Seasonal Changes in the Ovary of the Immature Hake, Merlucius merluccius L.

Abstract

A seasonal variation is found in the ovaries of immature hake (Merlucius merluccius L.).There appears to be a seasonal change in the rate at which young eggs are formed from resting oocytes, as indicated (1) by the change in the relative abundance of nuclei in synapsis, and (2) by the change in the average diameter of the eggs in the egg-stock in the ovary. These processes show considerable correspondence in their season of incidence with the ovarian cycle of the mature and adolescent fish.A physiological rhythm has now been detected in both somatic tissues and gonad in the immature hake, which foreshadows the physiological rhythm associated with the spawning cycle in the mature hake. The implication of this on the question of the formation of “growth-rings” in the skeletal structures is briefly discussed.