FAO/FIIT Fishing Gear Type Fact-Sheet Midwater trawls [TM] updated : 10-mai-2001 ISSCFG Classification : > Category : Trawl nets > Type : Midwater trawls   Midwater otter trawls   Midwater pair trawls Profile General Description: A midwater trawl consists of a cone shaped body, normally made of four panels, ending in a codend with lateral wings extending forward from the opening. It is usually much larger than a bottom trawl and designed and rigged to fish in midwater, including in the surface water. The front parts are sometimes made with very large meshes or ropes, which herd the targeted fish inwards so that they can be overtaken by smaller meshes in the aft trawl sections. The horizontal opening is maintained either byotter boards or by towing the net by two boats (pair trawling). Floats on the headline and weights on the groundline often maintain the vertical opening. Modern large midwater trawls, however, are rigged in such a way that floats are not required, relying on downward forces from weights to keep the vertical opening during fishing. Specific Equipment: Asonar is useful tool to detect fish concentration ahead the trawler and the trawl path and trawl depth can be adjusted accordingly. The fishing depth and the trawl is usually controlled by means of anet sounder (netsonde) or depth recorder. Specific Handling Equipment: Trawl winches installed on deck control the trawling wires and store them when not in use.Gilson winches and lifting tackle are provided to assist with handling gear at the vessel.Net drums are common tools to handle midwater trawls onboard vessels. Fishing Vessels using this gear: This type of trawl may be towed by a single or two trawlers (pair trawling). Fishing Operations: Midwater trawls are rigged to fish in midwater, from the surface to great depth depending on the position of the fish. It may be towed by one or two boats. Features Target Species: Pelagic species, sometimes some demersal fish. Areas: all The Gear and its Environment: Deployment Area: Midwater trawling is carried out mainly at sea, on the continental shelf, sometimes in deeper waters as well as in some lakes. Impact on the Environment: No impact on bottom habitats and bottom structures. Impact on Aquatic Species: In most cases it is a single species fishery, bycatch rates of other species are low. Incidental catch ofdolphins and marine mammals may occur in some areas.