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Open Access
Extent of adoption of scientific practices in prawn farming
(Department of Management Studies, College of Fisheries, Panangad, 1990) Sasikumar, P K; KAU; Pushkaran, P S
This study was undertaken to probe into the present situation of prawn farming in Kerala. The study aimed at assessing the communication media used for the dissemination of scientific prawn farming practices, the communication media utilized by prawn farmers at awareness and adoption stages, extent of adoption of scientific practices, correlates of adoption behaviour and the reasons for non-adoption or partial adoption of scientific practices. The study was conducted in Ernakulam district among 100 prawn farmers randomly selected. The data were collected through personal interview using a structured and pre-tested interview schedule. Appropriate standard statistical tools were used for analysis and interpretation. The extent of adoption was measured using the adoption quotient formula. Twenty four characteristics of prawn farmers were tested to find their association with adoption behaviour. The socio-economic variables studied were age, education, experience , land possession training participation, institutional credit utilization and income from prawn farming. The situational characteristics included total farming area, area under selective stocking , salinity, distance from bar mouth, average depth at high tide, average depth at low tide and number of crops raised. Scientific orientation, economic motivation risk preference, marketing orientation, extent of awareness of scientific practices in prawn farming and rationality in decision making were the socio-psychological variables tested. The communication variables studied were utilization of personal localite sources, utilization of personal cosmopolite sources and utilization of mass media sources. The study revealed that the extension communication media were very extensively used for the dissemination of scientific prawn farming technology. The most important individual method employed was farm and home visits. Other methods frequently employed were lectures, film shows, group discussions, training programmes and demonstrations. The farmers utilized more of personal localite sources, followed by personal cosmopolite and mass media sources for awareness as well as adoption. The mean awareness index of prawn farmers was 64.00 with majority of the farmers falling under the category of medium awareness. The mean extent of adoption of scientific practices was worked out , and majority of the farmers came in the medium category based on extent of adoption. Of the 19 scientific practices selected for study, all the practices except ‘acclimation of seeds’, ‘maintenance of dissolved oxygen level in the pond’ ‘monitoring and control of PH, control of algal blooms and ‘need based control of disease and parasites’ were heard by over 50 percent of the respondents. Only three practices viz. strengthening of buds and deepening of channels, fixing or repairing of sluice gate, and stocking the pond with selected prawn seeds were heard by all the respondents. Only two practices namely ‘strengthening of bunds and deepening of channels’ and ‘fixing or repairing of sluice gate’ were found fully adopted by 50 or above 50 percent of respondents. Highest full adoption was observed for the practices ‘fixing or repairing of sluice gate’. There was no full adoptes for the practices ‘maintenance of dissolved oxygen level in the pond’ ‘need based water exchange’ and ‘need based control of disease and parasites’. Highest partial adoption was observed for the practice ‘need based water exchange’ followed by ‘removal of aquatic weeds’, supplementary feeding based on biomass’ and ‘strengthening of bunds’ and ‘deepening of channels’. The partial adopters of these practices were 99 percent , 92 percent, 57 percent and 49 percent respectively. Important reasons for non-adoption and partial adoption of the practices were lack of awareness, lack of knowledge and non-adoption of the practice ‘stocking the ponds with selected prawn seeds’. Among the 24 variables tested to find out association with extent of adoption, only nine showed significant influence on adoption behaviour. The characteristics of prawn farmers which were found significantly contributing to extent of adoption were training participation, land possession, institutional credit utilization, area under selective stocking, number of crops raised, extent of awareness of scientific practices in prawn farming, rationality in decision making, utilization of personal cosmopolite sources and utilization of mass media sources. Multiple regression model fitted with the above nine variables illustrated that these nine variables together explained 86.82 percent of variations in extent of adoption. Further, the step-wise regression analysis revealed that the best subset of variables in predicting the dependent variables were utilization of personal cosmopolite sources, utilization of mass media sources and area under selective stocking. These three variables together explained 86.48 percent of variations in adoptive behaviour. Of the nine variables subjected to path – analysis all the variables except awareness of scientific practices in prawn farming and rationality in decision making had positive path coefficients. The indirect influence of the variables on extent of adoption were mainly channeled through utilization of personal cosmopolite sources and area under selective stocking.
Open Access
Growth response of penaeus monodon fabricus to pelleted feeds of different protein sources
(Department of Aquaculture, College of Fisheries, Panangad, 1991) Josekkutty, P A; KAU; Susheela, Jose
The efficiency and keeping quality of the five pelleted feeds formulated from different protein sources viz. clarm meal, prawn meal, slaughter house waste meal, soybean meal, single protein (marine yeast) were tested with a view to develop a suitable supplementary feed for Penaeus monodon The feeds were isonitrogeneous , crude protein content ranged from 39.76 to 40.3%) and isocaloric (Caloric value between 3.34-3.72 K.cal/g). The quality of the feeds over a period of four months of storage remained good, eventhough a slight reduction in nutritive value has occurred. P. monodon juvenile were reared for 6 weeks in experimental tanks with different artificial feeds the highest growth and survival were recorded in those fed with diet based on animal protein sources. Among the feeds tested, the clam meal based diet was found to be superior followed by diet based on slaughter house waste meal. The diet based on marine yeast was found to give better performance than those based on prawn meal or soybean meal. The food conversion ratios obtained with different feeds ranged from 2.18 to 3.26. The lowest FCR was recorded in diet based on clam meal (2.18) and the highest (3.26) in diet based on marine yeast. Protein efficiency ratios and protein digestability values were found to be higher in prawns fed with diet based on clam meal followed by diet based on slaughter house waste meal. Significant variations in the biochemical composition of prawns fed with diet based on different protein sources were recorded. Significant variation in oxygen consumption, ammonia, excretion and O:N ratios were recorded in prawns reared on different protein based diets. Highest oxygen consumption rate and lowest ammonia excretion rate were observed for diets based on animal protein sources than plant or single cell protein source. Among the different diets tested, diet based on clam meal recorded highest oxygen consumption, lowest ammonia excretion and highest O:N ratio values. The optimum food ration for P.mondon juveniles was found to be at 6% of the body weight while maintenance and maximum rations were 1.8% and 15% respectively for clam meal based diet. Food consumption, growth and survival of P.monodon increased, as feeding frequency was raised, however these parameters increased only upto an increase of 3 meal/day and there after they showed a declining trend.
Open Access
Utilization of prawn waste as pig feed
(Department of Animal Nutrition, College of Veterinary and Animal Sciences, Mannuthy, 1991) Syam, Mohan K M; KAU; Sivaraman, E
An investigation was carried out to assess the feeding value of prawn waste as a partial or complete replacement of unsalted dried fish in the rations for growing – finishing pigs. Thirty – two Large White Yorkshire weanling pigs with an average body weight of 9.1 kg were distributed randomly and uniformly as far as possible to four groups (Groups 1, 11, 111 and IV) of eight animals each, with regard to age, sex and body weight and housed in pairs of the same sex. The four dietary treatments A, B, C and D were allotted to the pigs in the groups 1, 11, 111 and IV respectively. Of the total protein, 25 per cent in the diets A, B and C and 12.5 per cent in the diet D were provided as animal protein. Unsalted dried fish was used as animal protein source in the diets C and D. Diet C formed the control diet. In the diets A and B, 50 per cent and 100 per cent replacements respectively of animal protein from unsalted dried fish were made using dried prawn waste. All the animals were maintained on the respective diets with 18 per cent total protein upto an average live weight of 50 kg and with 14 per cent protein till they attained a body weight of 70 kg or 8 months of age, whichever was earlier, when they were slaughtered to study carcass characteristics.
Open Access
Impact of training programme on hygienic measures followed in pelling sheds
(Department of Management Studies, College of Fisheries, Panangad, 1989) Daisy, C Kappen; KAU; Pushkaran, P S
The study was conducted in Quilon district of Kerala with a view to measure the impact of training programme on hygienic measures followed in peeling sheds. The major objectives were: 1. To study the level of knowledge about hygienic measuroe of trained peeling shed workers in comparison with those who have not attended the training programme. 2. To study the perception of the trained peeling shed workers about the quality of the product. • 3. To compare the association, if any, existing between the socio-psychological and economic factors of trained and untrained peeling shed workers with the level of knowledge and extent of perception. 4. To study the motivational factors responsible for attending the training programme by the peeling shed workers. The sample consisted of randomly selected 60 trained and 60 untrained peeling shed workers. Data were collected using interview schedule and suitable statistical techniques were employed for the analysis of data. The study revealed that the trained peeling shed workers had significantly higher knowledge than untrained peeling shed workers. They also had significantly higher perception about the quality of the product than untrained peeling shed workers. The peeling shed workers perceived the factor ‘Quality of the raw material’ as the most important one in determining the final quality of the product. The perception on the factors contributing to the final quality of the product were same for both trained and untrained peeling shed workers. The selected independent variables together contributed significantly in the variation in knowledge and perception about the quality of the product of both trained and untrained peeling shed workers. The correlation analysis revealed that education was positively and significantly related with level of knowledge of trained peeling shed workers; while age, occupation and family indicated negative and significant association. In the case of untrained peeling shed workers extension orienta¬tion is the only variable Which Indicated positive and signi¬ficant relationship with level of knowledge. Education showed positive and significant relationship with perception about the quality of the product of trained peeling shed workers. Age and occupation revealed negative and significant association. In the case of untrained peeling shed workers only age Indicated negative and significant relationship with perception about the quality of the product. Innovativeness was the major motive which induced the peeling shed workers to attend the training programme.
Open Access
Breeding biology of Villorita cyprinoides (Gray) in relation to salinity gradients
(Department of Fishery Biology, College of Fisheries, Panangad, 1991) Sudha, B Nair; KAU; Jose, T M
The present study was undertaken to investigate the influence of salinity variations on the breeding biology of populations of black clam Villorita cyprinoides (Gray), inhibiting two different cological zones of the Vembanad Lake. Two stations with perennial clam beds, but differing greatly in salinity conditions were selected for the study. Station I, in the northern side of Thanneermukkam barrier, has more influx of sea water and Station II, in the southern side has low saline influx. Monthly collections of black clams and bottom and surface waters were made from May 1989 to June 1990. Major environmental parameters such as salinity, temperature, dissolved oxygen and pH of bottom and surface waters were estimated with a view to understand the circannual variations within and between the stations. Among these, salinity was found to be the most important parameter showing prominent variations. At Station I, the bottom salinity values ranged from 0.0 to 18.12%0 and in Station II from 0.0 to 2.12%0. Histological studies of the clams collected from the two stations revealed that animals inhabiting Station I, a predominantly brackish water zone, have a protracted, almost year round breeding season extending from September to June with peak spawning during March to June and coinciding with the peak salinity levels and temperature. At Station II, a predominantly freshwater zone, the clams have a short duration spawning season extending from March to June with peak spawning during Apirl and May, again coinciding with the peak salinity levels and temperature. It is also observed that there exists a positive correlation between the bottom salinity and gondal maturation and spawning. Size – frequency studies of the calms collected from the two stations revealed that at Station I, the clam fishery was dominated by small sized animals, when compared to Station II. This may be related to the differences observed in the extend of spawning activity between the population of the two stations, resulting in the divergent apportionment of energy resource for somatic growth versus reproduction.
Open Access
Secondary production in brackish water culture ponds
(Department of Aquaculture, College of Fisheries, Panangad, 1988) Aneykutty Joseph; KAU; Jayasree Vadhyar K
Secondary production of zooplankton and zoobenthos (macrobenthos and meiobenthos) of two brackishwater ponds, A and B, each having 0.042 hectare area and connected to the Cochin backwaters, in the instructional fish farm of College of Fisheries, Panangad, Cochin have been studied for three culture periods. Viz, culture I.C. chenos (120 days, during August to December, 1986), culture II. P.indicus (60 days, during January to March, 1987) and culture III.P. monodon (45 days, during mid May to June, 1987). Fortnightly fluctuations in the biomass of zooplankton, meiobenthos and macrobenthos both group wise and total, their percentage dominance and frequency of occurrence have been studied during each culture period. Attempts have been made to correlate the fortnightly biomass of zooplankton, meiobenthos and macrobenthos with the fortnightly growth increment of C.chanos, P. indicus and P.monodon separately. Since zooplankton production is mainly dependent on primary production, fortnightly estimations of net and gross primary production have been carried out. The physic-chemical parameters of the pond water and soil have been studied fortnightly since both primary and secondary productivity of a culture pond depends mainly on these variables. The zooplankton groups are constituted by rotifers copepods and crustacean nauplii. The total biomass of zooplankton ranges from 22.388 mg/m3 to 5476.950 mg/m3 and 5.085mg/m3 to 1316.832 mg/m3 in ponds A and B respectively. The zooplankton biomass shows three peaks i.e., 1) in November 2) in March and 3) in June in pond A during culture I,II and III respectively while in pond B, it does not show such pronounced peaks. Neverthless, small zooplankton peaks are apparent in pond B in the former half of September, February and May during culture I ,II and III respectively. The relationship between the fortnightly biomass of zooplankton and that of growth increment of C. chanos is mostly an inverse one which could be because of the grazing effect of the latter on the former. An inverse relation is also observed between the biomass of zooplankton and growth increment values of P.indicus and P.monodon. Since the prawns are benthic feeders such an inverse relation cannot be attributed to direct consumption of zooplankton by them. However, zooplankton on dying sink to the bottom and form part of the detritus, constituting direct food for the prawns. The meiobenthos in both the ponds is constituted by nematodes and copepods. The total biomass of meiofauna ranges from 36.018 µg/10cm2 to 2539.322 µg/10cm2 in pond A and from 57.882 µg/10cm2 to 1556.616 µg/10cm2 in Pond B. A direct correlation is observed between the biomass of meiofauna with growth increment values of C.chanos whereas an inverse relation is noted between the former and the growth increment value of P.indicus and P.monodon. This suggests that meiofauna may not from direct food to C.chanos while it may be the contrary to the prawns. The macrobenthos is composed of amphipods, tanaids, polychaetes and mollusks. The total biomass of macrofauna groups ranges from 0.035 g/m2 TO 43.074 G/M2 in pond A and from 0.144 g/m2 5.712 to g/m2 (excluding villorita cyprinoides var.cochinensis) in pond B. One peculiarity observed in pond B is the presence of thick bed of black clam V. cyprinoides var. cochinensis during all the culture periods. A direct correlation between the fortnightly biomass of macrofauna with growth increment of C.chanos during the former half of culture period and inverse relation during the latter half of culture period are observed . this may be attributed to the utilization of macrofauna by c.chanos during the later stages of their growth. This supports the previous views put forward by several authors. An inverse relation is observed between the fortnightly biomass of macrofauna and growth increment values of P.indicus as well as P.monodon. This is in agreement with the views of several authors which highlight the utilization of macrofauna by the prawns. Fortnightly observations on primary productivity of phytoplankton as well as physic – chemical parameters of pond water and soil have also been discussed in general.
Open Access
Effect of sedatives on penaeus monodon fabricus seed under oxygen packing for transportation
(Department of Aquaculture, College of Fisheries, Panangad, 1991) Joshi, K; KAU; Jayasree Vadhyar, K
The study was performed with the objective of selecting a sedative at a suitable dose and testing its effect along with other factors viz. packing density, salinity and temperature on the P.mondon seed under oxygen – packed transport conditions. The selection of a sedative at an appropriate dose, from those tried viz. chloral hydrate, MS-222 and tertiary butyl alcohol, was made by conducting statistically designed experiments on the survival of the treated and untreated prawn seed for 72 hours in open containers and on the metabolic activities of the treated and untreated prawn seed for 2 hours. The experiment to find out the effect of the selected sedative was carried out in specially designed hard plastic containers fitted with facilities fpr packing oxygen under uniform pressure. The experiment was conducted as an asymmetrical factorial experiment with 4 levels of packing density (200/1, 400/1, 600/1 and 800/1) and 2 levels of sedation (without and with sedation), salinity (25 ppt and 20ppt) and temperature (29+ 10C and 23 + 20C). Chloral hydrate was selected at a dose of 400 ppm for application on P.monodon post –larvae under oxygen – packed conditions. The application of chloral hydrate on the prawn seed under oxygen packing at the selected dose evidently showed a negative effect. A lower dose (300 ppm) than the selected dose, studied separately, also showed similar results under oxygen packing . An increase in packing density decreased the time of initial mortality and percentage survival. At packing densities of 200/1, 400/1, 600/1 and 800/1, the safe durations of transport (duration of 100% survival) were 7.5 h,5 h, 3.5h and 2.5 h respectively at ambient temperature of 29+ 10 C. In P.monodon seed transport the number of seed has been found as more important than their weight in deciding the survival. A high salinity of 25 ppt was found better than a lower salinity for P.monodon seed transport. Lowering of temperature of the packing medium, rather than applying sedatives or lowering of salinity, has been found as a suitable method for increasing the survival during oxygen – packed transport of P.mondon seed. At the lowered temperature of 23+ 20C significantly longer duration of 100% survival (15h at 200/1 and 5 h at 800/1) and better percentage survival at 24 hours (92.5% at 200/1 and 83.13% at 800/1) than at the ambient temperature could be observed.
Open Access
Studies on texture and collagen content of commercially important tropical fishes
(Department of Processing Technology, College of Fisheries, Panangad, 1991) Femeena Hassan; KAU; Sajan George
Stroma proteins refer to slightly soluble proteins which are obtained after removing water and salt, soluble proteins in the muscle. The main constituent of stroma protein is collagen. The role of collagen in contributing to the texture and gaping of fish fillets has been studied using six commercially important fish species of India VIZ. sardine (SardineIla lonqiceps) ,mackeral ( RastralIiger kanaqurta ) , tilapia ( Oreochromis mossambicus ) , common carp (Cyprinus carpio), tuna (Euthynnus affinis) and shark (Scoliodon sorrakowah). The texture of raw fish meat was found to be influenced by the content of collagen in fish muscle. A significant correlation (P > 0.05) was obtained between soluble, insoluble and total collagen contents, and toughness of raw meat, as determined by sensory evaluation and two types of texturometers. Significant correlation was also obtained between actomyosin content and toughness of raw meat, determined either by subjective or objective methods (P > 0.05), but not to the extent of soluble or total collagen. In the case of cooked meat , although a significant correlation (P> 0.05 ) was obtained between actomysin content and cooked meat toughness ,no such correlation could be established between collagen content and cooked meat toughness. Stroma proteins seem to be important in deciding the texture of raw meat, whereas, In the case, of cooked meat, myofibrillar proteins are probably involved. The gaping phenomenon was studied in frozen fillets stored for a period of three months. A slight increase in gaping was noticed during storage period. However, this was not found to be statistically significant. Further studies have to be carried out to get a clear cut idea about the influence of collagen on gaping phenomenon in frozen stored fish. The two types of texturometers fabricated, spring - operated and weight - operated, were found suitable for assessing the toughness of raw fish meat, but not. Cooked meat.

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