Fish diversity, abundance, and distribution in Sungai Sepang Besar Estuary Estuary, Selangor, Malaysia / Nurul Asyikin Ya

This study was conducted from April 2014 to February 2015 to determine fish diversity
and distribution along Sungai Sepang Besar (SSB), Selangor, Malaysia. Fish sampling
was conducted utilizing gill nets (mesh sizes 1.25”, 1.5”, 2.25”, 2.5”, 2.75”, 3”) and
longlines. Fish and water parameters sampling were conducted at nine stations along
SSB. The dissolved oxygen (DO), salinity, pH, and ammonia were significantly
different (p<0.05) from sampling reaches while salinity, pH, and turbidity showed
significant difference (p<0.05) between spring and neap tides. A total of 832 fish
representing 50 fish species from 32 families were recorded. The Toxotidae was the
most abundant (56.97%) followed by the Engraulidae (9.62%), Leiognathidae (5.05%),
Plotosidae (4.81%), and Ariidae (4.45%). The most abundant fish species was Toxotes
jaculatrix (34.6%). The lower reaches recorded the highest abundance of fishes (62.2%)
followed by the upper reaches (19.3%) and the middle reaches (18.39%). The Shannon
Index was 2.37, Evennes Index was 0.21, and Margalef Index was 7.29. Higher fish
diversity was recorded during spring tide (H=2.85). There was significant differences
(p<0.05) of the diversity indices between spring and neap tides where the former
recorded higher values. One way ANOVA showed that density was significantly
different between gillnets (p<0.05) being highest from the 1.5” mesh while biomass
showed no significant difference (p>0.05) between mesh sizes. The 1.5’ mesh gillnet
recorded highest density (0.43 no/m2/hr) and biomass (32.00 g/m2/hr) during neap tide.
The fish density and biomass from gillnets was not significant between tides (p>0.05).
The length-weight relationship for the 7 most abundant species showed that 5 species
(Arius sagor, Photopectoralis. bindus, Toxotes jaculatrix, Stolephorus. indicus, and
Thryssa dussumieri) recorded positive allometric growth (b >3) while 2 species
(Plotosus lineatus and Toxotes chatareus) recorded negative allometric growth (b<3).
The Canonical Correspondence Analysis (CCA) indicated that DO, turbidity, salinity,
and pH were most important abiotic factors affecting fish diversity and distribution in
SSB.