Los Farallones

Dispatches from Point Blue’s field station on the Farallon Islands National Wildlife Refuge

Spring Tides Reveal Intertidal Treasures

Here on the Farallones, it is easy to focus mainly on the birds and marine mammals because they are large and iconic animals, but the great majority of the biodiversity can be found in the intertidal zone. This dynamic system where the rocky shore meets the ebb and flow of the tide is a dazzling world of miniature treasures. There are over 50 species of crustacean that have been recorded around the island ranging from Dungeness crabs (Metacarcinus magister) weighing over 2lbs to tiny krill-like Mysida only a few millimeters in length.


Striped Shore Crab (Pachygrapsus crassipes)


Kelp Crab (Pugettia producta)


Hermit Crab (Pagurus sp.)


Other diverse groups of invertebrates found along the intertidal zone include Cnidaria (coral, anemones, and sea jellies), Echinodermata (sea urchins, brittle stars, and sea stars), and Mollusca (nudibranchs, snails, muscles, and limpets).

Giant Green Anemone (Anthopleura xanthogrammica)


Ochre Seastar (Pisaster ochraceus)


California Mussels (Mytilus californianus)