![]() Much less is known about the shelf than is known about coastal kelp forests and sandy floor (0 to 30 meters) because most researchers using SCUBA equipment are limited to waters less than 30 meters deep. Pelagic predators, including seabirds and marine mammals, hunt for fishes and invertebrate prey along the benthos. The complex physical structure created by boulders, caves, pinnacles and outcrops is a favorite habitat of many rockfish species. Sessile invertebrates cover the rocky bottom, forming a biogenic habitat that supplies food and shelter to many mobile invertebrate and fish species. Small forms of brown and red algae grow on rock outcrops down to a depth of between 60 and 75 meters (off Point Sur), depending on the clarity of the water. Rock outcrops below 30 meters are teeming with life. The rocky habitat that speckles the seafloor between the edge of the kelp forest and the continental shelf break (30 to 200 meters) covers approximately 249 square kilometers – only 1.8 percent of the seafloor in the sanctuary. Occasional rock outcrops, in an otherwise soft-bottom habitat, provide substrate for large sessile, sedentary and habitat-forming invertebrates, including white-plumed anemones, crinoids and basket stars (image). ![]() The burrowing activities of fishes and invertebrates help to mix the surface sediments and also add some structural relief to a relatively flat habitat. ![]() Some of these animals, such as the burrowing tube anemone, build somewhat permanent tubes and burrows. Soft-bottom associated species live either on the surface of, or buried in, the sediments. The lack of hard substratum for attachment prevents algae and some invertebrates from colonizing soft-bottom habitats. The percentage of mud, silt and clay increases as depth increases on the shelf and beyond the shelf break. Sandy bottom is generally found in shallow waters of the shelf (less than 40 meters). The shelf narrows considerably south of Monterey Bay and remains narrow throughout most of the southern portion of the sanctuary, except around Point Sur and near the southern boundary.Ī large portion of the shelf in the sanctuary is composed of soft-bottom habitats, which cover approximately 3,584 square kilometers (1,384 square miles) from depths of 30 to 200 meters. In the Monterey Bay National Marine Sanctuary, the outer continental shelf is relatively broad from the northern boundary to southern Monterey Bay. For shelf areas shallower than 30 meters, see Rocky Shores, Kelp Forests, Beaches and Sandy Floor. The outer continental shelf is the focus of this section. the intertidal (salt spray to extreme low water).It can be subdivided according to depth, including: Beyond the shelf break (at a depth of approximately 200 meters, or 650 feet), the continental slope descends more steeply to the ocean floor. The continental shelf is the gradually sloping submerged margin of the continent that extends from the nearshore to the shelf break.
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