Trawl Selectivity Estimates of Thryssa dussumieri (Valenciennes, 1848) in Square and Diamond Mesh Codends
Trawl Selectivity Estimates of Thryssa dussumieri (Valenciennes, 1848) in Square and Diamond Mesh Codends
Date
2016
Authors
Madhu, V.R.
Remesan, M.P.
Meenakumari, B.
Journal Title
Journal ISSN
Volume Title
Publisher
Society of Fisheries Technologists(India)
Abstract
Codend selectivity of Thryssa dussumieri, an important
trawl resource along Gujarat coast was studied
using covered codend method. The selectivity
estimates were worked out for 40 mm diamond and
square mesh codends by staked haul method to
account variation associated with multiple hauls
considered for deriving the selectivity. The length at
50% retention of the species for the 40 mm diamond
and square mesh codends were worked out as
8.84±0.16 and 10.20±0.12 cm respectively. The
selection range, selection factor and selection ratio
for the diamond mesh codend was 7.96±0.42 cm,
2.21 and 0.9 respectively and for the 40 mm square
mesh codend these values were 3.76±0.19 cm, 2.55
and 0.37 respectively. Considering the length at first
maturity of the species as 125 mm, the optimum
mesh size for 40 mm diamond mesh and square
mesh codend were worked out as 56.6 and 49 mm
respectively for conservation of the species.
Description
Keywords
Selectivity, Thryssa dussumieri, codend, square mesh
Citation
Fiishery Technology 2016:53(2), 105--109