Field application of anabolic steroids in carp seed production. II. Rearing of spawn to fry stage.

Two synthetic androgenic steroids, Ethylestrenol (17 β - Hydroxy - 17 α ethyl - estr - 4 - en - 3 - one) and Stanozolal (17 β - Hydroxy- 17 α - methyl - 5 a - androstano - 3, 2 - C - pyrazole) were fed via diet at 3 ppm to the spawn of Rohu and Mrigal which were reared up to fry stage over a period of 15 days in earthen carp nurseries. Both hormones enhanced growth of spawn. A maximum of 25.78% increase in length and 25.69% increase in weight as compared to the controls has been recorded. Growth rate was recorded to be 0.8 mm & 2.48 mg/day (control), and 1.13 mm & 2.67 mg/day (Stanozolol treated) in case of Mrigal spawn; and 0.91 mm & 2.39 mg/day (control), 1.12 mm & 2.90 mg/day (Ethylestrenol treated), and 1.10 mm & 2.57 mg/day (Stanozolol treated) in case of Rohu spawn. A decrease in the values of Relative Condition Factor upon hormone administration was also noticed.

Study on the morphometric and meristic characteristics of splendid silver belly Leiognathus splendens (Cuvier) from Bombay coast

Ten morphometric and six meristic characters of Leiognathus splendens (Cuvier) of Bombay Coast have been studied sexwise. Regression and sexwise difference if any between the compared morphometric characteristics have been worked out. Range, mode, standard deviation, co-efficient of variation of 6 meristic characters have been analysed. There was no significant difference between the sexes in morphometric and any deviation in the meristic characters.

A note on application of hills procedure for growth-curve analysis of Indian major carp, Labeo rohita (Ham.), during the gonodal development period at Shillong, Meghalaya

The present study deals with the length increment data of 15 adult Labeo rohita (Ham.) over a period of five months by the applicatin of finite difference method at an altitude of 1496 m above mean sea level at Shilllong, Meghalaya.

Effect of some environmental factors on the acute toxicity of deltamethrin to common carp: a laboratory study under aerobic condition

The toxicity of xenobiotic in aquatic ecosystems is influenced by many factors such as ambient temperature, water hardness, pond soil type, etc. In the present study, it was observed that air temperature, water hardness and soil sediment have profound influence on the toxicity of deltamethrin to common carp fry (ay. length 3.5 ± 0.5 cm, ay. weight 0.58 ± 0.25 g); 96h LC(sub)50 values for common carp at 38.07 ± 2.20°C maximum and 27.86 ± 1.22°C minimum air temperature in soft and very hard water were 0.102 and 0.495 µg lˉ¹, respectively. This value had increased significantly to 2.37 and 3.02 µg at 30.55 ± 1.21°C maximum and 26.04 ± 0.61°C minimum air temperature, respectively. When sediment was included, 96h LC(sub)50 at 38.07°C maximum temperature in very hard water was 1.808 µg 1ˉ¹ and this had increased to 8.073 µg 1ˉ¹ when tested at 30.55°C maximum temperature. Due to the 7.5°C increase in maximum and 1.7°C in minimum temperature, toxicity increased significantly. Lower toxicity in very hard water in comparison to soft water may be due to the lower solubility of deltarnethrin and high level of calcium. Adsorption reaction of deltamethrin with clay, humus, FeOOH, MnOOH and particulate organic carbon, and complexation reaction with dissolved organic carbon were responsible for the lowered toxicity in the experiment with sediment. Exposure time had no significant effect on acute toxicity of deltamethrin.

The effect of feeding rate on the growth, food conversion and protein efficiency of silver dollar, Metynnis schreitmulleri (AHL), fry

A 30-day experiment was conducted to determine the effects of varying feeding rates on the growth of fry of silver dollar, Metynnis schreitmulleri (Ahl). Silver dollar fry with an average initial body weight of 1.100 ± 0.029 g were collected from a local fish breeder and fed a diet (35% protein and 6% fat) at the rate of 3, 6 and 9% of body weight per day in two equal meals. Per cent weight gain increased from 54.54 to 118.18 with increased feeding rates, which were significantly different (p<0.05) from each other. The highest specific growth rate was obtained in the fry fed at 9% body weight per day. In another study for 30 days, the effects of feeding frequency on growth, feed conversion and protein efficiency of silver dollar fry were evaluated. Groups of silver dollar fry with an initial individual weight of 0.700 ± 0.019 g were offered feed continuously for 24 hours during the day or night at different time intervals with varying meal sizes. The night time feeding with two meals gave the lowest weight and length gains (0.985 g and 0.30 cm). The growth rates of fish fed during day with three equal-sized meals are significantly (p<0.05) higher (4.66%) than the other treatments.

Carp polyculture in Central and Eastern Europe, the Caucasus and Central Asia: a manual

This Technical Paper is a basic guide to carp pond polyculture practicable in the Central and Eastern Europe (CEE) and the Caucasus and Central Asia (CCA) countries. It provides an overview on the guiding principles, aspects and tasks, and presents the most applicable production techniques and patterns of carp polyculture. For further reading and more in-depth information on the suggested techniques and technologies, it also includes a list of relevant FAO publications. It is expected that this publication will help identify resources and contribute to the successful planning and realization of fish production by those fish pond owners and operators who need to strengthen and improve their knowledge on the subject.

Hatching and rearing of carp (Cyprinus carpio L.) in the Polonnaruwa nursery

Carp fingerlings have been raised at Polonnaruwa since 1957 (Ling, 1962), by a method essentially the same as that described by Hora and Pillay (1962). The present work was initiated to assess and increase the efficiency of the nursery. Two experiments were carried out. In the first, 3 females and 6 males were used. Thirty bundles of Hydrilla were tied to the 3 strings and 10 of them taken at random were used for egg counts. In the second experiment the same number of fish was used but 36 bundles of Hydrilla were tied to the 3 strings and 9 of these taken at random for egg counts. The results of these 2 experiments are given in Table l.

Studies on the preparation of fish silage. 2. Rate of liquefaction in different parts of silver belly

An experiment was undertaken to determine from which part of silver belly (Leiognathus splendens) carcasses originate the autolytic enzymes responsible for liquefaction of silage. Findings show that it is important to leave head and viscera present in order to get a satisfactory liquefaction in silage prepared from silver belly using 3.5% formic acid. The storage life of silage produced from various parts of the fish carcasses is also discussed.

Scale structure, age and growth in the freshwater carp, Labeo calbasu (Pisces/Cyprinidae) from Harike wetland, India

Age structure and growth profile based on the scale studies of 468 specimens ranging from 17-62 cm total length of Labeo calbasu (Hamilton) from Harike wetland (30°13'N, 75°12'E), Punjab, India have been described, the present study showed better growth in terms of two important growth parameters namely index of species average size and population weight-growth intensity. Two distinct phases in its life history have been described that indicates the optimum exploitation of this species from this water body. Harvestable size is found to be fish of 34 cm total length. The detailed structural elaboration of scale (normal, regenerated, lateral line) has also been done using scanning electron microscopy (SEM).

Optimisation of stocking density of Thai silver barb (Barbodes gonionotus Bleeker) in the duckweed-fed four species polyculture system

The optimisation of stocking density of Thai silver barb (Barbodes gonionotus) in the polyculture with Labeo rohita, Catla cat/a and Cyprinus cmpio was investigated in seasonal ponds. Three different stocking densities of Thai silver barb i.e., 5,000, 6,000 and 7,000 fingerlings ha-1 were tested with stocking density of carps fixed at the rate of 10,000 fingerlings ha-1 Duckweed was applied to all ponds supplemented with rice bran and oil cake. There were no significant variations on either water quality parameters or abundance of planktonic organisms due to the different stocking densities of silver barb. A significantly higher fish production (psilver barb was maintained.

Effects of iso-nitrogenous fertilizers as nutrient sources on carp polyculture in Bangladesh

A 120-day long experiment was conducted to find out the effects of urea plus triple super phosphate (UT), cow manure (CM) and poultry manure (PM) having iso-nil:rogen content on pond productivity and fish yield. Three fertilizer treatments, with three replicates each, were randomly assigned into nine earthen ponds of 100 m2 each. The stocking fish were rohu (Labeo ruhita), catla ( Catla catla) and mrigal ( Cirrhinus mrigala) in each treatment pond at the rate of 10000/ha with the ratio of 1:1:1. All ponds were fertilized fortnightly at the rate of 125 kg/ha urea plus 100 kg TSP/ha, 7000 kg/ha cow manure and 3500 kg/ha poultry manure for the treatment of UT, CM and PM, respectively, having an iso-nitrogen content of 56 kg in each. Though the physicochemical water quality parameters were more or less similar in all treatment ponds, the chlorophyll-a content and abundance of total plankton were significantly higher (P < 0.05) in the ponds receiving the treatment PM. Final growth as well as per unit production of fish was significantly higher (pcarp polyculture system under prevailing conditions.

Growth and yield of GIFT (Oreochromis niloticus) and Thai silver barb (Barbodes gonionotus Bleeker) in rice fields and their effects on the yield of rice

(GIFT) (Oreochromis niloticus) and Silver barb (Barbodes gonionotus) in rice fields and their effects on the yield of rice was carried out in nine experimental rice plots. Three treatments viz., treatment-1 with 0. niloticus (T1), treatment-2 with B. gonionotus (T2) and treatment- 3 was kept as control (T3, without fish) were used in this study. Fertilizers such as, Urea (178 kg ha-1), T.S.P (125 kg ha-1) and M.P. (67 kg ha-1) were applied in each treatment. The fishes were stocked @ 6250 ha·1 and the experiment was continued for a period of 107 days. The values of water quality parameters such as, water temperature, dissolved oxygen, pH and chlorophyll-a were found within suitable level. Between the two species, higher specific growth rate was recorded in 0. niloticus than that of B. gonionotus. But B. gonionotus showed much higher survival (72%) than that of 0. niloticus (35%). Similar to survival, higher production (244 kg ha-1) and income (Tk. 6399 ha-1) were recorded in B. gonionotus than those of 0. niloticus (142.8 kg ha'1 and Tk. 2137 ha-1). Significant differences (p

Bacterial load in pond water and different organs of a Indian major carp Cirrhinus mrigala Ham.

During the study period (August, 1993 to July,l994) the mean bacterial load in surface water was found to vary from 1.39 xl05 (July'94) to 3.llxl07CFU/ml (September'93), while that of botrom water ranged from l.Olxl06 (May'94) to 5.90xl07CFU/ml (October '93). The mean total number of bacterial load in body slime, liver and kidney was found to vary from 0.58xl03 (July'94) to 2.37xl07CFU/g (March'94),from 0.22xl03(July'94)to 9.64xl06 CFU/g (March'94) from O.l5xl03 (July'94) to 9.36xl06 CFU/g (March'94), respectively. Bacterial load in slime was significantly correlated with bacterial load in liver, bacterial load in slime was significantly correlated with bacterial load in kidney and bacterial load in liver was significantly correlated with bacterial load in kidney.

Investigation of health status of juvenile exotic carps from various farming conditions of Bangladesh

Health status of juvenile silver carp, Hypophthalmichthys molitrix and silver barb, Barbodes gonionotus were investigated in three fish farms following different farming conditions through clinical and histopathological examinations for a period of nine months. Here the fishes and water quality parameters were sampled on monthly basis. Among the water quality parameters, water temperature has a distinct effect on fish health observed during the winter season. Different clinical signs like scale loss, dermal lesion, fin erosion were observed, while histopathologically necrosis, pyknosis, inflammation, haemorrhage, hypertrophy, vacuoles, missing of gill lamellae and clubbing were evidenced in the investigated fishes. The study showed that pathological symptoms were mainly increased during the winter season and H. molitrix exhibited severe pathological symptoms in compare to B. gonionotus during the investigation. It was also found that fishes of BAU farm was comparatively in the best condition, while, the fishes of other farms were severely affected during the experimental observations. In addition, disease like Epizootic Ulcerative Syndrome (EUS), protozoan disease and suspected bacterial colonies were clearly evidenced in the fishes of Government and NGO fish farms.