Whales’ daily diet of 171 plastic items
LARGE marine mammals are swallowing up to 171 plastic items every day, experts have warned.
A study concluded that microplastics are a major threat to filterfeeding animals such as whales and manta rays, which swallow thousands of gallons of water a day to sift out the plankton they feed on.
The creatures are considered to be at high risk of exposure since many inhabit some of the most polluted waters, namely in the Coral Triangle region, Bay of Bengal, Gulf of Mexico and Mediterranean Sea.
The fears are based on evidence that endangered whale sharks – which filter for food as whales do – may be ingesting 171 items on a daily basis around the important feeding ground of the Baja California peninsula.
Scientists found 0.7 plastic items per cubic metre (220 gallons) of water, while they believe fin whales in other areas are swallowing thousands of microplastics a day.
The study, published in the journal Trends in Ecology & Evolution, states that indigestible plastic particles can affect the fertility, growth and development of animals after building up for decades.
Lead author Elitza Germanov, of Murdoch University in Australia, said: ‘Despite the growing research on microplastics in the marine environment, there are only few studies that examine the effects on large filter-feeders.
‘We are still trying to understand the magnitude of the issue.
‘It has become clear though that microplastic contamination has the potential to further reduce the population numbers of these species, many of which are long-lived and have few offspring throughout their lives.’
Two-thirds of filter-feeding sharks and more than one quarter of baleen whales are listed as globally threatened species.
It comes after a December report revealed threats such as plastics could put many populations of whales and dolphins at serious risk of extinction. The findings, published by whale campaigners Orca, warned that growing pollution could soon mean Britain’s only pod of killer whales dies off.
Sally Hamilton, director of Orca said: ‘Thousands of tons of singleuse plastic is finding its way into the ocean every year, killing whales and dolphins by the thousand.
‘Being caught as “bycatch”, or snagged in fishing gear, results in whales, dolphins and porpoises drowning, sometimes slowly over the course of many months.
‘Despite this suffering, however, a huge proportion of fishing vessels are not reporting the issue…the deaths we know about may only represent a fraction of the issue.’
‘Killing them by the thousand’