Thermal performance
in an invasive
Predators,
prey, and invasion
predator
andworld
native prey interaction
in
a warming
Brian Cheng and Ted Grosholz
Bodega Marine Lab
University of California, Davis
Olympia oysters: a key species
• Ostrea lurida
• Historically abundant
• Subjected to fishing,
sedimentation, etc.
• “Foundation” species
• Failed recovery
• Focus of restoration
Baker 1995, Kirby 2004, Kimbro and Grosholz 2006
Oyster Narrative from Townsend
CA Dept. of Fish and Game 1893
Eastern oyster drills
•
•
•
•
Urosalpinx cinerea
Predatory snail
Native to eastern US
1890s: Introduced to SFB
Tomales Bay
We are here!
Giants dominate here (2x)
Oyster declines in Tomales Bay
60
Are native oysters and
invasive snails differentially
susceptible to warming?
Oyster density (m-2)
50
40
30
20
10
0
2002
0
2004
2006
2008
Year
2010
2012
methods
• Cultured oysters/snails from Tomales Bay
lethal performance
• Acute thermo-tolerance trials using
aluminum heat bar (n = 30)
lethal tolerance
1.0
Oysters
Snails
Proportional Survival
0.8
Similar lethal
tolerance
(LT50)
0.6
0.4
0.2
0.0
20
30
Temperature (C)
40
50
sub-lethal performance
Growth
• Chronic temperature effects across six
temperatures (16-30°C)
• Measured oyster shell area and snail shell height
Feeding
• Oyster consumption measured with fluorometry
• Snail consumption measured by examining per
capita oyster consumption
growth
16
Oyster
Snail
4.5
2
Oyster shell area (cm )
Field temperatures
at oyster optimum!
14
4.0
3.5
12
3.0
10
2.5
2.0
8
1.5
1.0
6
14
16
18
20
22
24
Temperature (C)
26
28
30
32
Snail shell height (mm)
5.0
feeding performance
6
-1
Oysters
Snails
5
60
4
40
3
20
2
0
1
0
14
16
18
Snail consumption (oysters 3 days )
Phytoplankton consumption (%)
80
20
22
24
26
Temperature (°C)
28
30
32
summary
• Lethal tolerances similar among predator/prey
• Oysters have decreased sub-lethal
performance at warmer temps relative to
snails (evolved under larger thermal window)
• Feeding rate is a
potential mechanism
• Field temps are near
oyster optimum
implications
• What is stressful for natives may not be for
invaders
• Greater thermal tolerance in invaders may be
a general phenomenon
Braby and Somero 2006, Schneider 2008, Sorte and Williams 2010
acknowledgements
Technicians
Jessica Couture
Sarah Covello
Grosholz Labbies
Holly Long
David Kimbro
BML
Eric Sanford
Nann Fangue
Joe Newman
Jill Bible
Lisa Komoroske
Pacific Coast Science and Learning Center
George Melendez Wright Climate Change Fellowship
bscheng@ucdavis.edu
Multiple stressors and
latent effects on Olympia
oysters
Brian Cheng1*, Jill Bible1, Andy Chang2
Matt Ferner2, Kerstin Wasson3, Chela Zabin2
Anna Deck2, Marilyn Latta4 and Ted Grosholz1
1Bodega Marine Lab, UC Davis
2 San Francisco Bay NERR
3 Elkhorn Slough NERR
4 State Coastal Conservancy
Email: bscheng@ucdavis.edu
GOAL: Increase resilience of
oyster restoration projects in
the face of climate change
1. Lab experiments – determine effects of climate
stressors and interaction with anthropogenic stressors
2. Field surveys – Characterize stressors at 18 sites in
San Francisco Bay and Elkhorn Slough
3. Connectivity – Description of oyster larval dispersal
patterns within and among bays
4. Synthesis – analysis of field and lab data in order to
index restoration sites
Stressors affecting oysters
Anthropogenic
Stressors
Invasive
Species
Sediment
Burial
Climate-related
Stressors
Hypoxia
Warming
OYSTERS
Low
Salinity
Acidification
Elkhorn Slough
Elkhorn Slough
Dissolved Oxygen (% sat)
200
150
100
50
0
Jun
Aug
Oct
Dec
2010 - 2011
Feb
Apr
Jun
Elkhorn Slough
25
30
20
20
15
10
10
0
Hypoxia/Anoxia
5
Jun
Aug
Temperature
Oct
Dec
2010 - 2011
Feb
Apr
Jun
Salinity (PSU)
40
Performance
Temperature (C)
30
Multiple stressor studies needed
Experimental Approach
30
Phase 2: Recovery
(90 days)
Performance
Temperature (C)
20
10
Phase 3: Low salinity trial
(5 days)
10
0
Hypoxia/Anoxia
5
Jun
20
Aug
Salinity
Outline
30
Phase 1: Temp x DO trial
(14 days)
25
15
40
Temperature
Oct
Dec
2010 - 2011
Feb
Apr
Jun
Questions
1. How do multiple simultaneous stressors
affect oyster performance? (temp x DO)
2. Are oysters capable of recovering from these
Hypotheses
time? will decrease oyster
A.stressors
Low DOover
conditions
growth
3. Does
early stress affect performance at later
B.stages
Higher
temperatures
will
enhance the DO
in response
to low
salinity?
effecteffect?)
by increasing metabolic demand
(latent
during hypoxia/anoxia
Methods
• Cultured F1 oysters from adult broodstock
collected from San Francisco Bay (May 2012)
• Oysters settled on
PVC tiles (10x10 cm)
Methods
• Subjected newly settled oysters to
– Temperatures: 20, 24 C
– Dissolved oxygen: 0.6, 2.0, 6.5 mg/L
• 10 hr nightly low DO for 14 days
• Oyster growth measured
by shell area (ImageJ)
• Lipid/glycogen content
Anne Todgham
Nate Miller
Trial conditions
10
Dissolved Oxygen (mg/L)
Normoxia
8
Hypoxia
Anoxia
6
4
2
0
12-Aug
13-Aug
Date
14-Aug
24 C Normoxia
24 C Anoxia
Temperature / DO effects
0.5
Shell Area (cm2)
0.4
1. Low DO results in less growth
(up to 3x!)
2. High Temp results in greater
growth under normoxia
3. High temp benefits oysters in
hypoxia
4. But not in anoxia
20 C
24 C
*
0.3
*
0.2
0.1
0.0
1
Normoxia
2
Hypoxia
Dissolved Oxygen
3
Anoxia
Summary
• Multiple stressors are common in the field and
timing of stressors with life stage is important
• Interactions of stressors may produce
surprising results
• Low DO results in lower oyster growth
• Moderate increases in temp may allow oysters
to compensate under hypoxia but not anoxia
– Increased feeding rates during daytime normoxia
Implications
Performance
• Restoration success depends on
understanding which stressors are important
• Threshold responses
may be common
• Where species reside on
thermal response curve
will be key
20 24
Temperature
Acknowledgements
Technicians
Charlie Norton
Chris Knight
Emily Seubert
BML
Joe Newman
Karl Menard
Philip Smith
Questions?
Brian Cheng
bscheng@ucdavis.edu