Growth Rate Of Tilapia Research Articles

Evaluation of organic tilapia culture in periphyton-based ponds

The introduction of hard surfaces in the water column to induce the growth of biofilms and peri- phyton on these surfaces is a method used to increase natural productivity of the water body and food for cultured aquatic organisms. In periphyton-based systems in Africa and Asia, substrate introduction and consequent periphyton development positively affected water quality and pro- duction of the target species. In Israel, this technology is being evaluated in the culture of organ- ically produced tilapia. Among other restrictions imposed by organic standards, fish stocking densities must be low and only organic feeds and manures must be supplied. Organic pelleted feeds cost twice as much as regular aquaculture feeds. Since feed constitutes the major pro- duction expense, economic viability is hampered by using costly organic feeds. An experiment was performed at the Dor Aquaculture Station to explore methods of improving natural food pro- duction for tilapia and reducing added feeds. Submerged plastic surfaces equivalent to 40% of the pond surface area were immersed in polyculture ponds containing 85% hybrid tilapia (Oreochromis niloticus x O. aureus), together with a reduction of 40% of the amount of pelleted feed. The treatment improved nitrification and saved 40% of the feed costs, with only a 10% reduction in the tilapia growth rate and yield. These results indicate that periphyton-based aqua- culture is an appropriate technology for reducing production costs and allowing economically viable organic tilapia production.

Effect of Protein Level in Supplemental Diets on the Growth of Cage-Cultured Nile Tilapia in the East Lake, P.R. China

Five diets containing different protein levels from 15.8% to 35.6% were fed to Nile tilapia (Oreochromis niloticus) reared in net cages in the eutrophic East Lake in Wuhan, Hubei, P.R. China, to investigate the protein requirement in the supplemental diet. After the 87- day feeding trial, the results shows that specific growth rate of tilapia fed the diets containing 15.8-25.5% and 25.5-36.5% protein were not significantly different. It was suggested that 15.8-25.5% dietary protein in the supplemental diet was sufficient for the optimum growth of cage-cultured tilapia in a eutrophic water body like the East Lake. This requirement is much lower than the level determined from laboratory studies. Fish body dry matter decreased with increased dietary protein levels while crude protein, crude fat, ash or energy content was not significantly affected.

Enhancement of growth of tilapia Oreochromis niloticus in iso-osmotic medium

Tilapia (Oreochromis niloticus) kept in 15 ppt sea water (roughly iso-osmotic salinity) had higher growth rates than fish kept in 0 ppt (freshwater) or 30 ppt seawater, but circulating level of growth hormone was highest in fish exhibiting the poorest growth rate (30 ppt seawater). Serum thyroxine concentration was highest in 15 ppt seawater. Intestinal trypsin may play a role in promoting growth in iso-osmotic salinity since its activity was highest in fish cultured in 15 ppt seawater. The results indicate that changes in the digestive power, coupled with changes in thyroxine secretion, may account for the variations in growth rate in tilapia reared under different salinities.

First data on rabbit dung as a water fertilizer in tropical fish culture and its effect on the growth of Oreochromis niloticus (Teleostei, Cichlidae)

The influence of rabbit dung on water quality, plankton occurrence and Nile tilapia growth (Oreochromis niloticus) was studied. pH and total alkalinity increased, dissolved oxygen concentration decreased but not below the critical level whilst the nitrogen parameters were not affected in a significant way. An important increase of plankton was recorded and was reflected in a decrease of transparency: the phytoplankton density was 2.7 times that of the controls. Tilapia growth rate in the manure treatments was 5.1 times that of the control group; no significant difference in survival rates was observed.

A test of an on-farm selection procedure for tilapia growth in Indonesia

Modern intensive fish farming encourages the use of superior strains of fish developed in centralized research institutions. In many artisanal fish farms these strains may not be available or suitable: environmental conditions may differ from those optimal for the superior strains, or the species of fish desired in particular farming systems may not have been the subject of a selection programme. In such cases, the option would be for farmers to improve their own strains using procedures that are within their financial and technical capabilities. One generation of mass selection for size-specific growth rate of tilapia was performed on a fish farm in West Java, Indonesia. Selection was applied in two steps over the 6 month grow out period following the initial stocking of size-graded fingerlings acquired from the farmer. Size grading, rather than age-matching, was a key step in simplifying the procedure for on-farm use. Selection and testing of the offspring were conducted in hapa nets set up in farm ponds. The selection resulted in a significant positive response of 2.3% as measured by the percent differences of the lengths of the selected offspring from the control offspring. A rough estimate of realized heritability amounted to 0.12.

Pond farming of Nile tilapia, Oreochromis niloticus (L.), in northern Cameroon. Mixed culture of large tilapia (> 200 g) with cattle manure and cottonseed cake as pond inputs, and African catfish, Clarias gariepinus (Burchell), as police-fish

An experiment was conducted with tilapia-catfish polyculture at the Lagdo Fisheries Station in northern Cameroon. The objectives were: 1. To estimate the effect of supplementary cottonseed cake on net pond production in ponds already receiving dried cattle manure as basic treatment: and 2. To study the performance of African catfish, Clarias gariepinus (Burchell). in recruitment control of Nile tilapia, Oreochromis niloticus (L.). Recruitment control is essential in obtaining large tilapia sizes demanded in the market. Cottonseed cake, the most important agricultural by-product in the region, is expensive. Dried cattle manure may be collected free from corrals deserted by pastoral ethnic groups. Three treatments were tested in duplo in six earthen ponds of 525 m2 each; treatment A. daily application of dried cattle manure only (266 kg ha−1 day−1); treatment B, daily manure + cottonseed at a nominal daily rate of 3% of tilapia biomass: treatment C, daily manure + cottonseed cake at 6% of tilapia biomass. Stocking densities per pond were 250 male Nile tilapia (mean Wo 222 g), 150 female tilapia (W0= 202 g), 30 ‘large’ African catfish (Wo= 198 g); and 30 ‘small’ catfish (W0= 52 g). Mean fish densities were 0.76 tilapia m−2 and 0.11 catfish m−2. Application of dried manure and cottonseed cake was 6 days per week, and the culture period was 100 days. Fish were sampled every month and feeding rates were adjusted accordingly. Dissolved oxygen content and algal turbidity (Secchi disc) were measured once a week. Extrapolated net pond productions, including recruits, were: -0.41 ha−1 year−1 (treatment A); 4.8 t ha−1 year−1 (treatment B) and 6.5 t ha−1 year−1 (treatment C). Differences between treatments B and C were not significant(P < 0.05). Fertilization with dried cattle manure only (zero cottonseed cake) led to a negative net pond production in treatment A (negative net tilapia production but slightly positive net catfish production). Dried manure at the given application rate did not contribute sufficient nutrients to maintain the stocked fish biomass via enhanced natural production, while pond biomass was high for such an extensive system (manure only). Best fish growth was observed in treatment C (male tilapia, 0.9 gday−1: large catfish, 6.9 g day−1) although differences between treatments B and C were not significant. Growth of male and female was not significantly different, but growth rates of tilapia and catfish were significantly different (P & lt; 0.05). Average yields of tilapia recruits in treatment B (1539 kg ha−1 year−1) and C (1829 kg ha−1year−1) were about four times the average yield of recruits in treatment A (468 kg ha−1 year−1) but differences between treatments A, B and C were not significant. It was sugcess, or the reproductive efficiency of tilapia in treatment A could have been lower as a result of that treatment. However, clouds of up-swimming fry appeared to be at least as numerous in the replicate ponds of treatment A as in the ponds of treatments B and C.

Use of a native predator to control overcrowding in warm-water polyculture ponds: simulation of a tucunare (Cichla monoculus)-tilapia (Oreochromis niloticus) system

Abstract In this paper we describe an ecologically mechanistic simulation model representing the use of native predators (tucunare, Cichla monoculus) to control overcrowding of the primary culture species (tilapia, Oreochromis niloticus). The model consists of a prey submodel representing population dynamics and growth of tilapia, a predator submodel representing the predation process and subsequent population dynamics and growth of tucunare, and an economic submodel that calculates total net revenue. Simulated harvest weights of tilapia and tucunare were not distinguishably different from field observations, although tilapia weights were overestimated slightly. Results of sensitivity analysis suggest that the model could benefit most from refined estimates of tilapia growth rate and a better understanding of the dynamic size relationships between predator and prey that determine prey availability. Simulation of 21 different management scenarios suggests that stocking 10 tucunare weighing either 2 g or 10 g yields the highest total net revenue at the earliest harvest data. Stocking 20 tucunare weighing either 2 g or 10 g yields only slightly less total net revenue, but postpones harvest time by 3 weeks. Given the complexity of predator-prey relationships within polyculture systems, the interpretation of field observations on fish survival and growth can be enhanced greatly when viewed within the framework of an ecological model. From a management perspective, ecological models provide a means of explicitly relating pond production, and hence net revenue, to the underlying ecological processes that ultimately drive system dynamics.

Growth, Survival, and Production of Hybrid Tilapia, Common Carp, and Sharptooth Catfish in Mono- and Polyculture Systems during Winter in Central Saudi Arabia

Abstract Hybrid tilapias (Oreochromis niloticus × O. aureus), common carp (Cyprinus carpio), and sharptooth catfish (Clarias gariepinus) were evaluated for winter growth, survival, and production in 10-m2 concrete tanks in mono- and polyculture systems. Common carp showed better percent weight gain than tilapias and catfish. Growth rates of tilapia and common carp did not differ significantly among mono- and polyculture treatments (P > 0.05), but sharptooth catfish grew better in polyculture with common carp than with tilapia or in monoculture (P 0.05).

Effects of Diffused Aeration and Stocking Density on Growth, Feed Conversion, and Production of Florida Red Tilapia in Cages

AbstractThe effects of four levels of diffused aeration (0, 6, 12, and 24 hours/day) and two stocking densities (400 and 600 fish/m3) on the culture performance of caged Florida red tilapia were evaluated in 1 m3 cages in a 2 ha watershed pond on St. Croix, U.S. Virgin Islands. Fish obtained a nutritionally‐complete (36% protein), floating feed from demand feeders for 143 to 146 days. Diffused aeration had no significant (P &gt; 0.05) effect on fish growth, survival, feed conversion, and production in cages. Combined across all levels of diffused aeration, fish stocked at 400/cage had a greater growth rate (2.21 vs. 1.97 g/day), larger final body weight (370 vs. 335 g), and a lower feed conversion ratio (1.69 vs. 1.80) than fish stocked at 600/cage (P &lt; 0.05). The final biomass of fish stocked at the higher density (181 kg/m3) was greater than at the lower density (140 kg/m3). The enhancement of water exchange rates by diffused aeration did not increase tilapia growth rate or production in cages.

Estimated heritability of sex ratio and sexual dimorphism in tilapia

. Evidence is presented that sex determination in Oreochromis niloticus (L.) has a multifactorial genetic determination. Families of O. niloticus reared in separate suspended net enclosures and cages in the same pond using the same procedures were sexed and weighed at 14 weeks of age. Heritability of sex ratio was estimated by the method of Bull, Vogt & Bulmer (1982) to be 0.26 (95% confidence interval = 0.13-0.48). The heritability of sexual dimorphism, the amount of deviation between weights of male and female siblings, was estimated by standard variance component analysis to be zero. Correlations between sex ratio and parameters of size of each family are given. The results are discussed in the context of earlier reports on changes in sex ratio of tilapia species in response to temperature changes. The implications of these results for genetic improvement of growth rate of tilapia are discussed.

Canonical correlation analysis of relationships between management inputs and fish growth and yields in polyculture

Canonical correlation analysis was used to study the influence of management factors on growth and yields in an experimental polyculture system. The major conclusions are: (1) yield of each species was affected mainly by its own stocking density, followed by interactions with other species; (2) the best yields and growth rates of tilapia were obtained with stocking weights of over 13 g and; (3) common carp, Cyprinus carpio L., was affected negatively by silver carp, Hypoihalmichihys molitrix (Valenciennes), density and positively by nutrient inputs. Its best performance was obtained at silver carp density below 1000/ha. Analyses of data from commercial production units are required to confirm these conclusions

The effect of phosphorus supplementation to common carp diets on fish growth

The effect of supplementation of fish diets with phosphorus was studied both in tank and pond experiments. In the tank experiments phosphorus (6.5% di-calcium or mono-calcium phosphates) was added to three diets: two containing fish meal as the main protein ingredient and the third containing algal meal to replace it. Feeding common carp in tanks with these diets significantly increased fish growth rate (P < 0.05) over fish fed the same diets without phosphorus supplementation. In the pond experiments phosphorus was added to a fish meal diet in two different compounds: mono- and di-calcium phosphates (at 1% of the feed). The diets were fed to fish in a polyculture system for two consecutive culture cycles. Due to supplementation with phosphate, growth rate of tilapia ( Sarotherodon aureus) increased in both culture cycles. The growth rate of common carp fed phosphorus-supplemented diets increased over the control only in the first cycle, when fish were large and the standing crop of carp exceeded 1.8 ton/ha. At lower standing crops the natural food seems to supply adequate amounts of phosphorus. Silver carp were not affected by phosphorus supplementation, probably because they consume very little supplementary feed. Total yield for the entire season (kg/ha) was significantly higher in ponds where fish were fed a phosphorus-supplemented diet. Di-calcium phosphate, which is soluble only in weak acids, seems to be more efficient than the water-soluble mono-calcium phosphate in affecting the growth of common carp even though this fish lacks a gastric acid secretion.