Research groups such as the University of Tokyo, the Ocean Research and Development Organization, and the National Museum of Japanese History have investigated the age of shells of "binosugai" collected from Funakoshi Bay in Otsuchi Town, Iwate Prefecture, and found that Vinosugai is the longest-lived marine bivalve in Japan. In addition, it was clarified that the annual growth of shells shows a fluctuation pattern similar to that of the Atlantic decades scale fluctuation.
The climate of the earth fluctuates in various cycles. Knowing "how big a shell grows in a year" is an indicator of "how suitable the environment of the year was for the growth of shells", so we will examine the annual growth of past shells. It has been thought that this could clarify past environmental changes, but long-lived bivalves have not been known and research has not progressed in the waters around the Sea of Japan.
Since the 2011 off the Pacific coast of Tohoku Earthquake, the research group has been continuously investigating the impact of tsunamis on the ecosystem in Funakoshi Bay, Otsuchi Town, Iwate Prefecture. I found several.One of them, 92 years old, was found to be a long-lived individual who survived the two major tsunamis.When the annual growth amount was investigated from the growth line of the shell by applying the method used for the annual ring of the tree, it was interesting to show a pattern close to the long-period climate change of the Atlantic Ocean, despite the shellfish collected in the Pacific Ocean. ..
It is expected that this study will greatly contribute to the mechanism of long-period climate change and fishery resource change in the hundreds of years by collating growth patterns with multiple individuals and connecting the times.
Paper information:[Marine Environmental Research] Stimpson's hard clam Mercenaria stimpsoni; a multi-decadal climate recorder for the northwest Pacific coast
