Local group studying Pismo Beach clam population

Posted at 7:15 PM, Jun 09, 2018
and last updated 2018-06-09 22:15:34-04

A new study on the Pismo Beach clam population is underway on the Central Coast.

June marks six months of that research.

A Cal Poly grad student recently presented their findings to the Pismo Beach City Council.

Pismo clams are iconic, but not much is known about their biology. Since December of 2017, Alex Marquardt has been taking samples of the clams from Pismo Beach in hopes of learning more.

"We have been seeing a period of growth over the last six months which has been really exciting," Marquardt said.

She’s working to find out how populations change over time like when juvenile clams end up on our beach and how long it takes a clam to grow to a harvestable size.

"When we first started sampling, they were all about an inch and a half and right now they’re closer to two to three inches," she continued.

"We haven’t actually seen any legal sized clams, about four and a half inches since 1990," said Benjamin Ruttenberg, Cal Poly Biological Sciences Professor.

Ruttenberg is also working with Marquardt to find out what’s happened to the declining population. 

"There had been some historical data from the 20’s, 30’s, and 40’s on Pismo clams, they used to be very abundant here, in some cases, harvested literally by the millions, here on Pismo Beach," Ruttenberg explained.

Several years ago, baby clams started popping up on the beach. Ruttenberg says that suggested there’s a population of reproductive adults somewhere in the area. Their sampling is in an effort to hone in on this too.

"We have been finding on Pismo Beach about two to four clams per square meter," Marquardt said.

"We’re really trying to understand what’s limiting their population so we might be able to bring them back," Ruttenberg concluded.

The study will run through December of 2019. It’s funded by the City of Pismo Beach.

They’re also looking into why some of the clams are dying off before reaching a harvestable size. If you are interested in helping with the sampling of the clams they’re looking for volunteers. To contact them, click here.