SUBLITTORAL ECOLOGY OF KELP BEDS OF THE OPEN COAST AREA NEAR CARMEL, CALIFORNIA

Abstract

1. Aqualung dives along the open coast south of Carmel, California, have been made over a period of two years. 2. The predominant kelp on the open coast in the Monterey area is Nereocystis luetkeana; the giant kelp Macrocystis pyrifera is scarce. Nereocystis is an annual plant producing a heavy subsurface canopy in the summer months. 3. Inshore water is deep; the granite walls drop to a depth of 10 to 30 feet. A dense growth of the branching red coralline alga Calliarthron cheilosporioides carpets the immediate subtidal rocks to a depth of 10 feet, to the exclusion of most sessile animals. 4. Below this zone large Laminaria setchellii replace Calliarthron and a profusion of sponges and tunicates occurs on the walls. The rock bottom at depths of 20 to 50 feet supports a forest of the perennial kelp Pterygophora californica which produces a subsurface canopy. 5. A typical Nereocystis plant presents 70 square feet and a Pterygophora plant 18 square feet of light absorbing area (on one side). 6. The most abundant large invertebrates are an anemone, Anthopleura xanthogrammica, the gum boot chiton, Cryptochiton stelleri, and the bat star, Patiria miniata. 7. Laminaria and Pterygophora stipes and holdfasts provide important microhabitats for many small animals. 8. Large urchins, Stronglyocentrotus franciscanus, are absent. California sea otters are known to prey heavily upon this species, probably accounting for its local extinction. I suspect that the absence of this urchin allows the luxuriance of algae and sessile fauna that is observed. 9. A total of 248 species from the sublittoral zone in this locality is listed.