Mercury in Local Fish & Shellfish

In 2012, coastwide sampling across California found the highest mercury levels in the state in leopard shark from Humboldt Bay. In 2016 and 2019, Humboldt Waterkeeper received grants from the California Environmental Protection Agency to test mercury levels in fish caught by local subsistence, tribal, and sport fishermen to determine the magnitude of local mercury contamination in fish and shellfish in Humboldt Bay and nearshore coastal waters.

We used our findings to develop recommendations for Eating Fish Safely (in Spanish, see Comiendo Pescado Con Seguridad Pautas; in Hmong, see Yuav Ua Li Cas Noj Ntses Yam Xyuam Xim Cov Txhooj Cai Rau Humboldt Bay). To request multiple copies of these fliers for health clinics, community events, etc. please email This email address is being protected from spambots. You need JavaScript enabled to view it..

Mercury Levels in Humboldt Bay Fish and Shellfish

UPDATED! Humboldt Baykeeper has been testing mercury levels in local fish since July 2016 with funding from the California Environmental Protection Agency. We’ve found that most local fish are safe to eat in moderation—with a few exceptions.

Click HERE for the revised 2021 guidelines on Eating Fish Safely.

Comiendo Pescado Con Seguridad Pautas - Revisado 2021

Yuav Ua Li Cas Noj Ntses Yam Xyuam XimYuav Ua Li Cas Noj Ntses Yam Xyuam XimCov Txhooj Cai Rau Humboldt Bay (2018)

Click HERE for the 2021 report on mercury in fish caught in nearshore ocean waters.

Click HERE for the 2018 Report on fish and shellfish from Humboldt Bay.

State Issues Humboldt Bay Fish Advisory using Baykeeper's Mercury Data

In October, the State of California issued an official fish advisory for Humboldt Bay using data from Humboldt Baykeeper's recent study of mercury in fish and shellfish. The advisory addresses eight species of fish, some of which are safe to eat up to seven times a week.

Only leopard shark is listed as unsafe to consume in any amount.

Group issues Humboldt Bay seafood eating guide based on mercury levels

When it comes to a recent Humboldt Baykeeper study of mercury levels in Humboldt Bay fish and shellfish, the group’s director Jennifer Kalt said there’s good news and bad news.

The study found that men, women and children of all ages should avoid ingesting unsafe levels of mercury by taking leopard shark out of their diets. The study also recommends women under 45 years old and children avoid eating lingcod above 10 pounds.

Weekly serving amounts for other species — such as bat rays, California halibut, black rockfish — are also recommended to be low, according to the study.

Photo: From left to right, Captain Phil Glenn of Bluefin Charters, volunteer angler Doug Epperley, and fisheries consultant Ross Taylor participate in the study on mercury levels in Humboldt Bay fish in 2016.

Is it safe to eat fish from Humboldt Bay?

Have you wondered whether it is safe to eat fish from Humboldt Bay? We’ve been testing mercury levels in local fish with fisheries consultant, Ross Taylor. We’ve found that most local fish are safe to eat in moderation – with a few exceptions.

Click HERE to listen to the radio interview.

Do you eat fish or shellfish from Humboldt Bay?

We want to hear from you! If you eat leopard shark, ling cod, California halibut, clams, or Dungeness crab, we hope you will help provide information for our mercury study.

In 2012, statewide sampling found the highest mercury levels in a leopard shark from Humboldt Bay. In July 2016, Humboldt Baykeeper received a grant from the California Environmental Protection Agency to analyze fish caught by local fishermen to determine the magnitude of mercury exposure from eating locally caught fish. Target species include lingcod, California halibut, bat ray, leopard shark, surfperch, oysters, and several species of clams. This study is ongoing and final results are expected in 2018.

Please print, complete, and mail or email this questionnaire about how often you fish, which species you eat, and how you cook them:

Download the Angler Survey

Encuesta sobre el consumo de pescado en Humboldt Bay