Effect of understocking density of channel catfish fingerlings in intensively aerated multiple‐batch production

Abstract

Multiple‐batch production is the most widely practiced method of raising channel catfish. Producers are increasingly adopting intensified production practices in multiple‐batch systems by increasing stocking density and aeration rates as a means to improve cost efficiencies. Proven stocking recommendations are required for the efficient implementation of recent developments in multiple‐batch production. Twelve 0.4‐ha ponds were understocked with 17,484, 20,612, and 26,124 fingerlings/ha (mean weight = 40 g/fish) over equal weights of carryover fish (0.46 kg/fish @ 4,589 kg/ha). Fish were fed once daily to apparent satiation with a 28% protein floating feed and aerated with a single 7.4‐kW electric paddlewheel aerator. Density‐dependent significant differences were absent for gross, net, daily net yields, marketable yields (≥0.54 kg), growth (g/day), and survival. Sub‐marketable yield (<0.54 kg) and feeding rate increased significantly with increased understocking density. Economic analysis revealed increased breakeven prices and diminished net returns with increased stocking density when sub‐marketable fish were not considered as revenue. These differences in production costs and profits among the three treatments became minimal when sub‐marketable fish were included as revenue. All three density treatments attained positive annual net cash flows. This study validates channel catfish understocking densities of 17,000–26,000 fish/ha to improve cost efficiency in intensively aerated, multiple‐batch production systems.

Economic Effect of Hybrid Catfish (Channel Catfish ♀ × Blue Catfish ♂) Growth Variability on Traditional and Intensive Production Systems

“…Although all three examined production systems were deemed profitable, the MB system, having the second-highest gross revenue, had the highest percentage of oversized fish (12%) compared to the SB (4%) and SP (4%) systems. This may be due to the continuous production schedule followed in the MB system, involving multiple stockings and partial harvests, which allow a certain number of larger and/or submarketable fish to stay in the ponds for the next cycle (Hanson et al 2020;Kumar et al 2021). The current study also showed that the average dockage loss can be $0.12/kg for undersized fish and $0.38/kg for oversized fish from the three production systems.…”

“…Production advantages of hybrid catfish include better growth, crowding tolerance, lower feed conversion ratio (FCR; a measure of the efficiency of converting fish feed into fish biomass), and greater disease resistance (Dunham and Masser 2012;Li and Robinson 2012). These characteristics allow hybrid catfish to be used in a more intensive production system and achieve economies of scale by spreading the total fixed costs over greater fish production (Kumar et al 2018(Kumar et al , 2021).…”

“…Commercial U.S. catfish farmers employ numerous production practices, which are variants of either single-batch (SB) or multiple-batch (MB) production systems (Engle 2003;Kumar et al 2021). The SB production system is characterized by stocking fingerlings, growing them to the desired size range, and completely harvesting the pond when the fish reach 0.4-0.8 kg/fish (Tucker and Robinson 2013).…”

“…The pond is then drained or otherwise "zeroed out" of any remaining fish before stocking a new year-class of fingerlings. In the MB production system, farmers stock 10-15-cm fingerlings each spring at densities varying from 12,000 to 25,000 fingerlings/ha into ponds that have subharvestable fish remaining from the previous year (Terhune et al 1997;Engle 2003;Hanson et al 2020;Kumar et al 2021).…”

“…Several studies have assessed the economic performance of hybrid catfish production systems (Kumar et al 2016;Mischke et al 2017;Hanson et al 2020;Kumar et al 2021). However, studies evaluating the economics of hybrid catfish size variation resulting from the commercial SB, MB, and SP production systems are nonexistent.…”