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Robert Spies, AMS Kathrine Springman, UC Davis Spring 2005

A Pilot Study of the Effects of Contaminants on Shiner Surf Perch in the San Francisco Bay-Estuary An update-November 22, 2005. Robert Spies, AMS Kathrine Springman, UC Davis Spring 2005. Problem. Populations of many fish in the SF Estuary are in a long-term decline.

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Robert Spies, AMS Kathrine Springman, UC Davis Spring 2005

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  1. A Pilot Study of the Effects of Contaminants on Shiner Surf Perch in the San Francisco Bay-EstuaryAn update-November 22, 2005 Robert Spies, AMS Kathrine Springman, UC Davis Spring 2005

  2. Problem • Populations of many fish in the SF Estuary are in a long-term decline. • There are many possible causes of the this decline including habitat loss, harvest, introduced species and contaminants. • Contaminants probably are having a negative effect.

  3. Conceptual model for shiner surf perch declines sewage, street runoff, atmospheric sources, et.c Breeding population females males PAH organophos- phate pesticides pharma- ceuticals, DDTs, PCBs, chlorinated pesticides, carbamate pesticides Early gametogenesis: yolk Late gametogenesis: Recreational fishing Mating Habitat damage Internal fertilization implantation Disease resistance gestation birth Growth Foraging

  4. Objective Determine if shiner surfperch (Cymatogaster aggregata; Embiotocidae) show effects of contamination on some aspect of their fitness, growth or reproduction.

  5. Strategy 2005: • Field studies relating exposure to growth, fitness and reproduction. • Analyze data; reformulate hypotheses. • Gather archived data. 2006: • Follow-up field studies*** • Laboratory exposure experiments ? • Evaluate modeling feasibility. • Reporting.

  6. Field studies-2005 • Collect 20+ fish each from 2 contaminated; 1 less-contaminated sites. • Measurements: length, weight, sex, no. young, growth of young. • Analyses: organic chemicals (carcass), P4501A (adult liver,viscera of young). • EROD (liver), Vtg, histopathology (gills, liver, heart). • Mother-vs-offspring measures: P4501A, Some histopathology.

  7. Progress to date • Collected 36 adults in 10 seine hauls from Oakland Middle Harbor (5/9/05) . • Collected 10 fish from IEP station 106 in northern portion of south Bay (5/10/05). • Collected 26 fish in 15 seine hauls from State Park Beach at Candlestick Park, So. San Francisco (5/11/05). • Collected 72 fish in 2 seine hauls at Big River estuary, Mendocino County (5/14/05). • All fish measured, weighed, dissected, sexed, young counted and weighed, tissues stored.

  8. Progress to date (cont’d) • Endocrine disrupting chemicals a strong possibility:carry out egg protein analyses • All fish livers tested were immunopositive for Vtg antibody • Carried out E2 injection study

  9. Preliminary observations • All of the fish caught in SF Bay were sexually mature. Smaller fish >8 g from Big River were generally not sexually mature. • All female fish from SF Bay were pregnant except 2 large females from Candlestick. • Sex ratio more skewed in SF Bay towards females. Big River: 50% female; Oakland Middle Harbor: 61%; Candlestick Park: 69%. • The incubating juveniles from SF Bay were further developed than those of pregnant females from Big River. • Big River was colder than SF Bay. • Big River fish are exposed to p4501A inducers

  10. Preliminary results (cont’d) • Livers of All field fish tested strongly positive with 2 anti-bodies: anti-salmon (Biosense) and anti-herring (BML). • 48-hr E2 injection experiment with 5 mg kg-1 to induce ZRP; uninjected controls, solvent control, injected w E2. YOY fish from Big River were used. Plasma of injected fish and controls reacted with anti-herring, but not anti-salmon. • No reliable anti-body identified yet.

  11. Priorities for additional work in 2005 1.Collect POCIS/SPMD samples for confirmation of 2006 sampling site selection. 2. Chemical analyses of POCIS/SPMD contents. 3. If surfperch present sample and test blood of males for ZRPs.

  12. SPMD Basics • Passive sampler • Time-integrated • Media-neutral (water, air, soil, sediment) • Lipophilic compounds at trace levels; environmentally relevant

  13. SPMD Basics: More Advantages • Mimics bioconcentration process • No metabolism of sorbate • Not susceptible to environmental effects or pathogens • Well-documented, standardized

  14. Factors that affect SPMDs: • Temperature: less problematic than some factors • Flow: greatest impact • Biofouling: impedes contact, hard to control

  15. SPMD Standard Processing SPMD : Remove biofoulants Hexane dialysis Dialysate: Concentration, GPC cleanup Extract: Chemical analysis (e.g. GC/MS, GC/ECD)

  16. Priorities for work in 2006 • Carry out field sampling at SF Bay sites and new control site. • Test for plasma ZRP in new ref. Site. • Emphasize analyses for EDCs and their effects in fish: sex ratios; reproductive cycle; egg proteins in males; possible sex reversal. • If histopathology positive in Bay sites this year, repeat. Otherwise, drop this aspect. • Chemical analyses of SPMD’s/POCIS.

  17. The Problem The relative binding capacity of synthetic chemicals to hormone receptors may be 1/100 to 1/1000 of that of the natural ligand (e.g., estrogen) and the chemical concentration may exceed the effective concentration by 100 to 10,000 X.

  18. The Problem:there are numerous and complex endocrine interactions in reproduction and growth of fishes(sensory input-endocrine cascades--feedback loops)

  19. Agonist for gonadotropin Iacceleration of gametogenesis

  20. Acceleration of oogenesis in kelp bass dosed with DDT and PCB

  21. Sex determination

  22. Starry flounder in SF Bay Reproductive success in relationship to a biomarker of contaminant exposure

  23. Shiner surf perch is a good choice • Accumulate high concentrations of contaminants (Davis et al., 2001). • High site fidelity (Fritzsche and Collier 2001). • Occur from Alaska to Mexico. • Habitat is in shallows and channels where RMP chemical data taken since 1993. • Analyzed by the sport fish program, included in the Pacific States Marine Recreational Fisheries Statistics Survey, & the IEP. • Favorite of urban fishermen. • Populations in decline. • Live-bearers --annual reproductive output (4-36 young annually) can be determined in early spring and summer.

  24. The evidence so far: contaminants 1. Starry flounder reproductive dysfunction linked to P4501A and PCBs (Spies & Rice, 1988). 2. Sex reversal and estrogenic effects in longjaw mud suckers (Cherr et al., unpubl.). 3. Chinook salmon in upper watershed show high proportions of females that are phenotypically male (Williamson and May, 2002). 3. Striped bass larval growth and histology negatively affected (Ostrach, unpubl.). 4. Speckeld sanddab histology (Spies et al., 1993; Gunther et al. 1997). 5. Herring egg abnormal development (Vines et al., 2000).

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