Developing bottom trawls to improve size and species selectivity in North Atlantic fisheries ...

• Main Author: Nguyen, Vang Y
• Format: Text
• Language: English
• Published: Memorial University of Newfoundland 2024
• Subjects: North Atlantic
• Online Access: https://dx.doi.org/10.48336/8k5k-2j48; https://research.library.mun.ca/16285/

Bottom trawling is an important and principal capture technique in groundfish fisheries, providing a high proportion of fisheries production to the Northern Atlantic. However, bottom trawling is associated with the bycatch of undersized fish and unwanted species, a large concern from a marine ecosystem perspective. Thus, developing gear designs to improve trawl selectivity (reduce the capture of non-target species and juveniles of target species) is necessary. This thesis has focused on developing trawl designs for an emerging redfish (Sebastes spp.) fishery in Canada and understanding the groundgear selectivity of an Icelandic commercial bottom trawl. Firstly, I developed a shaking codend by attaching an elliptical-shaped canvas at the posterior of a T90 codend (codend mesh rotated 90˚ in the transversal direction) to reduce the capture of undersized redfish in the catch. The results showed that the shaking codend had a higher amplitude ratio, period, and total acceleration and captured less redfish < 22 ...