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Mercury in Biosentinel Fish in San Francisco Bay Ben Greenfield 1, Andrew Jahn 2, Letitia Grenier 1, Mark Sandheinrich 3 1. San Francisco Estuary Institute,

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Presentation on theme: "Mercury in Biosentinel Fish in San Francisco Bay Ben Greenfield 1, Andrew Jahn 2, Letitia Grenier 1, Mark Sandheinrich 3 1. San Francisco Estuary Institute,"— Presentation transcript:

1 Mercury in Biosentinel Fish in San Francisco Bay Ben Greenfield 1, Andrew Jahn 2, Letitia Grenier 1, Mark Sandheinrich 3 1. San Francisco Estuary Institute, Oakland, CA Riverside Drive, Ukiah, CA 3. River Studies Center, University of Wisconsin – La Crosse

2 Key Management Questions Assessment of ecological risk to fish and wildlife Assessment of ecological risk to fish and wildlife Spatial and temporal mercury trends in the Estuary Spatial and temporal mercury trends in the Estuary Is risk of mercury exposure spatially variable, and are these risks predictable? Is risk of mercury exposure spatially variable, and are these risks predictable? What are trends in bioaccumulation of Hg vs. wetland restoration and TMDL activities What are trends in bioaccumulation of Hg vs. wetland restoration and TMDL activities Building upon conceptual models of Hg exposure Building upon conceptual models of Hg exposure

3 Multiple sites in San Francisco Bay margins Multiple sites in San Francisco Bay margins Wetland restorations vs. extant marshes Wetland restorations vs. extant marshes Benthic and pelagic species Benthic and pelagic species Topsmelt, Mississippi (inland) silversides Topsmelt, Mississippi (inland) silversides Arrow and cheekspot goby Arrow and cheekspot goby Additional collection in Bay shoals and channels Additional collection in Bay shoals and channels Bay goby, herring, anchovy (IEP Bay Study) Bay goby, herring, anchovy (IEP Bay Study) Sampling Design

4 Compositing Design 5-10 individuals per composite 5-10 individuals per composite 4 composites per species per site to allow statistical comparison 4 composites per species per site to allow statistical comparison Used size limits to reduce influence of any length:Hg relationships Used size limits to reduce influence of any length:Hg relationships

5 Primary Sampling Locations Alviso Slough Newark Slough Bird Island/ Steinberger Slough Eden Landing China Camp Benicia Park Oakland Middle Harbor Extant Marsh Restoration Area Point Isabel Candlestick Point

6 Opportunistic Locations USFWS Survey Primary Location IEP Bay Study

7 Preliminary Results Results from 97 samples in 2005 and preliminary results from 114 samples in 2006 Results from 97 samples in 2005 and preliminary results from 114 samples in seining locations and 9 trawling locations (IEP) 17 seining locations and 9 trawling locations (IEP) 10 Species 10 Species Inland silversides Animal Diversity Web Image by Mami Odaya, SFEI

8 Patterns among pelagic species Hg wet weight (  g/g)

9 Patterns among pelagic species Hg wet weight (  g/g) TMDL Target for prey fish to protect piscivorous wildlife Effects threshold for fish (Beckvar et al. 2003)

10 Patterns among benthic species Hg wet weight (  g/g) TMDL Target

11 Conceptual model Variation among species Variation among species Mississippi Silverside > Topsmelt and wetland gobies > Bay Goby Mississippi Silverside > Topsmelt and wetland gobies > Bay Goby Spatial patterns Spatial patterns Alviso Slough elevated in cheekspot goby Alviso Slough elevated in cheekspot goby South Bay elevated in silversides South Bay elevated in silversides Arrow Goby Cheekspot Goby Bay Goby Topsmelt Silverside Benthic Pelagic Polyhaline wetlands/margins Euhaline Bay open waters Higher Hg in fish Lower Hg in fish (closer to sources/methylation) (hydraulic mixing dilutes MeHg) Anchovy Herring

12 Why were arrow and cheekspot gobies higher in 2006? Hg wet weight (  g/g)

13 Broader size range in 2006 Arrow goby

14 Cheekspot goby Broader size range in 2006

15 Comparison to fish/wildlife risk thresholds * Tissue concentration dry weight

16 Spatial Patterns USFWS Survey ‘06 Primary (Topsmelt)

17 Letters indicate results of ANOVA followed by Student-Newman-Keuls test Hg wet weight (  g/g) 2005 cheekspot goby significantly elevated in Alviso Slough 2005 cheekspot goby significantly elevated in Alviso Slough

18 2006 arrow goby elevated in southern stations 2006 arrow goby elevated in southern stations

19 Hg wet weight (  g/g) 2005 silverside significantly elevated in southern stations 2005 silverside significantly elevated in southern stations 2006 silverside elevated in Point Isabel 2006 silverside elevated in Point Isabel

20 2005 topsmelt elevated in southern stations (not significant) 2005 topsmelt elevated in southern stations (not significant) 2006 elevated in southern stations, Pt. Isabel, and Tiburon 2006 elevated in southern stations, Pt. Isabel, and Tiburon

21 Why are concentrations often elevated in southern stations and Pt. Isabel? Why are concentrations often elevated in southern stations and Pt. Isabel?

22 Point Isabel Urban dump with disposal of car batteries and other metal waste Urban dump with disposal of car batteries and other metal waste Enclosed wetland with long drainage canal Enclosed wetland with long drainage canal Recall conceptual model – wetland methylation Recall conceptual model – wetland methylation Source: Google Earth

23 Pt. Isabel Source: Google Earth Steinberger Slough/Bird Island China Camp Benicia State Park Source: Google Earth

24 Southern stations Southern stations RMP data indicate higher sediment MeHg in southern stations RMP data indicate higher sediment MeHg in southern stations High sediment MeHg in Tiburon High sediment MeHg in Tiburon Source: RMP

25 Results Summary Some samples above TMDL risk threshold for wildlife risk Some samples above TMDL risk threshold for wildlife risk Variation among species Variation among species Mississippi silverside > topsmelt, anchovy, herring Mississippi silverside > topsmelt, anchovy, herring Arrow and cheekspot goby > Bay goby Arrow and cheekspot goby > Bay goby Spatial patterns Spatial patterns Southern locations higher trend Southern locations higher trend Pt. Isabel – interior wetland Pt. Isabel – interior wetland

26 What’s the big picture? Variable wildlife risk as a function of target prey and habitat Variable wildlife risk as a function of target prey and habitat Conceptual model: different exposure in Bay margins vs. open-water areas Conceptual model: different exposure in Bay margins vs. open-water areas Are there more “Point Isabels” throughout the Bay? Are there more “Point Isabels” throughout the Bay? What drives spatial variation? What drives spatial variation? Sources (e.g., historic Hg mining in South Bay watershed) Sources (e.g., historic Hg mining in South Bay watershed) Net Methyl Hg production in sediments (many drivers may vary: sulfur, reducing bacteria, salinity, water retention time) Net Methyl Hg production in sediments (many drivers may vary: sulfur, reducing bacteria, salinity, water retention time)

27 Plans for 2007 and beyond First year project report available First year project report available Same general sampling design funded through 2008 – begin trends analysis Same general sampling design funded through 2008 – begin trends analysis Organics analyses in 6 composite samples Organics analyses in 6 composite samples

28 Thanks to… April Robinson Aroon Melwani John Oram Rick Wilder Steve Slater Carrie Austin Collin Eagles-Smith Darell Slotten Max Delaney Fred Hetzel Meg Sedlak Mami Odaya Arthur Fong SF Bay National Wildlife Refuge USFWS Stockton USGS BRD California State Parks CA Department Fish & Game Interagency Ecological Program Image by Mami Odaya, SFEI

29 Topsmelt – also no obvious difference between years

30 Unpublished data provided by Darell Slotton Mississippi silverside 2005 Mississippi silverside 2005 Combine FMP and RMP data Combine FMP and RMP data Results indicate highest concentrations in South Bay fish Results indicate highest concentrations in South Bay fish

31 This project: Margins of South, Central, and North Bay This project: Margins of South, Central, and North Bay Fish Mercury Project: Central Valley, Delta, and North Bay – more freshwater focus Fish Mercury Project: Central Valley, Delta, and North Bay – more freshwater focus South Bay Salt Pond Hg Project: Marshes, ponds, and sloughs South Bay Salt Pond Hg Project: Marshes, ponds, and sloughs CBDA Bird Hg Project: Avian forage fish CBDA Bird Hg Project: Avian forage fish Petaluma Hg Project: Marsh fish in Petaluma Petaluma Hg Project: Marsh fish in Petaluma Produce comparable data sets by sampling same species Produce comparable data sets by sampling same species External Coordination

32 Fish vs. Sediments Silversides 2005 Sediment South Bay San Pablo Bay Hg wet weight (  g/g)

33 Small Fish Hg Project 3

34 Hg wet weight (  g/g) Mississippi Silverside 2005 Topsmelt 2005

35 Bay goby Bay goby Spatial pattern confounded by fish size Spatial pattern confounded by fish size Try to limit size range Try to limit size range

36 Cheekspot goby Cheekspot goby

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39 Striped bass Hg concentrations in SF Estuary over time For more information on sport fish monitoring, see poster # 27

40 Small Fish Hg Project Background Background Mercury (Hg) in N. California waters a longstanding management concern due to historic mining Mercury (Hg) in N. California waters a longstanding management concern due to historic mining Elevated concentrations in sport fish Elevated concentrations in sport fish San Francisco Estuary site of extensive wetland restoration activity San Francisco Estuary site of extensive wetland restoration activity Sensitive wildlife in region Sensitive wildlife in region

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45 Why Small Fish? Most sport fish over health advisory threshold (0.3 ppm) Most sport fish over health advisory threshold (0.3 ppm) TMDL has small fish targets but there are limited data from Bay TMDL has small fish targets but there are limited data from Bay Contaminant pathway to sport fish poorly known Contaminant pathway to sport fish poorly known Effect of extensive wetland restoration Effect of extensive wetland restoration Hg, ppm wet wt Ca. halibut Jacksmelt Leopard shark Shiner perch Striped bass Wt. croaker Wt. sturgeon

46 Regional Monitoring Program Small Fish Project Goals Monitor food-web mercury at fine spatial and temporal scales Monitor food-web mercury at fine spatial and temporal scales Assess regional trends in bioaccumulation of Hg related to wetland restoration Assess regional trends in bioaccumulation of Hg related to wetland restoration Develop conceptual model of Hg availability to prey fishes Develop conceptual model of Hg availability to prey fishes Collect prey fish appropriate for wildlife risk evaluations Collect prey fish appropriate for wildlife risk evaluations


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