To assure comparability with the NEFSC survey, NEAMAP adopted the bottom trawl developed for the NEFSC by the joint Mid-Atlantic/New England Trawl Survey Advisory Panel. We use a 4 seam, 3 bridle, 400 x 12 cm net with a cookie sweep and 2.54 cm knotless liner in the cod end. Thyboron Type IV 66" doors.
During science operations, trawl monitoring sensors provide near-real-time measures of gear performance, enabling the Captain and crew to adjust tow speeds and scope to obtain the optimum fishing geometry of the net. Equally important, these data are saved to computer files which, when combined with tow distance information from the GPS, allow subsequent data analyses (such as the generation of abundance estimates) to be performed on an area-swept basis. Such analyses provide standard adjustments for tow-to-tow differences in tow speed, tow duration, current speed, and so on.
NEAMAP Mid-Atlantic uses a suite of net monitoring sensors to assure that tows are conducted in a consistent manner and that the net is fishing within specified limits:
- Wing sensors: To measure the width of the mouth opening
- Headrope sensors: To measure the height of the net at the headline
- Door sensors: To measure spread
- Bottom contact sensor: Monitors constant sweep contact with seafloor
- Catch sensor: To warn when the cod end of the net is filling (set to trip at approximately 5,000 lbs)