Aquaculture Effects of Stocking (original) (raw)
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Effects of stocking density on the performance of juvenile pirarucu (Arapaima gigas) in cages
Aquaculture, 2012
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.
Asian Journal of Fisheries and Aquatic Research
The striped dwarf catfish Mystus cavasius being a least concern small indigenous fish it is necessary to protect the species from extinction in the near future. An experiment on production and economic feasibility of Mystus cavasius in cage was conducted for a period of six months from March to August 2020 in beel hilla at Naogaon district of Bangladesh. The study was carried out in nine cages (rectangular 8x5x2 feet size) under three treatments namely T1, T2 and T3 performed with the stocking densities of 46 fry m-2, 92 fry m-2 and 137 fry m-2 and designed each with three replications. The fish was fed with commercial pellet feed (containing 30% crude protein) twice daily at the rate of 5-7% of fish body weight. The total production was found to be significantly (p<0.05) highest in T3 among the three treatments. The net profit was better in T3 than T1 and T2 in terms of better production and money. So, stocking density of Mystus cavasius at the rate of 137 fry m-2 in cage could ...
Journal of Aquaculture Research and Development, 2020
A density dependent research was conducted on Oreochromis niloticus to determine the growth performance, body composition, survivability, yield and financial returns in floating cage fish culture system in a tributary of Tetulia River, Bhola. Juvenile monosex tilapia with an average weight of 40.2 g were stocked in 5 floating net cages at a density of 1000 (C1), 1200 (C2), 1500 (C3), 1800 (C4) and 2000 (C5) respectively. Fish were fed with a commercial floating feed twice daily in all the treatments. After 120 days, growth in terms of body final length and weight, weight gain, percent weight gain, specific growth rate, daily weight gain, gross and net production of fish were calculated and found C3 were comparatively higher than others. Survival rate was decreased with increasing stocking density. According to cost benefit analysis (CBA), stocking density 1200 per cage was the most suitable but it should not rise more than 1500 per cage for commercial monosex tilapia culture in cage aquaculture system.
The effect of stocking density on growth performance, production and survival of Pangas, Pangasius hypophthalmus were evaluated in cemented tanks. Fry of Pangas (1.52 ± 0.03 cm in length and 1.08 ± 0.02 g in weight) respectively were stocked into cemented tanks measuring 15 x 6 x 3 ft. Three treatments with two replicates were used: T 1-100; T 2-150 and T 3-200 fry/ tank. Pangas fry were fed twice daily with formulated feed 35 % protein at 10%, 5%, and 3% body weight for the first, second, and third month, respectively. After 90 days, the Highest growth performances (determined in terms of average weight) were recorded in T 1 (27.5±2.5 g) and T 2 (22.4±2.8 g) while T 3 (18.2±3.5g) recorded the smallest growth. Production differed significantly among treatments (P<0.05). Feed conversion ratio (FCR) of 1.0, 1.02 and 1.05 in T 1 , T 2 and T 3 , respectively were not significantly different (P>0.05). Survival was significantly different among treatments (P<0.01). Highest survival (100%) was attained in T 1 with lower stocking density, followed by T 2 (96%) and T 3 (90%). Survival was greatly influenced by the stocking densities in all treatments. The water quality parameters and their monthly fluctuations recorded throughout the study period were found within the suitable ranges for the fish culture such as temperature 27.0 to 28.7 °C, dissolved oxygen 5.7 to 6.2 mg/lit, pH 7.2 to 7.5, Ammonia from 0.45 to 0.51mg/L, Hardness 105 to 110 ppm and Nitrite 0.152 to 0.161 mg/L.
Boletim do Instituto de Pesca
The present study evaluated practical diets with increasing levels of protein and energy on performance, fillet composition, feed cost, and physiological responses of pirarucu (Arapaima gigas) juveniles during the grow-out phase in a net cage system. In an on-farm trial for 90 days 225 pirarucu juveniles with initial weight ± standard deviation of 2025 ± 335 g were fed to apparent satiety with extruded diets containing 37.4 (T-37), 40.8 (T-40), 43.9 (T-43), 45.5 (T-46), and 47.1% (T-49) crude protein (CP), increasing lipid levels, and energy:protein ratio fixed in 10 kcal g-1. Protein and lipid concentrations in the diets influenced the cost, fillet composition, and important physiological aspects of the health maintenance and productive performance of the pirarucu juveniles. Fish fed the T-37 diet had lower concentrations of fat in body cavity, fillet and blood, and had a lower cost associated with feeding. The increase in protein and energy levels in the other diets tested reduced the economic return, did not improve the zootechnical performance and caused physiological changes in the fish.
Different growth and production parameters of cage cultured Vietnamese climbing perch (Anabas testudineus, Bloach), locally known as koi, were studied. Fishes were reared in bamboo framed net cages under three different stocking densitiesina single experimental culture cycle of 4 months (July to October, 2013). The experimental earthen pond at Sher-e-Bangla Agricultural University (SAU) campus, Dhaka, was installed with a total of nine 1m3 (1m x 1m x 1m) cages; wherein 100 fish m 3, 150 fish m 3and 200 fish m 3 were set as the different stocking densities demarked as treatment T1, T2 and T3 respectively with three replications each. Mean initial length and weight of the fries were 4.21± 0.114, 4.42± 0.023 and 4.51± 0.047 cm for T1, T2 and T3, respectively. Mean initial weight for the same treatments were 1.62 ± 0.089, 1.54 ± 0.045 and 1.60 ± 0.0097 g, respectively. Whereas the mean harvesting length and weight for T1, T2 and T3 recorded were 16.63± 0.119, 16.12± 0.039, 16.67± 0.093 cmand 105.54±1.84, 118.60±2.535, 112.49±2.10 g, respectively. T2 showed the highest length and weight gain after harvesting (P<0.05). The specific growth rate of T2 was found significantly different among treatments and again T2 resulting the highest figure of 3.60±0.003 (%). The same treatment had the highest survival rate of 62.66 ± 4.66 (%) with a mean of 57.44±2.36 (%). However, no significant difference among treatments was observed for survival rate (P>0.05). Finally, the gross yield (kgm 3) was 7.929±0.92 in T2 (P<0.05) which was highest among all the treatments and T2 returned back lowest production of 3.39 ± 0.307 kg m 3 which was significantly lower than the yield found in remaining treatments.The gross revenue earned from selling of fish at a price of 220 Tk kg 1 were 747.98 ± 67.54, 1744.5 ± 203.6 and 1665.1 ± 187.7 Tk m 3 in T , 1 T2 and T3, respectively. Whereasthe values,in terms of net profit, stood at 418.3 ± 141.16, 779.0 ± 170.73 and 62.00 ± 43.40 Tk m 3 for the same treatments, respectively. Therefore, the cage with 150 fishes (T ) showed 2 promising growth, yield and survival rate which could be recommended to adopt. However, more trials are suggested to optimize the stocking density and feeding regime for better production performance and profit.
Anabas testudineus (Climbing perch) growth and production were estimated using locally constructed cages (1 m 3) at various stocking densities (40, 60, 80 and 100 fish m-3) in a forest water body, located in Tripura, NE India. Each rearing density was repeated three times. The size of the fish at release was 3.5 ± 0.3 cm/2.8 ± 0.35 g and they fed with pellet feed @ 2% (28% CP) of fish biomass. After 180 days of farming, we observed that an increase in stocking density decreased fish length, body weight, specific growth rate (SGR) and survival rate, as well as reduced feed conversion efficiency of fish. Maximum fish growth was recorded at a stocking density of 40 fish m-3 (84.5 ± 0.67 g fish-1) and minimum at density of 100 fish m-3 (53.4 ± 3.07 g fish-1). There was no significant difference in weight gain and SGR between 40 and 60 fish m-3 (p ≤ 0.05). The SGR ranged from 1.63 to 1.88%/ day and the FCR ranged from 2.3 to 2.8. Survival was highest at 40 fish m-3 (87.6%) and lowest at 100 fish m-3 (58.6%). Fish biomass production ranged from 2.96 ± 0.05 kg (40 fish m-3) to 4.0 ± 0.29 kg cage-1 (60 fish m-3). Based on this study, it can be concluded that a stocking density of 60 fish m-3 is optimal for cage farming of A. testudineus to ensure better growth and survival of the fish and forest water bodies can be explored for cage culture.
Egyptian Journal of Aquatic Research (Publisher: Elsevier), 2020
The influence of stocking density plays one of the major roles in the final production for profitable aquaculture. This study was conducted to investigate the effect of stocking density on growth, yield and economic return of striped catfish (Pangasianodon hypophthalmus). The fish were reared in cages at three different stocking densities. Fishes were stocked at 19, 22 and 25 fish/m 3 densities indicated as T 1 , T 2 and T 3. After 90 days of the experimental period, growth and yield parameters were studied and economic analysis regarding farm profitability was carried out. Fish growth performance significantly decreased with increasing stocking density. The mean yields were 12.27 ± 0.08, 14.00 ± 0.14 and 15.01 ± 0.20 kg/m 3 in T 1 , T 2 and T 3 , respectively and showed significant variations (P < 0.05) with increasing stocking density. RGR, SGR, PER between 19 and 22 fish/m 3 were not significantly different, but they were significantly higher than 25 fish/m 3. The FCR was significantly lower in 19 and 22 fish/m 3 than the 25 fish/m 3 stocked cages. Environmental parameters were within the acceptable range. The benefit-cost analysis revealed significantly higher BCR in 19 and 22 fish/m 3. Overall, best farm profitability was achieved from the stocking density of 22 fish/m 3 among three stocking densities experimented in the study.
Aquaculture Research, 2008
This research was conducted to investigate the effect of stocking density on the growth performance and yield of Oreochromis niloticus in cage culture in Lake Kuriftu. The treatments had stocking densities of 50 (50F), 100 (100F), 150 (150F), and 200 (200F) fish per m−3. All treatments were in duplicate. Juveniles with an average weight of 45. 76±0.25 g were stocked in the treatments. The fish were fed a composite mixture of mill sweeping, cotton seed, and Bora food complex at 2% of their body weight twice per day using feeding trays for 150 days in powdered form. The growth performance of O. niloticus was density dependent. The final mean weight of O. niloticus ranged 147.76±0.28–219.71±1.42 g and the mean daily weight gain was 0.69±0.01–1.15±0.02 g day−1. Fish held in cages with lower density were heavier than the ones held at higher densities, and showed higher weight gain and daily weight gain. The most effective stocking density, in terms of growth parameters, was 50 fish m−3. The gross yield (4.5–20.55 kg cage−1) showed a significant difference with increasing stocking density (P<0.05). Moreover, the apparent food conversion ratio (2.48–7.22) was significantly affected by stocking density (P<0.05). However, survival rate was not affected by stocking density (P>0.05). It can be concluded that the most effective stocking densities were at 50 fish m−3 cage for larger size fish demand in a short period and 200 fish m−3 for higher gross production with supplementary feed.
2015
The importance of aquaculture has become more apparent at present, with higher demanding pressure from an ever-increasing world population. However, the industry is facing copious challenges the major one being the need to obtain a perfect balance between precipitous fish growth and optimum use of the stocked feed. In any aquaculture system, the cost of feeds accounts for approximately 40 60% of the operating costs in intensive culture systems. These costs highly affect the output since the economic viability of any culture operation depends on the feed and feeding frequency. The relevance of fish farming in the aquaculture context lies in the urgent need for income generation. The economic viability of any specie lies in its ability to consume less and produce more. This study therefore sought to determine the growth performance in relation to economic viability of four fish species (rabbit fish (Siganusvermiculatus), red snapper (Lutjanusargentimaculatus), milk fish (Chanoschanos)...