Influence of mangrove ecosystem on the biological resources and fishery of Kakinada

Since there are no records of detailed investigation on the ecology of the mangrove Kakinada around Kakinada and keeping in view of the vastness, fertility and biological resources of the Kakinada Bay and the adjacent sea, the Institute took initiative to conduct a study on the ecology of mangrove areas around Kakinada during 1982-'85 to understand the various ecological aspects connected to the water, soil/ sediment and mangrove-associated fauna and their influence on fisheries

Studies on the mangrove ecosystem

Mangrove ecosystem is one of the most specialised and productive coastal habitats in the world. Due to human interference in many ways, most of the mangrove forests are on the verge of destruction and disappearance. The main causes for the degradation of Indian mangroves are land reclamation, pollution and overexploitation of the resources. A proper understanding of this specialised ecosystem and careful implementation of the conservation measures would alone save the ecosystem from further destruction and extinction. The present account deals with the ecological aspects of the mangrove habitats covering their extent, distribution, zonation, biological assemblage, hydrography and productivity, and giving importance to their role, man-made impacts and conservation aspects with emphasis on the approaches for the sustainable use of this ecosystem to the mankind with special reference to the mangroves of India

Occurrence of giant male and female groupers with a note on sex change in groupers

Serranid fishes are popularly known as 'Groupers' or 'Rock cods' and locally 'Kalava'.In view of their importance in the capture and culture fisheries, the present account on the record of giant female groupers [Epinephelus tauuina (Forskal), Epinephelus malabaricus (Bloch and Schneider) and Promicrops lanceolatus (Bloch)] of more than two metres in total length and their sex ratio] in the natural population from the Indian coast (Table 1) deserves special attention

Mariculture in India, its potentialities and practical applications

India is passing through a very critical period of food crisis and consequentiy calling for the necessity of adopting various techniques and methods to augment the food production. Among them , mariculture is an important means of getting additional source of human food

Notes on the juveniles of the rock cod Epinephelus tauvina (Forsskal)

The occurrence of the very young juveniles of the rock cod Epinephelus tauvina (Forskal) in Cochin backwater during February-June is reported here with brief notes on the morphometric variations between juveniles and adults and food and feeding habits of juveniles

Some observations on primary production and plankton biomass along the continental shelf and slope off the northeast coast of India during January 1989

The present study deals with the quantitative aspects of chlorophyll pigments, primary productivity and plankton biomass from the continental shelf and slope off the northeast coast of India between 16° and 20°N latitudes towards the end of northeast monsoon season. In surface waters, the mean values of chl-a, -b, and -c were 0.249,0.275 and 0.837 mg/m^ along the shelf and 0.246,0.260 and 0.805 mg/m^ in the slope respectively while the net primary productivity values were 0.074 and 0.081 g C/m /d for the shelf and slope waters respectively. Column productivity in the upper 0-50 m water in the shelf and slope regions were 2.9 and 3.25 g C/m /d with an average production of 3.08 g C/m /d. Higher rate of production was observed around 18° and 20°N latitudes. Zooplankton biomass exhibited progressive increase in volume from 16° to 20°N. The estimated mean zooplankton biomass volume of the study area was 28.83 ml/m . The mean transfer coefficient from primary to secondary production was found to be 14% when 50% of the zooplankton biomass was considered as the daily rate of production. From the mean primary and secondary productivity values, potential tertiary production of pelagic fishery resources in the upper 0-50 m water column of the study area for the month was assessed

Sediment and water characteristics of selected prawn farming sites at Cochin during premonsoon months

This paper deals with the studies on sediment and water characteristics of selected shrimp farming ponds located at Puthuvyppu and Valappu villages of Vypeen in the vicinity of Cochin carried out during premonsoon period (March-May 2001). Areawise distribution of sediment and water characteristics revealed that smaller and medium sized ponds were relatively more fertile than the larger sized ponds. Overall mean values of nutrients in sediment and water indicated that ponds at Puthuvyppu village (with high tidal influence) were relatively more fertile than those ponds at Valappu. TSS and primary productivity values also showed the same trend. Highly significant positive correlation was observed between clay and silt, organic carbon and available potassium, nitrite-N in sediment and water, salinity and TSS and water pH and dissolved oxygen

Rare Chimaeroid and Elasmobranch fishes from the continental slope off the West Coast of India

During exploratory trawling from the upper continental slope in depths between 180 and 450 metres off the West Coast of India, specimens of the Chimreroid fish Neoharriotta pinnata (Schnackenbeck) and the rare elasmobranchs Echinorhinus b"UC11S (Bonnaterrc) and Atractophorus armatus Gilchrist have been obtained. All three are new distributional records for Indian Seas and they are described and illustrate

Dial variations in temperature, salinity and dissolved oxygen from the neritic waters off Cochin during April (peak summer)

Dial variations of important hydrographic parameters were studied continuously for 7 days at a 100 m depth station off Cochin. The frequency of observations varied from 1-3 hourly intervals. In surface waters, the ranges in temperature, salinity and dissolved oxygen values recorded during 10-17 April were 30.64°-32.36°C, 34.56- 34.68 X lO''' and 4.06-4.65 ml/1 respectively. Tlie STD profiles in the diurnal study revealed clearly the premonsoon warming (30°-31°C) in the upper 0-30 m depth zone. In the water column up to 50 m depth, mean salinity values ranged from 34.6 to 35 X 10 while dissolved oxygen values were above 4 mI/1. Time series observations on the production and utilisation of dissolved oxygen revealed wide fluctuation from hour to hour. Vertical gradients in the diurnal study indicated the existence of thermocline around 60 m depth with sharp decline in temperature and dissolved oxygen and increase in salinity below 60 m. The diurnal variation on the distribution of temperature and dissolved oxygen exhibited significant rhythmic tidal impulse of a semi-diurnal wave pattern which was more prominent in the bottom layer below 60 m

Note on the biochemical composition of the Indian Shad Ilisha melastoma (Schneider)

Total protein, carbohydrate, fat and water content of the muscle, liver and gonads of Ilisha melastoma (Schneider) in the size range 90 mm to 185 mm in total length were determined. The variations in concentrations of these in relation to sex and maturation were noted. In /. melastoma, the existence of 'protein-water line" and 'fat-water line" was indicated