Do you know where sand crabs find love? Is there such a thing as a Match.com for sand crabs? It just so happens that there’s a great spot for sand crab love, and it’s along certain parts of Ocean Beach.
Ocean Beach isn’t only a great spot for sand crabs to find love, but it’s also a near many new Marine Protected Areas in California. The National Oceanic Administration Association informs us that California has established 120 new Marine Protected Areas (MPAs) that create safe environments for marine animals. MPAs conserve the nation’s cultural and natural resources and there are currently 437 MPAs in the United States. We wanted to study sand crabs on Ocean Beach so we could learn more about sand crabs and where they are most populated.
In November of 2007, the container ship, Cosco Busan collided with a Bay Bridge support tower. The ship was fatally wounded, oozing 53,569 gallons of oil into the San Francisco Bay. The aftermath of this incident may have accounted for a steep drop in the sand crab population on San Francisco’s Ocean Beach in the years to follow. The oil spill may have affected the number of surviving recruits, or young sand crabs, especially since the mating season for sand crabs occurs in spring and summer, thereby affecting the number of recruits in 2008.
Our Marine Biology class participated in the LiMPETS sandy beach monitoring program on September 20th, 2014 at Ocean Beach. To survey the sand crabs living on the beach, we took 50 random samples of sand from the swash zone, or the zone of wave action. In each of these 50 samples, we observed any sand crabs that were found. We recorded their gender and assessed whether they were a recruit (young crab) or adult.
Author: Jeff Sandler, teacher, The Berkeley School
In May 2014, the 7th grade life science class from The Berkeley School spent an entire week out in the field focusing
on some of our local communities. In addition to participating in both LiMPETS monitoring projects (sand crabs at Muir Beach and the rocky intertidal zone at Duxbury Reef in Bolinas), students and teachers spent a night camping and learning about the redwoods at Samuel P. Taylor park.