Pair trawling is a fishing activity carried out by two boats, with one towing each warp (the towing cables). As the mouth of the net

Fishing net

A fishing net or fishnet is a net that is used for fishing. Fishing nets are meshes usually formed by knotting a relatively thin thread. Modern nets are usually made of artificial polyamides like nylon, although nets of organic polyamides such as wool or silk thread were common until recently and...

 is kept open by the lateral pull of the individual vessels, otter boards are not required. By utilising the towing power of two boats, and as no otter boards are needed, a larger net may be worked than would otherwise be possible, or alternatively, the two boats can share increased fuel efficiency.

As doors are not necessary, the gear arrangements are simplified, with the warps attaching directly to the wings of the net. Setting and hauling of the nets are carried out by one boat, while the other is only used for towing; usually each will take turns at these operations.

Pair trawling is effective on all demersal species. In shallow waters, where the noise from a single vessel may scatter fish, two vessels operating a distance apart tend to herd fish into the path of the net. Catch per vessel often considerably exceeds that attainable through standard bottom trawling

Bottom trawling

Bottom trawling is trawling along the sea floor. It is also often referred to as "dragging".The scientific community divides bottom trawling into benthic trawling and demersal trawling...

. Pair trawlers targeting cod

Cod

Cod is the common name for genus Gadus, belonging to the family Gadidae, and is also used in the common name for various other fishes. Cod is a popular food with a mild flavor, low fat content and a dense, flaky white flesh. Cod livers are processed to make cod liver oil, an important source of...

 off the coast of New England

New England

New England is a region in the northeastern corner of the United States consisting of the six states of Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, and Connecticut...

 have reported average per vessel catches of three to six times that from single trawls.

Because of the increased efficiency of pair trawling, vessels are able to tow their gears in mid-water at a faster speed to target species which are normally able to escape trawl nets, such as the European seabass

European seabass

The European seabass, Dicentrarchus labrax, also known as Morone labrax, is a primarily ocean-going fish that sometimes enters brackish and fresh waters. It is also known as the sea dace...

. This has caused some controversy, due to the high level of marine mammal

Marine mammal

Marine mammals, which include seals, whales, dolphins, and walruses, form a diverse group of 128 species that rely on the ocean for their existence. They do not represent a distinct biological grouping, but rather are unified by their reliance on the marine environment for feeding. The level of...

 bycatch

Bycatch

The term “bycatch” is usually used for fish caught unintentionally in a fishery while intending to catch other fish. It may however also indicate untargeted catch in other forms of animal harvesting or collecting...

 associated, leading to the British government introducing a ban on pair trawling for bass in UK territorial waters

Territorial waters

Territorial waters, or a territorial sea, as defined by the 1982 United Nations Convention on the Law of the Sea, is a belt of coastal waters extending at most from the baseline of a coastal state...

.