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Biswas, G.; Kumar, P.; Kailasam, M.; Ghoshal, T.K.; Bera, A., and Vijayan, K.K., 2019. Application of integrated multi trophic aquaculture (IMTA) concept in brackishwater ecosystem: The first exploratory trial in the Sundarban, India. In: Jithendran, K.P.; Saraswathy, R.; Balasubramanian, C.P.; Kumaraguru Vasagam, K.P.; Jayasankar, V.; Raghavan, R.; Alavandi, S.V., and Vijayan, K.K. (eds.), BRAQCON 2019: World Brackishwater Aquaculture Conference. Journal of Coastal Research, Special Issue No. 86, pp. 49–55. Coconut Creek (Florida), ISSN 0749-0208. An integrated multi-trophic aquaculture (IMTA) model involving mullets (Mugil cephalus and Liza parsia) and tiger shrimp (Penaeus monodon) as fed-species, and estuarine oyster (Crassostrea cuttackensis) and seaweed, Enteromorpha spp. as extractive species was evaluated as a viable aquaculture option in brackishwater of the Indian Sundarban. A 150-day field experiment was conducted in six brackishwater ponds (600 m2 each). There were two randomly assigned groups, IMTA and polyculture (control) with three replicate ponds. Ponds under IMTA were stocked with mullets and tiger shrimp at 10000 and 30000 no./ha, respectively, C. cuttackensis at 1600 no./ha suspended with a basket in the water column and Enteromorpha spp. at 200 kg biomass/ha. Control ponds were stocked with mullets and shrimp at the same densities to that of IMTA, and devoid of oyster and seaweed. A common low-cost polyculture feed was provided to fishes and shrimp. Mullets attained a significantly higher growth (p <0.05) in the IMTA system compared to that of control ponds, whereas tiger shrimp had insignificantly higher growth in IMTA than in control. Significantly higher production of 1707 kg/ha (19% higher) with better water quality was obtained in IMTA system compared to that of control ponds (1434 kg/ha) (p <0.05). There was a significant reduction in apparent feed conversion ratio by 22%, and an increase in net income by 69% and benefit-cost ratio by 30% in the IMTA system than that of the control. Moreover, for the first time the estuarine oyster, C. cuttackensis was used as an extractive species in brackishwater IMTA system. From an indoor trial, it was observed that this oyster species has high water filtration capacity to remove suspended matters, including planktons. This preliminary experiment indicates the application of IMTA concept in brackishwater as a viable environment-friendly option and warrants further refinement for species combination with the economic viability and environmental suitability. [ABSTRACT FROM AUTHOR]

Abstract: The black tiger shrimp (Penaeus monodon), a commercially important penaeid species, is widely distributed across the Indo-Pacific region. Genetic diversity in P. monodon collected from eight geographical regions in Southwest, East and Andaman coastal waters of India (N =418) was investigated using 10 polymorphic microsatellite loci. Average observed heterozygosity at sampled loci were high, ranging from 0.643 (Coromandel Coast) to 0.753 (South Andaman). Pairwise F ST (ranged from 0.005 to 0.078) and R ST (ranged from 0.005 to 0.171) estimates revealed surprisingly strong and statistically significant genetic structure among tiger shrimp populations. A synthetic map generated by multidimensional scaling shows an apparent cline in allele frequencies paralleling the roughly circular flow of surface currents in the Bay of Bengal. Significant heterozygote deficiencies were noted in most population samples at most loci. Andaman Island sites showed the highest diversity. Recognition of high genetic diversity and distinct population structuring of P. monodon in Indian seas has important implications for future domestication of this species in India, for two reasons: identification of the best wild founding stocks for aquaculture and, subsequently, the potential impacts of release of domesticates to the wild, either accidentally or deliberately (i.e. for stock enhancement). [Copyright &y& Elsevier]

A disease outbreak in 42-d-old black tiger shrimp Penaeus monodon juveniles from a commercial aquaculture farm in Kerala, India, was investigated. The cause of the disease outbreak was confirmed as Vibrio parahaemolyticus by biochemical tests, PCR targeting the toxR gene and pathogenicity testing of the isolates. All of the isolates tested negative by PCR specific for V. parahaemolyticus associated with acute hepatopancreatic necrosis disease (AHPND), implicating vibriosis unrelated to AHPND as the cause of mortality. Among the 19 isolates obtained, 2 possessed the tdh gene (coding for thermo-stable hemolysin), whereas none of the isolates possessed trh. The LD50 value of 8 isolates of V. parahaemolyticus from diseased and apparently healthy shrimp ranged from 2.7 × 104 to 4.9 × 105 CFU ml-1 by immersion challenge of P. monodon postlarvae. BOX-PCR and dendrogram analysis of the bacterial isolates revealed that the isolates from moribund and apparently healthy shrimp formed separate clusters, indicating that these isolates originate from separate clones. The isolates from moribund shrimp including tdh-positive V. parahaemolyticus clustered together. The present study represents the first report of tdh-positive V. parahaemolyticus causing disease in a shrimp farm.