ग्रानडे द्दीप, गोवा के आसपास के प्रावाल खंडों पर जैवविविधता अध्ययन

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Coral fish diversity in Netrani waters off Murudeshwar Karnataka, south India

Fish diversity associated with coral reef patches around Netrani Island, in Karnataka (south India) was investigated by visual census method. Sampling was done in four sites around the Island. A total of 69 species belonging to 39 genera, 19 families and 3 orders were recorded in the transect in four sites. When comparing the abundance, the fishes of Balistidae family dominated in all the four sites (22 %) followed by Pomacentridae (12.5 %), Caesionidae (9.7 %), Labridae (7.8 %), Acanthuridae (7.3 %), Haemulidae (6.7 %) and Scaridae (6.1 %). In line with the abundance and number, Shannon diversity indices (H’) were 2.8 in site 1; 2.6 in site 3; 2.3 in site 4 and 2.2 in site 1. The evenness (J’) of species distribution was more in site 2 (0.9), followed by site 3 (0.8); site 4 (0.7) and site 1 (0.7). The Bray-Curtis similarity was in the range of 69.98 to 79.50. The dendrogram plotted showed that site 2 and 3 form a group with similarity of 79.50, to which site 1 and site 4 got linked. There was no significant difference in the hydrographic parameters of the surface and bottom waters in four sites and also between different sites. The study revealed high coral fish density in the area indicating the need for adopting conservation measures.invertebrates, cnidarians and worms, zooplankton dominated by copepods and nekton dominated by Acetes spp. and clupeid juveniles were the major food items of A. monoceros. The von Bertalanffy growth equation was Lt = 63.53 [1 – e - 0.22 (t + 0.077)]. Natural mortality, fishing mortality and exploitation ratio were 0.53, 0.58 and 0.52 respectivel

Spatial planning for integrated aquaculture development in coastal waters of Karnataka

Reduction in marine fish production in the last two decades has adversely affected the fishermen population along the coasts who solely depend on fishing for their livelihood. One option to tide over this situation is regional level planning to increase fish production from available water resources. Therefore, it is essential to have an integrated spatial planning of the available water resources as it has multiple uses. Marine spatial planning (MSP) and aquaculture zoning, the two major concepts implemented by international bodies, are still in its infancy in India due to, lack of information on its systematic implementation. Present paper describes the pioneering attempt of “Spatial planning” and “aquaculture zoning” in India, conducted in a progressive fishermen village, Tharapathi in Byndoor along Southeastern Arabian sea coast, following scientific methodologies. Through GIS mapping, potential aquaculture areas were identified for cage farming, bivalve farming, crab fattening/crab culture in pens in mangrove area, bottom culture of clams in sandy area, prawn farming areas, areas for seed production and nursery facility for finishes and shellfishes etc. Various advanced GIS based decision making tools available for future integrated aquaculture development plans, spatial mapping and Digital Elevation Models were included in this study. This is the first attempt to develop integrated aquaculture development through social consensus and scientific evaluation. Results of the study will be a precursor for spatial planning and aquaculture zoning in Indian coastal waters for sustainable aquaculture

Fabrication of green nanoinsecticides from agri-waste of corn silk and its larvicidal and antibiofilm properties

he corn silk (CS) is composed of the thread- like stigmas of female inflorescences of Zea mays L. and represents an important waste material from maize crop production that can be recycled in further applications. In this research, the CS was used for the bio-fabrication of Ag nanoparticles (AgNPs) that were evaluated against (I–V) larval instars and pupae of the mosquito vector Aedes aegypti. CS-AgNPs were characterized by UV-Vis spectroscopy, TEM, EDAX, XRD, FTIR, DLS, and zeta potential analysis. Z. mays extract analyzed by gas chro- matography mass spectrometry reveals 14 compounds. The larvicidal effectiveness of CS-fabricated AgNPs was 2.35 μg·mL−1 (I Instar) to 6.24 μg·mL−1 (pupae). The field application in water storage reservoirs of both CS extracts and CS-AgNPs (10 × LC50) led to a 68–69% reduction in larval density after 72 h post-treatment. Ecotoxicological impact of CS-fabricated AgNPs was evaluated on the pre- datory efficacy of Poecilia reticulata on all the larval instars and pupae of Ae. aegypti. Finally, CS-AgNPs were tested to elucidate its anti-biofilm attributes. The CS-AgNPs at 125 μg·mL−1 showed a biofilm inhibition of 90% on S. aureus and 79% on S. epidermidis. These results support the use of CS-AgNPs for futuristic green alternative to mosquito vector management

Decadal variations of sea surface temperature in the eastern Arabian Sea and its impacts on the net primary productivity

Ten-year satellite derived data (January 2007 to December 2016) were used to investigate the variability of Chlorophyll-a (Chl-a), sea surface temperature (SST), net primary production (NPP) in the eastern Arabian Sea (AS). This study is aimed to show the coupling of physical and biological processes to understand how temporal, annual and inter-annual variations occur and the forcing mechanisms behind these variations in the ocean environments. This work is linked to Indian Ocean Dipole and the El Nin˜o/Southern Oscillation, which frequently co-occur and drives inter-annual changes within the AS. Vertically Generalized Production Model was used to estimate NPP using chl-a, Photosynthetically Available Radiation, euphotic depth, and maximum photosynthetic rate from SST. The relationship between NPP and SST showed change in the pattern over the study period. The NPP in the AS is characterized by an unusual decline during El Nin˜o events. AS is more productive during summer monsoon (June–September) due to coastal upwelling, wind driven mixing and lateral advection processes. There was decline in NPP after 2014 and this trend continued in the following years. The present investigation revealed that the strong El Nin˜o condition was observed in 2015 and productivity of AS declined by * 19%, while SST increased by * 2% from an overall average of 2007–2016. Increased SST and low productivity could result in low fish catch in AS. Increasing trend in SST could be attributed to the extreme events like cyclones occurring along the west coast of India

गुजरात में बाँगडा (मलबारी) का अवतरण

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Fishery of threadfin breams along Saurashtra coast (Gujarat), and some aspects of biology of Nemipterus japonicus (Bloch, 1791) and N. mesoprion (Bleeker, 1853)

During 1997-2002, threadfin breams contributed 10% to the annual average landings by trawlers at Veraval and Mangrol. Peak landing of 26,457 t was observed in 2000, with a catch rate of 11.6 kg per hour. Nemipterus japonicus and N. mesoprion dominated the threadfin bream fishery along this coast. The length range of N. japonicus and N. mesoprion in the landings was 60-390 mm and 80-280 mm respectively.Occurrence of larger individuals was more during October-January. Females dominated the catches. The size at first maturity was estimated as 141 mm for N. japonicus and 135 mm for N. mesoprion. The spawning peak in N. japonicus was found to occur during September-December, with a secondary peak in May. N. mesoprion had a prolonged spawning period extending from October to March. The constants of length-weight relationships derived were a = 0.0000427; b = 2.777 and a = 0.0000983; b = 2.626 for male and female N. japonicus, respectively and a = 0.0000281; b = 2.895 and a = 0.0000277; b = 2.898 for male and female N. mesoprion, respectively. The relationships were found to be significantly different between sexes in both the species

Quantitative and qualitative assessment of exploitation of juvenile cephalopods from the Arabian Sea and Bay of Bengal and determination of minimum legal sizes

Using the minimum size at maturity (MSM) as a biological reference point and relatively low reproductive loads and generation times of the studied animals, the minimum legal sizes (MLS) for the Indian squid Loligo duvauceli, the pharaoh cuttlefish Sepia pharaonis and for the webfoot octopus Octopus membranaceous was fixed at 80, 115 and 45 mm Dorsal Mantle Length (DML) respectively with corresponding minimum legal weights at 25, 150 and 15 g. For L. duvauceli, during 1997-2001, 12.8% of the average catch was constituted by juveniles, the proportion being higher along the west coast. In 2002-05, the proportion of juveniles was lower at 5.3% and the total weights were also much less (1817 t as compared to 5354 t). In the case of S. pharaonis, 6.9% (2281 t) of the catch was constituted by juveniles, but the proportion was very high (22.4%) along the east coast. In O. membranaceous during 2002-04, an estimated 527 t (5.9%) of the total catch comprised of juveniles. The present Lmean in the fishery is lower than the Lopt and their difference is considerably high at 60 mm for L. duvauceli. However, in the case of S. pharaonis this difference is only 10 mm and in the case of O. membranaceous the Lmean is higher than the Lopt. If the juveniles are permitted to grow to Lmean by implementing the MLS, the estimated economic gain is to the tune of Rs. 426 crores per annum. The present study shows that harvest weights can be improved by up to 34 times and would result in higher incomes to trawl fishers

कर्नाटक तट की समुद्री और ज्वारनदमुख जैवविविधता

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Samarasya-National workshop on Harmonizing Coastal Industrialization with Marine Ecosystem Health

Sāmarasya, the Souvenir released on the occasion of National Workshop, HCIMEH, 2017 at Mangaluru, commemorating the Platinum Jubilee of ICAR- Central Marine Fisheries Research Institute (National workshop on Harmonizing Coastal Industrialization with Marine Ecosystem Health