Diablo Canyon power plant site ecological study Quarterly Report no. 10; October - December 31, 1975

Abstract

Field work during the quarter included surveys of permanent and random subtidal and intertidal stations. At permanent subtidal stations densities of the brown algae Laminaria and Nereocystis decreased as did densities of giant red sea urchins, Strongylocentrotus franciscanus. Counts of small invertebrates within one-quarter meter square (1/4-m2) quadrats at random subtidal stations were begun. A total of 32 quadrats was completed. Balanophyllia elegans was the most abundant and most common animal encountered. The annual surface count of bull kelp (Nereocystis) was not possible because of the increased density; instead we utilized subtidal counts to estimate the surface canopy. An estimate of 33,000 plants was made for this year's canopy; this compares with a count of 18,000 plants last year. Sampling of random intertidal stations for the Davidson period began; 15 stations were surveyed. In addition, permanent intertidal stations 1, 2 and 3 were surveyed for abalone densities. The sea otter, Enhydra lutris, herd continued to occupy the area around Point Buchon. In November daily observations were initiated on foam location and abundance in Diablo Cove. (13pp.)