The double environmental impact of trawling

Scientists and biologists are clear that large ships, by removing the substrate and creating large grooves in the bottom of oceans and seas, put an end to this carbon dioxide sequestration system. Marine sediments are one of the largest reserves of organic carbon on the planet and can remain so for thousands of years. But soil amendment can remineralize those megadeposits.

It is a situation that will lead to greater acidification and the accumulation of carbon dioxide in the atmosphere. Hence, conservationists advocate protecting the seabed as a nature-based solution and tool to fight the climate emergency.

prohibit or limit

For researchers, banning or at least imposing more serious limitations is an important mitigation measure against climate change. These fishing gear can reach 220 meters long and 292 meters wide, weighing almost 800 kilograms. The Spanish fleet, with almost 900 boats dedicated to this modality, is the first in the European Union. 73% of the activity registered in the Spanish Natura 2000 areas corresponds to trawlers. Of the 218 protected areas, trawling operations have been detected in 45 of them.

Last May, Oceana, along with other environmental groups, petitioned European Commissioners Virginijus Sinkevičius and Frans Timmermans to propose an ambitious action plan. The first step would be to ban destructive fishing in all marine protected areas in the European Union, a petition that has the support of more than 100,000 people within days of its launch. Along the same lines is Greenpeace, whose president in Spain, David Sandoval, advocates that the new Community Fisheries Policy «put an end to overfishing, trawling and that it supports artisanal and sustainable sectors, with more selective gear for prevent damage to the seabed.

Fishermen’s Opposition

Meanwhile, professional fishermen are opposed to greater shielding of areas that already have protection. Specifically, the Balearic Federation of Fishermen’s Guilds ensures that without trawling there will be no local fish. The Menorca channel, in the Levantine-Balearic demarcation, is one of the ten points in Spanish waters designated for the preservation of the most dragged habitats last year. The Mediterranean coast has another seven underwater enclaves affected by this type of fishing: South of Almería-Seco de los Olivos, Valles del Escarpe de Mazarrón, Gulf of León, Delta de l’Ebre, Costes del Garraf, Alborán Marine Area and the Strait of Dawn.

In the Atlantic there are two areas, the Avilés submarine canyon system and the mud volcanoes of the Gulf of Cádiz. In total, more than 16,200 square kilometers of protected surface and suffer more than 71,000 hours of fishing.

Oceana recalls that the Habitats Directive establishes the need to provide adequate management to these vulnerable points, providing them with management plans from the moment they are designated as such with preventive measures until the planning is finally drawn up, always within the six years. In the case of the Spanish, the deadline expired this December 2021, but they continue without that instrument, and with a lot of uncontrolled dragging inside, as they denounce.

Silvia García: «This activity emits more than the aviation industry»

Co-author of the Oceana report on trawling in protected areas

What does trawling imply for biodiversity?

It is an unsustainable, meaningless activity, much less within marine protected areas, and especially in the face of the biodiversity and climate crises we are experiencing. Bottom contact fishing gear inevitably causes damage to the seabed and the habitats it supports. The European Commission itself has described trawling as the most aggressive activity with the seabed. In addition, scientists have been warning of its negative impact on the sea for decades.

Does the situation get worse in a climate emergency context?

Totally, in addition to the direct emissions into the atmosphere by these ships, which often exceed the legal power of their registered engines, so the emissions would also be partly illegal. The towing activity globally emits more CO2 than the aviation industry, according to a recent study. By removing the substrate, creating large furrows, the stored CO2 is released, especially in the deep sea mud, saturating the sea, which can no longer absorb as much gas from the atmosphere, and therefore, limiting its great capacity to buffer the climate change. Whichever way you look at it, it is an activity that has no place, just like any other that is not sustainable.

What marine areas of Spain are the most affected by this type of aggressive fishing?

We found that 45 of the 218 protected areas in Spain are being washed away and it is a good part of large areas. They represent 64% of the total area designated for the protection of the seabed. There are ten that are especially relevant, since they account for 97% of the trawling hours recorded, such as the South of Almería – Seco de los Olivos, the Avilés Submarine Canyon System. These are large areas, with a lot of activity, but also heavily fished. Even so, another 35 smaller areas, in theory protected, are also suffering from high degradation.

What is the solution to end this impact?

Any aggressive activity must be prohibited. The first logical step is to remove trawling from protected areas and work on reconverting this fleet to sustainable gear that is not harmful to the environment or resources. In addition, the future Law for the Restoration of Ecosystems that the EU is preparing is a great opportunity for that recovery and for life to return to the sea.