Title: Matt Sloat and Gordon Reeves
1Influence of changing thermal regimes on
steelhead growth and life history expression
Matt Sloat and Gordon Reeves Fisheries and
Wildlife Management Oregon State University and
USFS PNW Research Station, Corvallis, OR
2Climate change will alter the thermal regimes of
aquatic ecosystems How will aquatic organisms
with complex life histories respond to these
alterations?
3O. mykiss life cycle
J. Tomelleri
Boughton et al.
J. Tomelleri
4O. mykiss life histories
- Males exhibit alternative mating tactics
FW resident- mature early at small size
Anadromous- delay maturation and mature at large
size
photos J. McMillan
51
Probability of early maturity
0
Length-at-age
6McMillan et al. (2011) Env. Bio. Fish.
7Probability of early maturity
Length-at-age (mm)
Redrawn from McMillan et al. (2011) Env. Bio.
Fish.
8(No Transcript)
91
Colder
Warmer
Probability of early maturity
0
Length-at-age
10Study objective Determine the influence of
thermal regimes on energy allocation and life
history expression in O. mykiss
11Overview of experimental design
- 2 thermal regimes
- 12 replicates per thermal regime
- 24 tanks total
12Overview of experimental design
30 individually marked fish per tank post hoc
analysis sex ratio 11
- 30 fish per tank
- 24 tanks total
- 720 individually marked fish
13- Methods
- Monthly growth measurements (FL, mass) of
individual fish -
- Life history categorization
- Assessment of smolt status April June 2011
- Assessment of maturity Aug 2011
- Retrace growth trajectories of fish within life
history categories
- Whole body lipid analysis (forthcoming)
14Results
15Male growth trajectories length
16Male growth trajectories mass
17Smolts
Mature males
18Male life history expression for steelhead
offspring reared under different thermal regimes
Smolts 46
UN 5
Mature 49
Cold thermal regime
Warm thermal regime
19Male growth trajectories by life history type
length
Cold regime
Warm regime
Length (mm)
Month
Month
20Male growth trajectories by life history type
mass
Cold regime
Warm regime
Mass (g)
Month
Month
21Warm regime
Cold regime
smolt
smolt
mature
mature
smolt
smolt
mature
mature
22- Conclusions
- Despite higher rates of somatic growth, fish
experiencing warmer - temperatures had lower rates of maturation
- Temperature may alter energy allocation in
important ways that - are not captured by measuring somatic growth
alone
- A mechanistic understanding of physiological
responses to altered - thermal regimes is needed to forecast effects
of climate change
23Acknowledgments Funding provided by USFS PNWRS
with additional support from USGS FRESC,
Corvallis, ORAFS Carl Bond Memorial
Scholarship. Thanks to Jason Dunham, India
Sloat, Jill Pridgeon, Haley Ohms, Amy Lindsley,
Stephanie Saunders, Matt Stinson, and staff at
ODFW Clackamas Hatchery.
24photo Becky Sloat