Is bottom trawling bad?

Is bottom trawling bad?

The act of dragging nets across the seafloor is often regarded as a certified form of environmental destruction. But can it ever be sustainable?

At Rockfish we hold sustainability, quality and freshness at the heart of all that we do.

It’s a terrifying reality that over a third of global fisheries have surpassed sustainable limits. Meanwhile, demand for seafood continues to rise.

Those beady-eyed may have noticed that our boat, The Rockfisher, is an under 10m demersal trawler. For some, this may cause you to take pause. Anyone who’s seen Seaspiracy will tell you trawling, especially bottom-trawling (like the Rockfisher), is an evil antiquated form of industrial fishing not fit for a modern sustainable society.

So why do we, Rockfish (so-called ‘purveyors of sustainable fish’), have a trawler boat?

To answer this, we have to take a step back and look at the seafood industry as a whole and the arguments against trawling as a method of fishing.

Bottom trawling is an efficient way to catch large quantities of fish and shellfish that live on the seafloor and is one of the world’s dominant fishing methods responsible for a whopping 26% of global marine catch. As an industry, it provides food and employment for millions.

While alternative fishing methods may be feasible in some cases, catching demersal species like cod, haddock, turbot, halibut, and Dover sole, often referred to as groundfish, can be challenging without some form of bottom trawling.

From this perspective, we must view bottom trawling as one form of food production. Meaning we must compare its sustainability and environmental footprint to other food production methods like beef, pork, or corn farming.

There is no denying the incredible environmental success story of our local Lyme Bay where a 120 square mile no bottom trawl zone was created in 2008. In the decade after the Lyme Bay Marine Protected Area was established, the number of species within the zone increased by 39%.

Yet, when considering the immense global demand for fish, we must contemplate what would replace bottom trawling and whether the alternative would truly be more environmentally friendly.



Concerns regarding bottom trawling include its impact on seafloor biodiversity, issues of bycatch, and its carbon footprint. Dragging a net along the seabed is going to have an impact, but its severity depends on factors such as trawl frequency, the amount of catch per pass, and the recovery rates of affected species.

The impact of trawling on less sensitive habitats, such as muddy and sandy seabeds, is not nearly as severe compared to more fragile habitats like sponge gardens or cold-water coral reefs.

For sedimentary habitats, depletion rates range from 4.7% to 26.1% depending on trawl type, gear depth, and habitat, with otter trawls, like those on the Rockfisher, causing the lowest depletion.

Meanwhile, in Brixham, fishing frequency is rigorously controlled through quotas, engine and gear size limitations, and restrictions on days at sea.

Bycatch, the unintended capture of non-targeted organisms, is managed carefully aboard the Rockfisher, with limited impact on undersized species due to shorter tows, ensuring a higher chance of returning fish to the sea alive.

Beyond that we have zero bycatch - our entire catch being utilised through various channels including our restaurants, our Online Seafood Market, or it enters our zero waste system to be blast frozen and sold another day.

Regarding the carbon argument against trawling, it's true that bottom trawls are among the less fuel-efficient fishing methods. However, efforts to improve efficiency are ongoing, The Marine Management Organisation - the authority in charge of UK fisheries - have just coordinated a round of grants to install hybrid electric engines into fishing vessels. While aboard the Rockfisher we are using recycled plastic trawl doors (the device used to keep the net open in the water) as these decrease the weight of the gear therefore improving fuel efficiency.


A total of 83 bottom-trawl fisheries worldwide are currently certified by the Marine Stewardship Council.

This means sustainable bottom trawling is possible. It's not the fishing method but the fishery management that defines sustainability.

Bottom trawling is a food production method that, like beef, chicken, corn or even tofu, has environmental implications. But these are pale in comparison to those of livestock or fed aquaculture in areas such as water use, fertiliser and antibiotic use, or nutrient release. Banning bottom trawling outright may reduce marine impacts but could increase negative global environmental consequences as trawl-caught foods would be replaced but some other evil.

The solution then is to improve the sustainability credentials of trawler fishing. The purpose of the Rockfisher project was to be a part of this change. We wanted to be on deck, in our oilskins, helping create this monumental industry shift.

Technological advancements and effective fishery management are crucial for mitigating bottom trawling's impacts. As is reducing pressure on overexploited fish stocks. The conclusion then is sadly not a headline-gabbing "ban bottom trawling now.” But rather, with improvements, fisheries can be sustainable. As consumers, we need to shift our mentality away from “what fish we want to eat” to “what fish is seasonally available right now”. So, tune in for our next post on why it’s time to start eating more cuttlefish.