Site icon Conservation news

Not just sea life: Migratory fish, birds and mammals also fall foul of plastic

Laysan albatross

A Laysan Albatross chick rests on a small derelict fishing net in the Pacific. Image by NOAA Marine Debris Program via Flickr (CC BY 2.0)

  • A new report from the U.N. Environment Programme and the Convention on the Conservation of Migratory Species of Wild Animals confirms that plastic pollution poses a major threat to land and freshwater migratory species.
  • Mammals, birds and fish are affected through various means, including entanglement, ingestion of plastics, accumulation of microplastics in the food chain, and using plastics in nesting material.
  • The report highlights that global capacity to manage plastic pollution is not keeping pace with projected growth in the plastics market.
  • The authors call for measures that will ultimately drive change upstream to reduce the volume of plastics entering the marketplace.

Humans have created so much plastic that it now exists from the slopes of Mount Everest to the extreme depths of the oceans. When we consider the effects of plastic on wildlife, images of whales entangled in discarded fishing gear or marine turtles that fatefully mistook plastic bags for jellyfish tend to spring to mind. But it’s not just ocean dwellers that are at risk. Land and freshwater species are in just as much danger, with migratory species especially vulnerable, a new U.N. Environment Programme report concludes.

The report focuses on the Asia-Pacific region and identifies the impacts of plastic pollution on land and freshwater species protected under the Convention on the Conservation of Migratory Species of Wild Animals (CMS). The CMS is an environmental treaty of the United Nations established in 1979 to protect migratory animals and their habitats. The report draws on case studies from two of the region’s major rivers, the Mekong and the Ganges, which together contribute an estimated 200,000 tons of plastic pollution to the Indian Ocean and the Pacific Ocean every year.

A herd of wild elephants consuming trash in eastern Sri Lanka, photographed in 2020. Image by Tharmapalan Tilaxan via Creative Commons (CC BY-SA 4.0)

“By far most scientific research into the impacts of plastic pollution on wildlife has focused on the marine environment, firstly looking at entanglement in large plastic waste and over the past decade looking more into the effects of microplastics in the ocean,” Amy Fraenkel, CMS executive secretary, told Mongabay. “This report, for the first time really, scopes out what do we know about impacts of plastics on migratory animals in land and freshwater environments.”

The report’s conclusions are stark: entanglements and direct ingestion of plastics are harming migratory species throughout the region, on land and in the water. Besides mortality, coming into contact with plastic affects animals’ behavior, health and long-term survival, the report says.

In major freshwater systems, marine mammals are particularly at risk from drowning following entanglement in discarded fishing gear. The report cites the Ganges river dolphin (Platanista gangetica), of which an estimated 3,500 remain, and the Mekong population of Irrawaddy dolphins (Orcaella brevirostris), which numbers less than 100, as particularly vulnerable. In the case of dugongs (Dugong dugon), although entanglement is also likely the leading cause of deaths, ingestion of plastics has caused a number of fatalities in India and Thailand in recent years. The fact that discarded fishing gear was such a large threat in the Mekong and the Ganges river systems points to a source that needs attention, Fraenkel said.

Throughout the Asia-Pacific region, wildlife-plastic interactions are prevalent. In Sri Lanka, Asian elephants (Elephas maximus) have been observed scavenging in trash dumps. In South Korea, black-faced spoonbills (Platalea minor) incorporate fishing debris into their nests, resulting in chick entanglements. On several Pacific islands, albatrosses that ingest high volumes of plastic while foraging at sea have been observed passing that plastic to their offspring through regurgitation.

According to the report, migratory species are especially vulnerable because they pass through a range of habitats during their migrations, heightening the likelihood of encountering industrialized or highly polluted environments.

When combined with other ways humans are damaging and polluting their environment, such as hydropower dams, overfishing, water extraction, release of other contaminants, and climate change, plastics are pushing a growing number of migratory species closer to extinction.

An osprey brings plastic trash to its nest site. Image by John Haedo via Creative Commons (CC BY 2.0)

The CMS report also spotlights that global capacity to manage plastic pollution is not keeping pace with projected growth in the plastics market. Given the longevity of plastics, global environmental contamination is likely to continue increasing dramatically for some years to come. A 2020 study in Science estimated that by 2030, even with ambitious efforts to reduce and manage plastic waste globally, up to 53 million metric tons of plastic per year will enter Earth’s rivers and oceans. If no urgent action is taken, this figure could reach 90 million metric tons annually.

Scientific understanding of how microplastics affect the food web and how that in turn affects wildlife and human health also lags behind, Fraenkel said.

“We need more research urgently, and we need to take the appropriate action to deal with the threat as we would with any other threat to our health and to the natural environment,” Fraenkel said, adding that actions to address global plastic pollution have fallen far short of what is needed. “The focus has thus far been on cleanup in our oceans, but that is already too late in the process. We need to focus on solutions and prevention of plastic pollution upstream.”

The report comes during the same week as a global ministerial conference to address the serious threat of marine litter and plastic pollution, during which a proposal was tabled to negotiate a binding legal treaty on plastic pollution.

Although such high-level action is vital, the CMS report calls for urgent transformative changes. In addition to advocating for reduced availability of plastic products in the marketplace, the authors outline an array of recommendations aimed at limiting the amount of plastic entering the environment.

Governments should implement better waste management and recycling policies, and product designers should make efforts to reduce the need for plastics by scoping out alternatives. Further proposals include education campaigns to raise awareness and reduce day-to-day plastic use, and the incorporation of plastic reduction goals into conservation plans for migratory species.

“All over the world we can find some very positive and innovative things that are being done with plastic waste and through laws, regulations and bans,” Fraenkel said. “But I think what has been missing most importantly is the upstream step, which is to really look at the marketplace for plastic and why it is so extensive and how much of that is necessary.”

By detailing and quantifying the impacts of plastics on wildlife, Fraenkel said she hopes the report will come to the attention of governments and industry and that they will try to make improvements.

“It can and should start now,” she said, “with governments and industry upstream having conversations and putting into place the policies that get us back to a less plastic-oriented marketplace.”

Banner image: A Laysan Albatross chick rests on a small derelict fishing net in the Pacific. Image by NOAA Marine Debris Program via Flickr (CC BY 2.0)


Borrelle, S. B., Ringma, J., Law, K. L., Monnahan, C. C., Lebreton, L., McGivern, A., … Rochman, C. M. (2020). Predicted growth in plastic waste exceeds efforts to mitigate plastic pollution. Science369(6510), 1515-1518. doi:10.1126/science.aba3656


FEEDBACK: Use this form to send a message to the author of this post. If you want to post a public comment, you can do that at the bottom of the page.