Press release

Tackling the Trawl Supremacy: OceanCare releases report highlighting need for global action on destructive bottom trawling

October 23, 2024

As the European Parliament prepares to vote on a new EU Commission, OceanCare has published a comprehensive report calling on EU Member States to honour their commitments to ban bottom trawling in Marine Protected Areas (MPAs) by 2030. With the world falling behind on achieving the Agenda 2030 and particularly the Sustainable Development Goal SDG14 related to marine conservation, the urgency to act is greater than ever. Failure to ban bottom trawling in MPAs not only threatens the health of marine ecosystems, but also jeopardises global efforts to tackle climate change and biodiversity loss.

  • Bottom trawling is one of the most destructive fishing practices, causing significant ecological damage to marine habitats and biodiversity.
  • The global scale of destruction caused by bottom trawling is enormous, contributing to biodiversity loss, ecosystem collapse and climate disruption.
  • There is an urgent need to impose measures within EU Member States to meet the objectives of the EU Fisheries Action Plan on phasing out bottom trawling in Marine Protected Areas (MPAs) by 2030, as well as taking action at global level.

Giovanni Bearzi, marine conservation expert and lead author of the OceanCare report, said:

“The environmental damage caused by bottom trawling, globally, is well documented. It is a fishing practice that has been known to be destructive since the 14th century. Our report summarises the evidence that bottom trawling is still a fundamentally destructive practice.

“Countless scientific studies spanning decades of fisheries research have documented the harmful nature of bottom trawling, with substantial cumulative evidence of damage to marine species and ecosystems. Bottom trawling reduces the biomass, diversity and complexity of benthic communities, and the action of trawl gear on the seabed causes dramatic mechanical and chemical changes that affect the functionality and productivity of the seabed. In addition to target species, most types of trawl gear catch unwanted species such as endangered elasmobranchs, sea turtles, seabirds and marine mammals.”

The OceanCare report, entitled “The Trawl Supremacy: Hegemony of Destructive Bottom Trawl Fisheries and Some of the Management Solutions”, provides an in-depth analysis of the harmful impacts of bottom trawling on marine life and habitats. The report summarises scientific research showing that bottom trawling depletes biodiversity, reduces the complexity of seabed ecosystems and even exacerbates climate change by releasing carbon stored in marine sediments. The report underlines the need for immediate action at EU and global level to protect our oceans and ensure sustainable fisheries.

Nicolas Entrup, Director of International Relations at OceanCare, added:

“The political stakes are high. With the upcoming appointment of the new EU Commission, it will be essential that the path towards the full implementation of the Fisheries Action Plan is continued. OceanCare calls upon those EU Member States, that have been reluctant to act, to move forward with banning bottom trawling in MPAs. At the same time, we are calling for urgent global action at the UN Ocean Conference and through Regional Fisheries Management Organisations. Continued bottom trawling has no place within a world that wants to meet its own agreed marine conservation targets.

“The amount of fish caught by bottom trawling can no longer justify or excuse the widespread damage it causes to marine ecosystems and small-scale fishing communities. It’s simply not sustainable. OceanCare is calling for the use of less destructive fishing gear, the elimination of harmful fisheries subsidies, and an immediate ban on bottom trawling in all fisheries restricted areas and MPAs. Strict enforcement of conservation measures will also be vital for compliance. This can bring longer-term benefits in the form of healthier, more diverse and resilient marine ecosystems that support local fishing communities and contribute to global biodiversity, sustainability and climate goals.”

In the run-up to the 3rd UN Ocean Conference, to be held in Nice, France in June 2025, OceanCare has launched the Because Our Planet is Blue initiative, proposing a six-step Action Plan to turn the tide on ocean conservation. The Action Plan includes a call for a ban on destructive fisheries and sets out measures to move towards properly managed sustainable fishing practices for a healthier and more resilient Ocean.

Publication

Notes to editors

The term trawling generally refers to the active towing of a fishing net by one or two vessels called trawlers. When the fishing gear ploughs through the seabed, the practice is called bottom trawling. Trawlers can range in size from small boats to large factory ships.

Bottom trawling by continent: where fish is caught and where it is consumed (OceanCare: The Trawl Supremacy, p. 24)
Some facts about trawling
  • Between 2007 and 2016, bottom trawling accounted for about one quarter of global fishery catches.
  • Annual catches are in the order of 30 million tonnes, roughly matching all the world’s catches by small-scale fisheries.
  • 10 countries are responsible for 64% of the global bottom trawling catch.
  • Bottom trawls have the highest discard rate of all fishing gears.
  • The Adriatic Sea is one of the seas most exposed to trawling, worldwide. More than 70% of its seabed has been trawled.
  • In 34 countries, mostly in Africa, over 90% of the bottom trawl catch was by foreign vessels.
Impacts of bottom trawling on marine ecosystems

Bottom trawling was regarded as a destructive fishing method since the early 14th century and was often vocally opposed by communities of fishers who saw it as a threat to marine resources and their own livelihoods. Today, there is ample and compelling scientific evidence that bottom trawling is the fishing practice with the greatest negative impact on marine ecosystems. For example, bottom trawls typically kill between 20 and 50% of the invertebrates in their path.

Many areas exposed to intensive bottom trawling have experienced ecosystem changes or even regime shifts (i.e. dramatic and persistent changes in the structure and function of ecosystems). For example, oyster reefs – once a dominant three-dimensional feature of European coastal waters – were essentially wiped out. Trawling damaged cold-water coral reefs off Ireland and Norway that were at least 4500 years old. Important habitats such as sponge reefs and seagrass meadows were also heavily damaged by bottom trawling.

Bycatch and discards

Bycatch in trawl gear affects all of the seven sea turtle species. In the Mediterranean Sea alone, bottom trawling was responsible for over 172,000 sea turtle deaths between 2000 and 2020. Bycatch of sharks and rays in trawl gear is a primary conservation concern, resulting in high rates of decline of these elasmobranchs. Bycatch also affects cetaceans, pinnipeds, seabirds and threatened fish species (e.g. seahorses), as well as corals, sea stars, sea pens and many other species.

Bottom trawls have the highest discard rate of all fishing gears, averaging 46% of the total annual discards by global fisheries (i.e. 4.2 million tonnes). Marine organisms thrown back into the sea after being caught in trawl gear normally account for 20–30% of the catch, but in some shrimp trawl fisheries these discards may be as high as 80–90%.

Carbon footprint, contamination and noise

Bottom trawlers are not only among the least fuel-efficient fishing vessels (due to the fuel required for dragging a heavy net across the seabed) but also resuspend and release centuries-old carbon from marine sediments – one of the most important long-term carbon stores. Consequently, the greenhouse gases footprint of seafood caught by bottom trawlers is particularly high.

Ploughing the seabed not only releases carbon, but also particulate-bound toxic contaminants, allowing them to re-enter marine food webs. For example, contaminated sediment plumes generated by bottom trawling in a Norwegian fjord made mussels unfit for human consumption. Trawling also represents a significant source of underwater noise pollution in some areas.

Social impact

Trawl fleets can deplete and jeopardize the marine resources that sustain small-scale, community-based coastal fisheries. Many communities that rely on fishing for employment and food security regard conflict with industrial trawlers as one of the greatest threats to their welfare. Depletion of local resources can fuel social and economic unrest, usually with loss of revenue and jobs.

Can bottom trawling be sustainable?

While total landings by trawlers may be judged stable (e.g. in terms of biomass), trawling can result in dramatic ecosystem shifts. Turnover of marine species or changes in technology can help maintain what appear to be steady catch levels and profit. However, much of the former biodiversity may be annihilated, with especially resilient species replacing those that are most vulnerable to trawling.

For example, in the Adriatic Sea – one of the areas most exposed to bottom trawling, worldwide, and one with the worst seabed status – trawl catches have remained largely stable for decades. That, however, happened after damage caused primarily by trawling resulted in a major regime shift: Vulnerable species have been lost, and a formerly rich three-dimensional habitats has been turned into flattened plains that trawlers continue to exploit.

Management solutions

Management efforts to eliminate or mitigate the impacts of bottom trawling can include:

  • modifications of gear and practices to mitigate harmful impacts on the seabed and to reduce bycatch;
  • setting limits on the practice, or banning it altogether;
  • transitioning away from trawling, e.g. using other fishing gear or other forms of employment.

Limiting the overall intensity of trawling can result in substantial ecosystem benefits, and in some cases these benefits may even exceed those that would result from the designation of protected areas. Management efforts to reduce trawling have included habitat-based restrictions (e.g. to protect coral and sponge reefs, and seagrass meadows), the designation of protected areas, and the spatial confinement of trawling to areas where trawling is already concentrated.

Countless studies have demonstrated that setting aside areas that are either fully protected from fishing, or at least protected from the most destructive types of fishing, allows marine ecosystems to rebound and recover. The best practice should be to close areas with complex seabed habitats to towed gear before the damage is done. While protected areas can effectively promote conservation, their raison d’être fails miserably when protection from bottom trawling is not included. For example, 60% of 727 formally designated protected areas located in Atlantic European waters were commercially trawled.

A positive example of place-based management in the Mediterranean Sea is the Fisheries Restricted Areas network created under the General Fisheries Commission for the Mediterranean (GFCM), which encompasses all Mediterranean and Black Sea seabed deeper than 1000 m, where the use of trawl nets and towed dredges is prohibited.

More recently (in 2023) the EU Commission proposed an Action Plan to phase out all bottom trawling within MPAs and Natura 2000 sites by 2030, consistent with existing obligations and requirements, and called on EU Member States to impose national measures accordingly.