Divers nicknamed her Sweet Girl. This young humpback whale was killed on October 8 by a merchant ship off the Tahitian coast of Faa’a.
Every year, thousands of whales like Sweet Girl are injured or killed after being struck by ships. Collisions continue to be the main cause of direct mortality of these marine mammals. A study published on Thursday, November 21 in the journal Science attempts to quantify the risks of these encounters for four species threatened by shipping: blue whale, fin whale, humpback whale and sperm whale.
The international research team crossed more than 435,000 whale locations with location data from nearly 176,000 ships. This work allowed us to identify “hot spots” Encounter between boats and cetaceans.
” These Collisions are very difficult to observe directly and often go unnoticed. Therefore, modeling collision risk as we do in our study is a useful tool for identifying areas that are likely to be the most problematic. “explains lead author Briana Abrahms, professor of biology at the University of Washington and researcher at the Ecosystem Sentinel Center.
Critical situation in the Mediterranean
The academic team reports that global shipping overlaps about 92% of the range of these four whale species. The entire phenomenon is impressive. The highest risk areas are mainly along the western coast of North America, several regions of the coasts of South America, the Mediterranean, the Azores, the African coast, the northern Indian Ocean, the coasts of Australia and East Asia. Only the southern region is spared due to less dense maritime traffic. However, only 7% of these risk areas currently benefit from adequate protective measures to limit these collisions, in particular by reducing the speed of ships.
Although it is difficult to estimate the exact number of whales affected, several regional studies have analyzed this phenomenon. A study published in BordersJuly 2019, revealed that 51 stranded whales were caused by collisions off the French coast between 1972 and 2017. The study highlights the critical situation in the Mediterranean, where one in five stranded whales showed signs of a collision with a ship . The two subpopulations present in the Mediterranean are classified as vulnerable on the red list of the International Union for Conservation of Nature (IUCN).
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