Further observations on the biology of the sting ray, Dasyatis imbricatus (Schneider) at PortoNovo

The length weight relationship of Dasyatis imbricatus (schneider) was calculated separately for males and females. The results show that exponent is greater than 3 for females suggest ing that growth is not strictly isometric. Analysis of gut contents reveal the bottom feeding nature of this ray with crustacean forms constiluting 64.8% followed by polychaetes with 33.5 of the feed. The size at first maturity is determined by relating the percentage of liver weight in body weight to the average body weight and also to the length of the body

Shark fishing in India

From time immemorial sharks have been the object of amusement for the sea faring men and anglers and they were fished for sports. At certain times of history they were dreaded as monsters of the sea because of the ravage they wrought on bathers, fishermen and their boats. Even the very appearance of an heavily built creature with open mouth full of sharp and ferocious teeth and black fins gives a fearsome apparition to unarmed people taking bath ill the shallow waters. Of all the 350 species of sharks inhabiting the seas of the globe, only less than 35 species are aggressive and attack human beings, boats and other objects. While it is true that there are a few ana,cks sporadically on human beings throughout the world, recent findings have shown that one , is less likely to be attacked by a shark than having a serious accident at bome or in the roads. One should give a wide berth to larger sharks considering their size and speed of action. Even a slight contact with their abrasive skin may resnlt in severe lacerations and damage will be irreparable. One should also avoid bathing in sea with fresh wounds especially when sharks are around

A brief description of the cat shark, Chiloscyllwm griseum Muller and henle, from Indian waters, with some biological notes

The cat shark, Chfloscyllium griseum, is described in detail based on samples collected frcm both the coasts of India. The patterns of growth of individual organs are also given. The length-weight relationship was not significantly different between sexes, so a common value, Log W = —4.8378 + 2.7314 log L, was obtained. The shnrk feeds on bottom fishes. Males mature at 520 mm and females at 530 mm TL. The egg-cases are laid outside for development

On some specimens of abnormal elasmobranchs

Instances of deformities or abnormalities have been reported on and off in fishes. The abnormality is extreme in certain cases that it is very difficult even to identify them correctly and this leads to creation of new taxa

On a Smooth Hammerhead Shark, Sphyrna zygaena (Linnaeus. J 758) New to Indian Waters

A mature female smooth hammerhead shark, Sphyma zygael1a ( Linnaeus), 2 .14 cm TL (T<lbJe I). was collected on 6- 10-1975 from the hook and line fishing operated from the mechanised vessels off Porto Novo at a depth of 80-90 meters. Since hammerheads are ident ified from the shape of head and teeth s truCtures only, the head has been preserved in the museum of the Marine Resea rch Laboratory of Annamalai University, Porto Novo

Sex change in hound shark, along Madras coast

The big eye hound shark, logo omanensis has been recorded from the continental shelf off Bombay and Kutch region along the west coast and the Gulf of Mannar in the east coast

Elasmobranch resources of India

Available information on the length-weight relationship, age and growth for some elasmobranch species was compiled and growth parameters discussed. Food and feeding habits studied for some species indicated preferences, except tiger shark, for certain food. In some cases there is shifting of food habits as the young shark grows to adulthood. Starvation of female sharks is a notable feature during advanced stage of pregnancy. The three types of development exhibited by different species are discussed. The size of litter, the relationship between the length of mother and litter size and fecundity are dealt with. Landings of elasmobranchs over the years were steadily increasing. There was spurt in landings during mid seventies. In recent years the elasmobranch production appeared to be stabilizing and a sign of stagnation in the landings is evident. Group wise, reqion wise and gear wise landings are discussed

Distribution and abundance of elasmobranchs in the Indian EEZ

Elasmobranchs were present in 100 trawling stations of depth up to 170 m, along the Indian EEZ, where the FORV Sagar Sampada carried out fishing operations during her first hundred cruises. Abundance and distribution of sharks, skates and rays in the different latitudinal zones are discussed. The catchable potential of this resource up to the 50 m depth zone has been estimated as 64934 tonne. Elasmobranchs being on exploitable resource, the potential yield beyond 50 m in the EEZ is estimated as 88985 m tonne. Though the maximum catch was obtained from the southwest area, the maximum c.p.u of elasmobranchs was observed to be along the northwest region

Distribution, abundance and biology of unicorn cod, Bregmaceros mcclellandi in the deep scattering layers of Indian Exclusive Economic Zone

In the deep scattering layer (DSL) the fishes have accounted for 5.4 % of the total (numerical) biomass. Juvenile fish belonging to different families were the most abundant component followed by Vinciguerria, myctophids, leptocephali, stomiforms, and unicorn cod. The "unicorn cod is represented by a single species, Bregmaceros mcclellandi (2.4%) in the total fish biomass. It occurred in 52 stations out of 445 IKMT stations. During day time the average number per haul was 21 where as in night hauls it was 29. The resource was fairly abundant along the northwest coast within the depth belt of 200 m. Biological studies on the size composition, feeding habits, and reproductive biology of the species were also carried out. The length ranged from 10-65 mm. The major diet consists of copepods, euphausiids, cheatognaths, ostracods and decapod larvae. Invariably the feeding intensity was low. The catch was composed of mostly females in maturity stages IV-V. The species spawns only once in a year. The fecundity ranged from 530 - 980 in fishes of 42 - 50 mm in total length

Flatfishes, goatfishes and whitefishes

Although in order to exploit these minor demersal resources there are no specialised fishing efforts, their contribution to demersal Jinjish production is substantial, mostly exploited by bottom trawling in recent years. The annual flat fish production has been amounting upto 63,344 t in 1992, that of goatfishes upto 33,300 t in 1991 and of whitefish to 25,340 t in 1985. Of late, Kerala has accounted for 47% flatfish production, followed by Karnataka-Goa 23% and Maharashtra 14%. For goatfishes, Tamilnadu-Pondicherry is responsible for 41% followed by Kerala 30% and Andhra Pradesh 13%. Gujarat has been harvesting 49% of the Whitefish yield, followed by Karnataka-Goa 18 % and Maharashtra 13%. The present paper brings together all the available data published and unpublished on the fishery and biology of various species contributing to the fisheries in different parts of the country. Based on these it is seen that the catch of the Malabar sole can be marginally increased in Calicut but not in Mangalore. In the case of the whitefish, there is an all-India decline in production in all the states due to indiscriminate exploitation of juveniles by considerably small cod end mesh size of bottom trawls. The present paper draws attention to the gaps still existing in our knowledge and the future research need on the fishery and biology of the important species, stock assessment estimates, relationships between the parental stocks and the progeny: the bottom hydrological conditions and the biological characteristics of the various populations in space and time, for realising the Maximum Sustainable Yield and for implementing their management and conservation