Investigations were carried out to determine the nutritional profile of Indian Ocean swimming crab Charybdis smithii, which is emerging as an unconventional resource in trawl discards of India. The average protein content was 9.38 g/100 g, fat 0.86 g/100 g, ash 0.34 g/100 g, fiber 0.13 g/100 g, and carbohydrate 1.8 g/100 g. One-way analysis of variance showed no significant variations of constituents except in dry matter and carbohydrate between sexes. Macronutrients, Na (317.1, 327.6/100 g), K (148, 177.40 mg/100 g), Ca (187.90, 285.80 mg/100 g), and Mg (34.31, 41.49 mg/100 g), showed significant variation between sexes. The composition of micronutrients in male and female were Cu (0.28, 0.15 mg/100 g), Fe (0.57, 0.71 mg/100 g), and Zn (1.71, 2.75 mg/100 g). Mineral content showed significant difference between sexes. Amino acid analysis showed that 12.04 and 11.47 g/100 g essential amino acid glycine was present in male and female, respectively, and lysine concentration was 13.96 and 12.65 g/100 g, respectively. The nutritional profile of the species was determined the first time and shows that it is comparable with any other edible crabs and could be exploited as a commercial resource to supplement nutritional demand.
Selected marine fishes with different feeding habits were screened for the presence of symbiotic cellulolytic bacteria in their gut. Four cellulolytic species of symbiotic bacteria were isolated from GI tract of marine fishes namely Carangoides praeustus, Filimanus similis, Sardinella longiceps and Sillago sihama. The strains were identified after polyphasic phenotypic and genotypic (16S rRNA gene) characterization as Bacillus subtilis strain TCPC1, Vibrio alginolyticus strain CFSS2C2, Pseudomonas stutzeri strain KSLS4C3 and Klebsiella oxytoca strain MSSC4. (Genbank Accession nos.: JN710380, JN710378, JN710377, JN712301).The results indicated the presence of cellulolytic bacteria in GI tract of marine fishes of carnivorous, phytoplanktivorous and omnivorous feeding habits. Cellulolytic activity was the maximum for B. subtilis strain TCPC1 (0.45?mg glucose ml?1) and V. alginolyticus strain CFSS2C2 (0.24?mg glucose ml?1) at 234?h. While P. stutzeri strain KSLS4C3 showed the maximum utilization (0.22?mg glucose ml?1) from 240 to 258?h. K. oxytoca strain MSSC4 (0.47?mg glucose ml?1) showed three peaks during the study. The maximum rate of cellulose utilization was shown by P. stutzeri strain KSLS4C3 (0.05?mg glucose ml?1 medium h?1) followed by K. oxytoca strain MSSC4 (0.03?mg glucose ml?1 medium h?1).
Effective and sustainable management of fish waste produced in markets and processing industries, is a major challenge faced by the coastal communities. Composting is an environment friendly method for fish waste disposal, and for the production of organic fertilizers. However, quality of compost depends on the use of proficient microbial consortia to mediate the bioconversion processes. Accordingly, as a first step in developing a competent fish waste composting strategy, suitability of a commercial organic waste composting consortium was assessed. For this, various selective media were used for outlining the metabolic activities required for waste degradation such as production of hydrolytic enzymes viz., chitinase, lipase and protease (both in standard media and fish waste component embedded media), ammonia oxidization, organic and inorganic phosphate solubilisation, nitrite oxidization and sulphur oxidization. There were potential producers for all organic waste degrading enzymes with highest enzymatic index (EI) as 1.8, 2.9 and 1.5 for protease, lipase and chitinase respectively. Among these, 10 microbial consortia were able to degrade fish waste components with the highest EI as 1, 2.4 and 0.2 for protein, chitin and oil respectively; indicating that efficacy of fish oil degraders in the evaluated consortia was very less. Four isolates were found efficient for denitrification. Highest organic and inorganic phosphate solubilisation efficiency was 1.9 and 7 respectively. Despite the presence of some AOB (ammonia oxidizing bacteria), NOB (nitrite oxidizing bacteria) and SOB (sulphur oxidizing bacteria), their efficacy was less. Potential isolates were characterized as Lysinibacillus xylanilyticus, Halotalea sp, Bacillus oryzaecorticis, Cronobacter condiment and Bacillus megaterium. As fish waste is rich in nitrogen and sulphur, inclusion of efficient AOB, NOB and SOB can improve the quality of final compost. Similarly, exclusion of denitrifiers can avoid the loss of nitrogen during composting. Consequently, while there were efficient organic matter degrading enzyme producers including fish protein and chitin, absence of efficient AOB, NOB, fish oil degraders and presence of denitrifiers recommends an improvisation of the evaluated consortium before application in fish waste composting.
A liquid fertilizer for foliar spray as well as a dry seaweed mulch for soil application have been prepared from Sargassum wightii and was evaluated on-farm for okra and cowpea in three farmers’ fields. Among the two crops tried, Cowpea responded better than Okra on basal application of Sargasssum mulch as well as foliar spray of its extract especially on the number of fruits per plant and wet weight of fruits. Mulching Sargassum powder to the base of okra and cowpea (T1) increased the root biomass significantly (p<0.05), 255% increase in organic carbon content in soil and 895% increase in soil microflora over the control. Foliar spray of Sargassum extract (T2) increased the number of leaves in both the crops and remarkably increased the number of pods, wet weight of pods and finally the yield in Cowpea than mulching (T1). In Okra foliar spray resulted a marginal increase only in wet weight of fruits. When the Sargassum mulch was mixed with two strains of bacteria (CMSS-1 and CMSS-4) associated with the decaying Sargassum thallus and later identified through 16s rRNA sequence analysis as Bacillus endophyticus with a similarity score of 98% and Bacillus infantis with a similarity score of 99%, the mulch became more effective and could assimilate in soil faster. Considerable increase in number and the fresh weight of fruits in Brinjal were also observed due to the value addition in the mulch.
Coastal waters of Kerala, which form an integral part of the Malabar upwelling zone off the southwest coast of India, constitute an important fishing region for small pelagics. Satellite remote sensing data from 1998?2014 were used to test the hypothesis that fluctuations in the landings of Sardinella longiceps, the major pelagic fish landed in the area designated as the South Eastern Arabian Sea (SEAS), are influenced by seasonal variability in phytoplankton biomass (measured as chlorophyll a [chl a] concentration), under the changing strength of physical para - meters such as sea surface temperature (SST), alongshore wind stress, Ekman mass transport, sea level anomaly (SLA) and Kerala rainfall. Multiple linear regression analysis (MLRA) was used to assess the influence of physical forcing mechanisms on chl a concentration on monthly and seasonal scales. We found that SLA, alongshore wind stress, SST and rainfall were ranked 1 to 4, respectively, and the first 3 factors significantly influenced the chl a concentration of SEAS. Pearson’s correlation analysis between monthly chl a and sardine landing (with chl a leading) showed a maximum positive correlation (+0.26) at 2 and 3 mo lags, emphasizing that the influence of chl a on the fishery of S. longiceps is seasonal (r = 0.35 for seasonal lead?lag correlation) in the coastal waters of SEAS. Variation in phytoplankton biomass, as evidenced by chl a fluctuations, seems to have a decisive role in regulating the physiological condition of larvae spawned during the southwest monsoon season, their juveniles and finally the adults that are recruited into the fishery in the next season. Using the quantity of phytoplankton as a predictive tool will exploit the presumptive trophic link to aid understanding of sardine fishery dynamics in upwelling zones.
Physical and biogeochemical observations from an autonomous profiling Argo float in the Bay of Bengal show significant changes in upper ocean structure during the passage of Tropical Cyclone (TC) Hudhud (7–14 October 2014). TC Hudhud mixed water from a depth of about 50 m into the surface layers through a combination of upwelling and turbulent mixing. Mixing was extended into the depth of nutricline, the oxycline and the subsurface?chlorophyll?maximum; thus had a strong impact on the biogeochemistry of the upper ocean. Before the storm, the near?surface layer was nutrient depleted and was thus oligotrophic with the chlorophyll?a concentration of less than 0.15 mg m?3. Storm mixing initially increased the chlorophyll by 1.4 mg m?3, increased the surface nitrate concentration to about 6.6 ?M kg?1, and decreased the sub?surface dissolved oxygen (30–35 m) to 31 % of saturation (140 ?M). These conditions were favorable for phytoplankton growth resulting in an estimated increase in primary productivity averaging 1.5 g C m?2 day?1 over 15 days. During this bloom, chlorophyll?a increased by 3.6 mg m?3, and dissolved oxygen increased from 111 % to 123 % of saturation. Similar observations during TC Vardah (6–12 December 2016) showed much less mixing. Our analysis suggests that relatively small (high) translation speed and presence of cold (warm) core eddy leads to strong (weak) oceanic response during TC Hudhud (TC Vardah). Thus, although cyclones can cause strong biogeochemical responses in the Bay of Bengal, the strength of response depends on the properties of the storm and the prevailing upper ocean structure such as presence of mesoscale eddies.