Off the coast of the small French territory of Mayotte, a revolutionary marvel has scientists reeling with concern for the fate of the local dolphin populations.
What’s happening?
The waters of Mayotte have become home to a hybrid dolphin, with blended traits of the Indo-Pacific bottlenose (Tursiops aduncus) and the Indian Ocean humpback dolphin (Sousa plumbea), according to Earth.org. While hybridization of cetacean species is not unheard of, it is extremely uncommon, especially in wild populations.
For scientists, the discovery raises red flags about the health of the respective dolphin species, whose populations have collapsed in the last decade. The humpback dolphin population, in particular, is estimated to have only five left in the local lagoon.
Why is the hybrid of these two species of dolphins a concerning trend?
The lagoon off the coast of Mayotte is historically considered a rich, biodiverse waterway, complete with a double barrier reef, 760 species of fish, and at least 22 species of marine mammals.
While these species of dolphins typically coexist in this lagoon, their behaviors and social structures are fundamentally different, keeping the Indo-Pacific bottlenose and humpback dolphins biologically independent. The fact that they are interacting enough to mate signifies that their populations are in severe distress, lacking options to breed with their own kind.
While this phenomenon is often nature’s way of building resilience against climate change, hybridization in such instances is particularly concerning for biodiversity. In Australia, a similar problem arose when an endangered frog species began to crossbreed with a more common species.
If hybrid breeds become more commonplace in the ecosystem, it could wipe out the two vulnerable dolphin breeds they’re derived from in the process. Plus, it’s unclear if this new species can reproduce given its genetic mix or whether it would be socially accepted in the purebred pods.
What’s being done about hybrid dolphins in Mayotte?
The region alarmingly has no conservation plan in place at present. However, efforts for other cetacean populations around the world — like a landmark lawsuit to protect the Māui dolphin earlier this year — show that when indifference is replaced with action, these species can be preserved.
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