Genetic stock characterization of fish using molecular markers

Accurate Identification of genetic resources is necessary for detecting new species and varieties for products of commercial value. Fish, as a group, apart from their economic value from a biodiversity viewpoint, have the highest species diversity among all vertebrate taxa. They exhibit enormous diversity in size, shape, biology and in the habitats they occupy. In terms of habitat diversity, fishes live in almost all conceivable aquatic habitats, ranging from Antarctic waters to desert springs. Of the 62,305 species of vertebrates recognized world over, 34,090 (nearly 52%) are valid fish species; a great majority of them (97 %) are bony fishes and the remaining (3 %) are cartilaginous (sharks and rays) and jawless fishes (lampreys and hagfishes). Further, on an average, 300 new fish species are described each year, and global surveys indicate that there could well be at least 5,000 species more to be discovered

Concept for estimation of secondary and tertiary biomass from primary production

Fixation of inorganic carbon to organic carbon in the ocean is driven purely by phytoplankton. Phytoplankton carbon fixation plays an important role in maintaining the quasi steady state level of atmospheric CO2. Relative contribution of marine primary productivity to global photosynthetic production is between 10 and 50%. Magnitude ranges from 20 to 55 Gt of C/ year (Ryther 1969, Smith et al., 1983, Walsh 1984 and Martin 1992). Ocean-atmospheric coupled climate models predict changes in the ocean circulation and hypothesize that changes in the ocean circulation will stimulate phytoplankton biomass production in the nutrient depleted areas in the open ocean (Roemmich & Wunch 1985). The effect on atmospheric CO2 is uncertain because the relationship between the enhanced primary production and air sea exchange of CO2 is not understood. The challenge is to study the magnitude and variability of Primary productivity, its time scales and changes in atmospheric forcing and upscale it into secondary and tertiary productivity

Satellite ocean colour sensors

The 70% of the earth’s surface is covered by the ocean and the life inhabiting the oceans play an important role in shaping the earth’s climate. Phytoplankton, also known as microalgae, are the single celled, autotrophic components of the plankton community and a key part of oceans, seas and freshwater basin ecosystems. They are significant factor in the ocean carbon cycle and, hence, important in all pathways of carbon in the ocean. Phytoplankton contain chlorophyll pigments for photosynthesis, similar to terrestrial plants and require sunlight in order to live and grow. Most of them are buoyant and float in the upper part of the ocean, where plenty of sunlight is available. They also require inorganic nutrients such as nitrates, phosphates, and sulphur which they convert into proteins, fats, and carbohydrates. In a balanced ecosystem, phytoplankton are the base of the food web and provide food for a wide range of sea creatures (NOAA). The measurement of phytoplankton can be indexed as chlorophyll concentration and is important as they are fundamental to understanding how the marine ecosystem responds to climate variability and climate change

Identifying mesoscale eddies- Relevance to mud banks and fishery

The most popular fishing area during mud bank formation in Kerala is off Punnapra coast in Alapuzha district. This place is equipped with unique crafts such as one-man operated expanded polystyrene thermocol made gill netters, and several other traditional crafts. The fishermen community along this coast is vigilant against any mechanized fishing during mud bank period which falls in the southwest monsoon months when there is a ban on mechanized crafts. There are comparable datasets, from mud bank vis-à-vis non mud bank in this region, which indicate that, the catch per unit effort (CPUE) do not vary significantly. Fishing in Thrissur and Malappuram districts are not restricted by the formation of mud banks. In these districts modified outboard crafts such as pair trawlers operating double net and the high horse power of the out board engines are generally on a look out for nonmud bank resources also. In Malappuram district, the occurrence of the mud bank fishery is for limited days and generally less reported. Therefore, the analysis of data sets indicated better production and CPUE from non-mud banks in Malappuram. In general we can say that there is no significant increase in abundance of fishes reported from the mud bank regions. But the calm waters generated at certain pockets of the otherwise disturbed coastal waters act as areas for seasonal landings of fish

Satellite Data Products for Marine Ecosystem Studies

Satellite Data Products for Marine Ecosystem Studie

El-Nino and its impacts on coral reef ecosystem in 289 the eastern Indian Ocean

The coral reef bleaching associated with the elevated Ocean temperature has been widely reported in the last three decades from different regions of the world. The rising temperature and acidification of Oceans makes a big challenge for the survival of reefs in the world. The other important stresses for the reefs include increased UV radiation, sea level variations, suspended sediments and increased turbidity of water. There are different studies which relate bleaching events with global warming and climate change. However, the increased frequency of mass bleaching events could not be sufficiently explained with current warming rates of the Ocean. Stone et al., (1999) put forward a new theory that recent increases in mass bleaching events were in response to the relative increase in El Niño experienced over the last two decades

Upwelling over the eastern Arabian Sea

Upwelling is a vital oceanographic phenomena determining the biological productivity of the coastal oceanic provinces in a greater extent. The annual pelagic fisheries of coastal rim countries, adjacent to the eastern boundary of the Ocean, over the trade wind zone are greatly dependent on upwelling. Over the North India Ocean (NIO), west coast of India, adjacent to the eastern Arabian Sea is well known for its seasonal occurrence of upwelling and downwelling annually. Over the past, several authors have studied upwelling along the west coast of India (Banse 1959, 1968; Sharma 1978; Johannessen et al., 1987

Satellite Remote Sensing Applications in Mariculture Activities

During the last two decades the marine fisheries sector in India has undergone considerable change. The fishing fleet became larger and more energy-intensive, and the catch and trade of marine fishes increased substantially. Concern arising from the increasing fishing effort and the potential for overexploitation in Indian waters, led to scientific assessment of the status of several fish stocks. Consequently, attempts were made to shift from open to regulated access fisheries through Marine Fishing Regulation Acts (MFRAs). However, conflicts in sharing the limited resources intensified within and with other sectors and this, in turn, had high economic, social and environmental costs (Vision 2050, CMFRI). Thus, in recent years, the sector recognized the need for effective management for sustainable fisheries and a healthy marine environment through ecosystem approach and habitat restoration. Success has been achieved in mariculture, raising hopes of producing a plentiful supply of fish in future by farming marine fis

Spatial variability in sea surface temperature and wind-driven coastal upwelling along the southwest coast of India

The coastal environment along the southwest coast of India is influenced by seasonal wind-driven coastal upwelling. The trend of upwelling index (UI) and sea surface temperature (SST) along the southwest coast of India during 1988-2015 were analysed in this study. In order to understand the spatial variation in SST and UI, the entire southwest coast of India was divided into three strata viz. stratum_1 (ST_1, southern part), stratum_2 (ST_2, middle part) and stratum_3 (ST_3, northern part). Temporal analyses of these parameters were carried out for three seasons such as monsoon (June-September), post-monsoon (OctoberJanuary) and pre-monsoon (February-May). In addition to seasonal changes in upwelling, large-scale latitudinal differences in upwelling were observed during this study, which is associated with spatial differences in coastal topography. The upwelling index along stratum_3 has increased after 1995 compared to previous period. Both SST and UI exhibited spatial variation along southwest coast of India. Eventhough, UI is higher during the summer monsoon compared to other seasons, a declining trend in UI during the summer monsoon was found from 1988 to 2015

Holistic Approach to Upwelling and Downwelling along the South-West Coast of India

An attempt has been made to develop a holistic understanding of upwelling and downwelling along the south-west coast of India. The main objective was to elucidate the roles of different forcings involved in the vertical motion along this coast. The south-west coast of India was characterized by upwelling during the south-west monsoon (May to September) and by downwelling during the north-east monsoon and winter (November to February). The average vertical velocity calculated along the south-west coast from the vertical shift of the 26 �C isotherm is 0.57 m/day during upwelling and 0.698 m/ day during downwelling. It was concluded that upwelling along the south-west coast of India is driven by offshore Ekman transport due to the alongshore wind, Ekman pumping, horizontal divergence of currents and by the propagation of coastally trapped waves. Whereas downwelling along the coast is driven only by convergence of currents and the propagation of coastally trapped Kelvin waves. Along the west coast of India, the downwelling-favorable Kelvin waves come from the equator and upwelling-favorable waves come from the Gulf of Mannar region