, Kenneth Pierce
Journal Title
Journal ISSN
Volume Title
Publisher
PeerJ
Abstract
In southern African waters, information about species distribution and habitat
preferences of many cetacean species is limited, despite the recent economic growth
that may affect them. We determined the relative importance of eight environmental
variables (bathymetry, distance to shore, slope, chlorophyll-a, salinity, eastwards sea
water velocity, northwards sea water velocity and sea surface temperature) as drivers of
seasonal habitat preferences of Bryde’s whales (Balaenoptera brydei), humpback whales
(Megaptera novaeangliae), southern right whales (Eubalaena australis) and sperm
whales (Physeter macrocephalus). Using presence only data from multiple sources, we
constructed predictive species distribution models (SDMs) consisting of ensembles
of seven algorithms for these species during both summer and winter. Predicted
distribution for all cetaceans was high in southern Africa and, in particular, within
the South African Exclusive Economic Zone (EEZ). Predictive models indicated a
more pronounced seasonal variation for humpback, sperm and southern right whales
than for Bryde’s whales. Southern right whales occurred closer to shore during winter,
humpback whales were more likely to occur along the east coast in winter and the west
coast in summer, and sperm whales were more concentrated off the shelf in winter.
Our study shows that ensemble models using historical, incidental and scientific data,
in conjunction with modern environmental variables, can provide baseline knowledge
on important environmental drivers of cetacean distribution for conservation purposes.
Results of this study can further be used to help develop marine spatial plans and identify
important marine mammal areas.
Description
Keywords
Conservation Biology, Ecology, Marine Biology, Zoology, Environmental Impacts, Cetaceans, Ensemble models, Important marine mammal areas, Species distribution models, South Africa (SA), Bryde’s whale (Balaenoptera edeni), Humpback whale (Megaptera novaeangliae), Southern right whale (Eubalaena australis), Sperm whale (Physeter macrocephalus)
Sustainable Development Goals
Citation
Purdon J, Shabangu FW, Yemane D, Pienaar M, Somers MJ, Findlay K. 2020. Species distribution modelling of Bryde’s whales, humpback whales, southern right whales, and sperm whales in the southern African region to inform their conservation in
expanding economies. PeerJ 8:e9997 http://doi.org/10.7717/peerj.9997.