Knowledge about fishing methods

The way a fish is caught has significant implications for the impact on the seabed environment. Broadly, there are two categories of fishing gear: the gentle methods and the non-gentle methods.

Gentle fishing methods generally involve little to no contact with the seabed while fishing is taking place. As a result, the seabed and its life are left largely unchanged after fishing with gentle gear. These methods are typically selective, with various tools developed for different fish and shellfish species. Most of these tools are passive, meaning the fish swim into the gear on their own. The only active method still considered gentle is traditional Danish seine fishing, conducted on smooth sandy bottoms with minimal seabed impact.

Additionally, pelagic trawl under 17 meters is designated as gentle gear in both regulations and under the Nature Friendly initiative. The size of the vessel is the only reason large pelagic boats fishing for herring and mackerel can't obtain NaturSkånsom certification. According to DTU Aqua, their "gentleness" is on par with the gentle coastal fisheries. Most fish caught with gentle gear can be released alive with relatively high survival rates, though slightly lower for roundfish compared to flatfish. Fishers using Danish seine, traps, nets, and bottom gillnets are exempt from landing obligations because nearly all fish or shellfish can be released alive.

Non-gentle methods generally involve substantial contact with the seabed while fishing is underway, altering the seabed's character and affecting its life. These methods are all active, meaning the gear is towed by the vessel during fishing. Non-gentle gear is typically non-selective, capturing various fish and other life forms that fit the mesh size. Fish and shellfish often aren't released alive after being caught, and despite high survival rates in some trawl fisheries, particularly for flatfish, the mortality is higher, especially for roundfish. Even for plaice, the survival rate is around 50%.

* List of gentle gear as per Annex 15 in Executive Order No. 1249 of August 24, 2020, on the regulation of fisheries.

Description of the most common gentle fishing methods:


Bottom Gillnets

Bottom gillnets have a history dating back to ancient Egypt. They consist simply of a head where the fish get trapped alive and a length of net leading the fish into the trap, capturing fish as they swim into the net's head. Most bottom gillnets are placed on points or at the mouths of fjords, where fish naturally swim close to the shore. Therefore, bottom gillnets have the lowest CO2e emissions because fuel is only needed to travel from the port to the fishing area and back. Bottom gillnets catch eel, mackerel, herring, dab, cod, fjordshrimps and garfish during the season. Fish that fishermen don't need can be released alive.



The most widespread gentle fishing method in Denmark is gillnetting. It's simple, consisting of a net, each designed for a specific type of fish. The net has a floating line at the top and a sinking line at the bottom to keep it taut in the water. The end of the net is anchored, and the net catches fish that swim into it. Virtually all fish caught in nets are alive and can be released if not wanted. 


Traps and pots

Traps and pots are traps that catch fish as they swim through a gate from where they cannot escape again. Pots are primarily used to catch shellfish such as lobsters, crayfish, and crabs. Bait is used in the pots to lure the shellfish. Traps, which actually resemble nets, one primarily fishes for bottom-dwelling species such as eels and fjord shrimp. Traps have two arms of netting that are spread out so that bottom-dwelling species are led into the center, where the trap is. All fish caught in pots and traps are usually alive at capture and can be released alive again if they are not a species that should be caught or if they do not meet the minimum size requirement. Pots and traps represent the future of shellfish fishing and can be developed to a much greater extent than they are today.


Jigging and longlining

Fishing with a line and a hook is an ancient fishing method, now modernized with two prevalent types. Longlining involves baited lines set on the seabed, while active jigging uses two large fishing rods on either side of the boat, with a line containing rubber worms between them. Jigging produces high-quality fish as they are only on the hook for a short time before being on the deck. Unintended catches can be easily released, making jigging a promising method.


Traditional Danish Seine

Danish seine, or "anchored Danish seine," is a distinct technique. It involves a net shaped like a bag attached between two ropes, each 3-4 kilometers long. The fishing process begins with anchoring one end of the rope, creating a semicircle as the boat sails in that direction. The net bag is then laid on the seabed, and the second rope is sailed out in a semicircle to enclose an area, say 4 km2. The boat anchors, and the two ropes are slowly pulled in while the boat remains stationary. This method has minimal impact on the seabed as it relies on audiovisual cues and doesn't disturb the bottom. Fishing with Danish seine is fuel-efficient compared to bottom trawling, as the boat remains anchored, and little fuel is used to maintain hydraulic pressure for pulling the net.

Non-gentle Fishing Gear


Beam trawl

Beam trawl is a non-gentle fishing method that involves attaching a metal bar to a net and dragging it over or through the seabed. It is used to catch bottom-dwelling species such as plaice and flounder and is also employed for harvesting shrimp in the Wadden Sea. Another variation of beam trawl is used for mussel fishing and is called "scrapers." In all beam trawl variations, the trawl is fished from two booms attached to the trawler at a 90% angle, used to steer the trawl so that it can be pulled along both sides of the boat. When fishing for mussels, the net on the metal bar is replaced with an iron net, resembling a coat of amour from the middle ages. Mussel fishing with beam trawl is prevalent in Limfjorden and is relatively fuel-efficient. However, fishing for bottom-dwelling species such as plaice and flounder is widely recognized as one of the most harmful fishing methods for the seabed environment. Unlike bottom trawling, beam trawl exerts a constant impact on the seabed during fishing. Fishing over reefs and other bottom formations has been extensively documented, especially by Thorup Strand fishermen who witnessed significant environmental damage when Dutch beam trawlers began fishing in Jammerbugt in 2016. Fiskerikajen never purchases fish caught with beam trawls.


Bottom trawl

The most widespread non-gentle fishing method is bottom trawling, with approximately half of the Danish fleet utilizing this technique. Bottom trawling can be conducted by small vessels or large trawlers weighing several hundred tons, but the principle remains the same. The trawl is a net bag deployed between two doors or skids, ideally skimming just above the seabed, with only the net bag making contact. Typically, the net bag is kept open with floating buoys on the top and weighted chains on the bottom. In this way, the bottom trawl functions like an open mouth moving across the seabed, capturing fish or shellfish in its path.In bottom trawl fishing, almost all species can be caught, and different trawls are designed for various types of fish. However, there are several challenges associated with bottom trawling. One major issue is its negative impact on the seabed. The structures and organisms on the seabed are significantly altered when the trawl passes over them, making it an environmentally harmful method. Another challenge is the lack of selectivity; non-targeted species are often caught in the net, and fish captured with bottom trawls are rarely suitable for release (bearing in mind that excessive releases are illegal). This makes it difficult to conduct bottom trawl fishing without capturing threatened species or those for which there is no quota, presenting difficulties in landing them. In the fishing industry, these are known as "choke species."An additional challenge with bottom trawling is its relatively high fuel consumption. Pulling a fishing gear through the water consumes much more fuel compared to passive fishing methods. The smaller the targeted species, the greater the fuel consumption, making bottom trawling for shrimp and langoustine among the most fuel-intensive fisheries. Some data even suggests that langoustines caught in trawls have a larger carbon footprint than beef.There is also growing concern that disturbing the seabed through trawling releases CO2 and reduces the seabed's ability to capture and store carbon. While this impact has not been quantified, institutions like the EU Commission are actively investigating and working to quantify it in the coming years.



Flyshoot is an advancement of traditional Danish seine fishing. Most techniques in both fishing methods are similar, with a crucial difference being that the vessel in traditional Danish seine fishing is anchored, and the lines working over the bottom are made of ropes. In flyshooting, fishing takes place from a large floating buoy rather than an anchor. Additionally, the lines are robust and can be equipped with rollers, allowing them to traverse over stones and reefs. As a result, flyshoot has a greater impact on the seabed compared to traditional Danish seine fishing. The flyshooting vessel sails out lines and sets the gear in the same way as a traditional Danish seine vessel. Afterward, the vessel sails up to the buoy, starts hauling in the gear, and simultaneously moves forward, effectively fishing a larger area.