The Indian Mackerel: IV. Bionomics and life history

Abstract

Mackerel is heterosexual and two instances of hermaphroditism were recorded one in a specimen caught from Majali, near Karwar (Prabhu & Antony Raja, 1959) and the other in a specimen obtained at Ullal, near Mangalore (Rao, 1962). In the first instance, the left gonad, situated slightly anterior to the right one, showed the characteristics of an ovary and contained yolky eggs ranging in size from 0.15 mm to 0.31mm mixed with a large number of transparent immature eggs. The right gonad had the characters of a normal testis. The genital ducts (oviduct and vas deference) emerging from them appear to open outside through a common aperture. The ovary was in stage III of maturity.