Maturation and spawning of Indian mackerel

The relation between body length and mature ovary is curvilinear whereas a straight line relation exists between the weight of the fish and weight of the ovary. Mackerel is a prolific breeder. Ova diameter studies indicated the presence of 6 batches of ova in the mature ovary at a time, the first batch ripening in a short period. Histological studies revealed the presence of early perinucleolar oocytes even in partially spawned ovaries, suggesting a continuous oogenesis and production of more than six batches of ova. Intensive spawning takes place from April to July. Monsoon and upwelling with consequent replenishment of nutrients effect a plankton bloom in the surface waters causing a spurt in the reproductive output of mackerel resulting in intensive spawning, reduced larval mortality and better recruitment