Otolith Sr : Ca ratios of the freshwater and anadromous cyprinid genus Tribolodon

Abstract

The ratio of strontium to calcium concentration in the otolith of four species of Tribolodon (Cyprinidae) was examined to reveal their migratory histories. The ratio was relatively stable from the core to the edge of the otolith in fluvial Tribolodon ezoe and T. hakonensis, whereas it changed from a low level to a higher level in anadromous T. brandtii and T. hakonensis. Four specimens of T. nakamurai from the Mogami River, Yamagata Prefecture, northern Japan, showed relatively stable ratios, indicating a fluvial life mode. On the other hand, the ratio increased once in only one specimen of T. nakamurai from the Koyoshi River of Akita Prefecture, suggesting the possibility that it was born in the Mogami River, the nearest major habitat of this species, and accidentally migrated to the Koyoshi River through the sea.