Effects of stocking density on the performance of juvenile pirarucu (Arapaima gigas) in cages (original) (raw)
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Aquaculture Effects of Stocking
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.
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.
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 ...
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.
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.
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.
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.
International Journal of Aquaculture, 2013
This study aimed at testing the feeding rates on growth performance of pirarucu juveniles, Arapaima gigas, reared in cages. A 210-day experiment was conducted in four cages installed at the Pereira de Miranda reservoir (Pentecoste, Ceará, Brazil). Pirarucu juveniles (1550.0±85.0 g and 59.2±1.15 cm) were stocked at 40 fish/cage and fed four times a day with a commercial extruded feed with 40% crude protein. Fish were fed at rates of 2.0% and 3.0% body weight/day during the experiment. Growth performance was investigated in a designed experiment employing two different feeding rates and each treatment had two replicate cages. Survival was high and not significantly affected by feeding rate. Mean survival rate ranged between 91.2±1.2 and 92.5±2.5%. Feeding rate not affect significantly final mean length (89.8±3.2 to 88.7±3.5 cm), final mean weight (6800.0±170.0 to 6680.0±420.0 g) and production (46.8±0.7 to 46.0±1.2 kg/m 3), but FCR was significantly affected by feeding rate. Feed conversion rates were 4.32±0.08 and 2.82±0.09 for fish fed with 3% and 2% body weight/day, respectively. Therefore, the data obtained suggest that pirarucu juveniles with weight ranged from 1550.0±85.0 to 6800.0±170.0 g could be fed with feeding rate of 2.0% body weight/day.
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.
Aquaculture, 1974
Shrimp farming is one of the most profitable and fast-growing segment of the aquaculture industry (Tacon, 2002) [1]. The world production of shrimp increased 250 folds during the last 35 years from 10,000 ton in 1970 to 2, 461, 000 tones in 2005 (FAO, 2002) [2]. The green tiger shrimp, Penaeus semisulcatus used in this experiment, which resembles giant tiger shrimp, P. monodon in geographical distribution in the world. It is tolerant to high salinity and females reach their minimum first sexual maturity 6 month age size at about 130 mm length or 6 months age [3]. It is easy to propagate in captivity with or without lateral eyestalk ablation [4]. Stocking density is a major factor that affects fish growth under farmed conditions [5,6]. Stocking density and therefore, the volume of water per fish is a significantly factor in determining production in earthen ponds. Increasing stocking density results in stress, which leads to enhanced energy requirements causing reduced growth and food utilization [7]. Consequently, identifying the optimum stocking density for a species may be a critical factor affecting growth and feed intake when shrimp cultured in earthen ponds. The level of water exchange rate appeared to influence size in shrimp. Shrimp received more food grow faster, matured at larger size, whereas shrimp that received less water exchange rate grow slowly, and matured at smaller size [6]. Little information is available concerning the effects of stocking density and water exchange rate under the earthen ponds rearing system condition. The major objective were to determine the combined effects of stocking density and water exchange rate on growth performance, food utilization, and finally the economic feasibility of green tiger shrimp as species suitable for earthen ponds culture in Egypt. Materials and Methods Experimental system and management The experiment was conducted in Shrimp and Fish International Company (SAFICO) in Sharm El Sheikh Resort, South Sinai, Egypt. This farm is located in a protected area. Water source and the discharged water were monitored twice a weekly. Three stocking densities (5, 15 and 25 Post larvae of shrimp (PLs/m 2) and two water exchange (WER) (10 and 20% daily) were tested. Therefore, we have six treatments in three replicates. Shrimp PLs were produced in the hatchery of the same farm using pond reared brood-stocks. The experiment was conducted in eighteen earthen ponds each of 2200 m 2 water area (1.3 m water depth) with one paddlewheel (1hp) per pound. The inlet water is coming from the Red Sea (40-41 ppt salinity). Shrimp meal, and soybean meal were added at 113 kg/ha as an organic fertilizer to improve natural productivity of the experimental ponds during the preparation period only (three weeks before stocking post-larval shrimp). The inorganic fertilizers were added weekly at 30 kg/ha of urea, 1.4 l/ha of phosphoric acid and 16.7 kg/ha of sodium silicate. The quantity of fertilizers was divided into 2-3 doses per week for the first three months. Then, the quantity was reduced to the half doses during the last three months. The nitrogen: phosphorus (N: P205). The concentration of silicate was 5 ppm. PLs with average weight of 4.5 mg were stocked in shrimp ponds simultaneously over a period of two weeks at night after pond preparation. Shrimps were fed on starter diet containing 52% protein during first 104 days, Table 1 and finishing diet containing 42% protein until the end of the experiment (205 days).