Endangered marine life is being caught in fishing nets, but it doesn’t need to be

Hundreds of thousands of marine animals are killed every year after becoming accidentally caught in commercial fishing nets. Sharks, skates and rays are at particular risk, alongside turtles, seals, whales and dolphins, many of which are endangered.

Much of this problem comes down to the design of fishing nets and how they are used. Particularly damaging are tangle nets, which typically use large mesh sizes and large amounts of slack that can indiscriminately catch anything that crosses their path. They are also typically left in the water for long periods and only checked every one to ten days.

A new four-year study from Ireland’s national Marine Institute highlights the particular problem the nets are causing in Ireland. Legally protected seals, for instance, are regularly caught in this type of net, widely used by the Irish fishing industry including in the country’s only marine national park.

Tangle nets were first introduced to Ireland in the early 1970s. This was to help boost the competitiveness of the Irish crayfish fishing sector and provide an alternative method to the traditional pot-based method that was used up to that point.

But tangle nets are known to potentially harm a variety of species. The estimated impact from the latest report (covering 2021-2024) about what the nets had caught was stark:

• 1,161 nationally protected grey seals

• 81 critically endangered angel sharks

• 1,712 critically endangered flapper skate

• 532 critically endangered tope sharks

Other species caught included the endangered white skate and undulate ray, as well as rarer records of common and Risso dolphins. Catches varied throughout the study region, and included Ireland’s marine national park in County Kerry. It is unclear whether similar numbers are seen in other fishing areas throughout Ireland.

The report argues for the reduction of these accidental catches to “safe biological limits”, but acknowledges that there probably is no safe limit for several of the shark and skate species given their conservation status and their approach to reproduction.

The documented numbers of catches is particularly concerning for the species’ designated as critically endangered by the International Union for Conservation of Nature. This classification stipulates an extremely high risk of extinction in the immediate future. Unlike many bony fish such as cod, tuna and salmon, sharks, skates and rays tend to mature slowly (often at more than ten years of age), have long gestation periods, and only produce a few young every year or two.

This makes it very difficult for them to recover if anything causes their populations to decline. The angel shark is a good example – once widespread throughout the north-east Atlantic, it has suffered drastic declines across its range, and the species is now locally extinct throughout much of Europe.

There are few remaining strongholds for the species, but County Kerry is one of the last northerly refuges for angel sharks. With so few left in the wild, numbers caught in Ireland’s tangle net fishery are a significant concern at a global level.

Fisheries at a turning point?

Irish commercial fishers are facing a challenging future, with a number of recent restrictions to activities and quotas creating severe pressure on numerous businesses and communities around Ireland , and closing the crayfish fishery would be another blow.

But there is a suitable and straightforward low-impact alternative to the tangle net, which is to fully return to the traditional pot fishery to target crayfish.

Currently in Ireland some fishers still use these pots, and others a combination of pots and nets. Pots are typically netted, baited cages with a narrow-funneled opening designed to only catch the target species with a minimal footprint when landing on the seabed and low risk of harm to the endangered and protected species documented in the Kerry report.

The report clearly states the urgent need of phasing out tangle nets, and highlights an upcoming Marine Institute report focusing on economic considerations supporting a complete switch from nets to pots. The current report suggests this is the “optimum solution”. And it adds that trials using the pots showed equivalent catches.

Fishing is an integral part of Irish culture, and the need for a fair transition with appropriate support is repeatedly highlighted as essential for effective marine conservation.

What happens next in Kerry is probably going to be influenced by proposed legislation relating to how Ireland’s marine landscape is managed. The potential introduction of the Marine Protected Area and Nature Restoration laws, currently being debated, are aimed at protecting and restoring marine biodiversity, and may soon change how fishing is carried out in Irish waters.

Examples from around the world show that it is possible to change the type of fishing nets used to protect marine life. Gillnets (which capture fish by entangling then around the gills) have been almost completely phased out in Australia’s Great Barrier Reef marine park due to risks to animals including dolphins and turtles. Large scale drifting gillnets were banned in the European Union more than 20 years ago due to similar concerns.

The deaths of the world’s most sensitive marine animals documented in the tangle net report highlight the urgency of how fishing needs to change globally, while also protecting the livelihoods of an industry important to coastal communities.

Nicholas Payne receives funding from Ireland's Marine Institute to study the ecology of sharks and rays. He is also a council member for the British Society of the British Isles

Louise Overy has received funding from National Parks and Wildlife Service for ecological research purposes and is a coordinator at the Irish Elasmobranch Group and Project lead of Angel Shark Project: Ireland.