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Environmental variables affecting the gillnet catches and condition of Labiobarbus Festivus and Osteochilus Hasseltii in northern Malaysia

The influences of technical factors on the catching efficiencies of gillnets are well understood, but less is known about the importance of environmental factors and how these might concurrently affect target-species condition. Here we address this deficit for two economically important southeast...

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Main Authors: Rahman, Mohammad Mustafizur, Fathi, Ahmad, Broadhurst, Matt K.
Format: Article
Language:English
English
Published: KeAi Communications Co. 2021
Subjects:
QH541.13 Ecology
Online Access:http://irep.iium.edu.my/90589/7/90589_Environmental%20variables%20affecting%20the%20gillnet%20catches_Scopus.pdf
http://irep.iium.edu.my/90589/8/90589_Environmental%20variables%20affecting%20the%20gillnet%20catches.pdf
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https://www.sciencedirect.com/science/article/pii/S2468550X20300885/pdfft?md5=a1bca9f397ef9c0335bbfbc2127817a7&pid=1-s2.0-S2468550X20300885-main.pdf
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spelling my.iium.irep.905892021-07-09T09:43:28Z http://irep.iium.edu.my/90589/ Environmental variables affecting the gillnet catches and condition of Labiobarbus Festivus and Osteochilus Hasseltii in northern Malaysia Rahman, Mohammad Mustafizur Fathi, Ahmad Broadhurst, Matt K. QH541.13 Ecology The influences of technical factors on the catching efficiencies of gillnets are well understood, but less is known about the importance of environmental factors and how these might concurrently affect target-species condition. Here we address this deficit for two economically important southeast Asian cyprinids (Labiobarbus festivus and Osteochilus hasseltii) during a one-year study at a key fishing location in Lake Kenyir, Malaysia. Three gillnets (each 200 m long, 2 m deep and comprising either 38-, 51-, or 76-mm mesh) were deployed each month concurrent with sampling of benthic macroinvertebrates and various environmental parameters. Various multivariate analyses (detrended correspondence analysis, redundancy analysis and permutational multivariate analysis of variance) were used to explore potential relationships between the extrinsic variables (mesh size, sampling season, water quality and, based on known prey items, benthic macroinvertebrates) and gillnet catches and the biological condition (growth co-efficient and hepatosomatic index) of the target species. Catches of L. festivus (the most abundant species) were positively influenced by water turbidity without seasonal effects, while their biological condition was positively influenced by benthic macroinvertebrates (mostly Trichoptera) and the concentrations of DO and phosphate, and negatively influenced by water temperature. By comparison, seasonal influences on the catches and biology of O. hasseltii were somewhat size specific with positive and negative effects of the monsoon on small and large fish, respectively. The abundance of phytoplankton also positively affected the catches of O. hasseltii, while their biological condition was positively influenced by water temperature, but negatively influenced by water turbidity. Such species-specific differences were attributed to life histories, and although the more abundant L. festivus might be best sought during any period of turbidity, effort should be focused during the monsoon when individuals have optimal condition (and therefore better flesh quality). In contrast, larger O. hasseltii might be best sought during non-monsoon months concurrent with greater catches and optimal condition. Collecting similar data for other freshwater species both nationally and internationally might facilitate future efforts at fine-tuning gillnet fishing effort. KeAi Communications Co. 2021 Article PeerReviewed application/pdf en http://irep.iium.edu.my/90589/7/90589_Environmental%20variables%20affecting%20the%20gillnet%20catches_Scopus.pdf application/pdf en http://irep.iium.edu.my/90589/8/90589_Environmental%20variables%20affecting%20the%20gillnet%20catches.pdf Rahman, Mohammad Mustafizur and Fathi, Ahmad and Broadhurst, Matt K. (2021) Environmental variables affecting the gillnet catches and condition of Labiobarbus Festivus and Osteochilus Hasseltii in northern Malaysia. Aquaculture and Fisheries. ISSN 2096-1758 (In Press) https://www.sciencedirect.com/science/article/pii/S2468550X20300885/pdfft?md5=a1bca9f397ef9c0335bbfbc2127817a7&pid=1-s2.0-S2468550X20300885-main.pdf 10.1016/j.aaf.2021.05.004
institution Universiti Islam Antarabangsa Malaysia
building IIUM Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider International Islamic University Malaysia
content_source IIUM Repository (IREP)
url_provider http://irep.iium.edu.my/
language English
English
topic QH541.13 Ecology
spellingShingle QH541.13 Ecology
Rahman, Mohammad Mustafizur
Fathi, Ahmad
Broadhurst, Matt K.
Environmental variables affecting the gillnet catches and condition of Labiobarbus Festivus and Osteochilus Hasseltii in northern Malaysia
description The influences of technical factors on the catching efficiencies of gillnets are well understood, but less is known about the importance of environmental factors and how these might concurrently affect target-species condition. Here we address this deficit for two economically important southeast Asian cyprinids (Labiobarbus festivus and Osteochilus hasseltii) during a one-year study at a key fishing location in Lake Kenyir, Malaysia. Three gillnets (each 200 m long, 2 m deep and comprising either 38-, 51-, or 76-mm mesh) were deployed each month concurrent with sampling of benthic macroinvertebrates and various environmental parameters. Various multivariate analyses (detrended correspondence analysis, redundancy analysis and permutational multivariate analysis of variance) were used to explore potential relationships between the extrinsic variables (mesh size, sampling season, water quality and, based on known prey items, benthic macroinvertebrates) and gillnet catches and the biological condition (growth co-efficient and hepatosomatic index) of the target species. Catches of L. festivus (the most abundant species) were positively influenced by water turbidity without seasonal effects, while their biological condition was positively influenced by benthic macroinvertebrates (mostly Trichoptera) and the concentrations of DO and phosphate, and negatively influenced by water temperature. By comparison, seasonal influences on the catches and biology of O. hasseltii were somewhat size specific with positive and negative effects of the monsoon on small and large fish, respectively. The abundance of phytoplankton also positively affected the catches of O. hasseltii, while their biological condition was positively influenced by water temperature, but negatively influenced by water turbidity. Such species-specific differences were attributed to life histories, and although the more abundant L. festivus might be best sought during any period of turbidity, effort should be focused during the monsoon when individuals have optimal condition (and therefore better flesh quality). In contrast, larger O. hasseltii might be best sought during non-monsoon months concurrent with greater catches and optimal condition. Collecting similar data for other freshwater species both nationally and internationally might facilitate future efforts at fine-tuning gillnet fishing effort.
format Article
author Rahman, Mohammad Mustafizur
Fathi, Ahmad
Broadhurst, Matt K.
author_facet Rahman, Mohammad Mustafizur
Fathi, Ahmad
Broadhurst, Matt K.
author_sort Rahman, Mohammad Mustafizur
title Environmental variables affecting the gillnet catches and condition of Labiobarbus Festivus and Osteochilus Hasseltii in northern Malaysia
title_short Environmental variables affecting the gillnet catches and condition of Labiobarbus Festivus and Osteochilus Hasseltii in northern Malaysia
title_full Environmental variables affecting the gillnet catches and condition of Labiobarbus Festivus and Osteochilus Hasseltii in northern Malaysia
title_fullStr Environmental variables affecting the gillnet catches and condition of Labiobarbus Festivus and Osteochilus Hasseltii in northern Malaysia
title_full_unstemmed Environmental variables affecting the gillnet catches and condition of Labiobarbus Festivus and Osteochilus Hasseltii in northern Malaysia
title_sort environmental variables affecting the gillnet catches and condition of labiobarbus festivus and osteochilus hasseltii in northern malaysia
publisher KeAi Communications Co.
publishDate 2021
url http://irep.iium.edu.my/90589/7/90589_Environmental%20variables%20affecting%20the%20gillnet%20catches_Scopus.pdf
http://irep.iium.edu.my/90589/8/90589_Environmental%20variables%20affecting%20the%20gillnet%20catches.pdf
http://irep.iium.edu.my/90589/
https://www.sciencedirect.com/science/article/pii/S2468550X20300885/pdfft?md5=a1bca9f397ef9c0335bbfbc2127817a7&pid=1-s2.0-S2468550X20300885-main.pdf
_version_ 1705056527680798720
score 13.211869

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