Fishing lines kill slowly — and anglers keep discarding them anyway

"Entangled Sea Lion," the 2025 winner of the Underwater Photographer of the Year competition, captured by British photographer Henley Spiers. [UPY website]

"An unbearable sight — discarded fishing line was to blame."

A sea lion with fishing line wrapped around its neck has no way to free itself. The wound deepens with time, and the line slowly tightens around its throat.

Eight months — that is roughly how long a sea lion can survive with fishing line caught around its neck. Even that time is marked by constant, worsening pain.

The damage caused by carelessly discarded fishing line is not limited to sea lions. Marine animals and coastal land animals alike treat fishing line as a minefield.

A cat with a fishhook lodged in its mouth and a pigeon with fishing line wrapped around its leg. [Provided by civic activist Kwon Eun-jeong]

Once ensnared, an animal cannot escape until it dies. Fatal cases involving fishing line continue to mount, fueling persistent calls for a fishing license system in South Korea.

A study published in an international academic journal in 2025 by researchers from the Korea Institute of Ocean Science and Technology, the East Asian Seas Community Ocean and Team Booster found that at least 77 species were caught in marine debris entanglement incidents along South Korea's coasts and underwater between 2003 and 2023.

Trash found along a coastline. [Ocean website]

The total number of documented cases reached 428 — 338 along the coast and 90 underwater. These figures represent only the minimum confirmed through photographs or rescue records, not the full scope of actual damage. The true toll is likely far higher once unrecorded cases are included.

Notably, recreational fishing gear — fishing line and fishhooks — accounted for 65.2 percent of all entanglement cases. Fishing industry equipment such as nets, ropes and fish traps made up 33.2 percent. Debris originating on land, including string and plastic bags, accounted for just 1.6 percent.

A bird with its beak caught in fishing line. [BIRD TLC website]

Birds suffered the most. Seabirds are injured when they swallow bait or fish attached to hooks, driving the hook into their beak or esophagus. Fishing line connected to those hooks can also wrap around their legs, wings or neck.

Of the 338 coastal entanglement cases, seabirds accounted for 294 cases across 34 species — 87 percent of the total. Sea turtles were involved in 33 cases across four species, and marine mammals in 10 cases across five species. The black-tailed gull was the single most affected species.

Fish, coral and marine invertebrates were among the at least 77 marine species affected. In addition, 13.0 percent of all affected species are listed as endangered or near-threatened on the International Union for Conservation of Nature's Red List. Another 14.5 percent are legally protected species in South Korea.

A turtle with fishing line caught in its mouth. [Emerald Isle Sea Turtle Patrol website]

The harm extends beyond marine life. Cases of pigeons found with fishing line wrapped around their legs and cats discovered with fishhooks lodged in their mouths have been reported in coastal areas.

The researchers called for urgent cooperation among government ministries and agencies to reduce maritime debris, citing a sharp rise in fishing waste incidents and the ongoing toll of discarded fishing nets. They urged stronger regulation of fishing waste, more effective waste management policies and the establishment of international cooperation frameworks, expressing hope that the study would inform policy decisions.

Jongdal, a young Indo-Pacific bottlenose dolphin, exhibiting stereotypic behavior — circling repeatedly in place — in January last year. Animals display such repetitive, purposeless movements under extreme stress. [Provided by Docu Jeju]

Unexpected animals continue to be found injured by fishing line and hooks. In 2023, a young Indo-Pacific bottlenose dolphin named Jongdal was discovered entangled in fishing line off Jeju, prompting a rescue operation. After several subsequent rescue attempts, Jongdal was found wrapped in new fishing line again in 2025 and has not been seen since.

The problem is not unique to South Korea. Last year, a young sea lion was filmed in distress off a Mexican coast with commercial fishing line wrapped around its neck, drawing wide attention. Adult sea lions carry a subcutaneous fat layer around five centimeters thick around their necks. When fishing line becomes wrapped around the neck, however, it cuts through that fat layer and compresses blood vessels, reducing blood flow and significantly raising the risk of death.

Rescuers remove fishing line from a sea lion's body. [Ocean Conservation Namibia website]

Meanwhile, calls are growing in South Korea to introduce a fishing license system similar to those already in place in the United States, Japan and Australia as a way to curb fishing waste. With the country's fishing population reaching about 7.2 million, the side effects — including illegal dumping of waste — are worsening.

Under a fishing license system, individuals must complete a designated education program or pay a fee to obtain a fishing permit, and are then required to comply with rules on catch limits, target species and designated fishing zones. The Ministry of Oceans and Fisheries included a review of introducing such a system in its third basic plan for fishing promotion, covering 2025 to 2029, announced in June 2025.

woo@heraldcorp.com