Environmental charity Ocean Pledge has issued a warning to beachgoers in Western Cape Province, South Africa, after a highly venomous Yellow Bellied Sea Snake, Hydrophis platurus, was found on a beach at Fish Hoek, near Cape Town. Yellow Bellied Sea Snakes are not native to the Western Cape, but are sometimes carried there by the Agulhas Current, which runs southeastward along the eastern coast of South Africa, occasionally pushing packages of warm waters from the Indian Ocean into the South Atlantic. When this happens, it can carry organisms from the southern Indian Ocean, such as Sea Snakes, with it. Because such occurrences are rare antivenoms for Sea Snakes (which have a limited shelf life) are not kept in hospitals in the Western Cape, meaning that a bite from one of these venomous Snakes is likely to have severe, even fatal consequences. Sea Snake incursions into the Southern Atlantic will often involve muiltple Animals carried from the warm water around Madagascar and the Comoros Islands reaching the coast of the Western Cape, with such Snakes having been found as far north as the southern coast of Namibia.
A Yellow Bellied Sea Snake, Hydrophis platurus, on a beach in Costa Rica. Wikimedia Commons. Sea Snakes,
Hydrophiinae, are thought to have diverged from their nearest relatives, Australian Tiger Snakes of the genus Notechis, about 10 million years ago during the Late Miocene. They have become entirely marine in nature, bearing live young in the water, and most species are unable to survive on land for any length of time. Most Sea Snakes are entirely tropical in distribution, dwelling on Coral Reefs in the Indian and Pacific Oceans, but the Yellow Bellied Sea Snake has a broader distribution, and is able to survive in the cooler waters around New Zealand, Tasmania, and southern California. It is this environmental tolerance that enables them to be carried into the Southern Atlantic on occasion, although the waters are far to cold for them to survive for any length of time. However, one possible outcome of a warming global climate is that the waters of the Southern Atlantic become warm enough for Yellow Bellied Sea Snakes to survive there for at least part of the year, enabling them to enter the warmer waters of the Central Atlantic and Caribbean, where both marine life and Human populations would be naïve to them, and should they reach these waters they would be likely to have a significant ecological impact.
Anyone encountering a Sea Snake on a beach in the Western Cape is strongly advised not to touch it, even if it appears to be dead, and never to attempt to move it. Instead it is recomended that sightings of Sea Snakes oe exotic marine life be reported to the Two Oceans Aquarium in Cape Town be contacted, as they will be capable of sending experts to help or recover the Animal.
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