समुद्र कृषि में व्यवस्था विश्लेषण और अनुरूपण नमूने

कृपया पूरा लेखा पढ

Production functions in mariculture.

Production function in aquaculture has received very little attention. An attempt has been made to evaluate the production function of mariculture systems. Production functions are generally based on growth and mortality. Numerous mathematical functions have been used to describe the age-weight relationship in cattle and poultry: however, little work has been done in modeling growth of organisms in aquaculture. The functions evaluated were Gompertz, Logistic, von Bertalanffy, Richards, modified Janoschek and polynomial growth equations. The Gauss-Newton and Quasi-Newton method of the nonlinear regression procedure of SYSTAT was used to estimate parameters of each function for individual weight-age curves. The growth models were used for the derivation of production functions along with no assumption on mortality and different assumptions of mortality like linear and exponential model. In the case of grey mullet Mugil cephalus logistic growth model gave the best fit while that for molluscs Crassostrea madrasensis and Pema v i^ is Gompertz growth curve was the best. The production function was estimated for the oyster data. It was found that the linear and exponential assumptions in mortality along with the Gompertz growth curve gave better results

उत्तरदायित्वपूर्ण मत्स्यन के लिए पारितंत्र आधरित प्रबन्धन

कृपया पूरा लेख पढे

Effects and consequences of small-scale cage culture technology adoption in Kerala

Small-scale fish farming is critical in ensuring food security and employment in many developing countries. Small-scale cage culture for Etroplus suratensis was introduced in the state by the Department of Fisheries, Government of Kerala with the same objectives. The demand for the species has shown considerable increase in the recent years and f m gate prices are as high as Rs 450kg in the peak season. Elevation to the status of State Fish has also helped the culture of the species in attracting the attention of policy makers leading to promotion of its culture. Cage culture in brackishwater bodies, a relatively new technology to the State, was popularized among the tsunami affected fishermen along with extension and technical support. The implementation of cage culture was promoted through the Brackishwater Fish Farmers' Development Agency (BFFDAs) and Agency for Development ofAquaculture Kerala (ADAK), two subsidiaries of the Department of Fisheries, Government of Kerala. The present study probes the effects and consequences of cage culture technology adoption among farmers based on primary data collected from sample respondents during the initial year of culture

Growth kinetic profiles of Aspergillus niger S14 a mangrove isolate and Aspergillus oryzae NCIM 1212 in solid state fermentation

Aspergillus niger is one among the many species of fungi thriving in mangrove ecosystem with potential for biotechnological and industrial applications. Understanding the growth profile and kinetics is of use in studying dynamics of mangrove ecosystem. In the present investigations, empirical equations and growth models commonly used in elucidating the dynamic nature of growth were fitted to the data of the biomass, protein and glucosamine levels during solid state fermentation (SSF) with wheat bran as substrate using Aspergillus niger S14, a fungal isolate from mangrove and Aspergillus oryzae NCIM 1212, an industrial strain. Linear, exponential, two-phase models, logistic equations, Richards, Michaelis-Menten, Weibull, Modified Gompertz and Morgan-Mercer-Flodin models were used. Among the models, logistic equation and Michaelis- Menten model could provide an adequate fit to the biomass variation for 21 days. The protein and glucosamine contents followed a different trend compared to the direct biomass measurements which made them inept for growth kinetic studies of the two fungal strains in SSF

Examining oral pre-exposure prophylaxis (PrEP) literacy among participants in an HIV vaccine trial preparedness cohort study

Background: PrEP literacy is influenced by many factors including the types of information available and how it is interpreted. The level of PrEP literacy may influence acceptability and uptake. Methods: We conducted 25 in-depth interviews in a HIV vaccine trial preparedness cohort study. We explored what participants knew about PrEP, sources of PrEP knowledge and how much they know about PrEP. We used the framework approach to generate themes for analysis guided by the Social Ecological Model and examined levels of PrEP literacy using the individual and interpersonal constructs of the SEM. Results: We found that PrEP awareness is strongly influenced by external factors such as social media and how much participants know about HIV treatment and prevention in the local community. However, while participants highlighted the importance of the internet/social media as a source of information about PrEP they talked of low PrEP literacy in their communities. Participants indicated that their own knowledge came as a result of joining the HIV vaccine trial preparedness study. However, some expressed doubts about the effectiveness of the drug and worried about side effects. Participants commented that at the community level PrEP was associated with being sexually active, because it was used to prevent the sexual transmission of HIV. As a result, some participants commented that one could feel judged by the health workers for asking for PrEP at health facilities in the community. Conclusion: The information collected in this study provided an understanding of the different layers of influence around individuals that are important to address to improve PrEP acceptability and uptake. Our findings can inform strategies to address the barriers to PrEP uptake, particularly at structural and community levels. Trial registration: https://clinicaltrials.gov/ct2/show/NCT0406688

Studies on Optimum Carrying Capacities of Mariculture Systems by Modelling Trophic Interactions

An attempt was made to construct trophic models of different aquaculture systems where shrimp was used as the key species of culture. The three different systems of culture viz., extensive system of aquaculture (where shrimp was cultured with crabs), modified extensive system (where shrimp and fish are stocked and fed with manufactured feed ) and polyculture system ( where shrimp was stocked along with different types of fish and mussel ) were modeled using the trophic modeling software ECOPATH. Two scenarios of each system i.e., initial (the day of stocking) and final (day of harvest) were created to know the ecological changes brought about by the aquaculture process. The different input requirements of the model were biomass, production per biomass, consumption per biomass, harvest details and diet compositions of all the organisms associated with the system. About 11 - 12 ecological groups were created in each system. On mass balancing ecological information of the species, ecosystem indices and flow indices were obtained. The results of the model give an overview of the resources found in the pond simultaneously and reveal the degree of trophic interactions. The ecotrophic efficiency (EE) of phytoplankton and detritus was very low in all the system showing that it is very sparsely utilized. Hence energy transfer from lower trophic level seemed to be very low. The cultured species had a high EE as they were completely harvested from the system. On comparing the initial and final model it was found that the final stages of the extensive system and polyculture system of culture was having better ecosystem stability while the modified extensive system was highly unstable. The relative ascendancy was high in modified extensive system indicating its unstable situation. Also the system overhead decreased showing a decrease in “strength in reserve”. The flow to detritus was found to increase in the modified extensive system where formulated feed was used. A hypothetical model was constructed by introducing mussels in the feed aquaculture system. On modeling it was found that the introduction of mussels could bring about better stability to the system as there was high variation in the ecosystem indices. Carrying capacity of the above modeled systems could be calculated and optimum stocking densities of the cultured species are also given