A comparative study of the morphometrics and the proximate composition of two edible molluscs Crassostrea cuculata (Born) and Perna perna (L.)

The morphometrics and the bio-chemical characteristics of Crassostrea cuculata and Perna perna were studied. In the oyster, the length was found to be positively correlated with breadth and total body weight. There was also a positive relationship between the total body weight and the total muscle weight. In the mytilid the total body weight was positively correlated with length and total muscle weight. The muscle weight was also found to be highly correlated with the length. In both animals the relationship between the length and the total body weight was curvilinear. In the oyster, the protein content was found to increase with the total body weight and the total muscle weight. In the mytilid the protein content increased not only with the total body weight but also with the length. In both animals, the relative content of protein is higher than that of carbohydrates, lipids and ash.

Fishery and biology of Penaeid prawns at Harnaii, Mahatashtra

Penaeid prawn fishery at Harnaii in Ratnagiri District of Maharashtra was investigated during fishing seasons of 2002-03 and 2003-04 from mechanized (MLD) and hand operated trawlers (HT). During the two years, MLD contributed 86% and HT 14% to the average annual penaeid prawn catch of 2,242 t. The catch showed two peaks, a major during October-December and a minor during April-May in both the gears but abundance of the individual species differed. P. stylifera, Metapenaeopsis affinis, Solenocera crassicornis, Metapenaeopsis brevicornis, P. merguiensis and Metapenaeopsis dobsoni mainly constituted the fishery and their species composition, seasonal abundance, annual size distribution and monthly mean size were investigated. Biological studies on food, size at maturity, spawning period, sex-ratio and juvenile abundance were carried out to explain temporal abundance of the species in the fishery. Among the species P. stylifera, M. affinis and S. crassicornis exhibited distinct seasonality with two spawning peaks, one in pre-monsoon and the other in post monsoon period to produce two discrete broods while P. merguiensis despite two spawning peaks exhibited a single dominant brood. M. brevicornis showed monsoon and post-monsoon spawning while M. dobsoni showed only post-monsoon spawning. Migrations between nearshore and offshore waters resulted in mixing of the broods and they remained inseparable in the catch.

Effect of lykamin on growth and biochemical composition of long whiskered catfish, Mystus gulio (Hamilton) fingerlings under laboratory conditions

A growth trial was conducted to test the effect of Lykamin (dietary supplement) on growth, survival and feed conversion in Mystus gulio. Four isoproteic diets were formulated by incorporating the growth promoter, Lykamin at the levels of 0, 0.25, 0.50 and 0.75% diet. The crude protein content was 30% in each diet. The diets were fed to triplicate groups of catfish fingerlings twice daily at a level of 5% of the total body weight for 120 days. Regular fortnightly sampling was done to evaluate the growth performance of the experimental animals. Water quality parameters during the experimental period were maintained within the range suitable for catfish. The results showed better specific growth rate, weight gain, protein efficiency ratio and feed conversion ratio in the group which was given 0.75% Lykamin diet.

Over-wintering performance of mixed sex and monosex tilapia (Oreochromis niloticus L.) in Bangladesh

An experiment was conducted for six months in 6 experimental ponds (each size 80 of m2) to assess the over-wintering performance between mixed sex and monosex tilapia, Oreochromis niloticus. The experiment was carried out with two treatments each with three replicates. In the first treatment (T1), mixed sex tilapia were stocked in 3 ponds with a mean initial of 4.80±0.18 g. In the second treatment (T2), monosex tilapia were stocked in another 3 ponds with a mean initial weight of 4.81 ±0.20 g. Each pond was stocked with 250 fingerlings. Fish were fed at the rate of 6% of fish body weight at the beginning. The feeding rate was gradually reduced to 2% for the third month and finally increased to 3% for rest of the period. Water quality was monitored fortnightly and the ranges were: temperature17.86-29.10°C, dissolved oxygen 4.25-6.10 mg/1, pH 6.97-7.20 and transparency 24.10-36.50 cm. After 6 months of rearing monosex tilapia attained a significantly (psex tilapia. Monosex tilapia also resulted in significantly (Psex tilapia. However, there was no significant (psex and monosex tilapia. The production of monosex tilapia (3723.10 kg/ha) was about 32% higher than that of mixed sex tilapia (2776.28 kg/ha). The net profit/ha generated from the 6 months culture period was calculated as Tk. 43,311.45 and. 69,277.32/- for mixed sex and monosex tilapia respectively. The results of the present study suggested that it is possible to successfully culture tilapia during the winter period and the culture of monosex tilapia is more profitable due to its higher growth rate than that of mixesex tilapia.

Determination of length-weight relationship in Sepia pharaonis and test for sex specific variation

The parameters a and b of the length-weight relationship of Sepia pharaonis of the form of W=a.L was determined. Sex separated size fequency data collected from Karachi fish Harbour was analysed the length-weight equations, separable by male, female and sex combined. The apparent difference in paired values of exponents b1, b2 for any combination i.e. male versus female and male, female versus sex combined was tested for their significant difference. No significant difference was observed for any combination, this indicated no sex specific variation in length-weigh relationship of Sepia pharaonis.

Seasonal and sex related haematological variations of the freshwater spiny eel, Mastacembelus armatus reared in the cemented cisterns

The seasonal and sex related haematological vanatlons in the freshwater spiny eel Mastacembelus armatuswere studied during summer from April to June 2001 and winter from November 2001 to January 2002. In total 60 fish (30 males and 30 females) ranging from 30- 55.6 cm in total length and from 55-95.5 g in weight were collected from the culture stock maintained in the cemented cisterns. It was observed that the values of the total erythrocyte count (TEC), haemoglobin concentration (Hb ), haematocrit values, packed cell volume (PCV) and neutrophil count were significantly higher (P< 0.05) in males than the females during summer (April to June- on-set of breeding season). Females were observed to have remarkably higher values (P< 0.01) of erythrocyte sedimentation rate (ESR), total leucocyte count (TLC) and thrombocyte count during summer. On the other hand, insignificant variations in the various haematological parameters were noticed during winter (November to January) between the two sexes of M. armatus.

Alternative phosphorus sources for formulated fish feed

An experiment was conducted to evaluate the possibility of using inorganic fertilizer triple super phosphate (TSP), inorganic fertilizer 16:20 (a 16:20 grade fertilizer contains 16 percent N and 20 percent P20 5), rice-bran and duck-manure as phosphorus sources in formulated fish feed for Nile tilapia ( Oreochromis niloticus). Experiment was conducted for a period of 2 months in net-cages suspended in fertilized earthen ponds and all male sex-reversed Nile tilapia (9.39- 10.37 g) were used in the experiment. Seven treatments including one non-feed treatment were used in this experiment. Treatment 1 (non-feed), treatment 2 (-P) where fish fed with phosphorus non-supplemented diet acted as control 1 and treatment 3, 4, 5, 6 and 7 where fish fed with 3% di-calcium phosphate (DCP), 3% triple supper phosphate (TSP), 7% 16:20 inorganic fertilizer, 30% rice-bran and 30% duck-manure supplemented diet, respectively. Results showed that the TSP and 16:20 grade inorganic fertilizer supplementation in diets as phosphorus sources were equivalent to DCP (Di-calcium phosphate) supplementation in terms of growth performance, feed utilization efficiency and final body composition of Nile tilapia. Ricebran and duck-manure were not found as good phosphorus sources.

Recovery, growth and carcass composition following periods of restricted ration and full feeding in indian major carp, Rohu (Labeo rohita H.)

A 90-day experiment was conducted to determine the effect of restricted ration and full feeding on the recovery growth and carcass compositions of fingerlings (average weight - 20.74 ± 0.13 g) of rohu, Labeo rohita (H.). Rohu fingerlings procured from a local fish breeder were fed with commercial pelleted feed (27% crude protein) during the two-week acclimatization in the laboratory condition. Experimental pelleted diet (30% crude protein) was prepared and the control group (T sub(CFR)) was fed at 3% of body weight for the 90-day trial period. The experimental group T sub(1FR) was fed for three days at 1% of body weight and the next three days at 3% of body weight, T sub(2FR) was fed for seven days at 1% of body weight and the next seven days at 3% of body weight, T sub(3FR) was fed for 15 days at l% of body weight and the 15 days at 3% of body weight and T sub(4FR) was fed for 25 days at 1% of body weight and the next 25 days at 3% of body weight, alternating between 1 and 3% for the specified period during the 90-day trial period. Daily rations were divided into two equal meals per day at 09.00 and 16.00 hours. Average percent survival rate of rohu during the 90-day trial period was more than 90. Percent live weight gain (98.90 ± 0.34, 113.0 ± 5.93, 125.71 ± 11.01 and 141.90 ± 2.89), specific growth rate (1.53 ± 0.01 1.68 ± 0.06, 1.80 ± 0.10 and 1.96 ± 0.02%/d) and absolute growth rate (1.33 ± 0.13, 1.38 ± 0.07, 1.39 ± 0.04 and 1.44 ± 0.07g/d) of the experimental groups (T sub(1FR), T sub(2FR), T sub(3FR) and T sub(4FR) respectively) increased with the advancement of the experiment in comparison to those in control, T sub(CFR) (90.92 ± 5.81%, 1.44 ± 0.07%/d and 1.34 ± 0.20g/d, respectively) and were proportionately correlated with the degree of deprivation probably through the mechanism of increased feed intake (hyperphagia), feed efficiency ratio or gross growth efficiency, protein efficiency ratio and the superior feed conversion ratio reflecting in better performance index. The body length and muscle composition of fish indicated that recovery growth happened due to protein growth but certainly not due to fat deposition in the gut. Feeding at 1 and 3% of body weight alternating over a period of 25 days might economize the culture operation of rohu.

Seasonal changes in the biochemical composition of liver in Garra mullya (Sykes)

Seasonal changes taking place in the biochemical constituents of liver of G. mullya are reported. An inverse relationship was noticed in the variation of fat and water. Maximum fat contents were observed during june-july. Reserve fat was utilized through gluconeogenesis during the spawning months. Protein and glycogen percentages were comparatively higher in liver than in the muscles and gonads. Decline in the glycogen content was associated with spawning during July to November. Nutritive values have shown more energy contents in the liver during pre-spawning months.

Technological aspects of preservation and processing of edible shell fish 2. Influence of season on the chemical composition of crab (Scylla serrata)

The purpose of this communication is to bring out the influence of season on the chemical composition of crab, covering a period of 2 years. Changes in moisture, protein, water extractable nitrogen, non-protein nitrogen, glycogen, lactic acid, fat and free amino acid composition of crab meat have been reported on a monthly basis.

Chemical composition of Sepia orientalis and Loligo vulgaris

The chemical constituents of Sepia orientalis and Loligo vulgaris weighing between 200-300g have been studied. It has been found that these species could be classed as high protein and low fat food and that these are good sources of calcium, phosphorus, iron and moderate amounts of B-group vitamins.

Fatty acid composition of three species of freshwater fishes

Fatty acid composition of freshwater fish tilapia, (Tilapia mosambica), barbus (Barbus carnaticus) and Varal (Ophicephalus) is determined by gas-liquid chromatography. Varal contained the highest amount of C sub(20:5) acid compared to other 2 spp. Of the odd-numbered fatty acids C sub(17) was the predominant fatty acid present. Palmitic acid was found to have a lower level in these fish compared to marine fish. Barbus recorded unusually high percentage of 23.3% of C sub(18:2) acid.

Fatty acid composition of Anchoviella and Thrissocleus

A study was made to elucidate fatty acid composition of Anchoviella and Thrissocleus, and bring to light similarities with other clupeids. The results are tabulated. The polyunsaturated fatty acids, eicosapentaenoic acid and docosahexaenoic acid, are the 2 major fatty acids in the phospholipid fraction of both fish. Myristic, palmitic and stearic acids are the major components of the nonphosphorylated fraction.

Effect of starvation on the biochemical composition of Clarias batrachus (Linn.)

Marked changes were observed in different chemical constituents of C. batrachus during starvation. The N and protein fractions showed a definite pattern of variations. The highest values of these were recorded on 10th day of starvation and thereafter values declined gradually. On the other hand, the acid soluble phosphorus exhibited a reverse trend, increasing gradually from the first to the 30th day of starvation. These changes have been attributed mainly to the energy and metabolic demands of the starving fish.

Studies on maturation, spawning, fecundity and sex ratio in Barbus (Puntius) sarana (Hamilton-Buchanan) from Lake Kolleru, Andhra Pradesh

Barbus sarana contains only one batch of mature ova in the mature ovaries to be spawned in one spawning act. It spawns during July-September. The fecundity ranges from 11,201 to 224,248 ova. There is a positive curvilinear correlation between total length and fecundity, the latter increasing with length at a rate of less than cube of length. The stock of this species from Lake Kolleru appears to be more fecund than that inhabiting Loni reservoir. The sex ratio indicates that females outnumber males in all months and in larger length groups. Females appear to reach a larger length than males.