6:15 PM - 7:30 PM
[HTT31-P11] 87Sr/86Sr of threespine sticklebacks and water in Otsuchi: Implications for the current habitat range and past movement
In this study, we analyzed 87Sr/86Sr of back bones of the freshwater form threespine sticklebacks and compared with that of ambient water in order to estimate the current habitat range and the past movement. Results and discussions are shown as follows.
1. 87Sr/86Sr of ambient water can be grouped into three regions (more than 0.709156, 0.708165~0.709156, and less than 0.708165). The result suggests that there are significant differences among the habitat of threespine sticklebacks in Otsuchi area.
2. There was a significant correlation between 87Sr/86Sr of threespine sticklebacks and that of environmental water in each sampling point. The result indicates that Sr of threespine sticklebacks mainly derived from the environmental water.
3. 87Sr/86Sr of threespine sticklebacks can be grouped into three regions as well as the ambient water. The result suggests that threespine sticklebacks moved only within each region.
4. There were significant differences between 87Sr/86Sr of threespine sticklebacks and that of the ambient water in each sampling point. The result implies that threespine sticklebacks moved among sampling points within each region. However, the detected differences were small, and the temporal changes of water 87Sr/86Sr need to be studied.
5. In the coastal area, 87Sr/86Sr of threespine sticklebacks was higher than that of the ambient water, probably because the water was affected by the sea water (87Sr/86Sr = 0.70918) at high tide. However, there was a significant positive correlation between them. The result suggests that although these sampling points were expected to have connected with each other at the flood, threespine sticklebacks did not move among the points frequently.