Comparison of mudcrab-based brackishwater polyculture systems with different finfish species combinations in Sundarban, India

Abstract

To compare production and economic performance of polyculture systems with different species combinations, a 210-day trial was carried out. In the first combination (T1), milkfish (Chanos chanos) and mudcrabs (Scylla serrata), and in the second (T2), mullets (Mugil cephalus, Liza tade and Liza parsia at 0.5:0.5:0.5 ratio) and mudcrabs were stocked keeping fish and mudcrabs at 15,000 numbers per ha, respectively, in both treatments. The finfish were fed floating pellet at 2%-3% and mudcrabs were fed fresh and farm made feed at 5%-8% body weight. Growth parameters of mudcrabs were similar in both T1 (407.64 ± 105.78 g) and T2 (418.89 ± 105.24 g), with no significant differences. Among finfish, M. cephalus attained highest final body weight, 241.55 ± 26.44 g followed by milkfish, 200.46 ± 11.82 g whereas lowest growth noticed in L. parsia (63.69 ± 6.62 g). Length-weight analysis of fish indicated negatively allometric growth (b < 3) for grey mullets, parsia and milkfish while L. tade recorded perfect cube low (b = 2.99). Male mudcrabs recorded positive allometric (b = 3.3) and female crab exhibited negative allometric growth (b = 2.68). The total productivity was 4,533 and 3,694 kg/ha with mudcrab contributes 53.69% and 60.56% to the total productivity in T1 and T2 respectively. The economic analysis indicated benefit-cost ratio (BCR) of 1.57 and 1.73 in T1 and T2 respectively with 10% and 35% insignificant increase (p > 0.05) in BCR and profit per kg, respectively, in T2 compared with T1. The study elucidates polyculture of mudcrabs with finfish can be a taken up as a profitable venture for sustainable diversification of brackishwater farming in Sundarbans. . chanos, L. parsia, L. tade, M. cephalus, polyculture, S. serrata K E Y W O R D S C

Integrated rearing system approach in the farming of mud crab, shrimp, fish, oyster and periphyton in bracksihwater pond

“…The water quality parameters recorded in the current experiment were conducive and within optimal level for the cultured animal (Anand et al, 2018;Vijayan & Diwan, 1995). Brackishwater animals especially mud crabs are able to withstand wide salinity variation (Cholik & Hanafi, 1992), and other reports pointed that growth of brackishwater animals are influenced more by temperature than by salinity (Ruscoe, Shelly & Williams, 2004).…”

“…Pond preparation was carried out according to Anand et al, 2018. The ponds were drained, muddy layer was removed, and agricultural lime (CaCO 3 ) was applied at a dose of 200 kg/ha in the drained pond to stabilize pH of the pond bottom soil. After two days of liming, ponds were filled with brackishwater drawn through tide from the nearby river to a depth of 130-150 cm and disinfected with bleaching powder (CaOCl 2 ) at 200 kg/ha.…”

“…Growth and productivity performances were evaluated in terms of average body weight (ABW, g), daily weight gain (DWG, g/day), specific growth rate (SGR, % per day), feed conversion ratio (FCR), total productivity (kg/ha) and percentage survival as follows (Anand et al, 2018): The economic analysis of the treatments was performed to estimate the net return and benefit-cost ratio (BCR) as follows:…”

“…. The feasibility of polyculture of mud crab S. serrata with brackishwater finfish (Anand et al, 2018), Penaeus monodon (Begum, Shah, Mamun, & Alam, 2007), milkfish (Lijauco, Prospero, & Rodriguez, 1980;Venugopal et al 2012), Tilapia (Rahman, Hoq, & Ahmed, 2004) and incorporation of mud crab in mangrove areas (Mwaluma, 2002, Putro, Fahrian, Widowati & Suhartana, 2015 has been worked out and proved to be highly remunerative. Due to the cannibalistic nature of mud crab, low stocking density is recommended (Mirera & Moksnes, 2015;Suprapto, 2001;Venugopal et al, 2012) which opens an area for stocking compatible species occupying different spatial and trophic niche in the crab pond for optimum utilization of space and resources.…”

“…Our earlier works on polyculture of mud crab with different brackishwater finfish indicated a profitable return (Anand et al, 2018), and with this background, the current experiment was conducted to find out the effect of different combination of culture species (Scylla serrata, Mugil cephalus, Penaeus indicus) and incorporation of organic (oyster, Crassotrea cuttackensis) and inorganic extractive (periphyton).…”