Protecting Humboldt Bay

Humboldt Bay is vitally important for birds along the Pacific Flyway.

Black Brant in Humboldt Bay. Photo: Neva Swenson

New proposals to expand oyster farming in Humboldt Bay have caused a great amount of concern for Audubon California and other conservation groups that understand the importance of this site for Pacific Flyway waterbirds. That the proposed expansions would further damage invaluable eelgrass beds and mudflats is even more concerning.

Second only to San Francisco Bay in its importance to shorebirds, Humboldt Bay is one of the most important migratory stopovers along the United States Pacific Coast. It is a globally Important Bird Area and a Western Hemisphere Shorebird Reserve Network site of international significance. It boasts the highest shorebird species diversity on the West Coast, with 46 shorebird species regularly using the bay. It provides habitat to significant portions of the populations of Black Brant, Western Sandpipers, Least Sandpipers, Marbled Godwit, and Dunlin, among many others.

The bay is so rich in bird life because of its unusually varied intertidal zone and rich subtidal habitat, which is home to approximately 50% of California’s remaining eelgrass. Eelgrass is particularly important as habitat for producing forage fish and crustaceans and to provide food for migratory and breeding birds.

This photo from 2015 shows the impact of oyster farming, also known as aquaculture, on eelgrass beds. Note how the beds stop right next to the equipment.

The Humboldt Bay Harbor District and Coast Seafoods, Inc. (a subsidiary of Pacific Seafoods) are proposing separate projects that will more than double existing oyster operations covering approximately 18% of Humboldt Bay remaining tidelands. The project areas are mostly comprised of dense and patchy eelgrass and mudflats.

Audubon California is working with a coalition of allies, including the Redwood Region Audubon Society, California Waterfowl Association, and local hunters, to oppose the expansion project. 

Audubon California has identified alternatives for the project that would reduce the footprint and impacts while allowing for oyster farming operations to continue. Despite Audubon’s science-based comments that attempted to improve the environmental review documents, the project proponents appear poised to proceed without adequately siting, sizing, or mitigating the impact of the project.

Birds of Humboldt Bay

Humboldt Bay is a vital stop for birds along the Pacific Flyway. In spring migration alone, Humboldt Bay hosts as many as 100,000 shorebirds each day. It hosts extraordinarily large percentages of many populations of shorebirds and waterfowl, including approximately:

  • 3.5% of the global population of the highly imperiled Long-billed Curlew;
  • 23% of the global population of Western Sandpiper;
  • 41% of the global population of Least Sandpiper;
  • 6% of the global population of Marbled Godwit;
  • 82% of the global population of Dunlin;
  • Up to 60% of the Black Brant global population, a species that is particularly reliant on eelgrass.

Areas available for Brant and other birds are dwindling as eelgrass resources continue to decline throughout California due to climate change and other factors.

Humboldt Bay is so valuable to birds because of its rich, varied habitats that include extensive eelgrass beds and an unusually diverse intertidal zone. The proposed project area supports up to 25% of California’s remaining eelgrass (Zostera marina) which is a foundational habitat for California’s coastal ecosystem. Eeelgrass provides structured habitat for fish, crabs and invertebrates, a significant food source for Black Brant and other waterbirds, and a means of buffering against ocean climate change.

It is well-documented that oyster farms significantly degrade eelgrass and mudflat habitats due to habitat loss, fragmentation, and disturbance from aquaculture activities. The proposed projects would expand oyster farming from approximately 300 acres to 1050 acres, covering approximately 18% of Humboldt Bay tidelands, mostly comprised of dense and patchy eelgrass and mudflats. These impacts would be cumulative in Humboldt Bay, where eelgrass is it has already declined by approximately 20% since 2009.

Recent news

Conservation and hunting groups sue to halt Humboldt Bay habitat destruction
Press Center

Conservation and hunting groups sue to halt Humboldt Bay habitat destruction

Lawsuit filed by Audubon California and California Waterfowl Association takes aim at faulty environmental impact studies.

Humboldt Bay Harbor District OKs controversial oyster farming project. Reversing a decision from just a few weeks ago, the Humboldt Bay Harbor District last night approved a controversial proposal to expand oyster farming in the bay. Audubon California has opposed this project from the very beginning out of concern that the proposal jeopardizes the eelgrass beds and mudflats that make Humboldt Bay one of the most important places for migratory birds along the coast. Last night's decision was not the final step in the process, and we will be tracking developments carefully. Stay tuned ...

Humboldt Bay Harbor District fails to approve environmental review for oyster farming expansion

In something of a surprise, the Humboldt Bay Harbor District last night failed to come up with the three votes necessary to approve an expansion of oyster farming in the bay. Audubon California has opposed this project because it will destroy eelgrass beds that provide critical habitat for all kinds of migratory birds. We're fairly certain they'll come back for another attempt -- and we'll be ready.

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Update on the fight to save Humboldt Bay
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Update on the fight to save Humboldt Bay

Humboldt Bay is one of the most important places for shorebirds and waterbirds. We're working to keep it that way.

How you can help, right now