Assessment of design and configuration of trawl nets and trawlers used in Nigerian trawl fishery

Abstract

Trawlers and trawl net used in Nigeria have undergone some modifications as observed the world over. Direct measurement was carried on the trawl nets to establish the current design and configuration. Trawlers used average 24.12m LOA and power by 608bhp. 99% of all the trawlers are above 18m and 250bhp consisting of medium size industrial trawler with 125 gross tonnage. Trawl net with total length of 24.15m and mono design of BRD, Square Mesh Window (SMW) is used in all the trawl nets with varying mesh sizes 35mm and 44mm. Codend extension are fitted with TED grid with top escape opening and double flap cover. 61% of the grid are installed at angle 40⁰ - 45⁰ while 32%, 35⁰ - 40⁰ and 7% are less than 35⁰. Three sizes of TED grid used and dominated by 34" x 34" 59%, 36" x 40" 33% and 42" x 50" 8%. Modifications allow for easy escape of sea turtle from the trawl net, maintenance of TED grid at the best angle of 45⁰ to avoid loss of catches and larger grid size are encouraged, 35mm as BRD are  illegal and urgent monitoring at sea is needed to ensure compliance with the regulation.