Iconic and Ancestral
Pismo clams were once an abundant recreational fishery species throughout California and on Pismo Beach in particular. They are iconic — important to Californians over the last century and to the indigenous Chumash People for many centuries before that. The abundance of Pismo clams declined statewide over the last several decades, but populations on Pismo Beach have shown strong evidence of a comeback in recent years. Cal Poly researchers are studying both of these trends.
Pismo Clam Research at Cal Poly
Our research aims to understand the current status of Pismo clams, the mechanisms that impact their abundance, and how we can collaborate with local organizations to ensure that the current population recovery is a lasting one. This research is made possible by Cal Poly undergraduates and graduate students, our agency partners, and community support. Generous funding has been provided by:
Our Research Process
To understand how Pismo clam populations are changing over time, we conduct quarterly surveys on Pismo Beach. We sample at low tide from the top of the beach into the intertidal (the area between high and low tide) as far as the tide will allow us to get. We dig trenches of specific sizes called transects, counting and measuring (and reburying) all clams found in each transect. This monitoring effort began in 2014 and continues today, helping us build a robust, long-term dataset. Such a dataset provides us with important information on Pismo clam abundance and size, essential to understanding population trends and informing management.
How You Can Help!
- Make a donation to support Pismo clam research at Cal Poly.
- Learn more about Pismo clam history and sustainability and share your knowledge.
- Read the FAQs below to learn more about our Pismo clam research surveys and how community members can participate with our tagging project.
FAQ's
What happens during a survey?
We start near the top (inland) portion of the beach and run transects perpendicular to the ocean (essentially a long line). Sand is dug in 3-meter sections as far into the intertidal as possible. We run the sand through a custom sieve which allows us to document very small clams. We measure each clam and either collect them for lab analysis or rebury them! Fieldwork is physically demanding (shoveling, lifting/carrying buckets of water, etc) and at the whims of the tides! Fall/winter tides are comfortably in the afternoon, while spring/summer tides are very early in the morning.
What about the tagging project?
In the summer of 2021, we started a mark and recapture study for Pismo clams on Pismo Beach. We collect clams, measure them, and tag them with a unique number, metal washer and a QR code. The unique number allows us to identify individuals, and the washer helps us find marked individuals with a metal detector. Recapturing marked individuals allows us to measure growth, survival, and movement of individual clams, critical data for understanding key ecological processes. This important project is ongoing, and we hope to continue it for many years.
The QR code allows members of the community to be a part of this study! If you find a clam with a QR code, please scan the code with a smartphone. It will open a short data form; answering a few questions will help us collect important data!
Learn More about Cal Poly Pismo Clam Research
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