Growth Performance of Bluntnose Black Bream, Channel Catfish, Yellow Catfish, and Largemouth Bass Reared in the In‐Pond Raceway Recirculating Culture System

Abstract

AbstractIn China, the in‐pond raceway system (IPRS) is a novel aquaculture model that was designed to better control water movement to improve water quality and allow for increased stocking density, thus increasing production efficiency and profitability compared to conventional earthen ponds. In this study, two IPRSs were constructed in a 4.13‐ha, annular ecological ditch (circumference waterway) with a mean water depth of 2.5 m. Each raceway (220 m3) consisted of an air‐lift area, a fish culture area, and a waste‐collecting area. The air‐lift system was used to circulate and aerate the water through the culture area, producing a water velocity of 0.03 m/s and a water flow rate of 18 m3/min. This flow rate was equivalent to an average water exchange every 12.2 min for each raceway. Bluntnose Black Bream Megalobrama amblycephala (initial weight = 90 g), Channel Catfish Ictalurus punctatus (initial weight = 150 g), Yellow Catfish Tachysurus fulvidraco (initial weight = 12 g), and Largemouth Bass Micropterus salmoides (initial weight = 10 g) were reared at densities of 16.36, 13.64, 4.36, and 1.14 kg/m3, respectively, with duplicate raceways for each fish species in the IPRSs. The experiment duration for these species was 176, 389, 208, and 412 d, respectively. Total harvest weight was 21,840 kg (5,288 kg/ha) for Bluntnose Black Bream, 17,850 kg (4,322 kg/ha) for Channel Catfish, 12,960 kg (3,138 kg/ha) for Yellow Catfish, and 10,750 kg (2,603 kg/ha) for Largemouth Bass. Daily weight gain for the four species was 2.90, 2.31, 0.81, and 1.19 g·fish−1·d−1, respectively, and the feed conversion ratio was 1.50, 1.85, 1.51, and 1.22, respectively. These results indicate a high potential for more controllable and efficient production of fish in the IPRSs. Design and engineering modifications need to be enhanced in the future to improve IPRS production capabilities.