The present research provides detailed information on the yearwise distributional patterns of fishes landed by trawl at Pamban therkuvady based on fortnightly samplings from September 2007 to April 2012. A total of 244 species belonging to 75 families under 18 orders were recorded. Quantitatively, Karalla dussumieri and family Leiognathidae dominated while by number of species, the family Carangidae contributed maximum with 20 species. The fish landing were the maximum during 2011-12 and was the minimum during 2008-09. Biodiversity studies were made using PRIMER 6 software. Different indices of conventional diversity as well as that of taxonomic distinctness based on dominance plot, dendrogram and funnel plots of delta+ and lambda+ are presented and discussed.
Sea cage farming of Asian seabass is a prospective aquaculture activity in India. Reports from India on betanodavirus-induced mortality in marine fish culture are not many. An outbreak of viral encephalopathy and retinopathy associated with red-spotted grouper nervous necrosis virus (RGNNV) genotype of betanodavirus in Asian seabass juveniles reared in indoor tanks and sea cages is described in the present paper. Mortality was less severe in cages when compared to tanks. Sequence analysis of the coat protein gene indicated that the virus belonged to RGNNV genotype but found to be distinct from other reported RGNNV isolates. Virus was able to induce cytopathic effects in fish cell lines. Light microscopic features of the disease are also described.
Bacterial diseases have turned out to be the primary constraint in sustainable aquaculture production, where, probiotics can play an important role to prevent or control fish and shellfish diseases. As the autochthonous preparations would be more effective than commercial products, continued search for novel antibacterial strains native to aquatic environment are warranted against aquatic pathogens. Further, knowledge on abundance, composition and role of hemolymph microbes is also essential to predict the health status and disease diagnosis. Hence, in present study, 4 commercially significant marine crabs that are important for aquaculture were used to unravel the implication and significance of cultivable hemolymph microbes. Bacterial abundance was found to be individual- and species-dependent; and statistically significant interaction was present between growth media and abundance. Gram negative isolates represented 84% of hemolymph microbes. Vibrio was the principal genera in all species; each carrying a specific hemolymph microbiota (both in terms of abundance and diversity). The present study forms the first report of genera viz., Enterovibrio, Pantoea, Kluyvera and Enterobacter in crustacean hemolymph. Interestingly, new Vibrio species were also found. Further, the study forms the first observation on inhibitory activity of marine crab hemolymph microbes against aquatic pathogens. Overall, the results highlight marine crab hemolymph microbiota as a promising moreover, an untapped resource for probiotics/ antimicrobial agents to combat aquatic pathogens. Concurrently, the present study fetches a platform for the prediction of health and disease diagnosis of 4 potentially important aquaculture crab species.
Routine field survey in the Palk Bay landings yielded a single ovigerous specimen of Pseudoporcellanella manoliensis after a gap of nearly 55 years in Indian coastal waters. Rediscovery of this species in ovigerous condition from the Palk Bay reassures that the population still exist in these ecosystems since its description by Sankarankutty in 1961.
A 16-member polyether macrocyclic lactone, with previously unreported framework was isolated as a result of the bioassay guided chromatographic fractionation of the ethyl acetate-methanol extract of the Babylonidae Babylonia spirata collected from the southwestern coast of Indian peninsular. The compound was characterized as 10, 14-dihydroxy-4-(1?-propyl-1?(Z)-hexen-1?-yl)-7, 12-dioxapentadecanolide based on extensive spectral data analysis. The antioxidant activities evaluated by in vitro free radical scavenging capacities reported that the studied compound possessed greater activity (IC50 0.058–0.065?×?10?2?M) than the commercial standards, butylated hydroxy anisole, butylated hydroxyl toluene and ?-tocopherol (IC50 0.118–0.189?×?10?2?M). The compound was found to possess greater anti-inflammatory potentials as recognized by its lower IC50 value for the 5-lipoxygenase inhibition assay (0.073?×?10?2?M) than the non steroidal anti-inflammatory drugs aspirin (0.211?×?10?2?M) and ibuprofen (0.436?×?10?2?M). Structure-activity studies showed that bioactivities of the polyether macrocyclic lactone were directed by electronic and lipophilic descriptors. The lipophilic parameter of octanol-water partition coefficient (log Pow) of the studied compound recorded a value as low as 2.76 when judged against commercial antioxidant ?-tocopherol (log Pow 9.98), and was recognized as a primary physico-chemical descriptor dictating the antioxidant characteristics of the isolated polyether macrocyclic lactone, whereas the electronic parameters appeared to contribute towards its anti-inflammatory activity. This is the first report of the occurrence of macrocyclic lactone featuring a dioxapentadecanolide framework possessing potential antioxidative and anti-inflammatory activities, and therefore, anticipated as a potential naturally-derived antioxidative and anti-inflammatory constituent in functional food and pharmaceutical applications.