Tomales Bay

Tomales Bay occupies the northern end of the San Andreas Fault Zone as it cuts across western Marin County; to the west lie the late Cretaceous granitics of Point Reyes Peninsula, to the east, the earlier Franciscan Formation. The Bay is 20.3 kilometers (12.6 miles) long and varies in width from 658 to 2,652 meters (2,160 to 8,700 feet).

Some 69 species of marine algae grow in the Bay. There are extensive stands of eel grass, Zostera marina.

The Bay is rich in animal life with 1,041 species of marine invertebrates, representing 21 phyla, having been collected here. Of interest is the Priapuloide, Priapulus caudatus, an inhabitant of arctic and antarctic waters, which here reaches its southernmost distribution in the northern hemisphere.

Nearly 100 species of water-oriented birds have been observed on or near the Bay. Seals and sea lions are occasional visitors. Among the numerous fish reported from the Bay is the white shark, Carcharodon carcharias, which breeds in the ocean north of the Bay.

Integrity: Though there are numerous residential, commercial and recreational facilities along the shoreline, including oyster farms, the Bay is in much better condition than most along the coast.

Use: Present

Ref: Pacific Marine Station U.O.P. Research Reports.

March 1960