Life History styles of three-spined stickleback, Gasterosteus aculeatus (L.) which inhabit the coast of Iwate, Japan

摘要

The Strontium: Calcium (Sr: Ca) ratio from an otolith section of three-spined stickleback, Gasterosteus aculeatus (L.) was examined in samples taken from the Hei River mouth, and the Gensui district of Otsuchi in the coast of Iwate, Japan. The samples were analyzed using an electron probe X-ray micro analyzer (JEOL JXA 8600). While the otolith from me Hei River showed a high Sr: Ca ratio, those from the Gensui district showed a low value and little fluctuation. We can conclude from these findings that G. aculeatus (L.) collected from the Hei River is an anadromous type, whilst G. aculeatus (L.) collected from the Gensui district is a fresh water type.