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Water budgeting for production of hatchlings, fry and fingerlings of Asian catfish, Clarias magur
... Water loss in the harvested biomass, which was a negligible amount, was ignored in the calculation of CWU (Boyd et al. 2007). The consumptive water use index (CWUI) was determined considering 1000 fry production as one unit using the following formula (Ferosekhan et al. 2024). The gross total water productivity (GTWP), net total water productivity (NTWP), and net consumptive water productivity (NCWP) were calculated in USD m −3 taking the total volume of water used into account as follows: ...
In the present study, spawn of rohu, Labeo rohita, of size 5.6 ± 0.15 mm (2.40 ± 0.06 mg) were stocked at four densities, i.e., 4000 spawns m⁻³ (T1), 6,000 m⁻³ (T2), 8 000 m⁻³ (T3), and 10,000 m⁻³ (T4) to evaluate the suitable density for the microbe-mediated biofloc system. Rohu spawn was reared in 20,000L poly-lined circular biofloc tanks (5 m diameter) in triplicates for 28 days. The spawn was fed with dust feed (36% CP, 4% fat) at 4 kg per one million of seeds in two split meals with a 10% daily increment. The floc was prepared with the use of molasses, and a C/N ratio of 12:1 was maintained, which enabled maintenance of floc volume at 8–10 ml⁻¹/L. High fry survivals of 79.7–86.8% were achieved and plotted an inverse relation with rearing densities from T4 to T1, and T1 was significantly different from other treatments (P < 0.05). The fry length after 28 days of rearing were 20.13 ± 1.7, 17.8 ± 1.6, 15.6 ± 1.5, and 13.0 ± 1.3 mm, and weights were 90.97 ± 5.52 mg, 74.10 ± 4.85 mg, 67.17 ± 2.62 mg, and 41.07 ± 2.99 mg in T1, T2, T3, and T4, respectively. While the fry growth, particularly in T1, T2, and T3, is comparable to those observed in rohu in concrete tanks (17–21 mm, 55–62% survival after 21 days). Higher survival was achieved, even at 2–4 folds higher densities in the biofloc system. However, the total length was relatively low and demanding an extension of the rearing period in T4 at fivefolds higher density despite the higher survival rate. The water consumption showed an inverse relation with rearing density, and accordingly, the water productivity increased with increased densities from T1 to T4. The level of stress biomarkers, like Superoxide Dismutase (SOD), Catalase, Glucose, and Alkaline Phosphatase (ALP) was significantly higher in T4 in comparison to other treatments. The calculated net profit and cost–benefit ratio were significantly highest in T3 (135.37 ± 8.63 USD) and significantly lowest in T1 (82.5 ± 5.92 USD) whereas T2 (109.7 ± 17.03 USD) and T4 (115.33 ± 8.11 USD) were statistically homogenous. Therefore, the study recommended a rearing density of rohu spawn in the biofloc of up to 8000 m⁻³.
Fungal infection on fish eggs leading to low hatching rate and production of larvae is a common problem encountered in fish hatcheries. Various disinfectants are applied on eggs for control of infection and improving larval survival of the aquacultured species. In this study, the doseresponse of methylene blue (MB) and hydrogen peroxide (HP) on the fungal infection and hatching success of eggs of Melon barb was studied. Fungal infection on eggs were observed during the incubation. Higher dosages of both MB and HP have resulted in significantly higher egg mortality and hatchling deformity (p<0.05). The MB dosage of 1.5 ppm has prevented the fungal growth on eggs along with improving the hatching rate and hatchling survival rate. HP dosage of 9.5 ppm has prevented fungal growth in the main study. Application of these disinfectants had increased 7-9% hatchling production than without using any disinfectant (control treatment).
Clarias magur (Hamilton, 1822) is a highly priced commercially important species targeted for aquaculture diversification in India and SouthEast Asian countries. Weaning from live to formulated feed during larval rearing is critical for successful seed production. Hence, the present study aimed to standardise the effective weaning age to achieve high growth and survival of C. magur. The 4 days post-hatch (dph) larvae with mean initial length and weight of 7.4 ± 0.83 mm and 4.97 ± 0.35 mg, respectively, were selected, and 2100 larvae were randomly stocked into 21 plastic tubs (100 larvae per tub) for six weaning treatments (W4, W7, W9, W11, W13 and W15 dph) and the control in triplicates. The study was conducted for 21 days and 4 to 24 dph. All larvae in the treatments groups were fed Artemia nauplii ad libitum and a weaning diet fed to apparent satiation according to W4 to W15 schedules. The control group larvae were fed with Artemia nauplii alone. Results revealed that final length and weight, weight gain per cent, daily weight gain and specific growth rate were significantly (P < 0.05) higher in the Artemia nauplii fed control group followed by W15 dph larval group. The survival rate was significantly (P < 0.05) higher for W15 larvae, followed by the control group. The present study indicates that the ideal protocol for C. magur larval fed with Artemia nauplii from 4 dph for weaning to formulated diet was at 15 dph until 24 dph for good growth and survival rates.
India needs to address the immediate concerns of water supply and demand, due to its increasing population, rapid urbanization, and growing industrialization. Additionally, the changing climate will influence water resources, which will subsequently impact the overall sectoral end-use demand patterns. In this study, we have integrated a water module with the existing bottom-up, techno-economic Asia–Pacific Integrated Model/End-use energy system model for India to estimate the future water demand in major end-use sectors under business-as-usual (BAU), nationally determined contribution (NDC), and low-carbon futures (2 °C and ‘well below 2 °C’) up to 2050. We also simulate the effects of water constraints on major sectors under different climate-change regimes. Our results show that water-intensive end-use sectors, specifically agriculture and power, will face major impacts under water-constrained scenarios. Over the period between 2020 and 2050, policy measures taken under the NDC scenario can cumulatively save up to 14 ⁶ 63.7% of the 2000 annual water demand or 2.5% of the 2015 annual water demand.
billion cubic metres (bcm) of water, while low-carbon scenarios can save 20–21 bcm of water between 2020 and 2050, compared with BAU. In a water-constrained future, NDC and low-carbon futures can save 28–30 bcm of water. There is a need to increase the current water supply by 200–400 bcm. The marginal cost of installing dry cooling systems in the power sector is considerably higher than the cost and benefits of installing micro-irrigation systems with solar PV. Integrated policy coherence is required to achieve sustainable development goals, e.g., NDC and Paris Agreement goals, in both water and energy sectors. Concurrently, regulatory and economic instruments will play an essential role in improving resource-use efficiency at a systemic level, to reduce the overall water demand.
Dissolved oxygen variation in fish ponds is a common problem. This is more critical at the early stage of the fish life when rate of metabolism is usually high and as such optimum water quality condition such as availability of sufficient dissolved oxygen is most required. An experiment was conducted to determine the effect of varied hours of aeration through water shower, on the spawning success of African catfish for the period of 10 weeks. The aeration treatments were T1 (0 hour of shower), T2 (4 hours of shower), T3 (6 hours of shower), T4 (8 hours of shower) and T5 (12 hours of shower). The experiment was laid out in a complete randomized design. Each treatment was replicated three times. Test for significant difference was carried out using Duncan Multiple range test. All test was carried out at 5% probability level. The effects of the five treatment were evaluated on hatchability, growth and survival rate. Data collected included egg hatching rate (%), biweekly weight gain and specific growth rates of hatchlings. There was significant difference (P<0.05) among treatments in terms of the egg hatching rate (30.12%, 54.76%, 60.44%,70.81% and 83.24% for T1, T2, T3, T4 and T5 respectively). The biweekly weight gain increased significantly from T1 to T5 (5.61, 7.67, 9.29, 12.93, and 17.03g respectively). Survival of hatchlings also increased significantly from T1 to T5(76.87, 76.60, 81.20, 84.80, and 88.80 respectively). The increase in hatching rate and growth performance was attributed to increased dissolved oxygen availability with increasing hours of aeration through shower. Increased dissolved oxygen content affected the fry appetite, feed consumption and utilization positively. These findings indicated that spawning success of African catfish can be greatly enhanced by 12 hours of water aeration through water shower. This could be used by hatchery operators in developing countries with limited resources for flow through system or water re-circulatory system.
A study was conducted to find the optimum water depth requirement for nursery rearing of rohu Labeo rohita (Hamilton, 1822). Nine concrete tanks of 50 m 2 each (10 x 5 x 1.2 m) were grouped into three treatments T1, T2 and T3 and were filled upto 1.0, 0.75 and 0.5 m water depths, respectively. Each tank was stocked with 0.5 lakh hatchery-produced spawn and reared for 20 days. The study revealed significant influence of water depth on growth and survival of fry (p<0.05). Though the final length of fry did not differ among the treatments (p>0.05), T3 with 0.5 m water depth showed significantly lower survival, final body weight and specific growth rate than the other two treatments (p<0.05), whereas tanks with 1.0 and 0.75 m water depths showed almost similar survival, final weight and SGR (p>0.05). Assessment of water use for production of every 1000 fry revealed significant reduction in total water use (TWU) with decreased water depth (p<0.05), while the consumptive water use (CWU) in terms of water exchange and replenishment did not differ between water depth treatments of 1.0 and 0.75 m. The results of the study indicate 0.75 m to be the ideal water depth with better water use efficiency for fry production of the species.
The world's appetite for fish is growing steadily. Aquaculture has bridged that gap between the growing demand for fish and the almost stagnated wild fish catch, contributing at present nearly 47% of the world's total fish production of 171 million tonnes. Global aquaculture production has almost doubled between 2000 and 2016, it is estimated that, to meet the demands of the growing population, aquaculture production will need to more than double again between now and 2050. Being a young industry, aquaculture has still wide scope to meet the demand of the nine billion people in 2050, through horizontal expansion as well as improvements in production systems. But the industry is facing 'access-limitation to freshwater resources' due to growing global water crisis. With more than 40% of the global population already facing the problem of water scarcity, the scenario in coming days will be worse, where there will be no freshwater available to drink even for human, and thus utilization of water for fish culture will be hard. So, if we wish to make available fish-the cheapest animal protein for future generation, we need to conserve our water to the height above human needs. In aquaculture, improving water use efficiency through intensification and diversification will not only contribute to 'future water security', but also lessen the conflicts the aquaculture industry is facing with other water users. Fishes like Snakeheads (Channa spp.), climbing perch (Anabas testudineus), which can live out of water for few days and tolerate extremely unfavourable water conditions, can also be promoted for 'future water-stressed aquaculture'.
One year grow‐out evaluation of four cropping patterns of carps, viz. control: single stock single harvest (SSSH); T‐1:intercrop of minor carps and Indian major carps (IMC); T‐2:single stock multiple harvests (SSMH); and T‐3:multiple stock multiple harvests (MSMH) was conducted in eight earthen ponds (0.09 ha each). Ponds were stocked with three IMCs (catla, rohu and mrigal) at 1:1:1 ratio at 10,000 fingerlings/ha combined density. T‐1 was additionally stocked with 10,000 fingerlings/ha of minor carps (Puntius gonionotus, Labeo fimbriatus and Puntius sarana), while T‐2 with additional 10,000 fingerlings/ha of the IMC. Periodic removal of partial biomass ensured prevalence of better water quality in treatments (higher water pH, higher dissolved oxygen and reduced inorganic nutrients). It helped to improve fish growth as average harvested weight of rohu and mrigal remained similar in treatments despite the presence of greater inter‐ and intraspecific competitions in intercrop and SSMH, respectively, and periodic stocking of younger juveniles in MSMH. Catla showed significantly higher growth in MSMH. The biomass yield in intercrop, SSMH and MSMH were 21%, 17% and 24% higher than SSSH, but the respective net incomes were 32.9, 21.3 and 56.5% higher. Partial harvest also helped reducing FCR in the order T‐3<T‐2<T‐1<control. While the study showed MSMH as the most productive cropping pattern for biomass yield, the intercrop of minor carps and IMCs proved to be the most water productive (gross and consumptive water use) cropping method to produce varied fish protein with higher biomass yield.
This experiment investigated the effects of water exchange on water quality parameters and growth of Clarias gariepinus. 225 C. gariepinus of mean weight 2.60 ± 0.01 g were stocked at 15 fish per treatment in three replicates. Water quality and growth parameters such as mean weight gain (MWG), specific growth rate (SGR), food conversion ratio (FCR) and protein efficiency ratio (PER) were calculated using standard procedures. pH of T3 (9.15) was significantly higher p<0.05 than other treatments. Dissolved oxygen indicated that T5 (3.45 mg/l) was significantly lower than other treatments. The ammonia values revealed that T5 (0.08 mg/l) was significantly higher p < 0.05 than other treatments. MWG of T1 (29.43 g) and T2 (27.77 g) were significantly higher p < 0.05 than T3, T4 and T5. SGR and PER of T1 (2.26%), (5.74) and T2 (2.22%) (5.31) increased significantly p < 0.05 than other treatments. The FCR of T1 (0.40) and T2 (0.42) were significantly lower than other treatments. It was evident in this study that exchange of water has an increase or decrease in the state of water quality parameters and growth of a fish.
India is well known for carp aquaculture, related to an intensive research effort and then massive adoption by farmers; carp remains a mainstay of Indian aquaculture. Next to carps, catfishes are considered to be potential cultivable species. Among these, Clarias batrachus is a preferred medium-sized catfish for pond culture. Clarias batrachus, popularly called “magur” in India, is in high demand for its taste and therapeutic value. Magur fetch a higher market price than carp and are sold fort US$ 4-8/kg in India. Magur generally is stocked at densities that are 5-10 times greater than carp stocking densities because its hardy and air-breathing nature is favorable for high-density culture.
The aim of this study was to determine the effect of different water change frequency on the growth of African catfish Clarias gariepinus. Fingerlings with initial mean weights of 7.02 ± 0.05g were stocked (50 fish each) in fifteen concrete tanks (2x2x2m) and were conditioned under five different treatments of water renewal, namely: TRT1 (no water change), TRT2 (water renewed daily), TRT3 (water renewed after four days), TRT4 (water renewed after eight days) and TRT5 (water renewed after fourteen days). After 56 days of feeding, results revealed best growth performance of fingerlings in tanks with water renewal frequency of TRT3 and TRT4. Similarly, survival was higher in these frequencies compared to the others; the control treatment, however, had the least performance for all parameters measured. It is therefore recommended that water renewal should be done once between four and eight days to enhance growth of African catfish fingerlings reared in a static system. © The Author(s) 2016. Published by University of Zagreb, Faculty of Agriculture. All rights reserved.
This paper presents the consumptive water use for freshwater pond aquaculture for semi-intensive carps farming practices. The consump-tive use of water includes evaporation loss, see-page loss and water exchanges requirements. The water requirement has been estimated to be 10.3 m 3 /Kg of fish production under present study for semi-intensive culture and with supplemental feeding. Out of which 7.6 m 3 /Kg of fish production is system associated requirement. On an average the evaporation loss from the pond is 1498.3 mm/year and seepage loss per year is about 1182.60 mm/year. Seepage and water exchange losses recharge the ground water aquifers and if they are treated and recycled , the water use in aquaculture can be reduced significantly. A further reduction in fresh water use in pond aquaculture is possible through development of intensive and super-intensive culture systems and aqua feeds.
The trial was conducted in earthen pond with average initial weight of 4.5 ± 0.4 mg/PLs of green tiger shrimp, to
examine the effect of three stocking density and two water exchange rate on growth performances, production
traits and feed composition. Eighteen earthen ponds (2200 m2
) were stocked with either, 5, 15 and 25 PLs/m3
,
and received either 10 or 20% of water exchange rate. The results revealed that, mean final weight (g/PLs), gain
in weight (g/PLs), gain in weight %, SGR (% /day), feed conversion ratio, protein productive value (PPV), protein
efficiency ratio (PER), fat gain and energy utilization were significantly (p≤0.01) the best at the lowest stocking
density. While, total production exhibited significantly the opposite trend. There significant differences (P≤0.05) were
found between water exchange rate in term of mean final weight (g/PLs), gain in weight (g/PLs), gain in weight %,
SGR (%/day), feed conversion ratio, PPV, PER, fat gain and energy utilization.
From the above results and the economic information of these study it can be concluded that, stocking density of 15
PLs/m2
of green tiger shrimp and 20% water exchange rate exhibited the highest net profit and would seem to be the
most desirable density and water exchange rate in the system studied.
In comparison to older life stages, the embryonic stages of fishes generally have narrow tolerance ranges for environmental conditions, as regards water quality, temperature and mechanical shocks. The knowledge of these factors is indispensable to appraise the threats brought about by climate or anthropogenic changes upon their resilience, and to define adequate ways of incubating their eggs for an efficient propagation of the species under controlled conditions. Clown loach eggs have a narrow thermal tolerance range in comparison to other tropical and temperate fishes. Hatching occurs at 22-30 degrees C, and non-deformed larvae can only be obtained at 23.8-30.2 degrees C. Furthermore, the thermal tolerance of any particular progeny was found dependent on the maintenance temperature of the female parent, thereby making the actual tolerance no broader than 4.5 degrees C. The (log-log) relationship between the duration of the incubation period and temperature was characterized by a shallow slope, which is more typical of coldwater fishes, as is a narrow thermal tolerance range. On the other hand, clown loach hatched more rapidly (20 h at 26 degrees C) than predicted by existing models on the basis of water temperature and egg diameter, a feature that is shared by other warmwater fishes producing eggs that undergo a strong swelling process (about three times the ova diameter in clown loach). Clown loach embryos are strongly sensitive to mechanical shocks, but their development is not viable either in protracted steady state conditions, in absence of water movement, as they develop various deformities (e. g. pericardial oedema). This is thought to originate from a hypoxic microenvironment around the embryo, as a consequence of an oxygen gradient developing inside and outside the egg, since the boundary diffusion layer is not refreshed by water movement. This issue is worsened by strong egg swelling and incubation at warm temperature.
During the past decade, the culture of air-breathing fish species has increased dramatically and is now a significant global source of protein for human consumption. This development has generated a need for specific information on how to maximize growth and minimize the environmental effect of culture systems. Here, the existing data on metabolism in air-breathing fishes are reviewed, with the aim of shedding new light on the oxygen requirements of air-breathing fishes in aquaculture, reaching the conclusion that aquatic oxygenation is much more important than previously assumed. In addition, the possible effects on growth of the recurrent exposure to deep hypoxia and associated elevated concentrations of carbon dioxide, ammonia and nitrite, that occurs in the culture ponds used for air-breathing fishes, are discussed. Where data on air-breathing fishes are simply lacking, data for a few water-breathing species will be reviewed, to put the physiological effects into a growth perspective. It is argued that an understanding of air-breathing fishes' respiratory physiology, including metabolic rate, partitioning of oxygen uptake from air and water in facultative air breathers, the critical oxygen tension, can provide important input for the optimization of culture practices. Given the growing importance of air breathers in aquaculture production, there is an urgent need for further data on these issues.
Ponds at Auburn University, Alabama, stocked with 10,600 channel catfish Ictalurus punctatus per hectare that were fed at rates up to 66 kg feed/hectare per day, received water exchanges totaling 0, 1, 2, or 4 pond volumes between July and September. Although feeding rate was high enough to impair water quality, concentrations of dissolved oxygen, total ammonia nitrogen, nitrite-nitrogen, and chemical oxygen demand did not differ (P > 0.05) among treatments, and fish production was not increased by water exchange (P > 0.05).
The effect of water exchange on water quality, plankton abundance, and the production of koi carp, Cyprinus carpio var. koi L., cultured in outdoor concrete tanks manured with poultry excreta was determined. Individual weight gain and survival rates of fish (initial weight 0.09 ± 0.02 g) were compared among five culture regimes, where a volume of 100 dm 3 water was exchanged: (1) every day (WE1); (2) every alternate day (WE2); (3) two times a week (WE3); (4) once a week (WE4); and (5) a control treatment with no water exchange (NE). Significantly higher concentrations (P < 0.05) of conductivity, NH 4 -N, NO 2 -N, NO 3 -N, PO 4 -P and bicarbonate alkalinity were recorded in the NE treatment. Plankton volume was highest in WE1 (P < 0.05). The weight gain and number of koi carp of marketable size were significantly higher (P < 0.05) in WE1. There was a significant difference in the survival of koi carp among the treatments ranging from 60.43% (NE) to 95.21% (WE1). The results suggest a water exchange of 100 dm 3 daily (WE1) was the most effective for koi carp tanks manured with poultry excreta as better water quality and greater plankton abundance were both maintained in the system.
The effects of photoperiod and water exchange rate on the larvae of gilthead sea bream, Sparus aurata, from hatching to metamorphosis, 60–70 days later, were tested. Survival, growth rate and condition factor were determined with photoperiods of 12 and 24 h, and water exchange rates of 0 and 25%/day.Continuous light supported the highest mean survival (3.25%), with a maximum of 7.8% from hatching to metamorphosis. Growth rate in dry weight was best under continuous light in a water system with no exchange, up to 20 days post-hatching. Highest growth rates of larvae 40–60 days old were obtained in tanks with 25% of their water exchanged daily, along with a 12-h photoperiod. Condition factor was directly correlated with larval age. For the first 30 days after hatching, condition factor was affected by photoperiod and was highest for larvae exposed to continuous light.
Efficient water budgeting for various species will help in establishing database for providing practical solutions to the aquaculture sector's water crisis. Hence, a 90‐day study was conducted to evaluate the requirement of water for culture of Penaeus vannamei in inland saline groundwater. The earthen grow‐out ponds (0.1 ha) were stocked with postlarvae of P. vannamei (2.50 ± 0.01 g) at three different stocking densities, that is 30/m2 (T1), 45/m2 (T2) and 60/m2 (T3) respectively. The total quantity of water supplied and evaporation and seepage losses were measured on a daily basis. The rainfall and surface runoff were measured in the event of rainfall. The water quality parameters were analysed once in 10 days and were found to be within the permissible limit. The mean total consumption of water for T1, T2 and T3 was 2093.33 ± 6.66, 2099.30 ± 3.33 and 2092.96 ± 5.77 m3 respectively. The survival and yield of P. vannamei in treatments T1, T2 and T3 were 80.49 ± 0.61%, 72.06 ± 0.74% and 68.70 ± 1.45%; and 283 ± 1.53, 322 ± 3.46 g and 311 ± 3.79 kg respectively. The consumptive water use index was significantly less (p > 0.05) in T2 (6.53 ± 0.07 m3/kg) followed by T3 (6.74 ± 0.08 m3/kg) and T1 (7.41 ± 0.04 m3/kg). The water productivity of P. vannamei was significantly higher (p < 0.05) in T2 (0.153 ± 0.002 kg/m3) followed by T3 (0.148 ± 0.002 kg/m3) and T1 (0.135 ± 0.001 kg/m3). Considering the total quantity of water used and the shrimp produced from the earthen grow‐out ponds using inland saline groundwater, a stocking density of 45/m2 and a water budget of 6.53 m3/kg production of shrimp could be recommended as optimum.
Influence of varied water exchange (total of 0%, 40%, 60%, 80% and 100% in four phases during three months) on fingerling production of Indian major carps-catla, rohu and mrigal under polyculture was evaluated in large outdoor concrete tanks (50 m²). Rearing density of 30 fry m⁻³ was used. Survival in the control tanks reduced during the 2nd month unlike the treatments, attributed to lack of water exchange in the tanks. While no marked variation in water quality was observed among the control and treatments, graded water exchange led to proportionate improvement in the fingerling performance in terms of survival and growth in the treatments. Harvested total lengths of fingerlings were similar in all, irrespective of varied exchange levels. Although no significant variation in net weight gain (NWG) and specific growth rate (SGR) were observed among the treatments during 1st and 2nd months of rearing in any of the species, these attributes increased significantly during 3rd month with higher water exchange in treatments. The harvested body weight (HBW) also increased significantly with increased exchange level. However, survival, HBW, NWG and SGR remained similar in all species between the 80% and 100% water exchange levels. Treatment with 80% water exchange had higher water productivity in terms of number and biomass production of fingerlings per unit (m⁻³) of TWU and CWU for which, the study recommended 80% to be the ideal total water exchange required for fingerling production of IMC in concrete tanks.
The Asian catfish, Clarias magur, is an endangered fish species, which is immensely important due to its high commercial value in India and other South‐East Asian countries. Various anthropogenic activities and natural habitat loss have greatly impacted the biodiversity of C. magur in natural water bodies, leading to the addition of this species to the endangered species list. The development of captive spawning and selection of an ideal broodstock size are critical steps to maximize the efficiency and robustness of conservation efforts for the catfish. An induced spawning experiment was conducted to ascertain the reproductive performance, egg and larval quality of catfish broodstock from fish with varying body weights. Five female C. magur broodfish from each of the following size ranges, F65 (65 ± 5.0); F130 (130 ± 7.9), F180 (180 ± 3.5) and F250 (253 ± 9.7g), were selected along with male broodfish with the same body weight range. The present study's results revealed that the stripping response was higher (F = 2.06; p = 0.15) for medium‐sized F180 magur female broodstock; however, no significant differences were observed for this group. Total (F = 20.79; p < 0.001) and relative fecundity (F = 3.09; p = 0.057) were found to be significantly higher for F250 and F65 broodfish respectively. Total fecundity had a strong significant positive correlation (r = 0.99; p = 0.012) and also had significant linear regression relation (R2 = 0.98; p = 0.012) to maternal size. Hatching rate was observed to be significantly higher (F = 7.82; p = 0.002) for the medium‐sized broodfish, F130. The medium‐sized broodstock of 130–180 g had strong positive influence on the growth and survival of the progeny, while F250 broodfish produced poor‐quality larvae, which resulted in reduced larval growth performance and survival. Specific growth rate (SGR) and thermal growth coefficient (TGC) were also found to be significantly higher for F130 female broodstock. Hence, the selection of medium‐sized (130–180) or 1‐ to 2‐year‐old female broodstock had a significant effect on the reproductive performance, egg and larval quality of magur in captivity. The results from this study can be utilized as helpful and practical information enhancing selection protocols for the hatchery operators to select ideal broodstock based on size, enabling the production of viable egg and larvae in indoor conditions and a scalable seed production system.
Larval growth and survival are significantly influenced by the various biotic and abiotic factors. Rearing tank background colour is one such factor affecting the larval production in finfish hatcheries. The present study evaluated the effect of five tank background colours (black, white, blue, green and red) on growth and survival of larvae of two commercially important freshwater catfish species, Clarias magur (magur) and Pangasius pangasius (pangas) in a completely randomized experimental design in triplicate. The larvae of magur (9.33 ± 0.15 mm; 3.85 ± 0.05 mg) and pangas (10.07 ± 0.27 mm; 3.31 ± 0.08 mg) were stocked at a density of 45 and 30 larvae per tank, respectively in 15 L tanks. Experimental duration was 28 days for both the species. The results revealed that the final weight, weight gain, daily weight gain, and specific growth rate (SGR) of larvae of magur were significantly (P < 0.05) higher in white background coloured tank whereas, pangas shown the best performance (P < 0.05) in black tank. Thermal growth coefficient (TGC) of magur and pangas were recorded significantly higher in white and black coloured tank, respectively. Larval survival was significantly (P < 0.05) higher in black (97.04 ± 1.96%; F (4, 10) = 2.95, P = 0.002) tank for magur and green tank (87.78 ± 4.84%; F (4, 10) = 8.28, P = 0.003) for pangas. Whereas green and black tank colour were significantly reduced the larval survival of magur and pangas, respectively. This study clearly indicates that tank background colour had a significant impact on the larval growth and survival in both the species studied. It was also noticed that the tank colour effect is species specific. The study thus showed that black background tank colour for magur and green tank for pangas are more suitable for the higher production of catfish larvae in hatchery.
Length-weight relationship (LWR) of 661 numbers of hatchery-produced magur, Clarias magur of all the life stages such as hatchlings, fry, fingerlings, juveniles, and adults were studied. The LWR of magur all the life stages were estimated and the equations are as follows, hatchlings W=0.0052*L1.282 (r²=0.8784), fry W=0.0088*L3.028 (r²=0.8113), fingerlings W=0.0065*L3.226 (r²=0.8906), juveniles W=0.0028*L3.420 (r²=0.8175), and adults W=0.0017*L3.491 (r²=0. 8310). A positive allometric growth (b>3) was observed in all the life stages except hatchlings. The annual growth rate of magur was observed with the body length and weight of 24 ± 1 cm and 115 ± 17 g, respectively, under the commercial production system. This is the first kind of study that describes about the LWR and growth performance of all the life stages of hatchery‐produced C. magur catfish from hatchlings to adults under commercial production system. This study will be more useful to the hatchery managers and fish growers to optimize the resources and husbandry practices to improve the growth, survival, and biomass production.
We studied the effect of rearing densities of Pacific white shrimp, Litopenaeus vannamei in three densities with three replicate treatments [T1: 0.4 million post-larvae (PL) ha⁻¹, T2: 0.5 million PL ha⁻¹, T3: 0.6 million PL ha⁻¹] and water cutback approach on rearing environment, water use efficiency, water footprint and production performance. Conditional water exchange was carried out based on water quality parameters. Water quality suitability index was very good (7.5–9.0) up to 13th, 10th and 5th week of culture in T1, T2 and T3, respectively; which was attributed to rearing density, smaller-sized shrimp and low early feed input. Optimum rearing density of 50 PL m⁻² (T2) led to total water use of 3.25 × 10⁴ m³. It was seeming as a way to improve shrimp productivity (10.58 t ha⁻¹ 120 d⁻¹), consumptive water use index (1.72 m³ kg⁻¹ biomass), total water footprint (1229 m³ t⁻¹ biomass) and net consumptive water productivity (USD 1.28 m⁻³). L. vannamei culture with low to moderate water exchange as in T2, helped uphold water quality suitable for the shrimp growth, improved water use efficiency (0.58 kg biomass m⁻³ water), minimized sediment load (45.3 m³ t⁻¹ biomass), effluent outputs (0.63 × 10⁴ m³), pumping cost (USD 30.1 t⁻¹ biomass produced), and ratio of output value to the cost of cultivation (1.97). The findings and advancement in knowledge would offer the basis to augment shrimp rearing efforts and the water management approaches will help in preventing the production of waste and effluent while increasing water use efficiency and production performance.
This experiment investigated the effects of water exchange on water quality parameters and growth of Clarias gariepinus. 225 C. gariepinus of mean weight 2.60 ± 0.01 g were stocked at 15 fish per treatment in three replicates. Water quality and growth parameters such as mean weight gain (MWG), specific growth rate (SGR), food conversion ratio (FCR) and protein efficiency ratio (PER) were calculated using standard procedures. pH of T3 (9.15) was significantly higher p<0.05 than other treatments. Dissolved oxygen indicated that T5 (3.45 mg/l) was significantly lower than other treatments. The ammonia values revealed that T5 (0.08 mg/l) was significantly higher p < 0.05 than other treatments. MWG of T1 (29.43 g) and T2 (27.77 g) were significantly higher p < 0.05 than T3, T4 and T5. SGR and PER of T1 (2.26%), (5.74) and T2 (2.22%) (5.31) increased significantly p < 0.05 than other treatments. The FCR of T1 (0.40) and T2 (0.42) were significantly lower than other treatments. It was evident in this study that exchange of water has an increase or decrease in the state of water quality parameters and growth of a fish.
Water budgeting experiments were conducted in three portable FRP carp hatchery units installed in three different places of Odisha State, India. Induced breeding programmes were conducted for spawn production for seven times in these FRP hatcheries taking rohu, Labeo rohita as the test species. Water requirement for one complete cycle of FRP carp hatchery operation was calculated to be 105 - 136.3 m3, when spawn production ranged between 0.7 and 1.4 million per operation in field condition. It was estimated that the water requirement per 0.1 million spawn production ranged between 8.86 - 15.01 m3. It was concluded that the water requirement for FRP carp hatchery operation was comparatively more when less quantity of carp spawn produced and was less when more spawn produced.
A study was conducted to observe the breeding and larval rearing of Asian Catfish, Clarias batrachus fed with live and/or artificial feed for 21 days in an indoor hatchery. The brooders of C. batrachus (Av. wt of female 160 ± 10.5 g; Av. wt of male 120 ± 6.75 g) were procured from outside ponds and stocked in a pond near the experiment site 2-months prior to spawning. The fishes were successfully induced bred using ovaprim @ 1.0–2.0 ml/kg body weight (bw) to females and 0.5–1.0 ml/kg bw to males. Fertilization, hatching and survival percentages at spawn stage were respectively recorded 70.6 - 72.8, 60.7 - 55.3 and 54.3 - 56.2. After yolk-sac absorption, fry of three age groups 7, 14 and 21 days were subjected to feed trial using Artemia nauplii followed by laboratory made feed for 21 days. Weekly sampling indicated that higher age groups constantly maintained higher lengths and weights with highest survival in the age group of 14-days old fry and SGR in 7-days old. The quality of hatchery water was recorded for temperature 29 ± 1°C, pH 7.2 ± 0.2, DO 7.1 ± 0.3 mgL-1 and total alkalinity 132 ± 4.0 mgL-1 respectively.
We used the margined madtom Noturus insignis as a model species to develop egg-hatching techniques for other madtom species. Twelve methods were tested at water temperatures between 22°C and 30°C, but only one method produced consistent, high hatches of madtom eggs. Use of broodfish to incubate eggs was not effective because they ate their tank-spawned egg masses. Consequently, madtom eggs must be artificially incubated. Use of sodium sulfite, Na2SO3, to facilitate artificial incubation by separating madtom egg masses is not effective because it causes premature hatching and subsequent low survival of larvae. Agitation strong enough to tumble eggs and high temperature appear to be key in consistently producing good hatches. We obtained hatch rates greater than 65% for 14 of 16 margined madtom egg masses by incubating them at 28-30°C within a 6-mm-bar-mesh plastic basket positioned over an air stream strong enough to keep egg masses in constant motion. The larvae hatched in about 7 d at 28°C, and the mean number of degree-days for hatching was 205 ± 14 (N = 6).
Channel catfish were cultured for 177 days in circular tanks containing 1.6 m3 of water at combinations of five stocking densities (90–720 fish/m3) and five water exchange rates (2.0–0.5 h per exchange). Net yield increased as stocking density increased up to 540 fish/m3 then declined at higher densities. Mean fish weight, feed conversion efficiency and survival all declined as stocking density increased.Water exchange rates of 1.5 h or greater achieved similar results at stocking densities of 180 and 360 fish/m3. However, at a density of 540 fish/m3 a faster exchange rate resulted in increased growth, feed conversion efficiency and survival. At 2.0 h per exchange, these parameters were depressed at 180 and 360 fish/m3.The following predictive equations (P = 0.01) were formulated from the data, where x1 represents the stocking density and x2 the exchange rate.Net yield: Mean fish weight: Feed conversion efficiency: The maximum predicted net yield of 93.1 kg occurs at a stocking density of 399 fish/m3 and 0.91 h per exchange.
During the incubation period, the number of bacteria on the surface of salmonid eggs in vertical tray hatchery stacks varied between 4.8 × 103 and 107 aerobic organisms per square centimeter of egg surface. The bacterial count in the tray water varied between 1.1 × 103 and 5.4 × 103 organisms per milliliter. The most common isolates from the eggs were species of Cytophaga and Pseudomonas. Aeromonas hydrophila was also isolated. These species remained on the eggs throughout incubation, and were also isolated from tray surfaces and tray water.
The bacterial flora of rainbow, Salmo gairdneri Richardson, and brown trout, Salmo trutta L., eggs was studied during incubation. Few bacteria were considered to exist internally, although Pseudomonas species and Aeromonas hydrophila were isolated. During incubation, large numbers of bacteria approaching 500 colony forming units/mm2 accumulated around egg surfaces. Both rainbow and brown trout eggs placed in a through-flow system were colonized mainly by Pseudomonas sp. and A. hydrophila, whilst rainbow trout eggs in a separate recycling system were dominated by a Cytophaga species. Glass beads were also incubated (as an inert surface) and found to support significantly lower numbers of bacteria. Egg mortalities were recorded daily and found to differ significantly between both fish species and water conditions. Statistical analysis indicated a potentially significant correlation between hatching success and numbers of surface bacteria.
The bullseye puffer (Sphoeroides annulatus) is a species with potential for aquaculture. However, preliminary studies on the biology and reproduction of the species in captivity have failed to produce consistent success at hatching. In this study, the effect of aeration and water treatment (filtration and ultraviolet (UV) sterilisation) on percentage hatch was assessed in a replicated experiment repeated on two occasions. Four treatments were used, filtered water (5 Am) treated with UV, in an aerated system (AT) and a static system (ST); water that had been coarse-filtered (20 Am) and not exposed to UV kept in aerated system (ANT) and a static system (SNT). The percentage hatch was ranked 87.5 F 5.0>80.6 F 9.4>77.2 F 12.8>62.8 F 10.4 (mean of all replicates from both experi-ments F S.D.) for the respective treatments AT>ST>ANT>SNT. However, percentage hatch for AT was only significantly (P < 0.05) higher than ANT and SNT, while hatch for ST was only significantly higher (P < 0.05) than SNT. A GLM analysis showed the use of treated water (filtered and UV treated) in the incubators and aeration had a significant positive effect on percentage hatch. These effects were additive with no significant positive or negative interaction. There was no significant differences in bacterial counts among treatments (AT, ANT, ST, SNT), but significant differences (P < 0.05) were observed among days. There was no significant interaction between days and treatments to affect bacterial counts. There was no correlation between bacterial counts and percentage hatch. The water treatments significantly improved percentage hatch, but did not affect bacterial counts. This paper reports an incubation system that consistently resulted in more than 80% successful hatching for bullseye puffer eggs. These results should help to improve the hatching success of this species and possibly others with demersal adhesive eggs. D 2004 Elsevier B.V. All rights reserved.
Water budgets were calculated for embankment fish ponds located in the dry tropics. Two 5-month studies were conducted at Comayagua, Honduras. Daily pond evaporation averaged 0·55 ± 0·22 and 0·64 ± 0·17 cm during studies 1 and 2, respectively. Pond evaporation was 14·5% greater during study 2. Significantly greater pond evaporation was measured during the 3 driest months compared to the 3 rainiest months. Mean daily seepage ranged from 0·11 to 0·43 cm and from 0·06 to 0·60 cm during studies 1 and 2, respectively. Total rainfall during study 1 exceeded that during study 2 by 43%. Regulated inflow water was required every month to replace water losses to pond evaporation and seepage. Pond evaporation accounted for 70% of total water loss during both studies, while seepage accounted for the remaining water loss. Rain accounted for 45·5 and 21·8% of gains during studies 1 and 2, respectively. Regulated inflow water accounted for 52·8 and 77·9% of the respective gains.
High stocking densities (600 fish/m3) of walking catfish resulted in slightly higher mortality rate, no difference in growth rate, and a much higher yield than low density stocking (300 fish/m3). Water flow rate (10, 5, or 2.5 turnovers/day, turnover here is one diluted replacement volume) had no effect on survival, growth, or yield. Fish were grown out from an initial weight of 5.4 g for 90 days, and most mortality occurred early in the cycle when the fish weighed <26 g. Growth was also high initially and declined with time. Dissolved oxygen did not differ between tanks of different density, but was altered by flow rate. Water supply parameters, such as short-term BOD, strongly affected dissolved oxygen content at all flow rates. Ammonia concentrations increased with density and decreased with increased flow rate. Mortality rate of all fish was strongly size dependent, and mortality of small fish was correlated with short-term BOD.
Fish culture without water
- Hussan
Sustainable development goals—United Nations
- Nino
Nino, F.S., 2015. Sustainable development goals-United Nations. United Nations
Sustain. Dev. 2.
The Effects of Water Exchange and Water Quality on Growth and Survival of Clarias gariepinus (Fingerlings) along the Mount Cameroon Region. Student Papers
- N A Ernest
Ernest, N.A., 2011. The Effects of Water Exchange and Water Quality on Growth and
Survival of Clarias gariepinus (Fingerlings) along the Mount Cameroon Region.
Student Papers, Lund University Libraries, Lund, Sweden. https://lup.lub.lu.se/stude
nt-papers/search/publication/8164305.