Comparative account of growth rate of body parts with total length in Rita pavimentata (Gunther)

The paper deals with sex-wise growth rate of different body parts in relation to total length in Rita paviinentata (Gunther). Growth rates calculated on pooled data by using the common regression coefficient 'b' reveals isometric and homogeneous nature in sexes.

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.

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.

Growth performance, recovery rate and fish yield of GIFT strain at various water depths under rice-fish culture systems

Effect of water depth on recovery rate, growth performance and fish yield of GIFT in the rice-fish production systems was studies in experimental plots of 123 m2 with a pond refuge of I meter deep which covered 10% of the total land area. Mortality rate of fish was very low ranging from 0.81-1.63%. However, at harvest, recovery rate ranged from 76.69-82.93% with the highest recovery at 11-15 em of water depth. Significantly the highest absolute growth (99.97) and specific growth rate (2.42%) were found at 21-25 cm water depth. The same treatment also produced significantly higher fish yield (909.76 kg/ha) although statistically similar to the fish yield (862.60 kg/ha) obtained at ll-15 em of water depth. Results also suggested that higher water depth can produce bigger fish but no significant effects of water depth was found on fish yield in the treatments 11-15 cm and 21-25 cm water depths of this experiment.

Diel feeding patterns, rate of gastric evacuation and foods of Indian sandwhiting, Sillago sihama in Mulki estuary, west coast of India

Diel feeding chronology of sandwhiting, Sillago sihama was examined from stomach collections taken during the months of April, July and December'99 in Mulki estuary along Dakshina Kannada coast, India. Significant differences in mean stomach content weight were found between several consecutive 3 hour periods with peak fullness occurring in early morning and evening hours. The rate of gastric evacuation of natural food (crustacea, polychaetes and fish) was measured in the field was best described by an exponential model, with an estimated evacuation time of 8.0 h at a temperature of 28.5 ± 1.2°C. Stomach content analysis indicated that this species is a carnivore on a wide range of benthic, epibenthic and planktonic prey. The principal food items of S. sihama were crustaceans, polychaetes and fish. Fishes less than 100 mm TL preferred mainly crustaceans while larger ones depends on polychaetes, crustaceans and fish. The feeding activity of S. sihama was influenced by tidal cycle.

Cumulative inbreeding rate in hatchery-reared indian major carps of Karnataka and Maharashtra states

The state fisheries department hatcheries are the major suppliers of seed to the farmers in Karnataka and Maharashtra. The brood stocks of these hatcheries are genetically closed units. In the present study, effective population size and cumulative inbreeding rates were estimated. The cumulative inbreeding rates ranged from 2.69 to 13.75, 8.63 to 15.21 and 3.02 to 5.88 per cent for catla, mrigal and rohu, respectively, in Karnataka state hatcheries. In Maharashtra, the cumulative inbreeding rates for catla ranged from 7.81 to 39.34 per cent and it was 5.84 to 14.09 and 2.46 to 10.20 per cent for mrigal and rohu, respectively. To estimate the inbreeding rates in future generations, predictive models were developed using linear regression, and polynomial and power equations separately for each hatchery. Their multiple correlation and standard errors suggested that simple linear regression can predict the future inbreeding rate efficiently.

Mapping of the Indian fisheries growth rate and fish consumption through GIS

In the present study, Indian fisheries growth rate and fish consumption have been analyzed through GIS mapping. The analyses were based on the state-level fisheries data of India collected from the secondary sources. Accordingly, the paper contains one thematic map containing two layers. To achieve this, all the data have been brought into a tabular form through Microsoft Excel and then joined to Map Info Professional Version 8.0 GIS software with digitized map of India for further analysis to generate thematic maps. In this thematic map, the first Jayer represents the growth-rate of fish production for the period 1990-2004 and the second layer represents fish consumption for the year 2003. The thematic map represented in graphic form presents inland, marine and total growth rates, and also the rural and urban fish consumption at the state levels. This study will be useful to fish traders, planners, researchers and administrators in fisheries policy formulation for sustainable development.

Features of wave field, its effect to erosion - deposition processes in the Cua Dai (Hoi An), Cai river mouth (Nha Trang) and Phan Thiet Bay in typical local wind conditions

Based on the hydrodynamic model and Shore Protection Manual (CERC - USA) we have calculated wave field characteristics in the typical wind conditions (wind velocity equal to 13m/s in the high frequency direction of the wind regime). Comparison between measured and calculated wave parameters was presented and these results were corresponded to each other. The following main wave characteristics were calculated: -Pattern of the refraction wave field. -Average wave height field. -Longshore current velocity field in surf zone. From distribution features of wave field characteristics in research areas, it could be summarized as following: - The formation of wave fields in the research areas was unequal because of their local difference of hydrometeorological conditions, river discharge, bottom relief… - At Cuadai (Dai mouth, Hoian) area in the N direction of incident wave field, wave has caused serious variation of the coastline. The coastline in the whole region, especially, at the south of the mouth was eroded and the foreland in the north of the mouth was deposited. - At Cai river mouth (Nhatrang) area in the E direction of incident wave field, wave has effected strongly and directly to the inshore and channel structure. - At Phanthiet bay area in the SW direction of incident wave field, wave has effected strongly to the whole shoreline from Da point to Ne point and caused serious erosion.

Status of the shore area from Tiengiang to Camau: causes of accumulation and erosion

The paper presents some results of the research programs which had been performed during 1996-1999 (“Studying of river-sea interaction in the mouth of Tien river” and KHCN.06.08). Based on these results the morphological schemes of the shore areas from Tiengiang to Camau were compiled; causes and mechanics of accumulation and erosion were also determined. These results may be used as scientific basis for forecasting the development of the shoreline, it will contribute to the management, protection and reasonable exploitation the shore areas.

Investigations on wooden floating materials: the loss of buoyancy under continuous immersion in water and the rate of its redemption by drying

A wooden fishing float under immersion in water for long periods is liable to absorb water, the quantity of water absorbed possibly being dependent upon the physical factors like the specific gravity and the inherent property of the material, the time of soaking and the pressure acting on it. Consequently a wooden float is likely to become heavy and loss its original buoyancy. However, when the float is removed from water and dried, the lost buoyancy is regained on complete drying. The present paper is an attempt to elucidate these two important characteristics of some of the chief wooden floating materials used on the West Coast of India.

Rate of filtration by Perna viridis pre-exposed to heavy metals

Perna viridis exposed to different concentrations of copper and zinc for varying periods and then the rate of filtration estimated under metal free culture conditions. The concentrations under which the animals were maintained before the experiments were 0.025 to 0.150 p.p.m. of zinc and 0.005 to 0.08 p.p.m. of copper.

Relationship between diet composition and growth rate of the zoeal and mysis stages of Penaeus japonicus Bate

Diets containing Chaetoceros gracilis plus Artemia nauplii artificially prepared diet, Diet-B, and two commercial feeds Tapes and mysid meals, were fed to larvae of P. japonicus. Highest survival rate was obtained when larvae were fed with Diet-B. The results show that the early larval stages of P. japonicus can be reared on artificially prepared diets. Since the chemical composition of the diet is known, it can be used as supplemental data for larval feeding development and nutritional requirement studies for the early larval stages of Penaeus japonicus and/or other penaeids. Information is tabulated on feeds and feeding rates used, composition of the artificial diet, fatty acid composition of lipids of the different diets, and of the sterols of the different diets.

Effects of dietary supplementation of commercial human probiotic and antibiotic on the growth rate and content of intestinal microflora in ornamental fishes

The effects of dietary supplementation of commercial human probiotic, Lactobacil and antibiotic, oxytetracycline on the growth, survival, disease resistance and content of intestinal microflora in two ornamental fishes, viz., goldfish, Carassius auratus and swordtail, Xiphophorus helleri were studied. The total wet weight gain, food conversion ratio and specific growth rate of C. auratus did not vary significantly (p>0.05) among treatments. While in X. helleri, significant differences existed in the total wet weight gain, survival, food conversion ratio and specific growth rate among treatment groups (p<0.05). The counts of antibiotic resistant bacteria in fish gut increased with days of culture in all the treatments and the increase was more in antibiotic fed fishes. A reduction in the development of antibiotic resistance among the bacterial flora of fish gut was noticed in probiotic fed groups of C auratus and X. helleri. The results of the present study revealed that the effects of human probiotic on the growth, survival and disease resistance of ornamental fishes are variable and difficult to reproduce the similar effect on different species.

Effects of different levels of energy and protein sources on the growth performance, feeding, survival rate and the chemical body composition of juvenile Pacific white shrimp (Litopenaeus vannamei)

The present study was carried out in order to establish an economical effective diet for the pacific white shrimp in the southern part conditions of Iran. With the consideration of three dietary energy levels (E1=262, E2=312, E3=362 kcal 100 g-1 diet) and six ratios of fish meal (FM) to soybean meal (SBM) [(P1=100%FM+0%SBM, P2=80%FM+20%SBM, P3=60%FM+40%SBM, P4=40%FM+60%SBM, P5=20%FM+80%SBM, P6=0%FM+100%SBM)], 18 experimental diets (with 36% crude protein) were prepared. Completely randomized design was used to assign 54 polyethylene 300 litre round tanks provided by aeration and flow through water system and was stocked by 19 juvenile as 3 replicates to each treatment. Shrimps average weight was about 0.77 grams at the start. After 56 days culture period, maximum growth and nutritional performances were observed in the P6E1 treatment (containing 100% soybean meal and 262 kcal 100 g-1 diet) and P5E1 treatment (containing 80% soybean meal and 262 kcal 100 g-1 diet). Also the highest survival rate of the shrimps was observed in the P1E1, P1E2, P3E3 and P5E3 treatments. Additionally interactive effect of different protein ratios and energy levels had significant difference on body protein, fat, fiber and ash contents (P<0.05). Results of the present study suggest the possibility replacement of at least 80% of dietary fish meal by soybean meal in the diet of pacific white shrimp in the conditions of southern part of Iran.