Coastal Aquaculture in India-Review and Future Prospects

Aquaculture is being practised by humanity since very early times. It has acquired importance during the last three centuries with progressive increase in the demand for fish and shellfish. Aquaculture both in inland and coastal waters has become a very important food production activity during the last three decades due to the limitations of capture fisheries, especially the latter reaching maximum sustainable limits in the case of a number of resources and the large rise in cost of fishing effort

A strategic approach for preparation of oxide nanomaterials

A microwave assisted solvothermal method is described for rapid preparation of nano-oxides. This method is based on exploiting differential dielectric constants to induce preferred heating and decomposition of the oxide precursors in the presence of suitable capping agents. This strategic approach has been used to prepare nanopowders of MgO, NiO, ZnO, Al2O3, Fe2O3 and ZrO2

Large nonlinear absorption and refraction coefficients of carbon nanotubes estimated from femtosecond Z-scan measurements

Nonlinear transmission of 80 and 140 femtosecond pulsed light with $0.79 \mu m$ wavelength through single walled carbon nanotubes suspended in water containing sodium dodecyl sulphate is studied. Pulse-width independent saturation absorption and negative cubic nonlinearity are observed, respectively, in open and closed aperture Z-scan experiments. The theoretical expressions derived to analyze the z-dependent transmission in the saturable limit require two photon absorption coefficient $\beta_0\sim$ $1.4 cm/MW$ and a nonlinear index $\gamma \sim -5.5 \times10^{-11} cm^2/W$ to fit the data.Comment: 10 pages, 2 figures. Accepted and to appear in Applied Physics Letter

Crafts and gear used for marine fishing along the Andhra Pradesh coast

Until the middle of nineteen sixties fishing for marine finfishes and shellfishes along the Andhra Pradesh coast used to be carried out employing indigenous non-mechanised crafts. Subsequently trawlers and later mechanised vessels operating gillnets came into use which resulted in the increased fish production. Use of outboard engine on indigenous crafts for reaching fishing grounds is a recent feature of near the coast fishing. The different kinds of non-mechanised and mechanised crafts and gear employed in the region are dealt with in this article

Some glimpses of the marine fisheries in Andhra pradesh

Andhra Pradesh stands 5th in the marine fish production among the maritime states of India. The advent of mechanisation of fishing craft and introduction of mechanised fishing vessels have brought significant changes in the marine fishing industry of Andhra Pradesh. As a result of this, the fisheries harbour at Visakhapatnam has become one of the key harbours for mechanised trawl fishing and Visakhapatnam itself has emerged as one of the most important centres for exporting marine products to foreign countrie

Relationship between morphological and amplified fragment length polymorphism (AFLP) marker based genetic distance with heterosis in hot pepper (Capsicum annuum L.)

Identification of potential parents that produce the hybrids with superior yield is the most important step in developing hybrids to save the substantial resources. The present study was carried out to assess the morphological and amplified fragment length polymorphism (AFLP) marker based genetic diversity, to estimate mid parent heterosis and to correlate the estimated parental genetic diversity with heterosis chilli. Five CMS B - lines and 30 testers were used for morphological and AFLP marker genetic divergence analysis. 150 hybrids were synthesized through Line × Tester (5 × 30) mating design and were used to estimate the mid-parent heterosis for nine characters at two locations. 35 parents were examined for nine morphological traits and were grouped in to six clusters. These parents were also examined for eight AFLP primers combinations and were grouped into seven clusters. More than 50% of hybrids showed significant mid-parent heterosis for both green and red fruit yield plant-1. Hence, there is a much potential for development of good yielding hybrids. The positive significant correlation was found between morphological and AFLP marker distance of the parents with heterosis for plant height (r = 0.17 and 0.38), green fruit yield plant-1 (r = 0.19 and 0.25) and red fruit yield plant-1 (r = 0.20 and 0.34); however, the correlation coefficients were not strong in these traits. Genetic distance between parents was not strong enough to predict the performance of the hybrids and proved to be of no predictive value.Keywords: Correlation, molecular markers, genetic diversity, chill

Seaweed resources of the Tuticorin-Tiruchendur coast, Tamil Nadu, India

The southern coast of Tamil Nadu (Mandapam to Kanyakumari) supports luxuriant growth of economic seaweeds. The entire indigenous phycocoUoid industry of the country gets the raw material from this region and during the last two decades, due to indiscriminate harvesting, there has been over-exploitation of the resource. The present paper deals with survey conducted in the first sector from Tuticorin to Tiruchendur during December 1986—March 1987. In this study 58 species of marine algae were recorded of which 7 belong to Chlorophyta, 12 to Phaeophyta and 39 to Rhodophyta besides 3 species of seagrasses namely Cymodocea seiriilata, Halophila ovalis and //. ovata within 650 sq. km area surveyed. The total standing crop of the seaweeds was estimated at 9,100 tonnes (wt.). The estimates for the dominant species are Dictyota maxima 530 t, Sargassum tenerrium 640 t, D. bartayresiana 8601, Selieria rebusta 2,0901 and Hypnea valemiae 2,4301. The seaweed potential for commercial exploitation has been briefly discussed

Seaweed resources off Tamil Nadu coast: Sector II. Alanthali - Manapad and Vembar – Nallathanni Thivu

The seaweeds are used for the production of polysaccharides such as agar, algin, carragennan and they are harvested from intertidal regions along the southeast shores of India. The resource potential from intertidal regions was estimated (Anon 1978

Commercial importance of marine macro algae

India with a vast coastline of more than 8000 km supports a rich standing crop of marine algae wherever rocky or coral formations occur along the coast. The current estimate of annual standing crop of marine algae of India is 3, 01,646 tonnes (fresh weight).The algae contain minerals, trace elements (iodine and bromine), proteins, carbohydrates, lipids etc.The marine algae are a good source of organic constituents such as vitamins, bioactive substances and polysaccharides and also are useful as raw material for biofuel production and liquid fertilizer. Important polysaccharides obtained from algae are agar, carrageenan and algin. The Indian red algae such as Gelidium, Gelidiella, Pterocladia and Gracilaria yield agar and agarose. Agarose is the most important medium for electrophoresis. The red algae viz. Hypnea, Kappaphycus, Acanthophora, Laurencia are the sources of carrageenan. Algin is extracted from brown algae like Sargassum, Turbinaria, Hormophysa and Cystoseira. Mannitol is also obtainable from brown algae. This is used as a diuretic and helps in excretion of some toxins. Many of the green, brown and red algae form part of the diet taken by people of South East Asia. In India, the red alga Gracilaria edulis is eaten in certain coastal areas of Tamil Nadu as porridge. Some of the marine algal constituents are of antimicrobial, antifungal, antiviral, diuretic and spasmolytic values. The algae are used in the treatment of goiter and as ichthyotoxic compounds. Other medicinal properties and commercial uses of algae in industry and biotechnology are reviewed in this paper. Efforts must therefore be made by concerned agencies and entrepreneurs to make best use of the renewable marine algae which are available along our coasts

Exploitation of marine algae in Indo-Pacific region

Marine algae are harvested from the coastal waters of numerous countries of Indo-Pacific region due to their value as food, feed for animals, fertilizers and a source of various minerals, trace elements and phycocolloids. Out of 20, 000 species of marine algae in the world, 145 are used for food and 101 for extraction of phycocolloids. The Indo – Pacific region encompasses approximately 75% of the world’s coral reefs and provides ideal habitat for marine algae and various other organisms. According to FAO Fisheries Statistics, 2006, the total estimated marine algal production in the world is more than 15.8 million tonnes and that of Indo–Pacific region is of the order of 13 million tonnes. The global production of edible marine algae has been assessed as four million tonnes (wet wt.).The Indo- Pacific region produced 2,60,00,00 tonnes wet weight. In India, the annual production of marine algae has been estimated as 3, 01,646 tonnes. The bulk production comes from Tamil Nadu coast and Andaman-Nicobar Islands amounting to 60 %.Information on global production of useful marine algae, important edible species, harvesting, industrial exploitation and culture of Indian resources is given in this paper. The marine algal industry has grown in leaps and bounds in other countries increasing the employment potential and gainful economic returns for them. There is an urgency in improving the culture and exploitation of our marine algal resources to face competition in the world markets