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Open Access
Standardisation of thermal processing of cuttle fish nidamental glant
(Department of Processing Technology, College of Fisheries, Panangad, 2007) Bikash kumar Pati; KAU; Sherief, P M
Cuttlefish nidamental gland is a pair of flattened glands associated with the female reproductive system in cuttlefish. The glands are exported as a frozen product under the name cuttlefish roe. The procedure for thermal processing of cuttlefish nidamental gland in brine packed in tin plate can is standardised to produce a ready- to- eat product. The standardisation process essentially involved determination of optimum blanching conditions, retorting temperature, process time, processing parameters, optimum solid- liquid ratio and process levels to produce a safe product and assessment of quality changes during storage at room temperature. Cuttlefish nidamental gland in brine was packed in tin plate cans in 65 : 35 ratio (gland : brine) and thermal processed in an overpressure retort. The optimum blanching condition was found to be 5 % brine for 5 min. The retorting temperature and process time were selected as 121.10C and 25 min, respectively. The F0 value attained by the process was found to be 11.25 min with total process time of 30.54 min. The cook value meant to achieve tenderness of product was 81.54 min. The processed product was found to be commercially sterile. The product was acceptable even after 3 months of storage at room temperature with regard to all sensory attributes like appearance, colour, odour, taste, texture and overall acceptability. There were significant variation in the salt, pH and TBA values (P<0.05). The cut- out test showed a marginal increase in solid weight. The study showed that the cuttlefish nidamental gland can be used for processing ready to eat product, which can be stored at room temperature for long periods.
Open Access
Effect of phosphatic fertilizer compounds on aquatic primary production in saline water
(Department of Fishery Hydrography, College of Fisheries, Panangad, 2005) Rajkumar, K R; KAU; Mrithunjayan, P S
Fish production in farms largely depends on the primary productivity In the water bodies. Among many factors, plant nutrient levels and their availability in absorbable forms for the plankton is the most important one contributing to primary production. The plant nutrient element, phosphorus often found to limit the production, mainly due to the behavior of phosphorus compounds to remain in unavailable form in aquatic environment. Hence it becomes imperative to supplement phosphorus in suitable chemical form to achieve better production. While the dosage is also important, the salinity of water bodies has an interactive effect. Thus species of compounds in phosphatic fertilizer is vital. In the present study, two types of phosphatic fertilizers and combination of these fertilizers with additives were tested for their effect on aquatic primary production. Synthetic fertilizer namely single superphosphate and natural phosphatic fertilizer namely rock phosphate were selected for study. Commercial grade trisodium phosphate was used as additive in combination with single superphosphate and rockphosphate in 1: 1 ratio with respect to phosphate- P. All the above four fertilizer materials were tested in brackishwater having two salinity levels, a low salinity level of approximately 10 ppt and a high salinity level of approximately 20 ppt. Each fertilizer was added in three different doses, ie, O.lppm, 0.2 ppm and 0.4 ppm of phosphate-P. A set of control with two salinity level of water and without adding fertilizer were also run. All the experiments were done in duplicate, in accordance with statistically designed 2x4x4 Factorial Completely Randomized Design. The experiments were conducted in wide mouth polythene drums having 25 litre capacity using 20 liters of water. The experiment was set up in a protected, undisturbed, elevated place and kept exposed to sun light for 30 days. Volume loss due to evaporation was compensated by adding appropriate amount of water having corresponding salinity. 140 Water samples were drawn on l " day (before the addition of fertilizer), i\ 14th and so" days and analysed for available phosphate, total phosphate, silicate, nitrite, nitrate, iron, water pH, dissolved oxygen, carbon dioxide, total alkalinity, total hardness and calcium. Productivity was assessed on 1 st day and so" day by estimating chlorophyll. The results were statistically analysed with ANOV A technique. In the experiment, maxrmum productivity in terms of chlorophyll (14.6mg/m3) was found under the treatment with single super phosphate along with additive trisodium phosphate when applied at a dose of 0.4 ppm of phosphate-P in the high saline media. For the same type of treatment in low salinity level, a little reduced value of productivity was observed (chloropyll =13.9 mg/rrr'), The next effective treatment was rock phosphate with trisodium phosphate at a concentration of 0.4 ppm of phosphate-P, here a chlorophyll concentration of 13.6mg/m3 and 12.6 mg/rrr' were obtained in high and low salinities respectively. The minimum productivity levels were observed in treatments with rock phosphate alone in all concentrations, compared to other treatments. It could be concluded from the experiments the following i) single super phosphate with a combination of trisodium phosphate was most effective compared to rock phosphate with trisodium phosphate, which could be due to the greater solubility of single super ph~sphate ii) single super phosphate was found to be more effective than rock phosphate, which could be due to the grater solubility as already explained. iii) the concentration level of 0.4 ppm of phosphate-P was found to be the most effective in enhancing the primary production compared to the lower doses tried ie, 0.1 and 0.2 ppm. iv) along with an increase in the available phosphate from the added fertilizers there was an increase in the primary production also v) salinity was found to have some effect on production, higher the salinity grater the production. This can be due to the availability of other minerals and intrinsic factors required for the synthesis of chlorophyll and biomass.
Open Access
Studies on the maturation and reproduction of pristolepis marginata jerdon under captive conditions
(Department of Fishery Biology, College of Fisheries, Panangad, 2005) Nisha, Raj; KAU; Anna Mercy, T V
Pristolepis marginata Jerdon commonly called “Malabar catopra” or “Malabar sunfish” or “Chutichi” in the vernacular is an attractive ornamental fish belonging to the family Nandidae. This species, which is endemic to the Kerala part of Western Ghats inhabits clear and rapid streams. The species has been enlisted as vulnerable by – the Conservation Assessment and Mangement Plan Workshop (CAMP, 1998) for fresh water fishes of India held at NBFGR, Lucknow. Conservation of the endangered/vulnerable fishes cannot become successful without protection to the resources, which support the diversity and abundance. Hence Pristolepis marginata was one of the prioritized species for the development of captive breeding technology under NBFGR – NATP programme entitled “Germplasm inventory evaluation and gene banking of fresh water fishes of India”. Anna Mercy et al., (2003) developed the captive breeding technology for Pristolepis marginata. In the present study, an attempt was made to understand the maturation and reproduction of P. marginata in captivity. Captively reared fishes from the NATP project of College of Fisheries were utilized for the present study. A total of 209 fishes (12 to 149 mm) were used for the study of reproductive biology. A six-stage key was used for the classification of the maturity stages. The size at first maturity for females and females were found to be 54 mm and 72 mm SL respectively. Gross picture of distribution of ova stocks in the anterior, middle and posterior regions of the ovary remained almost the same except for the slight variation in the percentage composition of the mode. Based on the ova diameter frequency studies, P. marginata was found to be a multiple spawner, which release eggs in two or three batches. Absolute fecundity of the fishes ranged from 1102 (first time spawner) to 4965 (repeat spawner) in fishes of size range 66 to 80 mm SL. Number and size of eggs was found to be directly proportional to the size and age of the fish. Fecundity showed a positive linear relationship with the length and weight of the fish as well as to length and weight of the ovary. The reproductive organs of P. marginata were built on the usual percoid plan with paired ovaries and testis. The ovaries of P. marginata showed asynchronous development, in which oocytes at all the stages of development were present in the same ovary at the same time. During the spermatogenesis, there is a gradual decrease in size of different stages from spermatogonia to spermatozoans. Length – weight relationship values showed that the juveniles are exhibiting allometric growth pattern with ‘ b’ value equal to 2.83. Males also showed allometric growth pattern with ‘b’ value equal to 2.68. Females have shown isometric growth pattern with ‘b’ value equal to 2.94. Average relative condition factor values were higher in juvenile (1.43) due to the higher growth rate encountered during this stage of the life cycle. Males showed higher average relative condition value than females.
Open Access
Studies on temporal and spatial variations of circulation and hydrographic characteristics of Panangad region of the Vembanad Lake
(Department of Fishery Hydrography, College of Fisheries, Panangad, 2003) Vijayakumar, C T; KAU; Varna, K K
The objective of the study was to find the seasonal and spatial variations of different hydrographical factors of the Vcmbanad Lake around Panangad region and compare the situation with that of the other parts of the lake. Salinity, temperature, current velocity and direction, dissolved oxygen, primary production and nutrients like phosphate, nitrite and nitrate were the parameters studied. For this monthly observations of these factors were made from nine stations located in and around Panangad region of Vembanad Lake. Beside this tidal cycle observations were carried out from two stations to study the tidal variation of the factors. S.T.D. meter was used to measure salinity, and temperature and a current meter for the current measurements. Water samples from surface and sub surfaces were collected with a clean bucket and a Van Dorn bottle. The estimation of dissolved oxygen, primary production and nutrients were done by standard methods. Marked seasonal fluctuation was noticed in the temperature of different stations. Annual variation showed two maxima. The temperature was minimum during southwest monsoon and maximum during pre monsoon months. In general, the vertical thermal stratification was small. The salinity exhibited marked seasonal fluctuation and generally the monsoon months recorded very low salinity values. After that there was an increase, reaching the maximum in pre monsoon months. Some vertical stratification was noticed during certain months. The Dissolved oxygen values were low during pre monsoon months and the content was more at surface than at the bottom layers. There was high seasonal fluctuation In the phosphate concentration. It showed high concentration during pre monsoon period. Generally bottom layers showed higher phosphate concentration than the surface layers. In the case of nitrite high values were observed durin 118 the monsoon and low values during dry season. Nitrate concentration also showed seasonal variation and high values were observed during the monsoon and low values during pre monsoon. The nutrient concentration was more in the inner smaller arms of the study area, in general. These inner arms were vertically homogenous also possibly due to higher mixing generated by the friction of the sides. In the tidal cycle observations it is found that salinity showed an increase during flood tide and decrease during ebb tide. At both stations considerable reduction in flood current speed was observed during post monsoon, compared to pre monsoon. During pre-rnonsoon a comparatively well mixed condition was prevailed. Post monsoon observations indicated very clear salinity stratification. This was due to the effect of freshwater discharge, which continued during this season though at reduced rate compared to monsoon season. It is found that the tidal effect on temperature was not well marked. It can be seen that different hydrographic factors of Panangad region of the Vembanad Lake exhibited much seasonal and spatial variations and the trend was in general, same to that shown by other parts of the lake.
Open Access
Community changes in zooplankton and macrobenthos of a prawn culture field in relation to hydrographical conditions
(Department of Fishery Hydrography, College of Fisheries, Panangad, 2003) Shreeram Sudheer, Gubba; KAU; Cherian, C J
The present study was carried out in the prawn filtration field of the College of Fisheries at Panangad adjacent to the Cochin backwater system to find out the faunal variations of zooplankton and macrobenthos and to correlate them with the variations in hydro graphic conditions and compare the results with those obtained from the observations in the adjacent lake. Monthly samples for hydro graphical and biological studies were collected during the period from November 2002 to July 2003 from the culture field and adjacent backwater. Hydrographical features like temperature, salinity, transparency, pH, total alkalinity, dissolved oxygen, nitrate-N, phosphate-P, silicate-Si were observed. Crustacean larvae, copepods, tintinnids, nematodes, rotifers and veliger larvae of molluscs were the zooplankton groups obtained in the present study. Crustacean larvae and copepods were the dominant groups in both places and were found during all the months whereas tintinnids and nematodes were observed during saline period and their number decreased with decreasing salinity. Rotifers were recorded during low saline period only. Veliger larvae were recorded during December and February in the culture field, whereas, they were not present in the samples form the adjacent backwater. Statistical analysis for the influence of hydrographical parameters on the zooplankton showed that none of these had significant influence independently and the variations in the zooplankton abundance may be due to the combined effect of all these factors. Even though the seasonal changes in the total zooplankton were not pronounced the per cent composition of different groups showed fluctuation. Tanaidaceans, gastropods, polychaetes, amphipods, bivalves, isopods and chironomid larvae were the benthic groups obtained. Among these 112250 124 gastropods, tanaidaceans and polychaetes were the dominant forms. In the culture field benthic populations were maximum during the post-monsoon months and a showed a decreasing trend during pre-monsoon. With the onset of the monsoon they showed an increasing trend. In the backwater high benthic abundance was observed during January and February when high salinity prevailed and gradually decreased from March onwards reaching the minimum in July. In the culture field benthic abundance was mainly influenced by substratum characteristics and pH, whereas in the adjacent backwater salinity also played a role. The area of the present study is away from the barmouth and the nutrient levels especially phosphate is low in the culture field. This may be limiting the primary productivity of the area leading to low secondary production in terms of zooplankton and macrobenthos in the culture field. The high pH noticed in the culture field may be another reason for the low productivity.
Open Access
Development of Malaysian Type Fish Crackers From Nemipterus Japonicus (BLOCH)
(Department of Processing Technology,College of Fisheries, Panangad, 2001) Venugopal, Dubakula; KAU; Sajan, George
A study was undertaken for the preparation of fish crackers using a low cost fish, threadfm bream (Nemipterus japonicus, Bloch). A method was standardised for making crackers based on that generally followed in Malaysia. Fish meat was mixed with various food additives such as starch, salt, sugar, monosodium glutamate, colour and water, and stuffed into high-density polyethylene casings as rolls, cooked, cooled, sliced and dried.
Open Access
Studies on the electrophoretic pattern of Fish/ Shellfish proteins subjected to frozen storage
(Department of Processing Technology,College of Fisheries, Panangad, 2000) Bomy, Chummar; KAU; Nambudiri, D D
Freezing considered as an excellent process for preserving the quality of fish for longer periods. But freezing may affect various flesh components, especially the proteins. Sarcoplasmic proteins play a major role in species identification of fish and fishery products. While myofibrillar proteins play a major role in the jellying properties of surimi and surimi based products. The changes to these groups of proteins due to freezing and frozen storage have received much attention. Four species Megalaspis cordyla, Labeo rohita, Penaeus indicus and Parapenaeopsis styli/era were used for the frozen storage study. Samples were stored for 90 days at -18°C and samples were collected at 15 day. intervals and Salt Soluble Nitrogen (SSN), Water Soluble Nitrogen (WSN) and Non-Protein Nitrogen (NPN) content were determined. Electrophoretic pattern of both Salt Soluble Proteins (SSP) and Water Soluble Proteins (WSP) of frozen stored sample were compared with that of the fresh sample.
Open Access
Microbial risk assessment and process standardization for cook-chill fish and partially processed value added fish
(Department of processing technology, College of fisheries, Panangad, 2007) Anju; KAU; Namboodiri, D D
A study was undertaken for the preparation of cook-chill fish from Selar crumenophthalmus and partially processed value added fish from Oreochromis mossambicus and their microbial risk analysis. Standardization of processing technique for both products was done. Parameters standardized were brining conditions and blanching conditions for cook-chill fish. Standardization of brining condition was carried out for partially processed value added fish. Various brining conditions studied were brine concentrations of 3%, 5%, 6% for 5min, 10min, 15min and blanching at 75oC for 60sec, 90sec, and 120sec for cook-chill fish. In the case of partially processed value added fish brining concentrations of 1%, 2%, 3% for 5min, 10min, and 15min. Salt content and sensory evaluation were carried out, in case of cook-chill fish to select best blanching time. TPC values were determined. Based on the results the following treatments were selected. In the case of cook-chill fish brine concentration of 5% for 10min and blanching at 75oC for 90sec were selected. For partially processed value added fish the brine concentration of 2% for 10min was selected. Both products were packed and chill stored using ice at 4oC. Cook-chill fish was packed in polyethylene and heat sealed. Partially processed value added fish was vacuum packed in 12 polyester laminated with polyethylene 200 gauge. Control was used for comparative study. Control in the case of cook-chill fish (Selar crumenophthalmus) was fish fillets stored without any brining, cooking treatments. For partially processed value added fish (Oreochromis mossambicus), control was not given any brine treatment, was packed in polyethylene and heat sealed using electric heat sealer. During storage TMA, TVB-N, TPC and test for specific microorganisms were carried out. Results of quality parameters showed a greater shelf life of five days for test samples compared to the control in both the products.
Open Access
Quantification of ammonia excretion by selected five varieties of freshwater ornamental fishes
(Department of Aquaculture, College of Fisheries, Panangad., 2006) Senthamilselvi, A; KAU; Mohan, M V
Ammonia excretion of five species of freshwater ornamental fishes, platy (Xiphophorus maculatus), swordtail (Xiphophorus helleri), angelfish (Pterophyllum scalare), goldfish (Carassius auratus) and blue gourami (Trichogaster trichopterus). Fishes acclimated for two weeks were incubated for a specific period in closed containers and the ammonia excretion rates were determined. Ammonia was determined using phenol hypochlorite method. Regression analysis of ammonia excretion rate and weight showed that ammonia excretion rate increased with body weight. The regression coefficient of the relationship was 0.4320 in platy, 0.7534 in swordtail, 0.4851 in angelfish, 0.6309 in goldfish and 0.6518 in blue gourami. The weight specific ammonia excretion rate decreased with bodyweight and the slope of the weight specific ammonia excretion rate – weight relationship was - 0.5680 in platy, - 0.2466 in swordtail, - 0.5149 in angelfish, - 0.3691 in goldfish and - 0.3482 in blue gourami. The regression coefficient of total length- weight and standard length- weight relationship are 3.1031 and 3.0565 for platy, 3.1512 and 3.1454 in swordtail, 3.0331 and 2.9656 in angelfish, 2.6191 and 3.0328 in goldfish and 2.9721 and 3.0011 for blue gourami, respectively. The regression coefficients were significantly different from 3 in both the relationships. The weight specific ammonia excretion rate ranged from 0.0032 to 0.0640 g NH3-N/mg/h for platy, 0.0028 to 0.0140 g NH3-N/mg/h for swordtail, 0.0033 to 0.1309 g NH3-N/mg/h for angelfish, 0.0043 to 0.0525 g NH3-N/mg/h for goldfish and 0.0091 to 0.0394 g NH3-N/mg/h for blue gourami. Ammonia excretion rate and weight specific ammonia excretion rate were highest for blue gourami, followed by goldfish, angelfish, swordtail and platy but the weight specific ammonia excretion rate was highest in platy than swordtail for the smaller size group. Quantification of ammonia excretion for standard weight and length facilitates prediction of ammonia build up in a freshwater aquarium

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