The hard tissues of cephalopod, namely statoliths were analyzed with PIXE for the Japanese common squid Todarodes pacificus of the Sea of Japan origin in order to examine the relationship between the amount of trace elements in statoliths and environmental temperature of the squid habitat. Calcium, iron, zinc. copper and strontium were detected in the statoliths. Negative relationship was observed between Sr concentration in statoliths and environmental temperature. On the contrary to Sr, Fe and Zn concentration in statoliths related positively with environmental temperature. These observations revealed that the statoliths would be a useful thermometer for reconstructing the environmental temperature of cephalopod habitat as seen in the hard tissues of other marine organisms.

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