Knowledge about fishing methods

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 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.

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.

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.