Showing papers by "National Institute of Oceanography, India published in 1976"

Ecology of the blue crab portunus pelagicus (linnaeus) and its potential fishery in zuari estuary

Abstract: The occurrence of the tblue cra'b Portill/IIS peiagicils was studied from December 1972 to April 1973 in Zuari estuary. Environmerital parameters, 'liz., temperature, saHnity, oxygen, light penetpation and nature of bottom wer~ also 9tudied. 4519 Crabs were caught in 26 trawls; the males were 67.54% and the females were 32.46%. The dominant size groups for males 'and females were 115 mm and 105 mm, respectively. Females mature at a smaller size and breeding Mkes place during February-March. The widthlweight reitationship study show,~d that females were heavier. The 'regression equation for female is: weight = 4.233 x 10-9 x L 4.969, and for male is: we:ght = 2.750 x 10-6 x L 3,636. The crabs were found to prefer loamy soil. The crab Portlll1l1S pefagiclIs constitutes a good food resource in the moutl>, region of Zuari estuary.

Abundance and distribution of penaeid larvae as an index of penaeid prawn resources of the indian ocean

Abstract: Andysis of the data on the abundance of larvae of penaeids in 1927 plankton samples collected from the Indian Ocean during the International Indian Ocean Expedition (1960-1965) has shown that these larvae are more commonly represented in the area nearer the coast as indicated in the preliminary observations by Menon et al (1967).

A new species of sergestid shrimp, Acetes orientalis (Crustacea: Decapoda, Sergestidae) from Goa, Central West Coast of India

Abstract: Acetes orientalis, a new species of sergestid shrimp belonging to the genus Acetes H. Milne-Edwards collected from the Mandovi estuary, Goa, Central West Coast of India has affinities to most of the Indo-Pacific species. The petasma of the male has resemblance in shape to. A. sibogae, A. vulgaris, A. sibogalis, A. australis, A. erythraeus and Acetes sp. and very much alike in structure to that of A. sibogae. The female genital area has a pair of protuberance as in A. vulgaris and A. indicus. These combinations in characters along with several other important features which justify the creation of this new species are discussed in comparison with those of the other Indo-Pacific species having closet affinities.

Occurrence of Rhyolytic Tuffs at Deep Sea Drilling Project Site 219 on the Laccadive Ridge

Abstract: A study of thin sections from the lower and middle parts of Unit V (Paleocene) from Site 219shows that these largely consist of acidic or rhyolitic tuffs. The overlying limestones in Unit V (Paleocene) and Unit IV (Lower Eocene) also contain tuffaceous material in varying proportions. Albite/oligoclase forms the phenocrysts as also needles in the groundmass of these tuffs and tuffaceous material in limestones. The euhedral fresh felspars suggest that the source of activity was nearby and possibly most of the activity was subaqueous rather than subaerial. Similar acidic tuffs in the Deccan Traps have been reported particularly from the West Coast of India. The acidic tuffs at site 219 are of the same age as the Deccan Traps and may represent a late phase of Deccan Trap activity on the Laccadive Ridge before its subsidence and separation from peninsular India.

A New Calanoid Copepod of the Genus Acartia From the Cochin Backwaters, India, and a Redescription of Acartia Centrura Giesbrecht

Abstract: [Acartia bowmani n sp a ete recueilli dans les "Backwaters" de Cochin, un estuaire caracterise par la grande diversite specifique des Acartiidae signales Cette espece est particuliere par la structure des P5 ♂ et ♀, les epines des A1 ♀ et des Ur II-IV ♂ L'espece etroitement apparentee et qui cohabite avec elle, Acartia centrura Giesbrecht, est redecrite de maniere comparative afin de mettre en evidence les differences morphologiques des deux especes, Acartia bowmani n sp a ete recueilli dans les "Backwaters" de Cochin, un estuaire caracterise par la grande diversite specifique des Acartiidae signales Cette espece est particuliere par la structure des P5 ♂ et ♀, les epines des A1 ♀ et des Ur II-IV ♂ L'espece etroitement apparentee et qui cohabite avec elle, Acartia centrura Giesbrecht, est redecrite de maniere comparative afin de mettre en evidence les differences morphologiques des deux especes]

Distribution of Iron, Manganese, Cobalt and Nickel in Sediment Cores of the Northeastern Arabian Sea

Abstract: A study of the distribution of iron, manganese, cobalt and nickel in sediment cores from the shelf, slope and basin regions of Bornbay-Kathiawar coast of India shows that cobalt and nickel are derived from the overlying sea water as adsorbants of manganese and iron hydroxides, clay minerals, and organic matter present in the sediment. Since the cores represent differing environments, the inter-relationship and the factors governing adsorption and fixing them in the sediment vary considerably. Mn/Fe ratio decreases uniformly with depth in the shelf sediments excepting in one core, whereas on the slope and the basin, it indicates a gain which is due to the enclosed slum and turbidite deposits. The manganese: iron ratios for (a) the shelf cores are 1 : 72; 3 : 205; and 6: 265; (b) for the slope it is 1 : 116; and (c) the basin 6: 170. The values are highest in one core. This suggests an enrichment of manganese in the shelf region and in the basin, but great mobility in the slope and parts of the shelf resulting in depletion. Iron-cobalt and manganese-nickel are the covariants, and hence correlatable. Significantly, the organic matter in the slope sediment is inversely proportional to the amount of manganese present in the sediment. One core shows some unusuIIy high values (56 ppm cobalt and 75 ppm nickel) as against the average values of 13 and 55, respectively, for near-shore sediments (total sediment) of North Atlantic and North Pacific.