PCSGA Sep 2009: Pacific Oysters & Ecosystem Health
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PCSGA Sep 2009: Pacific Oysters & Ecosystem Health



Pacific Coast Shellfish Growers Association Annual Conference

Pacific Coast Shellfish Growers Association Annual Conference



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  • Today I’ll be talking about the research I’m doing at the university of Washington evaluating physiological responses of Pacific oysters to see what they’re telling us about ecosystem health
  • I’d like to start out by briefly explaining why Pacific oysters are good indicators of ecosystem health. Historically bivalves such as oysters have been used as bioindicator species because they meet 4 criteria of a good bioindicator.
  • This recognizable species can be leveraged as a tool to engage the public, and educate them about the threats to Puget Sound and what they can do to keep our beaches healthy
  • I’m going to be talking about a new project that I’ve been working on. And so I’ll introduce the project by giving a general overview, then spend some time discussing the methods that we are using to evalutate physiological responses in oysters – show preliminary data
  • (and assess associated effects on shellfish)
  • WA stateDepartment of ecology
  • At T=0, shell height of oyster line B was significantly larger than that of oyster line AAt 2 months, the oysters had grown between 77 and 161% of their height at T=0. There was no longer a significant difference between lines regarless of growing area. Growth between Willapa Bay and Samish bay was not sig different (~25mm), whereas oysters at North Bay were significantly larger than at WB and SM (~33mm), p=0.00.Survivorship at this stage is between 95 – 99%
  • Gene expression – what are is the organism responding to. Over time, a baseline will be generated and deviations from this can serve as early warnings of a change in stress level. Also specific genes can tell about what type of stress the animal is under for example detoxIndirect biological effect – this is an effect of a stressor or a mixture of stressors that may not be seen at a population level (menaing it is not lethal), but it could still have a sensitizing effect – making the organism less fit to handle a second stress – such as a pathogen exposure making it less likely to be able to respond quickly and effectively to that stressorFinally – epigenetic characterization. Epigenetics referes to hertible trait s not at DNA sequence. Many compounds effect epigenetic mechanisms such as DNA metylation. Many of things compounds are present in aquatic systems, including puget sound and it is important to understand effects this may have on organisms living there – if it is affecting oysters, it is probalby also affecting us.
  • Why are we interested in characterizing epigenetic profiles in oystersFirst of all – because it’s poorly understood. Most of the epigenetic work has been done in mammals and very little is known about epigenetic mechanisms in aquatic speciesAlso, there are compounds that disrupt normal epigenetic fxn – these have been detected in PSFrom studies done in mammals we know that disrupting epigenetic systems can have some very negative effects such as….Therefore, characterizing in oysters can tell us not only what is “normal” epigenetic profile for an oyster, but also what effects environmental conditions have on those profiles.
  • To study this we are doing whole genome DNA methylation quantification.
  • Further characterization will be required in order to evaluation what impact environmental conditions play in this variability.
  • I am excited and motivated about the opportunities in this project, and I would be very interested in getting thoughts input and ideas about any of the aspects of this project.I am excited about the project and encouraged by the data, because it appears that these methods have the potential to provide valuable information about ecosystem health – and the associated effects on shellfish. I would be very interested in comments and input regarding how to move forward with this project and make it even better.

PCSGA Sep 2009: Pacific Oysters & Ecosystem Health PCSGA Sep 2009: Pacific Oysters & Ecosystem Health Presentation Transcript

  • Pacific Oysters and Ecosystem Health
    Mackenzie Gavery
    University of Washington
    School of Aquatic and Fishery Sciences
  • Pacific oysters as indicators of Puget Sound health:
    • Common, widely distributed
    • Immobile with high site fidelity View slide
    • Reasonably resistant to contaminants View slide
    • Bioaccumulate at levels relative to their environment
  • Pacific oysters as indicators of Puget Sound health:
    • Important to the region
    • economically
    • culturally
    • socially
  • Outline
    Overview of PROPS
    Next steps
  • PROPS: Physiological Response of Oysters in Puget Sound
    Implement use of biomarkers to assess Puget Sound ecosystem health
    Determine indirect biological effects of local stressors
    Characterize epigenetic impacts on shellfish
  • Methods: Site Selection
    Level of concern:
    Pacific oyster populations:
    natural set
    commercially farmed
    (outplanted juveniles)
  • Juveniles oyster siblings
    Low Mid High
    April June
  • Methods: Sampling
    Adults (n=20)
    gill tissue
  • Methods: Water Quality Data
    WA State Department of Health
    Department of Ecology
    University of Washington
    Mar-07 Jun-07 Sep-07 Dec-07 Mar-08 Jun-08 Sep-08 Dec-08 Mar-09
  • Methods: Integrated Approach
    Gene expression
    Indirect biological effects – response to a secondary stressor
    Epigenetic characterization
  • Gene expression
    Indirect biological effects – response to a secondary stressor
    Epigenetic characterization
    Methods: Integrated Approach
  • Indirect biological effects
    Are current environmental conditions impairing the ability of an organism to respond successfully to a future stress?
    Applying a stress in the field and evaluating response:
    stress (mechanical) response (noradrenaline)
    a “normal” response is an increase in noradrenaline after applying mechanical stress.
  • Noradrenaline: results
  • Gene expression
    Indirect biological effects – response to a secondary stressor
    Epigenetic characterization
    Methods: Integrated Approach
  • Epigenetics
    Heritable changes in trait or phenotype, caused by a mechanism other than mutation to the DNA sequence
    Most common epigenetic mechanism is DNA methylation:
  • Epigenetics
    Compounds that impact normal epigenetic functions:
    Endocrine disruptors
    Effects of epigenetic disruptions:
    tumor promotion
    alteration of development
    inhibition of reproduction
  • Epigenetics: DNA methylation analysis
    Whole genome DNA methylation quanitification
    ELISA based
    Result is % methylated DNA
    extract DNA
    bind DNA to plate
    add antibody to
    add secondary enzyme
  • Epigenetics: Data
  • Summary
    Noradrenaline concentration following stress may be a good candidate to evaluate indirect biological effects.
    Preliminary data show epigenetic variability between oyster populations in Puget Sound.
    These methods have the potential to provide valuable information on ecosystem health.
  • Acknowledgements
    Dr. Steven Roberts – UW, SAFS
    Samuel White – UW, SAFS
    Joth Davis - Taylor Shellfish Farms
    All the Volunteers