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US Fish & Wildlife Service FieldNotes
ARCATA FWO: Eelgrass Monitoring in Humboldt Bay, California
Region 8, July 31, 2009
Fish Biologist Bill Pinnix during eelgrass sampling in Humboldt Bay, California (photo: USFWS)
Fish Biologist Bill Pinnix during eelgrass sampling in Humboldt Bay, California (photo: USFWS) - Photo Credit: n/a
Eelgrass sampling on Humboldt Bay, California. (photo: USFWS)
Eelgrass sampling on Humboldt Bay, California. (photo: USFWS) - Photo Credit: n/a

by William Pinnix, Arcata FWO
Eelgrass beds in North and South Humboldt Bay have been monitored since July of 2007 as part of a global seagrass monitoring network called SeagrassNet. SeagrassNet is a program that investigates and documents the status of seagrass resources worldwide, with 70 sites in 23 countries.


Jeff Robinson, former Humboldt Bay Harbor District Conservation Director, was instrumental in starting the SeagrassNet Monitoring in North and South Humboldt Bay, which are monitoring sites for the native eelgrass Zostera marina. With his untimely passing while conducting the monitoring in July of 2007, the Arcata Fish and Wildlife Office was requested to take the lead in conducting the monitoring.  Monitoring has taken place quarterly and is an important source of data for the Humboldt Bay Ecosystem Based Management program.


Sampling of selected plant and environmental parameters is conducted quarterly (January, April, July and October) to determine eelgrass habitat status and trends.

Data is collected following a global monitoring protocol and reported via SeagrassNet’s web-based system. Funding to conduct the monitoring is being provided by the Humboldt Bay Harbor, Recreation and Conservation District (HBRCD). The field work is currently overseen by the US Fish and Wildlife Service under contract to the HBRCD, and is conducted by USFWS staff and volunteers from local agencies, consulting firms, and students from Humboldt State University.  South Bay has higher eelgrass density compared to North Bay. Grazing by Brant Geese and other birds in April of 2008 and 2009 severely decreased eelgrass percent cover, canopy height, and shoot biomass in South Bay and North Bay. Eelgrass shoot biomass is higher in North Bay compared to South Bay. Eelgrass in Humboldt Bay has distinct seasonal cycles that are reflected in data collected to date.. 


Contact Info: William Pinnix, 707-822-7201 x5129, bill_pinnix@fws.gov