A HIGH-SPEED MIDWATER ROPE TRAWL FOR COLLECTING COASTAL PELAGIC FISHES

The development and testing of a new high-speed midwater rope trawl (H SMRT) was initiated in the fall of 1992 by the National Oceanic and At mospheric Administration's (NOAA) National Marine Fisheries Service, S outhwest Fisheries Science Center and the California Department of Fis h and Game (CDFG). The HSMRT was designed to collect fishery-independe nt data for adult coastal pelagic fish species including Pacific sardi ne (Sardinops sagax), northern anchovy (Engraulis mordax), jack macker el (Trachurus symmetricus), and Pacific mackerel (Scomber japonicus). Originally the trawl was constructed as a four-panel net with 53-meter head- and footropes with 6.50-meter meshes in the opening panels tape ring down to 5-centimeter meshes in the rear and 10-centimeter meshes in the cod end. The net was modified after several cruises in 1992 and 1993 aboard NOAA's David Starr Jordan and CDFG's Mako. During fishing operations, targeted speeds of 4 to 4.5 knots were obtained by both v essels. For shallow tows, deployment took approximately 30 minutes wit h a fairly small crew (4-5 people). Fork lengths of fish captured rang ed from 136 to 280 mm for Pacific sardine, 30 to 140 mm for northern a nchovy, 50 to 320 mm for jack mackerel, and 60 to 450 mm for Pacific m ackerel. Mature hydrated female sardine were taken during April-May, 1 994, only by the Mako, which generally fished in deeper water than the David Starr Jordan. The HSMRT worked well on both the David Starr Jor dan and the Mako, but because the Mako had less horsepower, it was una ble to maneuver while trawling or to tow the net shallower than 18 met ers below the surface.