Spawning frequencies and breeding seasons of some freshwater fishes with special reference to those occurring in the plains of northern India

Abstract

It is well known that the differences in the spawning behaviour of teleosts can to a certain extent be illustrated on the basis of the condition revealed by • the unspawned eggs in the ovary (Heidrich, 1925; Clark, 1925, 1934; Hickling and Rutenberg, 1936). Many studies on the ova diameter frequencies have been undertaken during recent years and in almost all cases it has been accepted that species which have all the ovarian eggs of similar size spawn them together whereas those which have a wide range in oocyte sizes may have several groups of eggs matured and shed periodically during the breeding seaso