Histophysiological Appraisal of Ovarian Activity in an Indian Major Carp in Relation to Climatological Variables : A Data Based Approach

Abstract

The reproductive events in an annual cycle in different vertebrates including fish are known to be regulated by exogenous and⁄or endogenous factors. Taking a cue from the environment that undergoes changes regularly and reliably around the year, most animals use them for prediction of seasonal changes and programme their gonadal development and breeding activities in an annual cycle. Information regarding the changes in external environment is transduced to gonads through the pineal organ, which synchronises the various biochemical, hormonal, physiological and behavioural rhythms of the body. However, existing knowledge on the role of environmental factors in the regulation of fish reproduction is mostly based on the data collected from temperate zones, and such information on any fish in the low and mid­latitudes is severely poignant. Accordingly, an attempt has been made in the present communication to demonstrate month­wise variations in various histological and⁄or biochemical indices of activity of ovary and pineal complex in a hitherto unstudied free­living Indian major carp Catla catla and to draw possible relationship between the activities of these organs and different climatological variables. Various exploratory data analytic techniques have been used to give meaningful answers to some well posed problems.