SPAWNING FREQUENCIES AND BREEDING SEASONS OF SOME FRESHWATER FISHES WITH SPECIAL REFERENCE TO THOSE OCCURRING IN THE PLAINS OF NORTHERN INDIA

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