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Open Access
Genetic characterization, controlled breeding and development of transgenic varieties of puntius denisonii (day, 1865).
(Department of Aquaculture, College of Fisheries, Panangad, 2010) Manoj, C K; KAU; Mohanakumaran Nair, C
Puntius denisonii, a beautiful ornamental fish indigenous to the Western Ghats, which has been indiscriminately exploited from the different rivers of Kerala has been recently declared to be vulnerable by the IUCN. The population structure and genetic diversity of P. denisonii has not yet been studied and documented. Many previous attempts to breed this fish in captivity have yielded negative results. The increasing demand for this fish to decorate aquariums worldwide could be satisfied only by developing controlled breeding techniques and larval rearing of its fry. In the present study, the present population structure of P. denisonii has been studied combining both phenotypic and genotypic techniques. Fishes were collected from Irrity, Chaliyar and Periyar rivers of Kerala. Truss network analysis was conducted and the size adjusted morphometric variables were subjected to Principal Component Analysis and Canonical Variance Analysis. Scatter diagram and Dendrogram was plotted using PCA and CVA loadings. The Irrity and the Chaliyar populations were grouped on the positive sector of the PC and CV component showing morphological similarities between the two populations while the Periyar population was placed in the negative sector of the component separated far from the other two. The PC scores were used to find out the variables showing maximum variation between fishes collected from different rivers. RAPD PCR was conducted after isolating DNA from the fins of different populations of P. denisonii. Universal random primers were screened and the primers that produced reproducible bands were selected. Popgene analysis of the binary data yielded the genetic structure of different populations of P. denisonii. Number and percentage of polymorphic loci, Nei's (1973) gene diversity, Shannon's Information index Lewontin (1972), Nei's Unbiased Measures of Genetic Identity and Genetic distance and Dendrogram Based Nei's (1978) Genetic distance using UPGMA --Modified from NEIGHBOR procedure of PHYLIP Version 3.5 were studied. The results obtained supports the truss analysis in that the Irrity and Chaliyar populations in Northern Kerala are genetically more similar while that of Periyar population in Central Kerala are distinct. P. denisonii was successfully induced bred under controlled conditions with synthetic hormone preparations Ovaprim and WOVA-FH. Stress during transport and handling was minimized and live feed was supplemented to enhance maturation of the broodstock. The whole developmental sequence starting from fertilized eggs to hatching was photographed and documented. It took 29-30 hours for the eggs to hatch at 280C. Rearing of fry was successfully accomplished under laboratory conditions. In an attempt to develop transgenic varieties of P. denisonii, pCMV-GFP was electroporated into newly fertilized eggs, maintained in hypoosmolar electroporation buffer. The electroporation parameters that yielded best results were 20V, 3 bursts at 1 second interval. Fin clips were taken from the transgenic individuals reared for a period of 6 weeks. Dot blot test was positive showing integration of the GFP gene in P. denisonii, eventhough expression was not detected under blue or UV light. The genetic and phenotypic data of P. denisonii populations in the present study will aid as a base line for formulating conservation procedures to protect the genetic diversity of wild ones. Stock identification studies are recommended for more concise information on each population. Moreover, the larval rearing and controlled breeding techniques along with the genetic diversity studies will help to design captive breeding programs and enhance the production of hatchery bred ones to meet increasing demand. Further research is recommended for generating transgenic lines with uniform GFP expression.
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
Molecular taxonomy of selected species of macrobrachium bate, 1868 (DECAPODA, PALAEMONIDAE) of Kerala waters
(Department of Fishery Biology, College of Fisheries, Panangad, 2011) Jayaraj, G; KAU; Jayachandran, K V
Freshwater prawns of the genus Macrobrachium are a conspicuous and important prawn constitute one of the most diverse, abundant and widespread crustacean genera. They are distributed in different water bodies of the tropical and subtropical regions of the world and comprises over 200 described species (Jayachandran, 2001). The palaenonids have taxonomically difficult groups because they appear to be morphologically higher conservative and also greater confusion among the evolutionary status. The present study was carried out both on morphological and molecular data to investigate the confirmation of species status and finding phylogenetic relationship of selected species of Macrobrachium in kerala waters. The species of M. canarae, M. idella, M. latimanus and M. scabriculum were collected from different water bodies of kerala, such as hill streams, rivers and brackish water. The four species inhabit varied habitats: M. latimanus is a hill stream prawn; M. canarae inhabits valleys without migration; M. idella and M. scabriculum inhabits lower stretches of river with estuarine migrations. These species were accurately identified based on morphology of earlier literature done by Jayachandran, 2001 and it shows variations within the individuals of M. idella. The use of DNA based methods to infer phylogenetic relationship can potentially overcome some of the difficulties encountered through the use of morphological characters. In molecular part, 16S rRNA and COI genes of mitochondrial DNA were analysed. Sequences of 16S rRNA and COI were obtained and submitted to NCBI. Based on sequence information, M. canarae shows few minor variations within the individuals. M. idella is shows significant variations within the two types of individuals. M. latimanus is shows separate clades of other country species. M. scabriculum is also shows significant variation with NCBI sequence of M. scabriculum. Phylogenetic relationship is clearly shows two types of M. idella based on NJ and MP tree. Hence, both morphological and molecular data is very effective for finding species variants and phylogeny.
Open Access
Temporal variation in the hydrography and biodiversity of the Cochin backwaters of Puduveypu region.
(Department of Fishery Hydrography, College of Fisheries, Panangad, 2011) Trinayan Deb, Sarmah; KAU; Raman, N N
The study was carried out to find out the temporal variation in the hydrography of the Cochin backwaterS of Puduveypu region and to find out the richness of the biodiversity of the area. The study was conducted from April, 2010 to Apil, 2011. The present study was carried out to find out the temporal variation in the hydrography of the Cochin backwater of Puduveypu region and to find out the richness of the biodiversity of the area. The value of salinity in the backwaters of Puduveypu showed a wide fluctuation. The maximum value was recorded in the second half of January. The salinity showed considerable reduction during the period of March-April, 2011 due to Premonsoon showers. . Water temperature showed peak values during pre-monsoon period and with the onset of monsoon the value decreased. High pH was observed during the monsoon season while low values were observed during N.E. monsoon and pre-monsoon period. Alkalinity showed an increasing trend during the pre-monsoon, post monsoon and N.E. monsoon seasons but a decreasing trend was observed during monsoon season. Total hardness ranged between 22.22 mg CaCO3/l and 710.01 mg CaCO3/l. Dissolved oxygen showed high values during monsoon and post monsoon period. During the N.E. monsoon period the dissolved oxygen showed a decreasing pattern and reached a minimum of 2.1mg/l in the second half of February. The higher values of nitrate-N were observed during post monsoon and monsoon season. Seasonal variation of nitrite 133 was not that much pronounced. The phosphate value ranged between 2.2 μg at/l and 5.8 μg at/l during the study period. The maximum value of silicate-Si was recorded during the last phase of the monsoon. Turbidity ranged between 11.11 NTU and 40.4 NTU. It showed a negative correlation with transparency. Transparency value of the study region falls within a range of 30 cm. to 47 cm. Primary productions showed a wide range from 32 mgC/m3/day to 3707 mgC/m3/day. The highest value of chlorophyll was observed during the second half of July and the minimum value was observed during the second half of October. The sediment pH value ranged between 7.02 and 8.3 with an average of 7.78. The analysis revealed that sediment of the Puduveypu region contains maximum sand followed by silt and clay. Mangrove species like Rhizophora mucronata, Rhizophora apiculata, Rhizophora conjugate, Brugiuera cylindrical, Brugiuera gymnorhiza, Sonerasia caseolaris, Sonerasia alba, Avicennia officianalis, Exocearia agallocha, Acanthus ilicifolius, Clerodenterum innerme, Premma latifolia, and Acrostichum aureum were found in the study area. , Avicennia officianalis contribute 70% of the total population of mangrove. Penaeus monodon, P. indicus, Metapenaeus dobsonii, M. monoceros, Feneropenaeus indicus, Penaeus semisulcatus, Macrobrachium equidens, M. idella have been identified from the study area. Crabs in the study area include Scylla serrata, Scylla tranquebarica, Thalamita creneta, Charybdis annulata, Sesarma quadratum, Uca vocans. Bivalves includes Lamellidens 134 sp., Villorita Sp. and Cirriped in the study region include Balanus. 36 species of finfishes were collected during the study period. The fishes can be categorized into 10 order and 26 families.

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