740,000 km of fishing line, 14bn hooks lost at sea each year, harms aquatic lives – report

By Hauwa Ali

A new study has revealed that a staggering 740,000 kilometres of fishing line and 14 billion hooks are lost at sea every year; these nets, lines and hooks trap wildlife for years as they float in the ocean, sink to the bottom or are washed ashore.

Published in the journal ‘Science Advances’, researchers from CSIRO and the University of Tasmania used standardised interviewed 451 commercial fishers in seven countries to ask what was being lost.

The researchers matched those interviews with data on the amount of commercial fishing globally to estimate what was lost. Annual losses included:

• 78,000 sq km (30,000 sq miles) of purse seine nets and gillnets

• 215 sq km of bottom trawl nets

• 740,000 km (46,000 miles) of main long lines

• 15.5 million km (9.6m miles) of branch lines

• 13 billion longline hooks

• 25 million traps and pots

“The data we collected came directly from fishers themselves. They experience this issue firsthand and are best poised to inform our understanding of fishing gear losses.” The researchers said in the report.

“We surveyed fishers using five major gear types: gillnets, longlines, purse seine nets, trawl nets, and pots and traps.

“We asked how much fishing gear they used and lost annually, and what gear and vessel characteristics could be making the problem worse. This included vessel and gear size, whether the gear contacts the seafloor, and the total amount of gear used by the vessel.

“We coupled these surveys with information on global fishing effort data from commercial fisheries.

“These lost fishing equipments, known as ghost gear, can cause heavy social, economic and environmental damage. Hundreds of thousands of animals are estimated to die each year from unintentional capture in fishing nets. Derelict nets can continue to fish indiscriminately for decades.” They added.

“This is super confronting,” said Dr Denise Hardesty, of the Australian government’s CSIRO science agency, and one of the study’s authors.

“This is having an unimaginable toll of unknown deaths that could result in population level effects for marine wildlife.” He added.

Fishers in the United States, Morocco, Indonesia, Belize, Peru, Iceland and New Zealand were interviewed. The countries were chosen because they had a fishing industry using most fishing methods.

 According to the report, The estimates cover only commercial fisheries, and don’t include the amount of fishing line and other gear lost by recreational fishers.

“We also estimate that between 1.7% and 4.6% of all land-based plastic waste travels into the sea. This amount likely exceeds lost fishing gear.

“However, fishing gear is designed to catch animals and so is generally understood as the most environmentally damaging type of plastic pollution in research to date.” The report read.

Harming fishers and marine life

Lost fishing gear is not only an environmental risk, but it also has an economic impact for the fishers themselves. Every meter of lost net or line is a cost to the fisher—not only to replace the gear but also in its potential catch.

Additionally, many fisheries have already gone through significant reforms to reduce their environmental impact and improve the sustainability of their operations.

Nearly 700 species of marine life are known to interact with marine debris, many of which are near threatened. Australian and U.S. research in 2016 found fishing gear poses the biggest entanglement threats to marine fauna such as sea turtles, marine mammals, seabirds and whales.

Other marine wildlife including sawfish, dugong, hammerhead sharks and crocodiles are also known to get entangled in fishing gear. Other key problematic items include balloons and plastic bags.

Why fishing gear loses occur?

Some losses are attributable to how gear is operated. For instance, bottom trawl nets—which can get caught on reefs—are lost more often that nets that don’t make contact with the sea floor.

The conditions of the ocean can also make a significant difference. For example, fishers commonly reported that bad weather and overcrowding contributes to gear losses. Conflicts between gears coming into contact can also result in gear losses, such as when towed nets cross drifting longlines or gillnets.

Where fish are depleted, fishers must expend more effort, operate in worse conditions or locations, and are more likely to come in contact with others’ gear. All these features increase losses.

What can be done about it?

According to the researchers: “We actually found lower levels of fishing gear losses in our current study than in a previous review of the historical literature on the topic. Technological improvements, such as better weather forecasts and improved marking and tracking of fishing gear may be reducing loss rates.

“Incentives can further reduce losses resulting in ghost gear. This could include buyback programs for end-of-life fishing gear, reduced cost loans for net replacement, and waste receptacles in ports to encourage fishers to return used fishing gear.

“Technological improvements and management interventions could also make a difference, such as requirements to mark and track gear, as well as regular gear maintenance and repairs.

“Developing effective fishing management systems can improve food security, leave us with a healthier environment, and create more profitable businesses for the fishers who operate in it.”