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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
Growth and survival of penaeus monodon in monosex and mixed sex culture under laboratory condition
(Department of Aquaculture, College of Fisheries, Panangad, 2008) Bajaniya Viralkumar, Chhaganlal; KAU; Mohanakumaran Nair, c
Sexual dimorphism is apparent in the black tiger shrimp, Penaeus monodon with females achieve larger size than the males. This character may be attributed to behavioral and/or physiological differences between the sexes. An experiment was developed to determine if there were advantages in rearing all female or all male P. monodon as opposed to mixed-sex populations. Juvenile shrimps (4.46±0.54 g) were collected from earthen pond and individually hand sexed and stocked in the circular cement tanks. Treatments all male, all female and mixed-sex were stocked @ 8 nos./tank. Each treatment had five replicates. The shrimps were offered commercial shrimp feed. The experiment was conducted for a period of 50 days. At harvest, all female shrimps had shown significantly higher growth than all male and mixed-sex treatment. Survival was not significantly different among treatments. FCR of all female was significantly lower than the all male and mixed-sex treatment. Result of the present study demonstrates a benefit to all female culture of P.monodon against the all male or mixed-sex culture. Thus culture of all female may be commercially more attractive to entrepreneurs. Although additional research is required to find a reliable and quick procedure for separation of the sexes or techniques for the production of all female populations.
Open Access
Reproductive biology of macrobrachium canarae ( tiwari, 1958 ) (decapoda, palaemonidae)
(Department of Fishery Biology, College of Fisheries, Panangad, 2008) Sreedevi, K H; KAU; Jayachandran, K V
The aim of this project is to introduce the freshwater prawn Macrobrachium canarae (Tiwari, 1958) as a candidate species in a community aquarium. The orange red shining spot on the second cheliped where the movable finger joins with palm makes it appealing in the aesthetic sense. This species is found to breed in captivity also. For the effective management of the prawn in the aquarium, a thorough knowledge on the various aspects of its reproductive biology is a prerequisite. The various aspects of reproductive biology dealt with are 1. Taxonomy 2. Sexual dimorphism 3. Breeding dress 4. Maturity stages and ovarian development 5. Fecundity 6. Moulting Since the species do not exhibit sexual dimorphism in size, it is difficult to identify male and female. The difference in colour of antennular flagellum between sexes becomes useful especially when they are bred in captivity. The data on maturity stages and also the time of ovarian development finds its use especially in the aquarium rearing. The fecundity studies gives an idea of the number of offsprings which could be produced from a single brood .
Open Access
Ovararian maturation, breeding and early embryonic development of an indigenous ornamental cyprinid of the western ghats - chela fasciata silas
(Department of Fishery Biology, College of Fisheries, Panangad, 2008) Indira, Divipala; KAU; Anna Mercy, T V
Chela fasciata is an indigenous ornamental cyprinid endemic to the Western Ghats of Kerala. It inhabits the riffle zones of River Bharathapuzha at Thootha. A total of 144 fishes (94 females and 50 males) ranging in size from 26.0 to 82.0 mm were collected from the wild and used for the study of reproductive biology. The gonads were quantified into six maturity stages based on external morphology as immature virgin, maturing virgin, early ripening, late ripening, ripe and partially spent. Studies on oocyte distribution of the six stages of maturity were done to understand the maturation of ova in the ovary. The ovaries of Chela fasciata showed asynchronous oocyte development. The oocyte development was classified into nine different oogenic stages namely, chromatin nucleolus stage, early perinucleolus stage, late perinucleolus stage, yolk vesicle stage, primary yolk stage, secondary yolk stage, tertiary yolk stage, migratory nucleus stage and mature oocyte). The first mature females appeared in the length group of 40 – 45 mm and males in the group of 25 – 30 mm. The size at first maturity for female was found to be at 45.75 mm TL (45 – 50 mm) and for males at 36.25 mm TL (35 – 40 mm). All the females were mature by 60.00 mm TL and the males by 45.00 mm TL. Based on the ova diameter frequency study of the ripe ovary, Chela fasciata was found to be a multiple spawner, with a protracted spawning season, the individuals spawning intermittently. Absolute fecundity of the fishes ranged from 2669 to 4437 in fishes of size range 49.5 mm to 82 mm TL. The number and size of eggs were found to be directly proportional to the size and age of the fish. Fecundity showed a positive linear relationship (5% level of significance) with the length and weight of both the fish and ovary. The embryonic development studies showed that the cleavage stage of the egg lasted for about 2 hrs 10 min., post fertilization. The inside egg embryo stage had lasted for 21 hrs, post fertilization. The eggs hatched at the end of 21 hrs, and the embryos emerged tail first. Pigmented eye was seen in one-day-old free embryo. Free embryo stage lasted for three days post fertilization. By the end of third day, the mouth developed, the yolk sac was empty and the exogenous feeding started, the free embryo entering the larval period. A complete understanding of basic reproductive biology of this fish will definitely help in the commercial production under captivity for the domestic and export market of this indigenous ornamental fish.
Open Access
Studies on electrophoretic identification of fish species used in surimi(products) and their quality evaluation
(Department of processing technology, College of fisheries, Panangad, 2008) Mathivanan, A; Nambudiri, D.D
SDS-PAGE pattern of water soluble proteins and salt soluble proteins of raw fillets, surimi, sausage and different combinations (1:1; 3:1; 1:3; and 4:1) of surimi mixtures; sausage mixtures from the two species of fish, threadfin bream (Nemipterus japonicus), and bulls-eye (Priacanthus hamrur) were studied to see that whether these pattern are useful in identifying the species used for the preparation of surimi and sausage; and their quality evaluation. SDS-PAGE gave the effective species-specific pattern of raw fillets, surimi, sausage and surimi mixtures; sausage mixtures of extract of water and salt soluble proteins of threadfin bream and bulls-eye separately. Threadfin bream and bulls-eye were effectively identified by using their SDS-PAGE pattern of extract of water soluble proteins and salt soluble proteins separately. Threadfin bream and bulls-eye surimi and sausage were also effectively identified by comparing their SDS-PAGE pattern with species-specific SDS-PAGE pattern in their extract of water soluble proteins and salt soluble proteins separately. The SDS-PAGE pattern of water soluble proteins and salt soluble proteins were shown in this study to be effective in distinguishing the species specificity between threadfin bream and bulls-eye of raw fish fillets, surimi and sausage samples. Adultered/substituted species in the different mixture were identified by comparing their mixture SDS-PAGE pattern with species-specific SDS-PAGE pattern in their extract of water soluble proteins and salt soluble proteins separately. Different mixtures species-specific SDS-PAGE protein patterns can be used with reservation to detect/differentiate the adulteration/substitution in the fish mixtures, surimi and sausage when these two species mixed with the combinations of 1:1; 3:1; 1:3 and 4:1 ratios. The quality evaluation study showed that surimi, sausage and surimi mixtures; sausage mixtures of threadfin bream and bulls-eye used for the experiment were of good quality.
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
Influence of cryoprotectant levels on storage stability of surimi from a tropical fish, Nemipterus japonicus (Bloch) and quality of surimi-based products
(Department of Processing Technology, College of Fisheries, Panangad, 2009) Parvathy, U; KAU; Sajan, George
A study was undertaken with the aim of reducing the concentration of cryoprotectants in surimi without adversely affecting stability of the material during frozen storage. The concentration of sugar in commercially produced surimi is generally about 8% which may result in high sweetness in the products prepared. A tropical fish, Nemipterus japonicus (Bloch) was used as the raw material. Minced fish meat was strained, water leached, mixed with different levels (0%, 2%, 4%, 6% and 8%) of sucrose-sorbitol mixture in 1:1 ratio, quick frozen at -35 oC and frozen stored at -20 oC. Water leaching resulted in a slight absorption of water by meat and reduction in protein, fat and mineral contents. Surimi was found to have a moderately white colour. Sensory evaluation studies were conducted on three products, viz., sausage, patty and cake, prepared using surimi containing different concentrations of sucrose-sorbitol mixture. Sugar content varying from 0% (control) to 4% in surimi resulted in products that were more acceptable to the taste panelists compared to those prepared using surimi with 6% and 8% sugar mixture. A slight sweetness in the product (2% to 4% sugar in surimi) was more preferred by the panelists than their respective controls prepared using surimi containing no sugar. Frozen storage studies were carried out at -20oC on surimi treated with various concentrations of sugar mixture as mentioned above for a period of five months. pH and total plate count remained nearly steady for all sugar concentrations and throughout the storage period indicating insignificant microbial activity. Moisture content appeared to remain constant during storage, but decreased with increase in sugar concentration probably on account of addition of the sugar mixture. The salt soluble nitrogen content of surimi and gel strength of sausage prepared from it decreased with storage period in all surimi samples, and increased with sugar concentration, while expressible water content of the sausage showed an increasing trend with storage period and a decreasing trend with cryoprotectant concentration. These indicate a greater extent of protein denaturation occurring at low concentration of surimi samples. Sensory evaluation parameters - elasticity, sweetness and preference - remained more or less steady during storage. However, elasticity of sausage prepared from surimi with no cryoprotectant (control) and with 2% sugar level showed a decreasing trend with storage. Elasticity and sweetness increased while preference decreased with cryoprotectant concentration. Elasticity and gel strength seemed to be much lower for control (1.7 and 783.71 g.cm, respectively) compared to even the lowest concentration of sugar (2%) used (2.6 and 886.9 g.cm, respectively). From the study it may be concluded that a concentration of 2 to 4% sucrose-sorbitol mixture is well accepted by the consumers in products such as surimi sausage, patty and cake. At this range of concentration, surimi can be well-preserved in frozen condition at -20oC for at least five months.

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