One of our oldest inhabitants

Surprised to find this elderly animal on the big bare beach: it comes from deep waters.

It's a huge clam, roughly 5 inches long and almost as thick - an ocean quahog, Arctica islandica. This gastropod is the longest lived creatures on the earth, beating whales and elephants, and even the giant tortoises of the Galapagos Islands. 

As with trees, the annual growth rings of the quahog's shell can be measured, counted and even cross-checked with the growth rings of ancient shells.  
You can read about this here.

The clams that live in Arctic climes are the slowest growing and have been used  to assist with the study of gerontology. The oldest specimen so far dated was found to be 500 years old. Unfortunately the process of measurement required ending that long life.  

I did briefly think about cooking and eating this one but quickly decided against. Apart from the respect the creature deserves, its flesh would surely be incredibly tough after its long marination in brine.

I threw back as far as I could hoping it will survive for a few more years.