California beachgoers have been urged to steer clear of a species of highly venomous sea snake following a third, and unprecedented, instance of an aquatic serpent washing up on to the state’s beaches.
A 20-inch yellow-bellied sea snake was discovered on a beach near San Diego on Tuesday, where it was placed into a bucket before dying. The sighting was the third reported instance since October of the species, which prefers the tropical waters of the Pacific and Indian oceans, washing up on California’s beaches.
The only previous verified sighting of a washed-up yellow-bellied sea snake was in 1972. Experts believe the snakes have ridden a warm current of water, fueled by the exceptionally strong El Niño climatic event, farther north than they have ever previously ventured. A two-foot live snake was discovered in Ventura County in October, followed by another 27-inch deceased animal in December in Orange County.
All three animals have since died and have been preserved by biologists, who are increasingly puzzled by the array of tropical species entering California waters that are around 2C to 4C (4F to 7F) warmer than the long-term average. A spate of sea snakes have also washed upalong the coast of New South Wales in Australia.
“It’s been an incredibly interesting year for southern California. We’ve seen tuna and marlin and tropical bird species such as red-footed boobies,” said Greg Pauly, curator of herpetology at the Natural History Museum of Los Angeles County.
“It’s unprecedented to see this number yellow-bellied sea snakes in California. At first I was incredibly excited to see one and now I’m just perplexed. It makes us really wonder if there’s a bigger change occurring than just a big El Niño year. We have rising sea surface temperatures and also the ‘blob’ of warm water off the coast, so there are a lot of things going on at the moment.”
Yellow-bellied sea snakes are fully aquatic snakes capable of swimming vast distances. Although they are highly venomous, their targets are small fish and it’s thought they have yet to cause a recorded human death. However, Pauly said people should keep their distance if they encounter another washed-up snake.
“They are fairly docile and it’s unlikely for someone to be envenomated,” he said. “It’s rare for them to bite people, it’s usually fishermen who are carelessly pulling up fishing nets.
“The venom isn’t enough to kill an adult human unless they have pre-existing conditions, although saying that, I wouldn’t chance it. If you see one, just keep your distance, take some photos and enjoy the experience and then everyone will be safe.”
The snakes are in poor condition once they arrive on California shores because they hit cooler waters and are unable to muster the energy to find the prey fish they depend on. Other species have suffered from the unusual warm flows of water off the west coast, with a large number of dead or starving seals being washed ashore because prey has fled to colder climes.
According to the National Oceanic and Atmospheric Administration Fisheries, more than 4,200 sick sea lions have been washed up in California so far this year, comfortably the greatest number of strandings over the past decade. A further 100 Guadalupe fur seals and 150 northern fur seals have also been washed up, state-wide.
The strong El Niño event, which has warmed waters in the eastern Pacific, causing a series of global weather changes, has had some positive consequences in California. The drought-hit state has received a welcome burst of rainfall and fishing and skiing operators are reporting a surge in customers.
However, the presence of unusual marine creatures could be a preview of California’s future if ocean temperatures, which have risen by 1C globally over the past century, continue to climb.
“As the waters warm, it may be the case we see more snakes in southern California but we don’t know that as yet,” said Pauly. “I would’ve expected the snakes to have died or left the area by now, I wouldn’t have predicted this. The situation is unprecedented, so it’s hard to predict.”
Источник: theguardian.com
Фото:dic.academic.ru