Migrating fish, birds and mammals also fall victim to plastic


  • A new report from the United Nations Environment Program and the Convention on the Conservation of Migratory Species of Wild Animals confirms that plastic pollution poses a major threat to migratory species on land and in freshwater.
  • Mammals, birds, and fish are affected in a variety of ways, including entanglement, ingestion of plastics, accumulation of microplastics in the food chain, and the use of plastics in nesting material.
  • The report points out that the global plastic pollution management capacity is not keeping pace with the expected growth of the plastics market.
  • The authors call for measures that will ultimately lead to upstream changes to reduce the volume of plastics entering the market.

Humans have created so much plastic that now there are 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 abandoned fishing gear or sea turtles that fatally mistook plastic bags for jellyfish tend to come to mind. But it is not only the inhabitants of the ocean who are at risk. Terrestrial and freshwater species are equally threatened, with migratory species being particularly vulnerable, concludes a new report from the United Nations Environment Program.

The report focuses on the Asia-Pacific region and identifies the impacts of plastic pollution on terrestrial and freshwater species protected by the Convention on the Conservation of Migratory Species of Wild Animals (CMS). CMS is a United Nations environmental treaty established in 1979 to protect migratory animals and their habitats. The report draws on case studies of two of the region’s major rivers, the Mekong and the Ganges, which together contribute around 200,000 tonnes of plastic pollution to the Indian and Pacific Oceans each 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 on the impacts of plastic pollution on wildlife has focused on the marine environment, looking first at the entanglement in large plastic litter and, over the past decade, by paying more attention to the effects of microplastics in the ocean, ”Amy Fraenkel, CMS executive secretary, told Mongabay. “This report, for the first time really, lists what we know about the impacts of plastics on migratory animals in terrestrial and freshwater environments.”

The report’s findings are striking: entanglements and direct ingestion of plastics are harming migratory species across the region, on land and in water. In addition to mortality, contact with plastic affects the behavior, health and long-term survival of animals, the report says.

In major freshwater systems, marine mammals are particularly at risk of drowning after becoming entangled in abandoned fishing gear. The report quotes the Ganges dolphin (Platanista gangetica), of which an estimated 3,500 remain, and the Mekong population of Irrawaddy dolphins (Orcaella brevirostris), whose number is less than 100, as particularly vulnerable. In the case of dugongs (Dugong dugon), although entanglement is also likely the leading cause of death, ingestion of plastic has caused a number of deaths in India and Thailand in recent years. The fact that discarded fishing gear has been such a significant threat in the Mekong and Ganges river systems indicates a source that needs attention, Fraenkel said.

Across the Asia-Pacific region, interactions between wildlife and plastic are prevalent. In Sri Lanka, Asian elephants (Elephas maximus) were observed rummaging in landfills. In South Korea, black-faced spatulas (Platalea minor) incorporate fishing debris into their nests, resulting in entanglement of chicks. On several islands in the Pacific, albatrosses that ingest large volumes of plastic while feeding at sea have been observed transmitting this plastic to their offspring through regurgitation.

Migratory species are particularly vulnerable, according to the report, as they pass through a range of habitats during their migrations, increasing the likelihood of encountering industrialized or highly polluted environments.

When combined with other ways humans damage and pollute their environment, such as hydroelectric dams, overfishing, water extraction, the release of other contaminants, and climate change, plastics bring a increasing number of migratory species from extinction.

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

The CMS report also points out that the global plastic pollution management capacity is not keeping pace with the projected growth of the plastics market. Given the longevity of plastics, contamination of the global environment is likely to continue to increase dramatically in the 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, that figure could reach 90 million tonnes per year.

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

“We urgently need more research and we must take the appropriate measures to deal with the threat as we would with any other threat to our health and to the natural environment,” said Fraenkel, adding that the actions to tackle global plastic pollution have declined. away from what is needed. “Until now, the focus has been on cleaning up our oceans, but it’s already too late in the process. We need to focus on upstream solutions and prevention of plastic pollution.

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

While such high-level action is vital, the CMS report calls for urgent transformative changes. In addition to advocating for reduced availability of plastic products on the market, the authors present a series of recommendations to limit the amount of plastic entering the environment.

Governments should implement better waste management and recycling policies, and product designers should strive to reduce the need for plastic by researching alternatives. Other proposals include education campaigns to raise awareness and reduce daily plastic use, and the incorporation of plastic reduction targets into migratory species conservation plans.

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

Detailing and quantifying the impacts of plastics on wildlife, Fraenkel said she hoped the report would grab the attention of governments and industry and try to make improvements.

“It can and must start now,” she said, “with upstream governments and industry having conversations and putting in place the policies that bring us back to a less plastic-driven market.”

Banner image: A Laysan albatross chick rests on a small abandoned fishing net in the Pacific. Image from NOAA’s Marine Debris Program via Flickr (CC BY 2.0)


Borrelle, SB, Ringma, J., Law, KL, Monnahan, CC, Lebreton, L., McGivern, A.,… Rochman, CM (2020). The predicted growth in plastic waste exceeds efforts to mitigate plastic pollution. Science, 369(6510), 1515-1518. doi: 10.1126 / science.aba3656

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Animals, Biodiversity, Birds, Education, Endangered species, Environment, Fish, Fishing, Freshwater animals, Freshwater ecosystems, Governance, Marine animals, Marine mammals, Microplastics, Migration, Oceans, Plastic, Pollution, Rivers, Rivers tropical, United Nations, Water, Water pollution

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