Micro-PIXE Study of Whole Otolith of Japanese Eel at Elver Stage

bstract:Strontium and calcium contents, within the otolith of Anguilla japonica, were measured by external micro-PIXE. According to the measured metamorphic checks,each otolith was divided into three stages. Comparing with the Sr:Ca ratios in stage 2,the ratios in stage 1 had two different trends. Among these fish, it may reflect their maternal condition was not the same. The ratios in stage 3 which was corresponding to the estuarine habitat were smaller than that in any other stage which was corresponding to the ocean habitat in each otolith. Suggested by our results, the eels from the spawning site may separate into two groups when they are near to the south of Taiwan, and then move to the different estuaries in China. It could be proposed that,in general, the migration direction is from south to north along the east coast in China.