Some Considerations Concerning Sturgeon Spawning Periodicity

Abstract

In studying the age of sturgeons of the Danube (Romania), and of Acipenser fulvescens Rafinesque in the province of Quebec, I have observed a certain periodicity in their growth. This is seen not only in the age and length curves, but also in the cross-sections of the first ray of the pectoral fin which serve to determine the age of these fish. It is known that the growth of the body as a whole is in direct ratio to the growth of the bones, so the wide distance between two narrow (or winter) zones corresponds to the growth of the sturgeon during the summer. The growth retardations caused by the ripening of the gonads and the losses at the consecutive spawnings are visible in the ray sections in the form of "belts" of 2 to 7 narrower zones (or annuli). These indicate that the interval between spawning periods can vary from 4 to 7 years and more. It is noteworthy that spawning does not necessarily correspond with maturity, but may be delayed 2 or 3 years.