Trawling and the danger to marine biodiversity

fishing trawler

The destruction caused by Trawling It is devastating our oceans. This fishing method has serious consequences for the environment, leading to a decline in biodiversity as unwanted species, either dead or injured, are tragically caught and discarded. The lack of selectivity of trawling also represents a threat to protected areas, including those in Spain.

In this article we are going to tell you what trawling is, its consequences and what it is doing wrong.

What is trawling?

Trawling and the danger to marine biodiversity

The act of trawling, carried out by vessels known as trawlers, has become an issue of increasing concern for marine biodiversity and the general well-being of our oceans. This method, characterized by the sweeping movement of extensive nets along the seabed, has important ecological consequences. The destructive nature of trawling It is evident when the networks, similar to excavators, sweep and annihilate everything in their path.

The ecological consequences of trawling, despite its effectiveness in catching large quantities of fish, are substantial. This method degrades marine ecosystems and has a detrimental impact on vulnerable species. Furthermore, due to its lack of selectivity, trawling results in the involuntary capture of various marine organisms, including not only fish but also corals, algae, plants and even non-biological objects such as stones and garbage.

As a result, marine biodiversity is significantly reduced. The extensive fishing gear, which can reach lengths of over 220 metres, sweeps the seabed, causing greater damage to both the seabed itself and the surrounding ecosystems.

Consequences of trawling


The harmful fishing technique not only has an impact on the species that reside on the seabed, but also alters the entire ecosystem, including the vital flora and fauna that inhabit it. As if that were not enough, this fishing method also contributes to noise pollution. We cannot ignore the fact that marine biodiversity is not threatened solely by trawlers. The problem of marine litter, particularly plastics, poses a significant threat that we must address.

It should be noted that even designated protected areas are not exempt from the harmful practice of trawling. Within these areas, unregulated vessels operate freely, exacerbating the problem when there is a lack of oversight or illegal activities are carried out. As a result, the use of bottom and surface longlines, as well as trammel nets and trawl nets for fishing, contributes significantly to the decline of endangered species.

Fishing activities are also being carried out within protected areas. According to official data from the General Secretariat of Fisheries of the Government of Spain, a staggering 75% of bottom trawling fishing vessels in Spain during 2022 ventured into protected marine areas. This means that of the 887 specialized vessels that fish in Spanish waters, a total of 673 were unaware of the supposed inviolability of these areas and carried out their fishing activities there.

To put it another way, these ships employed techniques that caused damage to ecosystems within areas legally designated for biodiversity conservation. Although these areas are theoretically protected, they lack comprehensive management strategies that actually protect them from trawling. Furthermore, when such strategies exist, they are often insufficient.

The reality of marine protected areas in Spain is clearly evident in these data. Spain may be breaking the law by allowing trawling activities in these designated areas.

The marine protected areas in Spain were subjected to an astonishing 178.223 hours of trawling in 2022. Among these areas, the Menorca channel in the Balearic Islands stands out, the underwater channel valleys of the Mazarrón Escarpment in the Region of Murcia, and the Avilés underwater canyon system in Asturias, among others.

Challenges ahead

To address the obstacles presented by the debate around the seas and oceans, it is vital to advocate for sustainable fishing methods, including artisanal fishing, longline fishing and responsible aquaculture. It is imperative to enforce marine conservation measures, establish protected zones and closely monitor these areas to minimize the detrimental effects of trawling. Equally important is the need to educate the public about the importance of responsible fishing and implement effective regulations that restrict the scope of destructive fishing practices.

The sustainability of oceans and marine biodiversity faces considerable obstacles due to trawling. The harmful environmental impacts, such as bycatch and noise pollution, highlight the urgent need to adopt fishing methods that are more sustainable. It is imperative that the fishing industry transitions towards sustainability by safeguarding marine reserves and advocating for marine conservation within protected areas.

Consequences on ecosystems

marine biodiversity

These are some of the most serious consequences of trawling:

  • Destruction of marine habitat: Trawling of nets along the seafloor can cause physical destruction of underwater habitats, including coral reefs, kelp beds, and other important ecosystems.
  • Bycatch: Trawling is known for its high rate of bycatch, that is, the unintentional capture of unwanted or non-target species. They often refuse to fish species of fish, crustaceans, marine mammals and other creatures that are not the primary target of the fishery, but suffer significant damage or die as a result of being dragged by the nets.
  • Impact on fish populations: Although trawling can be effective in catching large quantities of fish in a short time, it can also have negative consequences for fish populations. The mass capture of juveniles and the destruction of breeding sites can negatively affect the ability of populations to maintain and recover.
  • Generation of waste and loss of fishing gear: Trawl nets often become snagged on objects on the seafloor, resulting in the loss of fishing equipment and the generation of debris that persists in the ocean.

I hope that with this information you can learn more about the negative consequences of trawling.

Leave a Comment

Your email address will not be published. Required fields are marked with *



  1. Responsible for the data: Miguel Ángel Gatón
  2. Purpose of the data: Control SPAM, comment management.
  3. Legitimation: Your consent
  4. Communication of the data: The data will not be communicated to third parties except by legal obligation.
  5. Data storage: Database hosted by Occentus Networks (EU)
  6. Rights: At any time you can limit, recover and delete your information.