Wild Birds in Japan Endangered by Fishing Lines, Other Plastic Waste, Survey of Rivers, Coastlines Show

The Yomiuri Shimbun

16:35 JST, September 19, 2025

Fishing lines and other plastic waste discarded along Japan’s coastlines and riverbanks are entangling, injuring and causing the deaths of many wild birds, including threatened species, according to a survey by the Wild Bird Society of Japan.

This survey was the first conducted to gauge the extent of the problem and confirmed that birds had been harmed by pieces of fishing line or other plastic waste in 19 prefectures. “We urge people to pay attention to the severity of the plastic waste problem around them,” said a representative of the society, which is a public interest incorporated foundation.

The online survey asked society members and others to provide information about wild birds they saw harmed by plastic products that had been discarded into the natural environment since April 2024. By June this year, the society had received 55 reports from 19 prefectures.

A breakdown of the types of harm inflicted, with multiple answers allowed, revealed the most common problem was birds becoming tangled in discarded sections of fishing line, with 38 cases listed in the reports. There were nine cases discussing birds that had mistakenly eaten or swallowed plastic products, six of birds that had a fishing lure embedded in them and six of birds that had become tangled in fishing nets.

Given that these confirmed cases were reported over a limited period, a society official believed they represented “only the tip of the iceberg.”

The affected birds included peregrine falcons and black-faced spoonbills, which are both designated as threatened species by the Environment Ministry. Fishing line made from nylon, a type of plastic, and other materials is light and durable, and it is difficult for birds to bite through and remove. A bird that becomes caught in a nylon fishing line could grow weak and die as the line gets tighter and tighter around them.

Lost or discarded plastic fishing equipment including ropes and nets that drift in the sea is known as “ghost gear.” This equipment has been responsible for harm to marine creatures such as sea turtles around the world. The society’s survey revealed that many wild birds are also falling prey to ghost gear in Japan’s rivers and coastal waters.

One reason behind the spate of birds being harmed is the lack of care taken by some fishermen, who abandon or do not properly clear away their used lines and lures.

“Even if I pick up old fishing line, after a few weeks there’s lots more all over the place,” fumed Tomomi Kimura, a 50-year-old fisher from Nagasaki and a wild bird society member.

Kimura finds several injured birds every year, including a cormorant that died with a fishing hook still piercing a wing, and a booby that had become too weak to fly after getting hooked on a lure.

A survey conducted by the Japanese Society for Preservation of Birds found that about 46 kilometers of fishing line had been retrieved from the river mouths and coastlines of 11 prefectures from 2020 to 2024. An official of the society, a public interest incorporated foundation, said, “Fishing lines sometimes get snagged on rocks underwater and can’t be reeled in, but in many cases, fishermen intentionally discard them and go home.”

Intergovernmental negotiations on developing an international treaty to prevent plastic pollution were held in Switzerland last month. Measures to prevent plastic fishing equipment from entering the ocean also were discussed, but attendees were unable to reach an agreement.

“The important thing is to make sure fishing line is always taken home,” said Hideshige Takada, a professor emeritus at the Tokyo University of Agriculture and Technology and an expert on environmental pollution chemistry. “International measures to prevent fishing gear from being discarded also will become necessary.”