Pilot Mark Recapture Study on Pismo clams!

Emily K., Senior in Biology, started a pilot mark-recapture study for Pismo clams on Pismo Beach!

Mark-recapture studies are a tool to estimate population size. In the simplest form, you “mark” a number of individuals and release them back into the environment. You later return to “recapture” individuals. Based on how many individuals are marked vs. not marked, you can estimate how large your population size is, understand individual growth rates (i.e. how much does a clam actually grow in a year?), and get an idea of mortality rates.
​
For her senior project, Emily tested several tagging options to mark Pismo clams and be able to identify individuals. Ultimately, she found a metal tag paired with a numbered tag was easy to detect through the sand. On December 8th, we set up a pilot study! A total of 50 clams were marked using Emily’s methods. In the coming months, we will attempt to find these clams again. If all goes well, this will be the start of a longer mark-recapture study. This is an exciting step towards understanding how far Pismo clams move across the beach and how quickly they grow on Pismo Beach!

Emily burying the last marked clam!

The survey team helping rebury clams.