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
• Reasonably resistant to
contaminants
• 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
 Methods
 Data
 Next steps

PROPS: Physiological Response
of Oysters in Puget Sound
 Objectives
 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:
High
Mid
Low
Pacific oyster populations:
natural set
commercially farmed
(outplanted juveniles)

Juvenile oyster siblings
40
35
A *
B
30
shell length (mm)
25
20
15
10
5
0
Low Mid High
T=0 Willapa Bay Samish North Bay
June August
Bay

Methods: Sampling
 Adults (n=20)
 size
 gill tissue
 hemolymph

Methods: Water Quality Data
 WA State Department of Health
 Department of Ecology
 University of Washington
Site A: Drayton Harbor (WA DOH)
40 1000
Fecal Coliform (FC/100mL)
900
Temp (ºC) / Salinity (ppt)
35
Salinity 800
30
700
25 600
20 500
15 400
Temp 300
10
200
5 100
Fecal Coliform
0 0
Mar-07
Mar-11 Jun-07
Jun-11 Sep-07
Sep-11 Dec-07
Dec-11 Mar-08
Mar-12 Jun-08
Jun-12 Sep-08
Sep-12 Dec-08
Dec-12 Mar-09
Mar-13

Methods: Integrated Approach
 Gene expression
 Indirect biological effects – response to a
secondary stressor
 Epigenetic characterization

Methods: Integrated Approach
 Gene expression
 Indirect biological effects – response to a
secondary stressor
 Epigenetic characterization

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
25
Low
noradrenaline (pg/mL)
20
15
10
5
0
1.4 pre- post-stress
1.2
noradrenaline (pg/mL)
Mid
1 High
0.8
0.6
0.4
0.2
0
pre- post-stress pre- post-stress

Methods: Integrated Approach
 Gene expression
 Indirect biological effects – response to a
secondary stressor
 Epigenetic characterization

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:
A
G
T
C
Me

Epigenetics
 Compounds that impact normal epigenetic functions:
 Endocrine disruptors
 estrogen
 BPA
 pesticides
 Effects of epigenetic disruptions:
 tumor promotion
 alteration of development
 inhibition of reproduction

Epigenetics:
DNA methylation analysis
extract DNA
 Whole genome DNA
methylation
quanitification bind DNA to
plate
 ELISA based
 Result is %
add antibody to
methylated DNA 5-me-cytosine
add secondary
enzyme

Epigenetics: Data
8
P = 0.03
estimated % DNA methylation
7.5
7
6.5
6
5.5
5
Site C
Low Site A
High

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