Cove culture of marble goby ( Oxyeleotris marmorata Bleeker) and carps in Tri An Reservoir of Vietnam

This study was conducted in the 5.24-ha Truong Dang Cove of Tri An Reservoir of Vietnam during June 2002–May 2003 to describe cove culture of marble goby ( Oxyeleotris marmorata Bleeker) with silver carp ( Hypophthalmichthys molitrix), bighead carp ( Aristichthys nobilis), common carp ( Cyprinus carpio) and grass carp ( Ctenopharyngodon idella) stocked at 960, 470, 470, 470 and 170 fish/ha, respectively. After about 7 months of culture period from October 2002 to May 2003, gross yield of marble goby was 251.1 kg/ha/crop, while gross yields of silver carp, bighead carp, common carp and grass carp were 90.5, 114.3, 84.6 and 35.0 kg/ha/crop, respectively. Survival was 73.7% for marble goby and 55.1–62.8% for carps. Results indicated that the cove had relatively good physicochemical conditions with diversified natural food resources such as terrestrial vegetation, phytoplankton, zooplankton, benthos, detritus, small wild fish and prawns. The major food item of marble goby was small freshwater prawns, followed by small wild fish and benthos. Addition of marble goby to carp polyculture in cove gave much higher economic return, compared to that without marble goby (US$2713.2 vs. US$260/crop). This study has demonstrated that cove culture of marble goby is a prominent prospect ecologically, technologically and economically.