Study on fish species composition in Cai Lon and Cai Be floodgates, An Giang province

Abstract

Assessment of environmental water quality and study on fish species composition were conducted from July to September at 12 sites inside and outside Cai Lon and Cai Be floodgates. Fish species was collected directly from fishermen by different kinds of fishing gears. The results showed that the pH ranged 6.58 – 7.30 for Cai Lon floodgate and 6.47-6.97 for Cai Be floodgate. In September, the temperature reached peak at 31.5 inside Cai Lon floodgate and 32.4 inside Cai Be floodgate. For Cai Lon floodgate, dissolved oxygen ranged 3.6-5.2 mg/l, water velocity ranged 0.11-0.35 m/s, water depth ranged 4-5.2 m, water transparency ranged 29-53 cm. For Cai Be floodgate, dissovled oxygen ranged 3.02-4.10 mg/l, water velocity ranged 0.07-0.32 m/s, water depth ranged 3.4-4.4 m, water transparency ranged 25-47 cm. Salinity remained constant at 0‰ in most sampling sites except for site 9 outside Cai Lon floodgate (2-4‰) and site 12 outside Cai Be floodgate (1‰) in three sampling periods. A total of 57 fish species belonging to 37 families and 18 orders were collected from inside and outside of Cai Lon and Cai Be floodgates. The most abundant order was Cypriniformes and Perciformes with 11 species in each order (19%), followed by Siluriformes with 9 species (16%), Anabantiformes with 6 species (11%), Gobiiformes with 3 species (5%). Others only had 1-2 species in each order with 17 species in total (30%). Overall, 42 species were recorded outside Cai Lon floodgate and 26 species outside Cai Be floodgate, while 37 species were collected from inside Cai Lon floodgate and 25 species inside Cai Be floodgate.