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Twin bottom otter trawls
Twin bottom otter trawls

ISSCFG code: 03.13 – standard abbreviation: OTT
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OverviewThis special rigging system for this particular gear was developed to increase the horizontal fishing area of the trawl and comprises two identical trawls ("twin") fixed together. The horizontal opening is provided by a single pair of otter boards, which are attached to the trawl close to the wings. Their inner wings are attached to a sledge towed simultaneously with the otter boards from a common crow foot. Another option used on modern vessels in the northern shrimp fishery is to tow the gear with three warps.Handling EquipmentTrawl winches installed on deck control the trawling wires and store them when not in use. In addition to the standard two-bobbins winch (or to two single-bobbin winches), a third winch with one bobbin can be necessary according to the rigging of the twin trawls (which can be either two or three warps arriving to the trawler).Vessel Overview Trawlers.Fish OperationIn twin trawling one vessel tows two to four trawls. In shrimp trawl and nephrops trawl fisheries it is common to tow twin trawls over the stern. With a special rigging there is also a possibility for towing three trawls using to warps. In tropical shrimp trawling with outriggers twin trawls are towed on each side (which makes a total of four trawls towed at the same time).Target SpeciesThey are generally used for catching shrimp or bottom species.Water Area OverviewAll over the world.Gear EnvironmentAll shrimp trawling areas.ImpactsSpecies Unwanted bycatch of fish is one of the main negative impacts. Use of bycatch reduction devices (BRD) can mitigate the problem.
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