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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
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.
Open Access
Studies on drying of fish using a BARC - TYPE solar dryer.
(Department of Processing Technology,College of Fisheries, Panangad, 2011) Vimaladevi, S; KAU; Sajan, George
A study was conducted with the aim of evaluating the drying efficiency of a newly designed solar dryer (modified BARC type) in comparison with conventional sun drying. The materials used for drying were beheaded prawn (Metapenaeus dobsoni) and salted fish (Cynoglossus macrostomus). Rate of drying was found to be influenced by the atmospheric temperature and humidity, either using dryer (test or by sun drying (control). In the case of prawn, the drying period was 7h by dryer compared to control which took about 10h whereas in the case of fish it was only 7h compared to control which took about 9h. Various parameters such as moisture content, water activity, TPC, TFC, TVBN content and PV, during drying were monitored. The quality variations in prawn or fish were significantly lower when dried using the solar dryer compared to direct sun drying. Sensory evaluation based on colour, odour, texture and taste, also proved that the solar dried samples were of superior quality compared to control. Sorption isotherm for test and control did not vary much in shape for both prawn and fish. This indicates that the effect of the type of drying on the bound water of the products. For conducting storage studies the dried prawn and dry salted fish, both test and control, were packed in low permeable polypropylene- polyamide bags and stored at room temperature for about 80 days. Quality parameters, viz., moisture content and water activity, TPC, TFC, TVBN content, PV and sensory evaluation based on colour, odour, taste and texture were evaluated during storage. Both test and control samples remained acceptable throughout the storage period. However, the quality of prawn or fish dried in solar dryer was found to be superior compared to their respective sun dried control samples. The additional cost was only Rs 2.40/ kg for dried prawn and Rs 2.00/ kg for dry salted fish. The equipment is recommended for small scale production of dried 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.
Open Access
Ecology of mangrove patches in the Vembanad lake at Panangad
(Department of Fishery Hydrography, College of Fisheries, Panangad, 2009) Sukam, Monalisha devi; KAU; Raman, N N
The present study was carried out in mangrove area and backwater connected to the backwater through a sluice gate where mangrove patches are present. The study was undertaken in order to identify the floral composition, fishes, prawns, crabs and molluscs found in the area. The seasonal changes of hydrographical parameters like DO, pH, water temperature, alkalinity, salinity, primary productivity, silicate-silicon, phosphate-phosphorus, nitrite-nitrogen and nitrate-nitrogen and the sediment characteristics like sediment pH, total organic carbon, sediment texture were also studied. The mangrove species found in the study area were identified. Water temperature was minimum during south-west monsoon and maximum was during pre-monsoon. Average water temperature was lesser in mangrove area. Negative correlation was found between dissolved oxygen and all the nutrients. Through out the study period pH was alkaline. pH increased with increase in salinity and alkalinity. Dissolved oxygen was high during monsoon when compared with pre-monsoon period. It decreased with increased in salinity. Maximum salinity recorded during pre-monsoon when there was less freshwater intrusion. Average salinity was higher in backwater. Salinity showed negative correlation with all the nutrients. Alkalinity minimum value was observed during south-west monsoon it increases in post-monsoon and attained maximum during pre-monsoon. Alkalinity is higher in mangrove area. Primary productivity was maximum when light intensity was maximum. Average concentration of nutrients was higher in mangrove area. Maximum concentration was seen when inflow of freshwater was more. Sediment pH was minimum during pre-monsoon. Average sediment pH was lower in mangrove area than to backwater. Average Total organic carbon was maximum during post-monsoon in mangrove area and backwater. Sediment texture showed that substratum was silty sand in both the stations. When sand percentage increased total organic carbon was lowered. t-Test was done to compare significant difference between mangrove area and backwater. It showed that there was no significant difference with any of the hydrographical parameters between the two stations except primary productivity. ANOVA was conducted separately for two stations to compare significant difference between three seasons- monsoon, post-monsoon and pre-monsoon. In mangrove area pH and dissolved oxygen did not showed significant seasonal difference. In backwater water temperature, phosphate and nitrite did not show any seasonal difference. Dominant mangrove plants include Rhizophora mucronata, Brugiuera gymnorhiza, Brugiuera cylindrica, Avicennia officinalis, Acrostichum aureum, Acanthus ilicifolius. Prawns and crabs were abundant. Among prawns Fenneropenaeus indicus was caught through out the study period. Among crabs Scylla serrata and Uca spp. were commonly found. Balanus, Lamellidens sp., Villorita sp. were also seen in the study area. 30 species of fishes were identified from the study area and major contribution was by fishes belonging to the Order Perciformes. Mostly juveniles contributed to the fish catch.
Open Access
Structure and the seasonal changes of the macrobenthic community in relation to the hydrography of a prawn filtration pond
(Department of Fishery Hydrography, College of Fisheries, Panangad, 2009) Jayasree, P S; KAU; Raman, N N
Present study was carried out in the prawn filtration pond of the College of Fisheries adjacent to Cochin backwater to find out the seasonal variation of macrobenthos and to correlate them with the seasonal variation in hydrographical parameters and sedimentary characteristics of the pond. Fortnightly samples for hydrographical parameters, sedimentary characteristics and biological studies were collected during the period from October 2007 to September 2008. Hydrographical parameters like salinity, water temperature, turbidity, pH, total alkalinity, hardness, nutrients, dissolved oxygen, primary production, chlorophyll – a and transparency were observed. Polychaetes, tanaids, amphipods, bivalves and gastropods were the benthic groups obtained. Prawn juveniles and cumaceans encountered very rarely, during the study period were grouped as ‘others’. Among these gastropods, tanaids and polychaetes were the dominant forms. In the culture field, benthic populations were maxi mum during post monsoon months and showed a decreasing trend during pre monsoon and with the onset of monsoon it further decreased. Gastropods were the most dominant group observed during pre monsoon, forming 80% of total macrobenthos. Tanaids were the second major group and they were the dominant group during the post monsoon period forming 54% of total macrobenthos. Polychaetes were the third major group and constituted 35% of total macrobenthos during monsoon season and they were the second maximum during that period. In the culture field benthic abundance was found to be mainly influenced by substratum characteristics. Among the different hydrographical parameters studied for seasonal variation, water temperature, pH, primary production and chlorophyll were found to be significantly different. Among the sedimentary characteristics studied for seasonal variation, sediment pH was found to be significantly different.
Open Access
Influence of hydrographical parameters on the composition and seasonal variation of the plankton population in a prawn filtration pond
(Department of Fishery Hydrography, College of Fisheries, Panangad, 2009) Maya, Ramachandran; KAU; Raman, N N
The present study was carried out in the prawn filtration pond located in the campus to study the influence of hydrographical parameters on the plankton population. Fortnightly samples were collected for the analysis of hydrographical parameters like salinity, water temperature, turbidity, pH, total alkalinity, total hardness, nitrate, phosphate, nitrite, silicate and dissolved oxygen. Samples for biological parameters like primary production, chlorophyll, phytoplankton and zooplankton also were collected fortnightly. Salinity increased with increase in alkalinity, hardness and pH. Highest average for salinity and pH occurred in postmonsoon. The peak temperatures were recorded during premonsoon which started showing declining trend with the onset of monsoon. But turbidity was highest during southwest monsoon due to runoff and churning up of the pond bottom due to low depth. Alkalinity and hardness showed correlation with pH indicating the presence of calcium and magnesium. Nutrients were effectively recycled in the pond due to shallow depth. This resulted in the absence of significant variation between postmonsoon and premonsoon. Throughout the study period due to the perennial nature of the pond and high primary production, dissolved oxygen values were high. Primary production values were high in premonsoon due to high light intensity and effective nutrient recycling. Chlorophyll and salinity showed correlation and might be due to the presence of euryhaline phytoplanktons in the pond. Total phytoplankton count was high in monsoon. The total zooplankton was limited in quantity and quality. The total zooplankton was maximum in premonsoon months. But no decrease was seen during monsoon. Major groups encountered were copepods, crustacean larvae, tintinids, nematodes, rotifers and veliger larvae. Copepods dominated the zooplankton and maximum number was collected during southwest monsoon. Crustacean larvae occupied the second position and were present in all the three seasons. Tintinids and nematodes were observed in high saline period and their number decreased with decrease in salinity. Rotifers were recorded during low saline period only. Veliger larvae were recorded during December, January and February. Total zooplankton did not show any significant correlation with hydrographical parameters except temperature and pH.
Open Access
Genetic variation in wood basic density and moe and their relationship with growth traits in teak (TECTONA GRANDIS L.F.) grown in seed orchards of Kerala
(College of forestry, Vellanikkara, 2016) Jilijith, K P; KAU; Anoop, E V
A study on the variation in wood basic density and dynamic modulus of elasticity of teak (Tectona grandis L.f.) trees grown in tree improvement trials at various locations in Kerala using destructive and nondestructive testing (NDT) methods was conducted in the College of Forestry, KAU, Vellanikkara, Thrissur during the period 2012-2015. The investigation focused on the variation in physical and mechanical wood properties of teak, and to understand their relationship with growth traits and evaluating the suitability of NDT methods as predictors of timber properties under field conditions. Pilodyn (6J) and Treesonic Microsecond Timer (FAKOPP) were the two NDT equipments used in the study. Teak logs collected from a forest plantation (Elival, Palakkad) were destructively analysed following nondestructive testing with the above equipments. Discs and logs were analysed for within tree variation in Pilodyn pin penetration depth (PPD) and were further subjected to various mechanical tests using UTM as well. Significant variation in mechanical properties, and Stress Wave Velocity (SWV) was observed between the trees sampled. Most of the mechanical properties assessed destructively were found to be highly correlated with SWV. PPD in the periphery of the trees was related to the same in the middle portion of the trees. Pilodyn readings also correlated well with the actual wood basic density analysed destructively. In general, both the NDT instruments were found to be useful in estimation of the respective properties using regression analysis. In standing trees of a CSO (Walayar, Palakkad), an SPA (Nilambur) and two clonal trials (Chettikkulam and Vellikulangara, Thrissur) non-destructive evaluation was repeated. The study revealed high genetic divergence in the wood traits and indicated greater scope for application in tree improvement trials. Growth traits didn’t show any consistency or trend with the differing age of the plantations, nor any convincing relationship with the wood traits. Clusters were also identified for the clones at Walayar and Chettikkulam based on which selection for further breeding programmes can be undertaken

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