A resume of the studies on early developmental stages of marine osteichthyes in India with suggestions for future research

Abstract

With more than seventy years history of research on identification of the early developmental stages of marine bony fishes in India, it is time now to assess the present status and to look forward for future lines of work. The number of species whose one or more developmental stages have been documented so far is less than 300, forming about 23 % of the total species reported from the country. The maximum output of important publications is in the fifties, followed by the sixties. In spite of these advances, only in a few cases that absolutely all the stages have been documented. Of the two methods of identification, the ' hatching method' has not progressed well so far, chiefly because oozing stages of most marine Osteichthyes are difficult to collect. Until ship-board and shore-based facilities are developed and/or perfected much more than as at present, in a country like India for the time being, there is no alternative, but to depend upon the 'series method' of identification. For this method to be effective, all the developmental stages of the concerned species should be documented. To achieve this, much more extensive and intensive collections are needed. Also, in order to make effective comparison and contrast of the developmental stages of allied species and genera, it is essential to define and standardise the important phases of development as well as to employ drawing skills, so that an uniformity of approach can be achieved. Besides, new characters, subtle features and differences in developmental sequences have to be found out and dociunented.