Influence
of seasons, habitat sanctuaries, gears and
environmental
variables on the catches of hilsa shad
(Tenualosa
ilisha) in Bangladesh waters
M.
Jalilur Rahman1, S. M. Nurul Amin2*, M. Nahiduzzaman1,
M. A. Wahab1 and N. Romano3
1ECOFISH-Bangladesh
Project, WorldFish, Bangladesh & South Asia Office, Banani, Dhaka, 1213
Bangladesh
2Laboratory of
Fisheries Biology and Ecology, Department of Aquaculture, Faculty of Agriculture,
Universiti Putra Malaysia, 43400 UPM, Serdang, Malaysia
3
Aquaculture/Fisheries Center, University of Arkansas at Pine Bluff, 1200
North University Drive, Pine Bluff 71601, AR, USA
*Corresponding
Author E-mail: smnabd@gmail.com
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Key
words
CPUE variations
Dissolved oxygen
Environmental variables
Habitat sanctuaries
Hilsa shad
Publication Data
Paper received : 15.03.2017
Revised received : 20.05.2017
Re-revised received :
05.09.2017
Accepted : 28.12.2017
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Abstract
Aim: Variations in
catch per unit effort (CPUE) of hilsa (Tenualosa ilisha) at different
habitats (sanctuaries) of Bangladesh waters were observed to understand
whether CPUE variations were due to differences in habitat complexity,
environmental factors or both. ??
Methodology: CPUE of hilsa
data were collected from five different habitats in Bangladesh waters between
July 2015 and June 2016. Various in-situ physico-chemical parameters were
measured monthly and then examined for any relationship to CPUE. ???
Results: The overall mean
CPUE of hilsa from the investigated areas was estimated to be 7.93 ? 6.03 kg
gillnet-1 day-1. The monthly average values of CPUE was
the highest in January 2016 amounting 11.63 ? 1.21 kg gillnet-1
day-1 and the lowest in March 2016 amounting 3.63 ? 0.83 kg
gillnet-1 day-1 with significant differences among the
months (p < 0.05). Gillnet mesh sizes influenced the capture of hilsa with
the highest (9.18 kg gillnet-1 day-1) and lowest (6.05
kg gillnet-1 day-1) catch obtained from the smallest
(3.0 cm) and largest (11.0 cm) mesh size, respectively. There was a lower
degree of positive and negative correlation (p > 0.05) with environmental
variables and CPUE. Multiple regression analysis tests also indicated a weak
overall correlation (62%) between environmental variables and CPUE of hilsa.
Interpretation: Results likely
indicate that habitat structure was more important in determining CPUE of
hilsa (highest in Padma sanctuary) compared to environmental factors at the
tested sites. This study emphasizes the need to conserve habitats that are
often used as important fishing grounds for hilsa to ensure their adequate
recruitment and ultimately sustainable management of this fishery.
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