Transcript Biosentinel Fish Monitoring Presentation 9-26

CBDA BIOSENTINEL
MERCURY MONITORING PROGRAM
FIRST YEAR DRAFT DATA REPORT
COVERING SAMPLING CONDUCTED AUGUST 2005 – FEBRUARY 2006
June 6, 2006
Darell G. Slotton
Shaun M. Ayers
Ronald D. Weyand
Department of Environmental Science and Policy
University of California, Davis
Why Biosentinels?
Biosentinel Mercury Monitoring
Using small, young fish as
localized, time-sensitive measures
of methylmercury exposure
• Spatial patterns on a fine scale
• Interannual trends and variability
• Within-year seasonal trends
Fall 1999 UC Davis
Inland Silverside
Regional Spatial Recon.
Biosentinel Program Goals and Objectives
• Develop baseline data and ongoing
performance data at major
restoration and remediation sites.
• Help define conditions leading
to greater or lesser levels of
methylmercury exposure.
• Track inter-annual trends at a set
of index sites and restoration sites
• Seasonal trends and inter-species
relationships at intensive sites.
• Link to process studies, large fish
monitoring, and wildlife issues.
Pilot Wetland Restoration
Cache Creek Nature Preserve
Bioaccumulation Signal
51-65 mm red shiners, (May 2003)
Multiple composites of n=15
Means ± 95% conf. intervals
upstream
downstream
Hypotheses / Questions:
Do restorations and particular habitat types alter methylmercury
exposure and bioaccumulation patterns, locally and/or regionally?
Are there underlying regional patterns of methylmercury
exposure across the system?
What is the range of natural interannual variation in relation to
potential restoration-related changes we are monitoring?
Does methylmercury exposure and bioaccumulation
exhibit significant within-year seasonality?
Do annual winter flood inputs play a significant role in
Bay-Delta methylmercury exposure and bioaccumulation?
Do restorations effect methylmercury exposure differently
in different parts of the system?
Requirements for Ideal Biosentinels
• Relatively short-lived and non-migratory.
• Widespread across study area.
• Important component of local food web.
• Linkage to aqueous methylmercury exposure.
• Linkage to sport fish and wildlife.
• Bioaccumulate methylmercury at high enough
concentrations to differentiate subtle variability.
• Exhibit consistent mercury bioaccumulation
across a useful and defined size range.
• Feasible to collect with sufficient replication to provide
strong statistical measures of variability.
Central Project Area Primary Species:
Inland Silverside (Menidia beryllina)
Primary Species in Salmon Restoration Areas:
Prickly Sculpin (Cottus asper)
• Merced River
• Tuolumne River
• Clear Creek
Main Secondary Species Across Central Region
Threadfin Shad
(Dorosoma petenense)
Grass Shrimp
(Crangon sp.)
Largemouth Bass (juv)
(Micropterus salmoides)
Bluegill Sunfish (juv)
(Lepomis macrochirus)
Concentration Separations and
95% Confidence Intervals
(means of 2 sample sets)
C.I. overlap
= not
separation
=
statistically different
at 95% confidence level
30 individual analyses per
sampling, from statistical
power analyses
100 ng/g
THg
125 ng/g
THg
Multiple Individual Fish Analyses
Ideally: consistent over size range,
distinctive from other sites and times
Mean Hg
±
95% C.I.
Ability to detect outliers
Distinguish spatially distinct populations and exposure
levels at adjacent sites: Inland Silversides
“Shotgun” scatter patterns may indicate mixing of
individuals from varying exposure areas or microhabitats
Distinguish cases of mixed populations: Threadfin Shad
Size:Hg relationships apparent in individual data:
Largemouth Bass
Entire Biosentinel
Monitoring Region
Clear
Creek
Salmon-based restorations
with historic dredge tailings
Sacramento
River
Hamilton
City
Cache
Creek
Tuolumne
San
Joaquin
River
Merced
Mud, Salt Sloughs,
Upstream San Joaquin
Central Region With Most Restorations
Yolo
Bypass
Intensive Sites
Index Sites
Restoration
Sites
Napa
Marsh
and
North
Delta
Sacramento
RM44
McCormack
Williamson
Tract
Suisun
Marsh
Prospect
Slough
Cosumnes
River
Frank’s
Tract
Petaluma
River
Dutch
Slough
San Joaquin
Vernalis
Yolo Bypass and
North Delta Sites
Yolo
Bypass
Wildlife
Area
Toe
Drain
Toe Drain alongside Bypass WA
Passive tidal gate
at Lisbon
Prospect Slough with breaches
to Liberty Island
North marsh areas
Liberty
Island
Little
Holland
Tract
Prospect
Slough
Index
Yolo Bypass and
North Delta
Inland Silverside
Mercury Trend,
Fall 2005
• Very high levels in Bypass ponds:
(147-169 ng/g Hg, means)
• Elevated in adjacent Toe Drain
(both sites) but 50% lower
• 68% lower by Prospect Slough
• Mercury in marsh portions of
North Delta flooded tracts lower
Yolo Bypass and North Delta Silverside Fall 2005 Mercury Trend
Bypass
Ponds
Toe Drain
At YBWA
Sac RM44
Index
Prospect
Slough
Little Liberty Island
Index
Holland Marsh Flats
Suisun Marsh Region (from 2004 Suisun Marsh Bay-Delta Consortium, 2004)
Back
Spring Branch
Suisun
Slough
Montezuma
Slough
Suisun Marsh
Inland Silverside
Mercury Trend,
Fall 2005
Suisun
Slough
Back Spring
Branch
• Montezuma inflow site
same as Sherman, etc.
• Natural site (Back Spring
Br.) same as N Suisun Sl.
Montezuma • Apparent declines across
both main sloughs
Slough
(at this time)
Suisun Marsh Region: Inland Silverside Fall 2005 Mercury Trend
Grizzly
Index
Montezuma
Slough
E
W
Suisun
Slough
N
Back
Spring
Branch
Suisun
Slough
S
Suisun
Bay SW
Index
Napa Marsh and Petaluma River Region
RiverSlough
at Napa
Mid China
Pond 2a Napa
American Canyon
CBDA Wetlands
Black John Slough
Pond 3
Petaluma
River
• American Canyon
Wetlands CBDA
• Extensive area
Restoration
of former salt
ponds
Napa
River
San Pablo Bay
Napa Marsh and Petaluma River
Silverside Mercury Trend, Fall 2005
• Highest Napa Region Hg
above restorations at Napa
and outside at San Pablo Bay
• Vegetated Pond 2A: lowest Hg
• Petaluma sites elevated
Napa and Petaluma Marsh Region: Silverside Fall 2005 Mercury Trend
Napa River and Marsh Sites
Napa
R. At
Napa
Am. Pond
Cyn 2A
(veg)
Mid
China
Slough
San
Pablo
Bay
Index
Petaluma
River
Seasonal Studies
Yolo Bypass
Intensive Sites
Index Sites
Restoration
Sites
(Toe Drain)
Sacramento
River
Napa Marsh:
Mid-China Slough,
Am. Cyn Wetlands
Suisun Marsh:
Cosumnes
River
N Suisun Slough,
Back Spring Branch
Prospect
Slough
San
Pablo Bay
Grizzly
Bay
Beyond main fall (~Nov) sampling:
• February
• May
• July
• September
Frank’s
Tract
San Joaquin
Vernalis
(extended concentration axis)
A Different Story in Some of the Regions: Suisun Slough North
(extended concentration axis)
(extended concentration axis)
(extended concentration axis)
Summary Seasonal Silverside Data: Fall vs Winter:
Means ± 95% Confidence Intervals
Cosumnes
Yolo Bypass,
Prospect Sl
Frank’s
Vernalis
Suisun
Marsh
Napa
Marsh
China
Slough
Am.
Cyn.
Summary Seasonal Silverside Data: Nov/Feb/May/Jul:
Means ± 95% Confidence Intervals
400
869 ± 209
October/November 2005, Inland Silverside Hg
360
February 2006, Inland Silverside Hg
May 2006, Inland Silverside Hg
July 2006, Inland Silverside Hg
Hg (ng/g wet weight, whole body)
320
280
Napa
Marsh
China
Slough
240
Cosumnes
200
Yolo Bypass,
Prospect Sl
160
Suisun
Marsh
Am.
Cyn.
120
80
Vernalis
Frank’s
40
0
San
Cosumnes
Frank's
Toe Drain Prospect
Joaquin R.
River
Tract
at Yolo
Slough
at Vernalis (Intensive) (Intensive) Bypass WA (Intensive)
(Index)
Suisun
Slough
North
Back
Spring
Branch
Grizzly Bay American
NE (Index) Canyon
Wetlands
Napa
San Pablo
Marsh mid Bay (Index)
China
Slough
Napa Marsh and Petaluma River Region
Petaluma
River
Napa
River
San Pablo Bay