This document summarizes a study on the foraging and growth potential of juvenile Chinook salmon following tidal restoration of the Nisqually River delta. Researchers compared restored tidal marshes to unaltered reference marshes. They examined diet composition, energy density of prey, stomach fullness, water temperatures, and calculated fish growth using a bioenergetics model. The results showed similar but more variable growth opportunities in the restored habitats. Increased sensitivity to warm air temperatures may limit growth potential there compared to the reference marshes. Overall, the findings were consistent with other estuary restoration projects.

1. Foraging
and
growth
poten/al
of
juvenile
Chinook
salmon
following
/dal
restora/on
of
the
Nisqually
River
delta.
September
20,
2013
Aaron
David1,
Christopher
Ellings2,
Isa
Woo3,
Charles
Simenstad1,
Kelley
Turner3,
John
Takekawa3,
Ashley
Smith3,
and
Jean
Takekawa4
1University
of
Washington,
School
of
Aqua/c
and
Fishery
Sciences
2Nisqually
Indian
Tribe,
Department
of
Natural
Resources
3U.S.
Geological
Survey,
Western
Ecological
Research
Center
4U.S.
Fish
and
Wildlife
Service,
Nisqually
Na/onal
Wildlife
Refuge

2. Acknowledgements
Jesse
Barham
Walker
Duval
MaS
Holt
Emiliano
Perez
Lisa
Belleveau
Caitlin
Guthrie
Jus/n
Hall
Ben
Ryken
Peter
Markos
Sam
Stepe/n
Kyle
Kautz
Eddie
Villegas
Tom
Friedrich
The
Wetland
Ecosystem
Team
And
many
others…
Cartography
by
Amy
Calahan
Funding:
US
EPA,
Nisqually
Tribe,
US
Fish
and
Wildlife
Service,
NSF
Graduate
Research
Fellowship
Program
Photo:
Michael
Grilliot

4. Nisqually
River
Estuary,
Fall
2009

6. Ques/on:
Do
restored
and
reference
marshes
provide
equivalent
growth
opportuni/es
for
juvenile
Chinook
salmon?
Growth
is
primarily
a
func/on
of:
-­‐
The
amount
of
prey
consumed
-­‐
The
energe/c
quality
of
prey
consumed
-­‐
The
temperature
regime
experienced
by
a
consumer
Tidal
channel
reconnected
in
2009
Unaltered,
reference
/dal
channel

8. Fyke
trap
ne`ng
Diet
analysis
Bioenerge/cs
model
Consump/on
rate
study
Temperature
loggers

9. Bioenerge/cs
model
Growth
=
Consump/on
–
(Metabolism
+
Wastes)
Inputs:
• Consumer
mass
• Consump/on
rate
• Prey
energy
density
• Consumer
energy
density
• Temperature

10. Results:
Chinook
salmon
densi/es

11. Results:
Diet
composi/on

12. Results:
Diet
energy
density

13. Results:
Stomach
fullness

14. Results:
Temperatures

15. Results:
2010
Growth

16. Results:
2011
Growth

17. Results:
2012
Growth

18. Conclusions:
• Our
findings
are
generally
consistent
with
other
studies
of
estuary
restora/on
projects
• The
reconnected
habitats
appear
to
provide
similar,
but
more
variable
opportuni/es
for
Chinook
growth
• Increased
sensi/vity
to
air
temperatures
may
limit
the
growth
value
of
these
habitats
when
temperatures
are
warm
Photo:
Jean
Takekawa

19. Es/ma/ng
Chinook
daily
consump/on
for
each
sampling
event
•
Number
of
hours
in
a
day
Gastric
evacua/on
rate
Mean
stomach
fullness
over
the
whole
day
Mean
stomach
fullness
at
the
beginning
and
end
of
the
24
hour
period

20. Results:
Consump/on
study