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Spatial and temporal changes in the fish communities from a mangrove‐dominated creek system near K arachi, P akistan
Author(s) -
Khatoon Z.,
Paperno R.,
Makhdoom Hussain S.
Publication year - 2014
Publication title -
journal of applied ichthyology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.392
H-Index - 62
eISSN - 1439-0426
pISSN - 0175-8659
DOI - 10.1111/jai.12377
Subject(s) - mugil , mangrove , sardinella , biology , fishery , pelagic zone , monsoon , abundance (ecology) , ecology , community structure , fish <actinopterygii> , geography , sardine , meteorology
Summary The objectives of the study were to inventory the fish community, examine how the fish communities changed in these creeks temporally (season), and compare the fish communities between creeks of varying structure (width). During February 1999 to December 2001, a survey was undertaken to monitor the distribution and abundance of fishes in the Korangi‐Phitti Creek ( KPC ) system (24°45′N, 67°20′E) near Karachi, Pakistan. Fish were collected from 123 stations using a combination of monofilament gillnets of 8.9 cm, 5.7 cm, and 3.8 cm stretched mesh sizes. A total of 17 023 fish representing 86 species were collected during the study; S ardinella gibbosa and N ematalosa nasus were the most abundant taxa (in terms of numbers of individuals) collected, accounting for over 60% of the total catch. Physical conditions in the study area were found to have significant seasonal (monsoon) patterns related more to temperature and salinity than to rainfall. Seasonal comparisons indicated that the communities were significantly different between the northeast monsoon ( NEM ) and southwest monsoon ( SWM ) seasons. Taxa primarily responsible for distinguishing the NEM were the mullets ( M oolgarda cunnesius, L iza carinata, M ugil cephalus ). The SWM was characterized by A nodontostoma chacunda , S comberoides commersonnianus, and the engraulid ( T hryssa hamiltonii ). The community sampled in wide creeks (shipping channels) was very different in composition than the community in small creeks within this system. Wide creeks were characterized by schooling pelagic species ( S . gibbosa, N . nasus ), while the smaller creeks were characterized by the presence of mullets ( M . cunnesius, M . cephalus, L . carinata ) and scat ( S catophagus argus ). The KPC system was shown to contain a highly diverse fishery, which in turn contributes to regional offshore fisheries (shad, mackerel, tuna and perches). The various negative natural and anthropogenic events in this region highlight the need for information regarding the fish community, water quality, and the mangrove forest to evaluate ecosystem changes, the effects of disturbances, and for the development and making of sound management decisions.