February 17, 2012

The Marbled Murrelet Benefits from MPAs

Article by Gary Strachan


The marbled murrelet is a small seabird that breeds along the west coast of North America from the Aleutian Islands south to the Santa Cruz Mountains. This species is listed as both a federally and state endangered species and is a unique seabird due to the fact that it nests inland in old-growth redwood and Douglas Fir forests.

The Santa Cruz Mountains population of the marbled murrelet is thought to be the smallest geographical population of this species, in the range of 500 birds utilizing the nearshore coastal areas to forage for small fish.

Murrelets forage by diving in shallow waters between 20 and 80 meters in depth. They dive for small inshore fish, like juvenile rockfish, sand lance, smelt, Pacific herring, and a number of invertebrates.

In the last decade researchers have gained a good understanding of the relationship between marbled murrelets, their foraging habitat and prey species. Año Nuevo State Marine Reserve, a local Marine Protected Area, holds the largest concentrations of marbled murrelets in the central California population as well as high concentrations of its prey.

Scientists have found that Año Nuevo Bay is one of the most important marine habitats for murrelets to forage and loaf, and is an excellent location for adult murrelets to teach juveniles how to forage for fish and prepare them to be independent. Researchers estimate around 200 birds visit Año Nuevo Bay during the breeding season.

Scientists agree that the number of marbled murrelets in the Santa Cruz area is decreasing, though the cause remains unknown. The creation of MPAs in areas where marbled murrelets occur, such as the Año Nuevo SMR, offer some protection to their prey species. We're hopeful the outcome will be that fish populations increase dramatically in these protected areas, and the availability of more juvenile fish will benefit the endangered marbled murrelet.

These kinds of secondary and tertiary benefits from MPAs are just beginning to be realized. By creating these "networks" or "strings of pearls" of MPAs along the coast, many species may directly or indirectly benefit along the coast of California.

And this is great news.

Article by Gary Strachan
On behalf of the Monterey Bay Sanctuary Foundation

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