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Thirty species of marine algae collected from different localities of Mandapam coast (Gulf of Mannar) were analyse!! for their photosynthetic pigments suct. as chlorophyll and carotenoids. The lowest value. of chlorophyll as well as carotenoids content were found in Rhodophyceae. The grouping and separation of algae based on coloration has been practiced for over 100 years (Harvey, 1841). Pigments such as chlorophyll and carotenoids play important roles in photosynthesis. Several studies have been conducted in the algal pigment by Ramus el al. (1976); Brody el al. (1959); Jones el at. (1965) and Waaland el al. (1974). As there is no detailed work in this line on India.l seaweeds, the present study.of thirty species of marine algae belonging to Chlorophyta, Phaeophyta and Rhodophyta from Mandapam coast has been carried out.

FAO fisheries fact sheet of Porphyra tenera (Kellman 1897), also known as nori and laver.

Data collected on the commercial exploitation of seaweeds from the natural seaweed beds of Tamilnadu during 4 years period from 2000 to 2003 showed that the quantity of agarophytes viz. Gelidiella acerosa, Gracilaria edulis, G.crassa, G.foliifera and G.verrucosa varied from 965 to 15 18 tonnes (dry wt) and alginophytes Sargassum spp and Turbinaria spp from 1433 to 2285 tonnes (dry wt) per year. The commercial harvest of seaweeds in Gulf of Mannar and Palk Bay is recommended only during the peak growth period of the algae from July 1 August to January. The harvest of commercially important seaweeds in a rational way from other parts of Indian coast, Lakshadweep and Andaman-Nicobar Islands is suggested. The need for large scale cultivation of agarophytes to augment the resources and uninterrupted supply of raw materials to the seaweed industries is emphasised.

The study analyzed the characteristics, chemical composition, and in vitro gas production kinetics of Porphyra umbilicalis and Saccharina latissima silages. Each seaweed was ensiled in vacuum bags (three bags/silage) following a 2 × 3 factorial design, with two pre-treatments (unwilted or pre-wilted) and three silage types: unwashed seaweed ensiled without additive; seaweed washed and ensiled without additive; and seaweed washed and ensiled with 4 g of formic acid (FAC) per kg seaweed. Silages were kept for 3 months in darkness at 20 °C. Pre-wilting prevented (p < 0.001) effluent formation and reduced (p ≤ 0.038) the production of NH3-N and volatile fatty acids for both seaweeds. Both pre-wilting and washing increased (p < 0.05) the ruminal degradability of P. umbilicalis silages but not of S. latissima silages. The pH of the FAC-treated silages was below 4.0, but ranged from 4.54 to 6.23 in non FAC-treated silages. DL-lactate concentrations were low (≤23.0 g/kg dry matter) and acetate was the predominant fermentation product, indicating a non-lactic fermentation. The estimated ruminal degradability of the P. umbilicalis and S. latissima silages was as average, 59.9 and 86.1% of that for high-quality rye-grass silages, respectively, indicating a medium-low nutritional value of these seaweed silages for ruminants.