The Pismo clam needle in a haystack

A few years ago, Cal Poly undergraduate Emily Knighton conducted a pilot tagging study of Pismo clams as part of her senior project. She developed methods to mark them, tested finding them (with a metal washers and a metal detector!), and then marked 50 clams and put them back on the beach. A month later, we went back to look, but a series of swells had rearranged the beach. We found none, and thought they were gone forever...

...until this month, when someone found one of our marked shells, posted a picture on social media, and the social media science world helped us connect. Clam #18 was 57mm when it was tagged on Dec 8, 2018, and the shell was found on Oct 11, 2020, almost two years later! It was dead (but with hinges still attached, so probably hadn't been dead long) and it had grown to 77mm. So not only do we get a little growth data, but we have evidence that the tags will last at least 2ish years. We will try again, so stay tuned for more info. And, if you happen to find a marked clam, please let us know!