Whale sharks victim to ocean plastic

Whale sharks could be swallowing 137 pieces of plastic an hour because the surface waters where they feed are so contaminated.

Whale sharks could be swallowing 137 pieces of plastic an hour.

Whale sharks could be swallowing 137 pieces of plastic an hour because the surface waters where they feed are so contaminated, an Australian study has found.

The biggest fish, which can reach 12m long and weigh 40 tonnes, ingest hundreds of cubic ­metres of water a day and filter it to extract plankton.

Scientists used fine nets to gather samples and measure the amount of plastic in the inshore surface water off Indonesia, where whale sharks and manta rays gather to feed. They used these measurements to estimate how much plastic big filter-feeders were likely to be consuming.

The study, in the journal Frontiers in Marine Science, says reef manta rays could take in up to 63 pieces of plastic an hour of feeding in Nusa Penida and Komodo National Park, while whale sharks, which seasonally gather in Java, could be ingesting up to 137 pieces an hour.

Elitza Germanov, the study’s lead author, said: “With time, plastics break down into smaller pieces called microplastics that large marine filter-feeders might accidentally scoop up because they float among their prey.

“Manta rays and whale sharks can ingest microplastics directly from polluted water or ­indirectly through the contaminated plankton they feed on,’’ said Ms ­Germanov, a researcher at the Marine Megafauna Foundation at Murdoch University in Perth.

The scientists also found 26 pieces of plastic in a sample of manta ray faeces weighing half a gram and 66 pieces in a sample of manta ray vomit.

The study also found that the amount of plastic in seawater was up to 44 times higher during the rainy season, when rivers carry vast amounts of waste to the ocean.

The Times