Plants and Animals

These Are the Plastic Items That Most Kill Whales, Dolphins, Turtles and Seabirds

How do we save whales and other marine animals from ocean plastic? Our new reviews show that reducing plastic pollution can prevent the death of favorite species. Over 700 marine species, including half of the world’s cetaceans (such as whales and dolphins), all of its sea turtles, and a third of its seabirds, are known to ingest plastic. When animals eat plastic, it can impede their digestion, leading to long, slow deaths from starvation. Sharp pieces of plastic can also pierce the intestinal wall, causing infection and sometimes death. A piece of plastic ingested can kill an animal.

About eight million tons of plastic enter the ocean each year, so solving the problem may seem overwhelming. How do we reduce the damage to whales and other marine life from so much plastic? We also triage like a hospital overwhelmed by patients. By identifying the deadliest items for the most vulnerable species, we can apply solutions that target these deadliest items.

Some plastics are deadlier than others: In 2016, experts identified four major items that they considered the most deadly to wildlife: fishing debris, plastic bags, balloons, and plastic containers. We tested the expert’s predictions by evaluating data from 76 published research papers comprising 1,328 marine animals of 60 species (132 cetaceans, 20 seals and sea lions, 515 sea turtles, and 857 marine lions).

We examined which items caused the highest number of deaths in each group and the “lethal” (how many deaths per interaction) of each item) we found that experts found it correct for three out of four items.

Flexible plastics such as plastic sheets, bags, and packaging could cause intestinal obstruction and be responsible for the highest number of deaths among all animal groups. These film plastics caused the most deaths in cetaceans and sea turtles. The remnants of fishing nets, lines, and tackles are responsible for the deaths of larger animals, especially seals and sea lions.

Turtles and whales that eat debris may have difficulty swimming, which increases the risk of injury by ships or boats. In contrast, seals and sea lions do not eat too much plastic but can die from eating fish debris.  Of these, balloons, ropes and rubber were deadly to small animals. And hard plastics cause the most deaths among seabirds. Rubber, fishing debris, metals, and latex (including balloons) were the deadliest for birds, with the highest incidence of recorded injection deaths.

What’s the solution?: The most expensive way to reduce the death of marine megafauna from plastic injections is to target the most deadly items and prioritize their reduction in the environment. It’s also smart to target large plastic items, as they can fall into smaller pieces. Smaller debris such as microplastics and fibers are a lower management priority, as they cause significantly fewer deaths in megafauna and are more difficult to manage.

Flexible film-type plastics, including plastic bags and packaging, rank among the top ten items in the global marine debris survey. Banning plastic bags and fees for bags have already been shown to reduce environmentally bound bags. Improving local disposal and engineering solutions to improve the recycling and development of plastics can also help reduce waste. Lost fishing gear is especially deadly. Fisheries have a high gear loss rate: 5.7% of all nets and 29% of all lines are lost in commercial fishing. The role of minimum standards in corrosion-resistant or high-quality gear can reduce damage.

The combination of policy change with the promotion of behavior change is known to be most effective in reducing coastal litter across Australia. Plastic reduction such as film, fishing debris, and latex/balloons entering the environment may be the best results in reducing marine megafauna mortality.

Lauren Roman, Postdoctoral Researcher, Ocean and Atmosphere, CSIRO; Britta Dennis Hardy, Principal Research Scientist, Ocean, and Atmosphere Flagship, CSIRO; Chris Wilcox, Senior Principal Research Scientist, CSIRO, and  Qamar Schuyler, Research Scientist, Ocean and Atmosphere, CSIRO This article has been republished from the conversation under the Creative Commons license. Read the original article.

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