Showing papers by "Nankai University published in 1951"

Studies on the Stocks of Sharks and Rays

Abstract: The method usually used for age determination of teleostean fishes on the basis of the annual rings as observed in the scale, otocyst and centrum cannot be safely applied to elasmobranchs since the characters in question lack certainty in this group. Casting about any character which may answer this purpose, the present author hit on the clasper length. While the body as a whole grows in this class of the fish almost continnonsly, the clasper lengthens step-wise once a year possibly immediately after the spawning scason. The approximate age thus estimated are shown in Figs. I-III, Tables I-II, and also in Tables III-VIII.