Spawning Experiments of the Common Squid, Ommastrephes Sloani Pacificus Steenstrup, in An Indoor Aquarium

Abstract

In the course of making some experiments on the spawning of the common squid, Om-maatrephes sloani pacificus STEENSTRUP, the present author obtained four egg-masses from a number of fully matured specimens and reared them in an indoor aquarium at Kasumi Branch, Japan Sea Regional Research Laboratory, located on the Japan Sea coast of Hyogo Prefecture during the period from June to August, 1962. Out of the four egg-masses which were demersed and adhesive, three masses were found composed of nidamental gelatin, oviductal gelatin and fertilized eggs. Such masses had also been observed in the previous experiments made by the present author (Hamabe, 1961, Zool. Mag., 70, (11)). But unlike these three, there was still another mass of eggs quite new to-the author, which was composed of merely nidamental gelatin and fertilized eggs. It remains to be seen why those two different types of egg-mass are produced, now that they are both found to be fertilized with the larvae in potential. If this unreported mass of eggs were found naturally in the sea, it might be inferred that this particular mass of eggs is obliged to float in the mid-lower water of the sea, being caused by gravimetrical balance, when it is partly or wholly separated by chance from the substance to which it has been adhering. © 1963, The Japanese Society of Fisheries Science. All rights reserved.