Transcript 9B-Biosentinel Methyl Mercury Monitoring Ben Greenfield (SFEI)

Monitoring Recommendations
• Clarify and refine key regulatory and
management monitoring objectives
• Design a multi-year monitoring plan to
meet objectives
• Not necessarily more expensive
• More value per dollar
Likely Management Questions
• Q1: Does the project negatively impact
existing aquatic and wetland habitats?
 Monitoring: Pre- and post-project
comparisons of existing conditions
Monitoring Recommendations
• Q2: Do the restored habitats increase the
risk of Hg bioaccumulation?
 Monitoring: Compare habitat types within
breached areas to the ambient condition of
same types of habitats within the North Bay.
Q1: Impact to
Existing Habitats?
• Marsh restoration
does not appear to
affect risk in subtidal
habitats adjacent to
marsh (see right)
• Risk to adjacent
marsh habitats is
unknown
Q2: Do Restored Habitats increase Risk?
• Pond 2A restored in
1995
• MeHg in subtidal
food web is typical
of North Bay region
• MeHg in restored
marsh food web is
unknown
Use Biosentinels to Standardize
• These comparisons should be based on
the same biosentinel species for each
habitat type that is monitored
 shallow subtidal
 intertidal aquatic
 intertidal marsh
Silversides Excellent Subtidal Biosentinel
• Bay margin, large sloughs, and managed
ponds
Add Marsh Biosentinels
• Silversides, and other transient fish, do not
provide information about Hg risk in marsh
• Assess bioaccumulation in tidal marsh
• Does not need to increase overall cost.
Prioritize based on management questions
and what is already known.
Small fish indicate subtidal
Other indicators for marsh risk
Song sparrow
Small fish
Is Winter Monitoring Necessary?
• How do we use results of winter fish Hg
concentrations in management decisions?
• Lower risk to wildlife in winter, because birds are
not breeding
• Lower biomass of small fish in winter, so less
important in the food web
• Save costs by eliminating winter monitoring, in
the absence of a specific management question?
For project report and data:
http://www.sfei.org/projects/NBaySmallFishHg
Thank You
• Karen Taylor, CDFG
• Tom Gandesbury and Betsy Wilson, State
Coastal Conservancy
• Project collaborators – Darell Slotton,
Shaun Ayers, Letitia Grenier
• John Ross, Cristina Grosso, Don Yee, April
Robinson, Josh Collins, SFEI
• The California State Coastal Conservancy
and the San Francisco Foundation