Otter trawls specifically targeting Norway lobster (Nephrops norvegicus) are linked to specific “Nephrops fishing grounds”, where the gear is adjusted for these typically muddy areas, for instance by the usage of light ground gear. This “pure” nephrops fishery is mostly located in Kattegat. In addition, a multi-rig gear is often used to increase gear width without using more engine power. Vessels deploying multi-rig gears have multiple trawl nets between the otter boards. In between the different nets, a clump weight is added to ensure bottom contact. Often the Nephrops fishery additionally targets a mix of demersal fish such as cod, plaice, lemon sole and monkfish. This is mostly the case in the North Sea and Skagerrak and here the fishery is less confined to muddy grounds and the ground gears more heterogenous.
Otter trawl fishing for deep-water shrimp (Pandalus borealis) takes place almost exclusively in the deep part of the Skagerrak and the easternmost part of the North Sea. Despite a relatively low effort, the intensity of fishing is therefore relatively high in the limited area where fishing takes place. The trawling takes place on soft bottom in deep water with large and heavy otter boards and relatively light ground gear.
Otter trawls targeting demersal fish are widespread and can be used in single-species fisheries targeting plaice or cod, but most frequently fishermen catch a mix of several demersal fish species, depending on location and season. This type of otter trawl is often fished on different sediment types and the ground gear adjusted accordingly with e.g., the use of bobbins or rockhoppers.
The otter trawl fishery targeting Norway pout (NOP) takes place on even, mostly soft bottom and is primarily localized to Fladen ground in the North Sea. The trawl gear is designed so that both otter boards, sweeps, and ground gear have bottom contact.
Otter trawls targeting sandeel (Ammodytes marinus) are linked to specific sandbanks, mainly in the North Sea, where this species can be caught in dense shoals off the bottom during the 2nd quarter of the year. The trawl gear is often designed so that only the ground gear and parts of the sweeps are in contact with the seabed, while the otter boards are towed slightly above the seabed.
Otter trawls targeting small pelagic fish like sprat and herring are widespread and are deployed on different types of generally smooth sediments. The trawls are often designed so that only the ground gear, which is generally relatively light, and parts of the sweeps are in contact with the seabed, while the otter boards are towed slightly above the seabed.