Effects of square mesh panels position of bottom trawls on by-catch bluefish Pomatomus saltatrix (Linnaeus, 1776) selectivity in the Southern Coast of the Black Sea, Turkey
[ X ]
Date
2014
Journal Title
Journal ISSN
Volume Title
Publisher
Cahiers De Biologie Marine
Access Rights
info:eu-repo/semantics/closedAccess
Abstract
The selectivity parameters for by-catch bluefish Pomatomus saltatrix caught by demersal trawl, a nominal 40 mm diamond mesh size codend outfitted with square mesh escape panels, was determined on the southern coast of the Black Sea. Square mesh panels of nominal 36 mm were evaluated in two separate combinations: left-right and middle on the codend. The 50% retention lengths (L-50) and selection ranges of left-right (SDS), middle (DSD) combinations and control codend for blue fish were estimated to be 13.03 and 3.82 cm, 12.91 and 3.71 cm, 12.49 and 3.68 cm respectively. The L-50 value of SDS and DSD codend were comparable with the L-50 value of the control codend; however, the control codend value was rather low. The values of SDS and DSD codend weren't very close to MLS of the bluefish (20 cm). For this reason, more than 36 mm square mesh panels can be used alternatively, instead of the 36 mm square mesh panel on the codends for the fishery of the bluefish and higher size selectivity can be obtained. However, it may not be successful fisheries when considering the minimum landing size for dominant species (whiting Merlangius merlangus (Linnaeus, 1758) and red mullet Mullus barbatus ponticus (Essipov, 1927), 13 cm) in the Black Sea trawl fishery. These results show that increasing the size selectivity in a multi-species trawl fishery using a single position or square mesh size is quite difficult. Furthermore, square mesh panel codends were more selective than diamond mesh codend (p < 0.05). Differences between left-right (SDS) position and middle (DSD) position were no significant (p > 0.05) for the square mesh panel codend. Although the left-right (SDS) combination had a higher total area than the other combination (DSD) with square mesh in the middle and was preferable for bluefish.
Description
Keywords
Square Mesh Panel, Selectivity, By-catch, Bluefish Pomatomus saltatrix, Demersal Trawl, Swimming Behaviour
Journal or Series
Cahiers De Biologie Marine
WoS Q Value
Q4
Scopus Q Value
Q3
Volume
55
Issue
3
