Some observations on the reproduction of the milkfish Chanos chanos (Forskal)

Several aspects of reproduction of the milkfish are still baffling and the progressive reproductive phases of the gonads and the spawning cycle in the fish are not properly understood. The validity of a statement by Chaudhuri (1916) that the ripe roe of Chanos is dried, smoked and sold by fishermen around the Chilka Lake which conveys an impression of common occurrence of the breeders was inquired into and it is understood thai the fish are now rare in these places

Utilization of saline mud flats for fish culture-An experiment in marine fish farming

The scope for economically feasible fish farms in brackish water areas in India has long been realised and practically demonstrated by the numerous fish and prawn farms adjoining the backwaters of Cochin along the west coast. Apart from these even some of the other low-lying saline coastal mud flats of the south-east coast of the Indian Peninsula, which periodically get flooded with sea water but usually with a relatively low biological productivity owing to certain inherent ecological drawbacks, also show potentialities for development. Attempts at fish culture in similar marine environments have not been many in this country except for the earlier enterprises by the Madras Fisheries Department as reviewed by Chacko and Mahadevan (1956). A project was recently undertaken at the Central Marine Fisheries Research Station in order to determine to what extent these apparently low productive areas can be brought under more effective utilization for fish culture purposes and the preliminary results are given in this account

Pituitary of Chanos chanos (Forskal)

It is well established by previous workers that the glandular component of the pituitary in teleosts is derived from the ectoderm of the buccal cavity. Haller, Matthews, and Kerr have obsorved that the first appearance of the pituitary in all teleosts is as a solid ectodermal inpushing of the buccal epithelium, without any cellular differentiation, which extends below the brain and bocomes stalked

Anatomy of Armandia leptocirris Grube (Polychaeta)

The genus Armandia is one of the three genera of subfamily Polyophthalminae belonging to the Family Opheliidae (Hempelmann, 1927) and includes four known species A . polyophthalma, A. cirrosa, A. lanceolata and A. leptocirris. Of these the last two species occur in restricted localities in the Indo-Pacific region and have been collected from the Indian Ocean in the Persian Gulf, Gulf of Mannar, around the Andaman Islands and the Mergui Archipelago (Fauvel, 1932

New hope for salt water fish culture

With the recent success in induced fish-breeding techniques a major impediment in fresh water fish culture has been removed and henceforth we may expect greater progress in inland fish culture. However, our low-lying, coastal, saline areas remain neglected except for brief spells of fishing activity

Salt Water Fish Culture in India

Despite a tradition that dates back to the very ancient times, salt water fish culture as a profitable industry is only a recent development in India, largely prompted by the urgent need to increase our much-needed protein food. But within the past half a century even after the realisation of our potential, it must be said at the outset that we have not made adequate progress in harnessing our resources, especially when compared to the great strides this industry has taken in the east-Asian countries or along the Adriatic coast of the Mediterranean region. Generally speaking, fresh water fish culture has shown much greater promise and improvement and this practice is fast developing in our country, perhaps on account of easier management and quicker results that are obtained. The following discussion, however, will be confined to some of the special aspects involved in fish farming in environments that are more akin to marine conditions, and the scope for improvement in the existing methods of salt water fish culture

Utilization of saline lagoons for fish farming

While exploring the possibilities of increasing our food resources, the question of proper utilization of coastal mud-flats and lagoons has special significance. On account of their highly saline nature, agriculture of any kind is impossible in these areas and as such extensive coastal regions remain barren

Pelagic swarming of Polyophthalmus (Family Opheliidae-(Polychaeta)

The Opheliid is identified as a-juvenile Polyophthalmus pictus (Djuardin) and a slightly contracted specimen is shown in the figure. When freshly caught these worms swim about vigorously with a wriggling or more often a darting movement characteristic of many of the adult Opheliid

Oxygen consumption and viability of Chanos chanos (Forskal) in relation to size

The importance of the size factor in metabolic studies on fish has been emphasised by Rubner (1924) who found that the oxygen consumption in the pike and in the tench was correlated exponentially with the body weight of the fish. More recently, Busnel, Drilhon and Raffy (1946) have investigated the oxygen consumption of the fry and alevins of the rainbow trout in waters of varying salinity; their results indicate that the salinity of the external medium is a second decisive factor influencing respiration

Review of work programmes carried out in India on the biology of the milkfish Chanos chanos

This account is a brief review of the investigation carried out in India on the various aspects of the biology of the milkfish. It covers the records of observations on the distribution of Chanos fry in the coastal areas, food and feeding of the fish, its growth, maturity, fecundity and spawning, and also certain experimental results on the physiological adaptation of the fish together with the histological structures of its kidney, pituitary and thyroid. While emphasising the paucity of data on the adult milkfish in the wild, the priority areas where information is lacking especially on the spawning ground, reliable identifying characters of the egg as well as on the possible existence of different racial stocks have been discussed