Maturation of intra-ovarian eggs andspawning periodicities in some fishes

It is well known that, in the temperate as well as in the tropical waters, fishes exhibit various types of spawning tendencies which are closely connected with the development of the intra-ovarian eggs in batches. Examination of the periodicity in the production of ova in batches from the ovigerous lamellae in the ovaries of oviparous teleosts and a statistical study of the distribution of intra-ovarian eggs in the ovaries of various stages of maturity have been found to give reliable evidence on spawning habits of fishes Such a study of the intra-ovarian eggs in the ripe and earlier stages of maturity is the basis of the present investigation which was initiated with a view to determining the duration of spawning period in some of the edible food fishes. The work was started in 1945 at the suggestion of Dr. N. K Panikkar the then Director of the Madras University Zoology Research Laboratory' and continued later in the Central Marine Fisheries Research Station, Mandapam Camp.