History of Pismo Clams in California

History of Pismo Clams in California. . Pismo clams (Tivela stultorum) were harvested by the millions on Pismo Beach and supported a thriving commercial and recreational fishery. Early clammers would use horse-drawn plows to find Pismo clams in the sand. From 1916 to the closure of the commercial fishery in 1947, an estimated 6.25 million pounds of Pismo clams were harvested in the state of California. The majority of these clams were harvested on Pismo Beach and surrounding areas. Annual harvests were nearly 100,000 pounds per year, with the highest harvest recorded at 665,700 pounds. While impressive, this level of harvest was unsustainable and commercial harvesting of Pismo clams was prohibited in 1947. Recreational harvesting of Pismo clams is still legal in California Department of Fish and Wildlife, however the last legal size clam was documented on Pismo Beach in 1993. Clams must bigger than 4.5 inches (114MM) south of the Monterey/San Luis Obispo county line and bigger than 5 inches (125 mm) north of the boundary to legally harvest., Life History of Pismo Clams , Pismo clams are found on open, sandy beaches from Monterey, California to Baja, Mexico. They primarily live in the intertidal or the portion of the beach that is covered during high tide and exposed during low tide. Living in this surfy habitat allows the clams to fee on microscopic algae and detritus floating in the ocean. Having access to this high quality food allows Pismo clams to grow up to 20mm (3/4 inch) per year. Every year Pismo clams create growth rings within their shell, so we can tell how old a clam is by how many rings are in it’s shell. It takes 5 to 8 years for clams to reach a legally harvestable size (4.5/5inches) and the oldest Pismo clam was estimated at 53 years old., As clams age they grow more slowly since they spend more energy on reproduction. Pismo clams are broadcast spawners, meaning they release eggs, sperm into the water, and fertilization occurs in the water column. It’s only by chance that a baby, larval Pismo clam is created in the ocean. Larval slams float in the ocean feeding and growing their first shell before they settle onto the beach they’ll live on for the rest of their lives., In 2016 research began at nearby Cal Poly, funded by the City of Pismo Beach, to try to understand more about the populations of Pismo clams. This research found that occasionally small clams appear on our beach. If you find a Pismo clam on the beach, rebury it where you found it to help populations recovers.