The largest fish on the planet, the whale shark, is under threat from plastic pollution off one of the world's most remote islands, conservationists have warned.
The tiny volcanic island of St Helena, 3,130km from Cape Town in the South Atlantic, was where an exiled Napoleon died in 1821.
Yet despite its isolated location, the island is now plagued by plastic rubbish that washes in from South America and beyond, even though its nearest neighbour is thousands of kilometres away.
In 2003, there was estimated to be one plastic item per every 3m on the black volcanic beaches. Now ecologists say that they are finding hundreds of items in the same area, with each tide bringing in a new batch of refuse.
Environmentalists and wildlife groups are concerned the amount of plastic could prove deadly for whale sharks, which inhabit St Helena’s waters from November to June as they migrate across the South Atlantic.
Many tourists are drawn to St Helena in the summer, from January to March, in the hopes of getting to swim with the whale sharks, which are already listed as endangered by the International Union for the Conservation of Nature because they often become tangled in fishing nets, or collide with boats.
Whale sharks are particularly at risk from refuse in the ocean because their main diet is plankton which they need to suck up in huge gulps, and they often accidentally ingest micro-plastics at the same time. David Barnes, of the British Antarctic Survey, said: “There has been an absolutely dramatic change in St Helena.
“In 2003, there was one plastic item per every 3m. By 2007, that had grown by three times the amount and now we’re finding hundreds of plastic items per metre in some places so that’s a thousandfold increase – there are unbelievable levels of change and it’s happened in our lifetime.
“The animals that eat plankton and smaller algae are not discriminating between micro-plastics and their food. They can process the natural food but the micro-plastics stay in their stomach and build up until they have a stomach full of plastic which, in some circumstances, can weigh more than the actual organism.
“Then they die.”
It is estimated that eight million tonnes of plastic are dumped in the world’s oceans each year and the Ellen MacArthur Foundation has estimated there will be more plastic than fish in the oceans by 2050. It also states that 83% of the world’s tap water is now contaminated by micro-plastic.
As well as problems with micro-plastic, large pieces can pierce stomach linings, and plastic bags are mistaken for jellyfish and can block intestinal tracts when consumed.
There is growing evidence that plastic is entering the marine food chain with fish, turtles, sea birds and cetaceans from around the world all testing positive for contamination.
Although the locals on St Helena organise regular beach cleans, experts say the onslaught is relentless and have urged people to cut down on single-use plastics.
Beth Taylor, the St Helena National Trust marine project manager, said: “Given the remoteness of St Helena, if there are still plastics washing up from other places, it shows how huge a global issue it is and it needs to be highlighted.
“The message from St Helena is, if an island community of just under 5,000 can really roll up their sleeves and make a difference with plastic collection, reuse and recycling, then there’s absolutely no reason why people living in cities with access to all sorts of facilities can’t do the same,” she said.
The World Wide Fund for Nature has called for people to avoid using single-use plastics and straws.
Lyndsey Dodds, head of UK marine policy at the group, said: “We need to go further and faster – plastic is choking our oceans and leading to the demise of some of our much-loved marine animals.
“Many of us are doing our bit, but it’s time producers were made to face up to their responsibilities too.
“We need a ban on all unnecessary single-use plastic items by 2025, and other laws that respect the amazing natural systems upon which we all depend, weaning ourselves away from our throwaway culture.” – The Telegraph