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Theses

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2010 - 20112
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Subject: Aquaculture × Author: KAU × End date: 2012 × Start date: 2010 × Type: Thesis × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Survey and disease surveillance of newly introduced L. Vannamei (Boone, 1931) in India
    (College of Fisheries, Panangad, 2011) Roshan Maria, Peter; KAU; Devika, Pillai
    P. monodon (tiger shrimp) was the most preferred cultured species in India, but repeated occurrence of diseases especially white spot disease (WSD) caused by white spot syndrome virus (WSSV) had a severe setback to the shrimp culture industry. This prompted the industry to actively promote the introduction of a non-native species, the Pacific white shrimp, Litopenaeus vannamei, as an alternative to P. monodon for commercial aquaculture operations in the country. The authority to issue licenses to take up L.vannamei culture was vested with the Coastal Aquaculture Authority (CAA), who issued licenses for 1,208 aqua farmers in 2009. Availability of SPF stock, ability to grow well even at high stocking densities, reduced days of culture (DOC), lesser protein requirement (28-35%) and demand in the international market attracted aquafarmers to switch to culture of L.vannamei. A survey carried out in the Nellore district of Andhra Pradesh to understand the level of acceptance and the nature of culture practice among the farms culturing L.vannamei revealed that only 33% of the farms surveyed had obtained permission from the CAA, 41% followed biosecurity measures and merely 10% had the facility for Effluent Treatment System. 53% practised chlorination and de-chlorination of water during water exchange and only 38% farms maintained trained personnel. It was observed during the survey that only 84% procured tested SPF seed from certified hatcheries. While 90-92% of yhe farms depended on pelleted feed, only 80-85% of the farms surveyed carried out regular monitoring every 1-2 weeks. Disease surveillance in the farms surveyed did not detect the presence of any of the major shrimp viruses (WSSV, IHHNV, MBV, HPV and TSV) in the 60 samples screened using molecular methods. However, Vibrio sp. was detected in samples exhibiting obvious signs of bacterial disease. High stocking densities without adequate number of aerators can be stressful to the shrimps and might be the reason for bacterial infection. Economic analysis indicates that L.vannamei culture is more profitable than P.monodon culture.
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    ThesisItemOpen Access
    Comparative evaluation of different feed ingradients for stinging catfish heteropneustes fossilis(Bloch)
    (College of Fisheries, Panangad, 2010) Kumar, Katya; KAU; Mohanakumaran, Nair
    Stinging catfish Heteropneustes fossilis (Bloch) is commercially and nutritionally important in India, fetching high price locally and enjoying good potential for aquaculture. One of the major limiting factors restricting the expansion of H. fossilis culture is the high cost of trash fish used as feed for its grow out. Trash fish supply is irregular and unreliable and not always recommended in fish culture. In the present study an attempt was made to evaluate different feed combination as replacement diet for trash fish in the growout of H. fossilis using three sources of protein. Three isonitrogenous diets containing 40% of protein viz. fish meal (FM), clam meat (CM) and soymeal (SM) as protein sources were tested, with five replications for each treatment, and fed to the fingerlings of H. fossilis of initial size.(11.22 ± 1.27g and 12.24 ± 0.40 cm), collected from the wild and acclimated for two weeks in freshwater and stocked in 380L capacity cement cisterns at a density of 10 numbers per tank, provided with soil substratum. Tapioca flour and vitamin mixture were added at the rate of 10% and 1% respectively in all the feeds, while rice bran constituted 36%, 18.6% and 23.3% in FM, CM and SM feeds respectively. The test feeds were fed to the fingerlings at the rate of 5% of body weight, twice daily for duration of 42 days. At the end of the trial, final length and weight measurement of each juvenile in treatments were made, and the data statistically analyzed, using One-Way ANOVA. Multiple comparisons of mean values were carried out using Tukey’s HSD test, and the means were compared using two sample Student’s t-test. Water quality parameters in the experimental tanks were monitored weekly. All the treatments recorded cent percent survival, and there was no significant difference in length gain among the three feeds. Although the highest weight gain was obtained from the FM (8.56 ± 2.40g), followed by SM (6.09 ±1.40g) and CM (5.68 ± 0.72g) respectively, statistical analysis revealed that there was no significant difference between FM and SM treatments, indicating that soymeal is equally good as fish meal. However the lowest food conversion ratio (FCR) of (2.74) for FM, followed by CM (4.07), and SM (4.53), which suggest that fish meal is the best source of protein in the feed for the culture of H. fossilis, but soymeal could also be used to replace fish meal, upon further refinement of growth trials. Highest ammonia was recorded in FM tanks, followed by CM and SM, which indicate that water quality needs to be closely maintained, when sources of animal protein are used in the feed of H. fossilis. Additional research is recommended, supplementing the deficient amino acid lysine in soymeal, which might perhaps improve the weight gain and FCR of H. fossilis fingerlings.