Cuthona adyarensis; A New Nudibranch (Mollusca Gastropoda) from Madras

Examination of an algal bed of Hypnea on 15th March, 1948 revealed a fair number of small Nudibranch molluscs in shallow waters of the estuary of Adyar River, off its northern bank about a hundred yards of the Elphinstone bridge. The algae were found covered with microscopic hydroids upon which the Nudibranh were feeding

Life-history studies on Indian sea mussels

Mussel culture operations are in good progress at the demonstration farms of the Central Marine Fisheries Research Insti tute at Vizhinjam and Calicut along the west coast and at Kovalam near Madras on the east coast

Sex change in the oviparous Indian backwater oyster, Ostrea madrasensis Preston

The adult larviparous oysters are always hermaphrodite whereas the oviparous ones are of separate sexes. Following the discovery of a single hermaphrodite individual in one species of oviparous oyster by Kellog,a other workers, viz., Burkenroad,4 Loosanoff,() Amemiya.1,2 Awati and RaP and RoughleyB have observed occasional change of sex in the American oyster

Induced spawning of the adults and laboratory rearing of the larvae of the edible oyster Crassostrea madrasensis (Preston)

The papsr dascribes the results of an early experiment on spawning of Crassostrea madrasensis and larval rearing in the laboratory. When the gonad was ripe the female readily spawned in the presence of milt from the mile oyster in the surrounding water. The results of stimulation by the use of aqueous solutions of chemical substances showed erratic trends

Results of the exploratory fishing operations of the Government of India vessels at Bombay base for the period 1961 - ' 67

The fishing vessels of the Government of India, Deep Sea Fishing Station, Bombay, conducted exgloratory fishing operations in areas between latitudes lSoN to 23 10'N and longitudes 6So10'E t o 730 S0'E, cover ing 25,100 nautical square miles on the continental shelf during 1961-1967 . The paper presents the results of, operations giving details of regional, seasonal and depth distribution of fish categories

Indian Mackerel; Identity

The family Scombridae (under the order Perciformes of sub-class Actinopterygii) comprises four subfamilies viz., Gasterochismatinae, Thunninae, Scomberomorinae and Scombrinae. The first subfamily includes just one member, Gasterochisma melampus Richardson, popularly known as the butterfly mackerel which has a southern and disjunct distribution, occurring on coast of South Africa, New Zealand, Australia and Argentina. Thunninae includes a large assemblage of species, called tunnies coming under the genera Auxis Cuvier, Cybiosarda Whitley, Sarda Cuvier, Gymnosarda Gill, Thunnus South, Allothunnus Serventy, Orcynopsis Gill, Katsuwonus Kishinouye and Euthynnus Jordan and Gilbert. The genus Thunnus comprises several subgenera, viz., Thunnus S.Str., Parathunnus Kishinouye, Kishinoella Jordan and Hubbs and Neothunnus Kishinouye.Scomberomorinae has the seer fishes under the genus Scomberomorus Lacepede and the Wahoo under Acanthocybium Gill. The subfamilyScombrinae includes the chub mackerels or the true mackerels and the double-lined mackerel under the genera Scomber Linnaeus, Rastrelliger Jordan and Starks and Grammatorcynus Gill. Most members of these four subfamilies are well distributed in the Indo-Pacific region. Some, however, are restricted in their distribution to temperate regions only as Scomber scombrus, Orcynopsis unicolor and Allothunnus fallai Serventy. The genus Rastrelliger has two valid species i.e. R. kanagurta (Cuvier) and R. brachysoma (Bleeker) occurring in the seas aound India, the former being by far the commonest and most abundant mackerel species in this region

Problems related to seed procurement for culture of marine edible bivalve molluscs : Crassostrea madrassensis and mytilus (= Perna) viridis

Procurement of adequate quantities of seed is an essential primary step in undertaking culture practices of economic species of bivalve mollusc

Observations on the probable effects of salinity on the spawning; development and setting of the Indian backwater oyster, Ostrea madrasensis Preston

The salinity of sea-water, like its temperature, is one of the abiotic factors having a remarka ble innuellce on the development of oysters as is well known from the work of Amemiya (1921. 1926 and 1928), Nelson ( 1921), Seno, Hor; and Kusakabe (1926), Hopkins (1931), Gaarder (1932, 1933), and Gaarder and Bjerkan (1934) on differ~nt species of European, Ja panese, Portuguese and American origin

Trawl fishing in India

Attempts at offshore fishing by trawlers since 1900 and the results obta inec are described. In the first half of this century some useful information on the trawling grounds was gathered but all efforts at commercial offshore fishing operations f ailed. Since about 1950 remarkable progress in offshore fishing operations has been made. The regiona l abundance of fish catches and the extent of trawling operations conducted at present from different bases are discussed. The nonavailability o f sufficient numbers of seaworthy fishing vessels has hampered intensive exploratory and commercial fishing operat ions in recent year

Exploratory Fishing

While the exploitation of the inshore fisheries with the help of indigenous non< mechanised craft and gear is being carried out fairly intensively from very ancient times, combing of the depths of the high seas in India using power driven vessels operating trawls and other types of gear has come into vogue only within the last few decades. Different organisations at present are conducting large scale exploratory and commercial offshore fishing operations from different bases viz, Bombay (Government of India Deep Sea Fishing Station, Directorate of Fisheries of Maharashtra State and the New India Fisheries Company Ltd.), Goa (Directorate of Fisheries, Government of Goa), Karwar (Indo-Norwegian Project), Cannanore (Indo-Norwegian Project), Cochin (Government of India Offshore-Fishing Station, Indo-Norwegian Project, The Cochin Company, New India Fisheries Ltd., Island Seafood Private Ltd.), Tuticorin (Government of India Offshore Fishing Station^, Mandapam (Indo-Norwegian Project) and Visakhapatnam (Government of India Offshore Fishing Station