Effects of stocking density on the performance of juvenile pirarucu (Arapaima gigas) in cages

Abstract

Pirarucu, Arapaima gigas, is a carnivorous freshwater fish that exists along the Amazon Basin. This study investigated the effect of stocking density on growth performance and economic return of pirarucu in cages. Fish were stocked at densities of 10 or 12.5 fish/m 3 in 4.0-m 3 cages installed in Sítios Novos Reservoir (Ceará State, Brazil), with three replicate cages for each density. Fish were fed a formulated diet containing 40% crude protein and 14.2 MJ/kg of feed and cultured for 140 days. The following physicochemical parameters of the water were always at satisfactory levels for fish culture throughout the experiments: water temperatures ranged from 26.3 to 30.2°C, DO 3.2 to 7.7 mg/L, pH 6.9 to 7.7 and transparency 100 to 130 cm. Survival was high and ranged between 100.0% and 94.7 ± 5.0% in cages at 10 and 12.5 fish/m 3 , respectively. Density significantly affected (P b 0.05) final mean weight (2630.4 ± 213.7 and 2138.0 ± 148.2 g) and weight gain (2516.9±202.0 and 2043.1±142.9 g). In contrast, specific growth rate (2.25±0.09 and 2.22±0.06%/day), feed conversion ratio (1.2±0.1 and 1.2±0.2) and production (26.3±2.1 and 25.4±2.6 kg/m 3 ) were not significantly (P>0.05) affected by stocking density. Economic analysis was emphasized mostly on sales price and pirarucu juveniles and feed costs. The total costs of production were estimated at US$4.52/kg and US$5.31/kg for stocking densities of 10 fish/m 3 and 12.5 fish/m 3 , respectively. At a local market price of US$5.55/kg, the model used suggests that a commercial enterprise can be profitable only for density of 10 fish/m 3 . Furthermore, the economic viability of implementing of pirarucu culture in cages was analyzed using profitability indicators such as internal rate of return (IRR), net present value (NPV) and payback period. The high survival, very fast growth and moderated production rates of pirarucu stocked demonstrate that cages are a viable alternative method to standard ponds for the commercial production of pirarucu. The economic indicators appear to be attractive, thus pirarucu cage culture can become a profitable industry.

VALORES HEMATOLÓGICOS Y BIOQUÍMICOS DE JUVENILES DE PAICHE Arapaima gigas EN CULTIVO INTENSIVO

“…(Pereira-Filho et al, 2003;Menezes et al, 2006;De Oliveira et al, 2012). La mortalidad de peces fue mayormente debido a infecciones por hongos y bacterias en heridas de la aleta caudal ocasionadas por mordeduras relacionadas a la alta -densidad de cultivo.…”

DISTRIBUSI NITROGEN DAN FOSFOR PADA BUDIDAYA IKAN GABUS (Channa striata) DENGAN APLIKASI ECENG GONDOK (Eichhornia crassipes) DAN PROBIOTIK

“…Kisaran pH optimum untuk budidaya ikan berkisar 4,25-9,4 (Oliveira et al, 2012;Courtenay & Williams, 2004) . Namun demikian, secara umum parameter kualitas air terukur pada saat penelitian masih sangat mendukung untuk pertumbuhan dan perkembangan dengan baik, serta tidak berpotensi mengakibatkan stres pada ikan yang dipelihara.…”

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“…The stocking density is one of the most important variables in aquaculture as it directly influences survival, growth, behaviour, health, water quality, feeding and production (de Oliveira, 2012). Several studies have been carried out to record the influence of stocking density on growth, survival, welfare and production of fishes.…”