Otter Harbor | MARINe

Otter Harbor

Click here for Long-Term trends

Otter Harbor is located in the Northern Channel Islands, within the Channel Islands National Marine Sanctuary, on San Miguel Island, California. This site is located in an Area of Special Biological Significance (San Miguel, Santa Rosa, and Santa Cruz Islands ASBS) in Channel Islands National Park. The gently sloping site consists of moderately uneven terrain, with long channels almost parallel to shore.

Otter Harbor biodiversity survey overview

Otter Harbor is dominated by consolidated sandstone bedrock, and the area surrounding the site is comprised of a mixture of consolidated bedrock and sandy beach. Offshore from the site is a detached reef rising 1-2 m serving as a breakwater for the site.  A channel about 5 m wide and 1-2 m deep separates the reef from the main island. The primary coastal orientation of this site is north.

Otter Harbor long-term monitoring overview

Long-Term Monitoring Surveys at Otter Harbor were established in 1985, and are done by Channel Islands National Park. Long-Term MARINe surveys currently target the following species: Chthamalus/Balanus (Acorn Barnacles), Mytilus (California Mussel), Silvetia (Golden Rockweed), and Endocladia (Turfweed). In addition, motile invertebrates, mussel size structure, and water temperature are monitored at this site. Click here to view Long-Term trends at this site.

For more information about Otter Harbor, please contact Stephen Whitaker (

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