Transcript A Mechanistic Model of Foraging and Bioenergetics to Explore

A Mechanistic Model of Foraging
and Bioenergetics to Explore
Salmon Growth in Pacific Northwest
Reservoirs During Drought
Christina A. Murphy
Ivan Arismendi*
Sherri Johnson
Pacific Northwest Reservoirs
• Community of primarily cold-water native species and
warm-water exotics
• Undergo Water Level Fluctuations of >30 m
• ESA listed, naturally produced Chinook Salmon enter study
reservoirs in the spring (Feb-April) and typically exit the reservoirs
in the fall (Sept-Dec)
Life History X – Reservoir Rearing
• Age-0 Chinook Salmon rearing
in reservoirs reach much larger
than their stream rearing
counterparts
• Limited evidence suggests they
may return at higher rates as
adults
These photos were taken
the same day, on the same
stream – both are age-0
Spring Chinook Salmon
Stream Rearing
above Hills Creek Reservoir
Reservoir Rearing
below Hills Creek Reservoir
How do we expect the physical
and biological conditions
within a reservoir to affect
Chinook Salmon growth?
Management actions?
Drought years?
Existing study
• Summer full-pool data corresponding to the
reservoir rearing period
• Physical and community data
• Including: light, temperature, and zooplankton (density and
distribution)
Reservoir
Length
(km)
Depth
Area
Elevation Standard winter
(m)
(hectares)
(m)
drawdown (m)
Fall Creek
Hills Creek
Lookout
Point
10.9
14.7
49
91
736
1100
255
471
31
29
22.8
71
1765
287
31
Study area
Fall Creek
Lookout Point
Hills Creek
2015: Drought year –
early warm surface temperature
• Fall Creek was maintained approximately 8 m
below a typical water year.
5
10
Temperature (°C)
15
20
25
0
251 m
5
247 m
243 m
239 m
Depth (m)
10
15
20
June
25
2014
30
2015
35
2015: Drought year –
midsummer warm + shallow thermocline
• Hills Creek was maintained 3-9 m below a
typical water year, with late summer
5
Temperature (°C)
10
15
20
25
0
267 m
460 m
454 m
Depth (m)
5
10
15
20
25
30
35
July
2014
2015
2015: Drought year –
late summer warm deep temperature
• Lookout Point was maintained approximately
12 M below a typical water year
5
277 m
Temperature (°C)
10
15
20
25
0
268 m
261 m
259 m
Depth (m)
5
10
15
20
25
August
30
2014
35
2015
Data inputs
• In addition to species specific model
parameters:
• Temperature profiles
• Light profiles
• Daphnia (prey) densities by depth
• Chinook Salmon starting size
Fall Creek
Hills Creek
Lookout Point
Existing models: Visual Foraging
• Visual Encounter Rate Model (Beauchamp et al. CJAFS 1999)
Reaction distance
Search volume
Encounter rate
RD = 3.8 * (light^0.47) * (daphnia size^0.95)
SV = π * RD^2 * swimming speed
ER = SV * daphnia density * daphnia weight / weight
• Drawback:
• Developed for salmonids feeding as piscivores
Existing models: Wisconsin
Bioenergetics
• Wisconsin Bioenergetics Model
(Hanson et al. 1997)
Energy budget
= respiration + active metabolism + specific dynamic action + egestion + excretion
Temperature
• Parameters have temperature dependent specific rates
Fish size
• Parameters are mass dependent
• Drawbacks:
• Parameters for Chinook Salmon are from adults
• Original model does not allow for diel vertical migration
Merging Foraging and
Bioenergetics Models
1. Consumption efficiency (P) is constrained by
physiology (BioE model) and foraging (foraging model)
2. Combined model uses hourly time-steps
3. Each hour has either a day or night designation
(light impacts foraging; allows for diel vertical
migration)
Model schema
Programming: Python 3.0
• Advantages:
• Accommodates future need for Graphical User
Interface
• Managers and casual users
• Not proprietary software
• Ease of linking models - outside of existing
program
• Clear troubleshooting and error messages
• Disadvantages
• Without GUI, requires programing skills to set-up
and run; initial programming time investment and
future GUI development time
Model outputs and interpretation
Growth conditions
• Growth: g/g/day
Behavioral patterns
• Optimal depth and temperature use given
temperature profile, light and food availability
Effects of management
• Changes in growth with changes in environment
• Or through introduction of constraints (e.g.
exclusion zones for predation risk)
Modeling applications:
In discussion with managers and stakeholders explore scenarios
How is growth influenced by:
• Management decisions which alter depth,
temperature, light, or zooplankton?
• Climate change?
• Predator exposure / depth exclusion?
Observations from 2015 results
• Model results indicate that most growth is early
season and that by late summer Chinook
Salmon are maintaining or losing weight
• The 2015 drought conditions had the greatest
impact on Lookout Point where wind driven
mixing led to larger predicted weight loss in
late summer than for the prior year
• Diel vertical migration is more beneficial early
in the summer when temperatures at depths
with abundant forage are not prohibitive
Predicted diel vertical migration
for juvenile Chinook Salmon
May 2015
0
Depth (m)
4
8
12
16
Fall Creek day
20
Hills Creek day
24
Fall Creek night
Hills Creek night
Lookout Point day
Lookout Point night
June 2015
July 2015
August 2015
Example:
Explore effects of streambed drawdown
Thanks!
USACE
Lookout Point
Greg Taylor
Katie Rayfield
Terri Berling
Ben Cram
Todd Pierce
NOAA
Kim Hatfield
ODFW
Portland
Cindy Studebaker
Bob Wertheimer
Kathryn Tackley
Dan Turner
OSU
Jason Dunham*
Angela Strecker (PSU)*
Steve Arnold*
Brendan Coffin
Brent Johnson
Margaret Whitmore
Kailan Mackereth
Tim Glidden
Chelsea Duke
Margaret McCormick
Michelle Weaver
Dan Peck
Springfield
Jeff Ziller
Kelly Reis
Shannon Richardson
Reservoir Dogs
Tom Friesen
Fred Monzyk
Jeremy Romer
Ryan Emig
Khoury Hickman
Meghan Horne-Brine
Andrew Nordick
Matt Price
Ryan Flaherty
*Committee
Questions?