African Catfish Larvae Research Articles

Quantitative and Weight Indicators of African Catfish Eggs and Larvae Development under Exposure to the Low-Power Ultrasound

Introduction. The growth of the world population and changing climate conditions on the planet induce the search for the innovative methods and technologies capable to increase the productivity and efficiency of the agricultural sector, and in particular — industrial fish-farming. In recent years, ultrasound has become one of such methods, widely used in many industries due to its unique properties and capabilities. In fish-farming, the use of ultrasound can significantly improve the processes of fish breeding by increasing the growth rate, improving digestion and overall health of fish, however, the issue of biostimulation of eggs and larvae with low-power ultrasound remains unexplored. The aim of this work is to study the biostimulation of eggs and larvae of African (clarias) catfish with ultrasound in aquariums as an advanced method of improving the growth and survival of this biological object at the early stages of its development, as well as a potential method for preventing the infectious and invasive diseases.Materials and Methods. The object of this study is an African clarias catfish, also known as the marbled clarias catfish (Clarias gariepinus). During the experiment, carried out at the fish-farm the “Marbled Catfish” Fish Farm” LLC (Lipetsk) from March to September 2023, 4 groups were formed — three experimental and one control. The eggs and larvae of the African catfish were exposed to the low-power ultrasound, in the experimental groups the exposure lasted for 30 s, 60 s and 120 s, respectively; the control group didn’t undergo any ultrasonic treatment. Biostimulation was carried out with a low-power submersible source of ultrasonic waves (0.243 W/cm2) and was performed 6 times. Sorting was carried out on the 15-th day from the start of incubation. In total, four series of experiment were carried out.Results. The first, second and third groups in all series of the experiment, according to sorting results, contained the largesized larvae of the African catfish in a percentage ratio of 44 to 46%; the percentage of the large-sized larvae in the control group was 19%. In terms of average-size, sorting gave the following result: in 1–3 experimental groups — from 52 to 54% of the total number of larvae; in the control one — 72%. For small-sized larvae, the following values were obtained: in groups 1–3 — from 2 to 3%, in the control group — 9% of the total number of larvae in the groups and series, respectively.Discussion and Conclusion. The growth and development of African catfish eggs and larvae are greatly influenced by the hydrological parameters of water: temperature, oxygenation, illumination, pH, hardness, content of hydrocarbonates, phosphates, nitrates and other chemical elements. In addition, fertilization of eggs may occur unevenly due to non-uniform mixing of eggs and milt, quality and maturity of eggs during fertilization, which can result in different quantitates of the catfish larvae output. The exposure of eggs and larvae to the ultrasound in the experiment resulted in an increase of a number of large-sized larvae, which is favourable for obtaining the fish seed material. Timely sorting of fish seed material before transferring an African catfish to the closed water supply systems reduces the cannibalism during further cultivation. The use of ultrasound in fish-farming requires further study to identify the optimal frequency of treatment and the effect on the commercial fish immunity and growth rate, which will foster the satisfaction of the growing needs of the population in the high-quality products of fishing industry.

Effects of stocking density and water flow rate on performance, water quality and economic benefits of African catfish larvae (Clarias gariepinus Burchell, 1822) in the aquaponic system integrated with Azolla fern

The effect of stocking on fish performance is known is most systems, and for many fish. Meanwhile water flow rate remains an important factor in recirculating aquaculture systems. However less information is still available on the influence of aquaculture management practices on the performance of aquaponics. This study determined the effect of stocking density and water flow rate on growth performance of African catfish larvae (Clarias gariepinus) and Azolla spp. in catfish-Azolla aquaponics system. The 4 × 4 factorial experiment consisted of four larval stocking densities (1500 larvae/m3, 3000 larvae/m3, 4500 larvae/m3 and 6000 larvae/m3) and four water flow rates (0.25 L/min, 0.5 L/min, 0.75 L/min and 1 L/min) executed in triplicate. The stocking density and water flow rate had an interactive influence (P < 0.05) on the concentration of DO, TAN, and NO3−. The stocking density and water flow rate had an interactive influence (P < 0.05) on the final mean weight, SGR, and survival of C. gariepinus larvae, but not for FCR and yield (P > 0.05). The highest fish weight was achieved under combination of stocking density 3245 larvae/m3 and water flow rate of 0.87 L/min, but growth will still be optimized upto a stocking density of 4850 larvae/m3 but at higher combinations of water flow rates (> 0.875 L/min). The stocking density and water flow rate had an interactive influence (P < 0.05) on chlorophyll a concentration, but not fresh weight, dry weight and yield (P > 0.05). Enterprise budgets for aquaponic with different stocking densities and water flow rate for fish and Azolla production allowed all the treatments to post positive returns to risk and were viable investments. Cash flow projections were made over a 10 year period for each of the units with the net present value (NPV) and internal rate of return (IRR) revealed that sales of larval fish and Azolla sp. at stocking density of 1500 larvae/m3 were not profitable. However, all the other stocking densities were profitable except at 3000 larvae/m3 and water flow rate of 0.25 L/min. Although at all stocking density the revenue were able to cover the variable costs, this study recommends stocking at 3000 to 4500 larvae/m3 and water flow rate of 0.75 L/min and 1.00 L/min.

Cannibalism and survivorship of early juvenile African catfish (Clarias gariepinus) in relation to stocking density and 17β-estradiol treatment

ABSTRACT There were two stocking densities (i.e. 9,000 and 12,000 larvae m−2), two doses of 17β-estradiol and control without any hormonal treatment i.e. 0, 2.5, and 5 mg L−1. Hormone were given by immersing larvae in water for six hours to reduce cannibalism in African catfish larvae. Fishes were reared for 14 days intensively. The highest fish survival was at a stocking density of 12,000 larvae m−2 with 2.5 mg L−1 17β-estradiol. Cannibalism decreased at higher densities compared to the control. The level of 17β-estradiol in treated fish tended to be higher than that of the control group but the coefficient of variance decreased. At the end of rearing, the use of 17β-estradiol at higher densities improved the specific growth rate and relative body length.

Possible sensory control of cannibalism in the African catfish (Clarias gariepinus) larvae by electrical ablation of electroreceptors

The culture of African catfish (Clarias gariepinus) faces a number of challenges which have to be addressed in view of the growing economic importance of this fish. The captive larvae and early juveniles are aggressive and cannibalistic, resulting in considerable economic losses and shortage of seed to meet demands of the farmers. Improving larval survival and health while the fish is held in captivity is a subject of great interest. C. gariepinus generates a weak electric discharge during the aggressive interactions with the conspecifics and their electroreceptors are highly sensitive. While very little is known on the role of electroreception in the aggressive behaviour, we attempted a sensory control of the cannibalism in the larvae by applying an excess direct current (DC) stimulus (0.67 V/cm or 2.65 V/cm) and ablated the function of the electroreceptors. The number of surviving individuals and those which were lost were compared between the control and the treated groups. Six trials were conducted involving larvae at the different initial ages, from 4 to 9 days after hatching, and with different observation periods ranging from 5 to 11 days. The electric treatment resulted in higher survival in five trials and the number of fish lost to cannibalism was significantly lower in the treated group than in the control in one trial. While the electrically-ablated electroreceptors might regenerate, the ablation seemed to be effective during whole larval phase.

Influence of Photoperiod and Shelter on Some Phenotypic Traits in African Catfish (Clarias gariepinus Burchell 1822) Larvae

Influence of Photoperiod and Shelter on Some Phenotypic Traits in African Catfish (Clarias gariepinus Burchell 1822) Larvae

Digestive system and growth performance of African catfish larvae Clarias gariepinus, (Burchell, 1822) maintained with biofloc technology with the addition of Chlorella sp.

The production of catfish in aquaculture is still limited by the low supply of good quality seeds. One solution that can be done to overcome this problem is by the application of biofloc technology with microalgae addition. This study aims to evaluate the performance of digestive system, growth and robustness of the African catfish larvae maintained with biofloc technology and the addition of Chlorella sp. This research applied a completely randomized experimental design consisted of three treatments and triplicates, i.e larvae maintained with regular water exchange as the control (K), larvae maintained biofloc system (BF) and larvae reared with biofloc treatment and Chlorella sp. addition (BFC) with a rearing period of 15 days. Length growth, specific growth rate, condition factor, the activity of protease, amylase and lipase were not significantly different between treatments (P&gt;0.05). The villi length in fish maintained in BF treatmen (136μm), was higher than those of BFC (121μm) and K treatments (105μm). The particle size of floc in BF and BFC were 0.44±0.025 and BFC 0.79±0.048 mm, respectively. The survival of catfish larvae in the BFC treatment was (51 ± 0,32)b, which was significantly higher (P&lt;0.05) than those of K (45±0.52)a and BF (45±0.15)a. The results of stress test using 15 g L-1 water salinity demonstrated that the fish maintained in BFC has a higher survival (63%) than those of BF (47%) and K (43%). Overall results of the present study showed that the addition of Chlorella sp. could improve the growth performance and robustness of African catfish larvae against salinity stress.

Supplemental enzyme in artificial diets for north african catfish larvae Clarias gariepinus Burchell, 1822

Supplemental enzyme in artificial diets with difference doses for African catfish Clarias gariepinus (initial weight of 0.0048±0.0001 g and total length 0.7633±0.0392 cm) were examined for 12 days feeding trial. The aim of this study was to analyze the effectiveness supplemental enzymes in diets for growth performance of catfish larvae. Tubifex sp. (control) and a multi enzyme was included at the level of 0.00 (ME0), 1.00 (ME1) and 2.00 g kg-1 (ME2 diet as a test diets. Each of the four experimental diets was randomly assigned to four plicate groups. Larva was allocated into 150 L aquaria at a density of 1350 larvae per aquarium. Data was analyzed using SPSS 20, followed by Duncan’s test. The result showed that the survival rate and condition factors were no statistical difference between experimental diets and control group. The highest final length, final weight, total food consumption, villi length and enzymes activity were recorded in the Control (P&lt;0.05) and significantly different with other treatments. Feed efficiency’s control significantly different with other. Harvest size distribution, in the small size group (1-2 cm) did not show significantly different, in the medium size group (2-3 cm) and large size group (3-5 cm) the Tubifex sp. treatment were significantly different from the other treatments (P&lt;0.05) whereas between ME0, ME1 and ME2 treatments were not significantly different. Among the supplemental enzyme in test diets, ME2 can improve weight and total length 6.25% and 13.4%, respectively than ME0 treatment. The results suggested that enzyme supplementation can improve intestinal structure and growth performance of catfish larvae. The supplemental enzyme in diets with doses up to 2 g kg-1 can increase intestinal villi’s length but have not been able to increase fish growth performance as use worm.

Factors for increasing the survival rate of catfish fertilized eggs and larvae

The improvement of the quality of eggs, decrease of developmental anomalies, increase of progeny survival rate are urgent problems of industrial fish breeding. We used biologically active agents – vitamins and adaptogens to solve the above problems. Adaptogen trekrezan (ethanolammonium salt of 2-methylphenoxyacetic acid) – a synthetic analog of ginseng – was applied in fish breeding. It does not demonstrate any gonadotoxic, embryotoxic, mutagenic, teratogenic, carcinogenic and allergenic action and is not accumulated in the organism. The agent has high immunotropic activity, stimulates cellular and humoral immune response, phagocytosis, demonstrates interferon inducer activity. We also used vitamin B1 – thiamine. The need for it is the highest in early ontogenesis. It is required for normal functioning of nervous, digestive and cardiovascular systems, hematopoietic system and is considered essential. The study of the influence of thiamine and trekrezan on egg fertilization rate showed that under the influence of these biologically active agents both individually and in a complex the fertilization increased by at least 14%. The study of the influence of thiamine and adaptogen on larvae hatching showed that they can increase the hatching by more than 20%. The study of the influence of thiamine and trekrezan on the level of developmental anomalies of African sharptooth catfish larvae showed that both components reduce this indicator. With the use of thiamine and trekrezan the level of developmental anomalies decreased in all groups by more than 10%. The study was supported by the Russian Foundation for Basic Research, grant No. 18-016-000127.

Effect of different water pH on hatching and survival rates of African catfish Clarias gariepinus (Pisces: Clariidae)

Water quality parameters influence the growth and survival of different stages of fishes and hence determining the optimal water quality variables is greatly important for any aquaculture farming. Among the variables, water pH is considered the key factors and plays an important role in the maintenance of the homeostasis in fishes. A study was conducted to determine the influence of different water pH on the incubation period, hatching rate and survival rate of African catfish (Clarias gariepinus) larvae. The fertilized eggs were incubated at 28.0 ± 1.0 °C with different levels of water pH ranging from 3-10. Twenty four pH levels were tested for incubation period and egg hatchability while 15 pH levels were tested for larval survivability in a completely randomized design with three replicates for each treatment. Just hatched larvae were used for this study and the effect was observed until 72 h post-hatching. Water pH was maintained by the addition of NaOH or H2SO4solutions. The incubation times of fertilized eggs were recorded to be 23.5–25.0 h at pH levels of 6.1–8.8. The increased incubation time was noticed at the rest of the acidic and alkaline pH levels. Significantly highest hatching rate was observed at the pH levels of 6.7–7.6 compared to those at lower and higher pH levels (P0.05). However, no significant differences (P0.05) were recognized in the hatching rates at the pH levels of 6.7 – 7.6. No hatching occurred at low pH levels between 3.1 and 3.4 and at high pH of 10. After 72 h of exposure to different pH levels, no larvae survived at pH levels below 4.5 and above 9.0. Highest larval survival (98%) was observed at pH 7.0 followed by 94% at pH 7.5 and 92% at pH 6.5. The results obtained in the present study revealed embryos and larvae can survive and tolerate to a low pH level of 3.7 and 4.5, respectively but the survival rates decreased with decreasing pH levels. Therefore, a water pH level of 6.7–7.5 is highly recommended for optimal hatching and highest larval viability of C. gariepinus.

Growth Assessment and Microbial Flora Presence in African Catfish (Clarias gariepinus) Larvae Fed Live and Commercial Feeds

Growth Assessment and Microbial Flora Presence in African Catfish (Clarias gariepinus) Larvae Fed Live and Commercial Feeds

Aggressive and cannibalistic behavior of African catfish larvae: effect of different doses of methyltestosteron injecting to female broodstock and larval stocking densities

ABSTRACT This study aimed to evaluate the effect of 17α-methyltestosterone hormone (MT) injecting to female broodstocks and stocking densities on the aggressive and cannibalistic behavior of African catfish larvae. Two-day-old post-hatching larvae were used in this experiment. Larval rearing was started at three-day-old post-hatching (body weight 0.004 ± 0.003 g and total length 0.2 ± 0.05 cm) in a 40 cm×30 cm× 25 cm rearing aquaria. This study used a completed randomized factorial design which consisted of two factors. The first factor were the larvae from females broodstocks without MT injection (0 μg/g body weight) (A), injected with MT (1 μg/g body weight) (B), and injected with MT (2 μg/g body weight) (C), while the second factor were larval stocking densities of 3.000/m2 (V1) and 6.000/m2 (V2), with three replications. The results showed that the larvae from female broodstocks injected with MT 2 μg/g body weight (C) and stocking densities 6.000/m2 (V2) increased the aggressiveness of swim and decreased cannibalism. The highest cannibalistic behavior occurred from 00.00‒06.00.Keyword: aggressiveness, cannibalism, Clarias gariepinus, methyltestosterone ABSTRAKPenelitian ini bertujuan untuk mengevaluasi pengaruh hormon 17α-metiltestosteron (MT) yang diinjeksikan pada induk betina dan padat tebar terhadap tingkat agresivitas dan kanibalisme larva ikan lele. Ikan uji yang digunakan adalah larva berumur dua hari setelah penetasan. Pemeliharaan larva dimulai saat larva berumur tiga hari setelah penetasan (bobot tubuh 0,004 ± 0,003 g dan panjang total 0.2 ± 0.05 cm) yang dipelihara di dalam akuarium berukuran 40 cm×30 cm×25 cm. Penelitian ini menggunakan rancangan acak lengkap faktorial yang terdiri atas dua faktor. Faktor yang pertama adalah larva dari induk tanpa diinjeksi dengan hormon MT (0 μg/g bobot tubuh) (A), diinjeksi dengan hormon MT (1 μg/g bobot tubuh) (B), dan diinjeksi dengan hormon MT (2 μg/g bobot tubuh) (C), sedangkan faktor yang kedua adalah padat tebar 3.000 ekor/m² (V1) dan 6.000 ekor/m² (V2), dengan tiga kali ulangan. Hasil penelitian menunjukkan bahwa larva ikan lele dari induk yang diinjeksi hormon MT dosis 2 µg/g bobot tubuh dan dipelihara pada padat tebar tinggi 6.000 ekor/m² (V2) dapat meningkatkan agresivitas berenang dan menurunkan kanibalisme. Tingkat kanibalisme tertinggi terjadi pada pukul 24.00‒06.00 WIB. Kata kunci: agresivitas, kanibalisme, Clarias gariepinus, metiltestosteron

Seasonal studies of caviar production and the growth rate of the African catfish (Clarias gariepinus, Burchell, 1822)

Issues of African catfish caviar production organization were studied in the present work. Prospects of all-season African catfish caviar production in recirculating aquaculture system were investigated. The purpose of the study was to evaluate season-dependent dynamics of caviar production, duration of pre-spawning period and dynamics of postembryonic ontogenesis of African catfish generations, reproduced within autumn-winter and spring-summer periods. The tasks of the study included: comparative analysis of male and female pre-spawning periods in different seasons; hormonal stimulation; eggs fertilization; eggs growth to larval stage; evaluation of dynamics of larvae and fry growth reproduced in spring and autumn period. The study results showed that caviar productivity of African catfish females, characterized by multiple spawning, decreased by two times in November as compared to spring period, and depended on the duration of pre-spawning period. Dynamics of gonads development was also season-dependent. In autumn period the duration of pre-spawning preparation, necessary for gonads maturation, was twice as long as spring one. Males and females did not respond to hormonal stimulation if pre-spawning conditions failed to comply. Growth rate of African catfish larvae and fry, reproduced in autumn period, was slower as compared to those that were reproduced in spring.

Growth performance and intestinal morphology of African catfish (Clarias gariepinus, Burchell, 1822) larvae fed on live and dry feeds

Effects of live and dry feeds on intestinal morphology and growth of African catfish, Clarias gariepinus, larvae (Burchell, 1822) were investigated from 2 days post hatching (dph) to 6 dph and 11 dph, respectively. Feeding trials were carried out at Fleuren and Nooijen hatchery, Netherlands, in glass tanks connected to a RAS system. Five test diets (Artemia nauplii combined with dry feed (A), decapsulated Artemia cysts combined with dry feed (B), Artemia nauplii only (C), decapsulated Artemia cysts only (D) and commercial dry feed (E)) were assigned randomly in triplicate. The proportion of live feed in the combined diets was gradually reduced until 6 dph. Thereafter, all treatments were fed on the dry feed. Histological parameters were analysed in the proximal, middle and distal part of the intestine using standard H and E staining methods. At the end of the experiment, final wet weight (17.90 ± 0.38 mg) and specific growth rate (SGR) (24.12 ± 0.35%/day) were significantly higher (P < 0.05) in larvae fed nauplii combined with dry feed. A diet of decapsulated Artemia cysts resulted in the lowest values for these parameters (8.90 ± 0.44 mg and 17.18 ± 0.28%/day, respectively). FCR was best in the diets using nauplii only (0.53 ± 0.12) or nauplii combined with dry diet (0.70 ± 0.30). Feeding decapsulated Artemia cysts or its combination with dry feed resulted in the poorest (1.62–1.66) FCR values. Microscopic observation of the intestinal morphology demonstrated a decrease of mucosal folds, mucosal fold height, perimeter ratio (inner/outer perimeter) and wall thickness from the proximal to the distal intestine at 6 dph. Generally mucosal morphometric parameters were significantly (P < 0.05) higher when feeding nauplii combined with dry feed, than when feeding other diets. Goblet cells counts relative to PAS staining decreased from the proximal to the distal intestine. Nauplii and its combination with dry feed resulted into significantly (P < 0.05) higher counts of goblet cells in all intestinal parts. The highest goblet cell count was on 4 dph (range 57–254) before decreasing by 6 dph (32–54) in all diets. A gradual reduction of nauplii daily ration in its combination with dry feed stimulated morphological development that resulted in improved growth performance. Different starter feeds thus had an impact on intestinal morphological development and on growth in the larval phase, but could also affect further rearing results.

Optimum low salinity to reduce cannibalism and improve survival of the larvae of freshwater African catfish Clarias gariepinus

The freshwater African catfish Clarias gariepinus is carnivorous and cannibalistic even during the larval and juvenile stages and this behavior causes economic losses in aquaculture. This study examined for the first time the effect of salinity on cannibalism, survival, and growth of African catfish larvae in the hatchery. Larvae (4 days old, median 7.8 mm TL, 2.8 mg BW) of the African catfish were reared for 21 days at nominal salinity 0, 1, 2, 3, 4, 5, 6, and 7 ppt. After 21 days, they grew to 10–39 mm (median 22 mm) and 10–490 mg (median 90 mg), with no significant difference by salinity treatments. Survival ratios were similarly low (24–31%) at 0, 1, 3, and 7 ppt and significantly higher (49–55%) at 2, 4, 5, and 6 ppt. Cannibalism was significantly lower, 15–30% at 4–6 ppt, than the 40–50% at 0–3 and 7 ppt. Size variation was lower at 4–6 ppt and higher at 0–3 and 7 ppt. We recommend hatchery rearing of African catfish at the optimum low salinity of 4–6 ppt rather than in full fresh water at least up to 21 days. This rearing method fosters larval welfare and improves hatchery production.

14. PENGARUH LAMA PERENDAMAN LARVA DALAM HORMON METIL TESTOSTERON ALAMI TERHADAP PENJANTANAN IKAN LELE DUMBO (Clarias gariepinus) The Effect of Soaking Time of African Catfish Larvae (Clarias gariepinus) in Natural Methyl Testosterone Hormone on Masculinization

The purpose of this study was to determine the effect of immersion time on African catfish (Clarias gariepinus) larvae in natural methyl testosterone hormone on masculinization. This study was conducted in Center of Fish Culture Lamnyong, Banda Aceh. Experimental animals used in this study were 270 African catfish larvae aged 10 days. The study was designed using completely randomized design (CRD) with 3 treatments and 3 replications. African catfish larvae aged 10 days in group P1, P2, and P3 were immersed in natural methyl testosterone hormone for 10 hours, 20 hours, and 30 hours, respectively. Observations were carried out until fish reach 50 days old. Data were analyzed by analysis of variance (Anova) followed by least significant difference test (LSD). Percentage of male catfish observed in P1, P2, and P3 were 64.24 %, 93.11%, dan 59.94% respectively. As a conclusion, immersion with natural methyl testosterone hormone can change the sex of catfish to be male. ____________________________________________________________________________________________________________________ Key words: african catfish, methyl testosterone natural, masculinization

Early appearance of the retinal tapetum, cones, and rods in the larvae of the African catfish Clarias gariepinus

In the retina of the African catfish Clarias gariepinus, the pigment epithelium and the tapetum were formed in newly hatched larvae, the cones developed within 2 days, and the rods within 3 days after hatching. The retinal tapetum shone under surface light under a light microscope; the shine was located in the apical projections of the pigment epithelial cells. Early appearance of the retinal elements enables African catfish larvae to see and feed well even in dim light.

Use of Probiotics as First Feed of Larval African Catfish Clarias gariepinus (Burchell 1822)

African catfish larvae do not have fully developed digestive system at onset of first exogenous feeding. Live feed like artemia have been used more than dry diets but is also costly. The gut microbiota may be influential in larval diet utilization. We therefore made three larval feed from two commercial probiotics and tested their growth and nutritional effects on first feeding hatchlings (larvae) of African catfish. The three diets were labeled as feed 1 (F1) made up of mixtures of mixtures of Lactobacillus acidophilus, Bacillus subtilis and Lactobacillus bugaricus, feed 2 (F2) was made up of 100% Saccharomyces cerevisiae and feed 3 (F3) was made up of 50% Lactobacillus mixtures and 50% Saccharomyces cerevisiae. The control diet F4 was decapsulated artemia. African catfish hatchlings were produced by artificial dry fertilization of brooders maintained in our lab. First feeding hatchlings 48 hours post fertilization (48 h pf) were stocked in well aerated 15l plastic aquariums at density of 100 larvae aquarium-1. There were three replicate aquariums per treatment feed. The photoperiod of the larval rearing system was 12 h D: 12 h L and the light intensity were maintained at 8 lux using black nylon coverings. The hatchlings were fed to satiation

Combined effects of photoperiod and temperature on growth and survival of African catfish (Clarias gariepinus, Burchell 1822) larvae under laboratory conditions

ABSTRACTThe effect of photoperiod (24L:00D, 12L:12D, and 00L:24D) and temperature (22 ± 1°C and 28 ± 1°C) on performance of Clarias gariepinus larvae was tested. Larvae weighing 3.2 ± 0.24 mg were cultured in aquaria at a stocking density of 20 fish L−1 and fed twice a day on catfish starter diet (40% CP) at 10 % BW day−1. Highest mean weight gain (31.00 mg), SGR (7.56% day−1), and survival (83%) were achieved at photoperiod and temperature combination of 00L:24D and 28 ± 1°C. Percent survival of larvae differed significantly (p < .05) among treatments with optimal survival of (83%) in treatment combination of 28 ± 1°C and 00L:24D, while lowest survival (40%) in treatment combination of 22 ± 1°C and 24L:00D.

Development of Fry Diets for African Catfish (C. gariepinus) Larvae in Uganda

Development of Fry Diets for African Catfish (C. gariepinus) Larvae in Uganda

Efektifitas ovaprim terhadap lama waktu pemijahan, daya tetas telur dan sintasan larva ikan lele dumbo, Clarias gariepinus

Abstract This study aimed to determine the effect of different doses of ovaprim on spawning time, egg hatchability, and survival of African catfish larvae (Clarias gariepinus). The research was done in the Central Local Fish Seed (BBI) Jayapura, Papua Province. Experimental design used was Randomized Complete Design. The study consisted of four treatments namely 0 ml, 0.3 ml, 0.6 ml and 0.9 ml ovaprim, each with three replications. Data collected were spawning time, egg hatchability, and survival rate of African catfish larvae. The number of containers used was as much as 12 buckets (for spawning, hatching, and observation of survival rate of larvae). The results showed that treatment with different doses of ovaprim hormones provided a significant influence on the latency time of spawning, egg hatchability and survival rate of larval. The dose of 0.3 ml ovaprim caould increase the latency time of spawning, egg hatchability and survival rate of African catfish larvae. The average latency time of hatching was 552 minutes, spawning and egg hatchability 84.16% and survival rate of living larvae was 85.76%. Keywords : African catfish, Ovaprim, spawning time, egg hatchability, survival rate