The Spawning of Echinus Esculentus and Some Changes in Gonad Composition

Abstract

1. The spring inshore migration of Echinus at Port Erin in 1930 started in early February and reached its maximum in the middle of March. Mature gonads were found at the end of February and throughout March and early April. At the end of June all gonads examined were spent. The sea temperature throughout this period was observed. It is probable that May was the chief month in which natural spawning took place. 2. A cycle of changes in the composition of the gonad are recorded from November 1929 to July 1930. The chief of these are: (a) In the males an increase in percentage dry weight as the gonads mature ; the opposite taking place in the females. (b) A large and simultaneous decrease in percentage glycogen in both male and female gonads prior to spawning followed by a great post-spawning increase. The fatty acid content does not alter with the maturation of the gonad, but an indication is given that an increase in the percentage of carbohydrates other than glycogen occurs. Hence it is suggested that glycogen is transformed in the maturing gonad into carbohydrate food reserves for the ripe eggs and sperm.