Occurrence of Johnius hololepidotus (Lacepede ) in Indian waters

While slight changes have been introduced in the nomenclature of Indian Scia:mids by Fowler1, 2 and Weber and Beaufort,3 no species essentially different or additional to those described by Day have so far been recorded from Indian waters

Notes on Littorina saxatilis and allied shells examined at the British Museum of Natural History, London

This short note records some notes made by the author on the shells of Littorim saxatllis (Olivi) and certain allied forms while examining these from collections in the British Museum of Natural History, Londo

Occurrence of growth checks in the scales of the Indian mackerel, Rastrelliger canagurta (Cuvier )

Age and growth studies form an essential part of fishery biological research. Owing to the well-known limitations of the length-frequency method in these studies the need has been frequently felt for other suitable method

Phosphate content of mudbanks along the Malabar Coast

The importance of the phosphate content of water masses as a limiting factor in their organic productivity has long been recognized. The investigations of Mortimer Moore, Stephenson and Rochford have stressed the importance of the bottom muds in the phosphate cycl

Studies on the age and growth of the malabar sole, Cynoglqssus semifasciatus, Day

For the development of a scientific management policy for any fishery, it is essential to know among other things, the rate of growth of the species concerned and the changes in the age-composition of its stocks from season to season and from year to year. The present paper deals with the results of investigations which were designed to collect information on these two aspects in relation to the Malabar sole, Cynoglossus semifasciatus. Although this forms a valuable fishery along the Malabar Coast no attention has been paid in the past to a detailed investigation of its biology. There are however, brief general references to certain aspects of this species by Chidambaram and Venkataraman (1946) and Devanesan and Chidambaram (1948) in their accounts of the fisheries of the West Coast of Madras State. A detailed study of the fishery and biology of this species has been carried out by the present authors at Calicut and a short note forming part of this work has recently been published (1951) on the possibility of age determination in this species by means of scales

On some eye-abnormalities in the Malabar sole, Cynoglossus macrostomus Norman

In a previous note (Seshappa, 1970) the present author has described a specimen of Cynoglossus semifasciatus Day with the right eye on the ' blind ' side of the head, almost in the original unmetamorphosed symmetrical position, and the left eye in its normal adult position on the coloured side of the body ; this is apparently the first instance of this kind recorded for any flat-fish in the Indo-Pacific region. Two more such specimens with the eyes situated in positions similar to the above have been since discovered. Also a large number of instances of eye-abnormalities of various degrees have been noticed by the author so far in the routine collections of this species examined during the years 1965-69. As the position of the eye and its migration form a very important part of the metamorphosis in the flatfishes, these specimens have been examined in some detail and the present paper gives an account of the results of these studies together with a discussion of the probable significance of the various abnormalities noticed

Age determination studies in fishes by means of scales with special reference to the Malabar sole

One of the outstanding achievements of fishery research during the last half- a-century has been the discovery and application of the method of analysis of the age composition of fish stocks based on the study of- growth marks on scales, otoliths and in a few instances vertebrae or other bones

Studies on the fishery and biology of the Malabar sole, Cynoglossus semifasciatus Day

The Malabar sole, Cynoglossus semifasciatus Day, is a fish of considerable commercial importance along the Malabar Coast. Apart from the fact that it ranks often next only to the sardine and the mackerel in total landings, it is the only fish available on this coast during certain periods of the year. The species was therefore taken up for detailed investigations in the programme of the Central Marine Fisheries Research Sub-Station at Calicut. The work was commenced in April, 1948, and the present paper embodies the results of these investigations up to March, 1952

The problem of age-determination in the Indian Mackerel, Rastrelliger kanagurta, by means Of scales and Otoliths

• The study of the scales of Rastrelliger kanagurta (Cuvier) collected from different centres during the period 1955-67 and 1969-70 showed that at all centres specimens below 21 cm in total length were without scale-rings; a small percentage of specimens in the • 21-22.9 cm group showed rings, while a large percentage among those above 23 cm total length showed the rings in all the centres, this percentage being the smallest (63.1 %) at Calicut and largest (94.3%) at Karwar. Two rings occurred frequently in specimens above 25 cm and up to four rings occurred in the very large specimens of Vizhinjam and Mandapam, but in these large specimens reading of the rings was difficult as they frequently became faint and obscured as a result of the thickening of the scales subsequent to the ring-formation. The scale-rings seem to be formed as a result of a physiological strain on the fish during the process of growth and ripening of the gonads and also spawning. When clear rings were not noticed in mackerel with gonads in advanced stages, there were thin margins, which indicated the beginning of ring formation. The otoliths did not show any annuli that could be used for age-determination. It is suggested that the mackerel reaches a total length of 11-15 cm by the end of the first year, 21-24 cm by the end of the second year, 25-27 cm by the end of the third year, and 28-29 cm by the end of the fourth year of life

Some morphometric studies on five species of Cynoglossus (Family Cynoglossidae, Order Heterosomata) from the west coast

^Selected morphometricaaii meristic characters Have been analysed in live common species of Cynoglossus at Calicut, namely, C. macrostomus Norman,.'C. dubius Day, C puncticeps (^chardson), C. M/nea/«s (Lacepede) and C lida (Sleeker). For comparing the morphometrrc ratios Pearson's coeflScient pf variation (P.C.), is used as a measure of the degree Pf >%riability. The total length/body length ratios >^ere found to be the least variable while the ratios connected with the eye and orbit showed the most variable P.C. in all the species. A comparative table and description are given of the ratios studied of the different characters for the five species chosen. The calculated values of t for the mean ratibs in all paired combinations of the five species have been tabulated, and the Probability (P) is found to be significant for most of the comparisons made