Effects of climate variation and change on Okanagan salmon

stateofthesalmon.org

Effects of climate variation and change on Okanagan salmon

Potential impacts ong>ofong> ong>climateong> ong>changeong> on life

history events ong>ofong> Okanagan salmonids.

Kim Hyatt 1 , Margot Stockwell 1 , Clint Alexong>andong>er 2 1. Pacific

Biological Station, Science Branch, Fisheries ong>andong> Oceans Canada, Nanaimo, B. C., 2.

ESSA Technologies, Kelowna, B.C.

State ong>ofong> the Salmon Symposium, Portlong>andong>, Oregon, Nov. 2011.

Fisheries ong>andong> Oceans Pêches et Océans

Canada Canada Canada


Outline for This Talk

• Sketch history & status ong>ofong> Okanagan sockeye salmon.

• Comment on evidence for regional to local scale

ong>climateong> ong>changeong> (CC) ong>andong> CC projections.

• Summarize work on potential impacts ong>ofong> ong>climateong>

ong>changeong> on Okanagan aquatic ecosystems & salmon.

• Identify implications for resource managers ong>andong>

communities in the Okanagan.


Columbia River Sockeye Adult Returns

1970 – 2011 (Okanagan = 81% ong>ofong> returns after 2004)

Sockeye (1000's)

400

350

Preseason Forecast

Observed Returns

300

Mean Returns 1970-2007

250

200

150

100

50

0

1970 1980 1990 2000 2010 2020

Return Year

Okanagan Sockeye in Columbia River Returns

1970 - 2003 2004 - 2011

Mean: 54% 81%

Range: 15-85% 63-90%


Signature ong>Effectsong> ong>ofong> Climate Change in the Pacific are

Detectable & Especially in the Southern Interior ong>ofong> B.C.

Air, freshwater ong>andong> sea surface temperatures have all exhibited

trends to increase in the Pacific over the past 100 years.


Signature ong>Effectsong> ong>ofong> Climate Change in the Pacific

Average precipitation has increased by 3% per decade in the B. C. Southern

Interior with most ong>changeong> occurring during spring ong>andong> summer.


GCM ong>andong> Regional Climate Models Project Many

Changes for Watersheds & Freshwater Ecosystems:

(1) Regional

Snow pack

Joint Institute

for the Study ong>ofong>

Atmos. &

Ocean, U ong>ofong>

Washington

(2) Flow Timing ong>andong> Variability in

Snow-fed Rivers (Leith ong>andong> Whitfield, 1998)

(3) Changes to Seasonal Thermal

Regimes in Freshwater Lakes,

Rivers ong>andong> Streams


Okanagan Study Methods

• Use Global Climate Models (GCMs) for high level predictions

(we used ong>climateong> ong>changeong> projections from three GCM’s including HadCM3-A22,

CGCM2-A21 ong>andong> CSIRO MK2 A21).

• Complete additional “downscaling” steps to predict regional

or local ong>climateong>.

• Generate CC impacts on salmon by using future conditions

(temperature, rain, flow) ong>andong> biophysical “rules” that govern

salmon life history events to predict ong>changeong>s in those events

• Compare the frequency ong>ofong> occurrence, timing or magnitude

ong>ofong> life history events from a base period (1961-1990) versus

those in the 2050’s (i.e. 2035-2065).

• Consider implications ong>ofong> findings for coldwater fishes

(sockeye, kokanee, trout) throughout the Okanagan valley.


Results

100

Adult Migration

Delay, Jun - Oct

Days (#) Delay at Zosel

80

60

40

x 81

x 74

x 71

x 40

Future (2050)

Delay 75 Days

Current (


100

Peak Spawn Date (# Days from September 1)

80

60

40

20

Adult Sockeye

Spawn Timing

Future (2050)

Date, Nov. 2

x 67

x 63

x 60

Current (


250

100 % Hatch (Days from Sept. 1)

225

200

175

150

Egg & alevin Incubation

* Nov - May

Future (2050)

Date, Feb. 24th

x = 188

x = 187

x = 180

x = 176

Current (


275

Fry Emergence

* April - May

250

Future (2050)

Date, April 11th

100 % Hatch (Days from Sept. 1)

225

x = 242

x = 236

x = 232

x = 227

Current (


Useable Volume (millions m³)

Useable Rearing Volume (millions m 3 )

Depth (m)

Fry Rearing (Juvenile sockeye rear for 14 months in Osoyoos L

Hyatt et al (in review) have established seasonal temperature ong>andong> oxygen

extremes operate together to restrict the useable rearing volume ong>ofong> Osoyoos Lake

which can induce density-independent mortality processes.

(a)

OSOYOOS LAKE

North Basin Central Basin South Basin

> 17 O C

< 4 ppm O 2

Useable Volume

(b)

(c)

(d)

200

175

150

1997 HF

y = -1.61x + 195.95

R 2 = 0.39

200

175

150

User specified threshold for

DD or DI mortality

125

125

100

100

75

50

75

50

Density dependent (DD)

25

0

2001 LF

0 20 40 60 80 100 120 140

Rearing Days @ ST > 17°C (Apr 1 – Nov 30)

Density independent (DI)

25

0

0 4 8 12 16 20

July-August Total Discharge (millions m 3 )


Optimal water volume for summer fry is correlated with wind

velocity & temperature. CC will increase both & intensify temp-O2

“squeeze” for rearing fry.

180

OWV (x 10 6 ) m 3

120

60

-

600 700 800 900 1000 1100

Velocity * number days ST >17 o C


Implications ong>ofong> Results

• Predicted ong>changeong>s to sockeye LHEs vary among

GCMs but all project large shifts by 2050 relative

to the “base-case” (1961-1990).

ong>Effectsong> identified here will apply to salmon ong>andong>

resident fish in the Okanagan ong>andong> southern B.C.

• Not clear if life history flexibility ong>ofong> Okanagan

sockeye will accommodate such large ong>changeong>s (i.e.

migration delays increase from 40 to 75 days etc…).


Life history, ong>climateong> ong>changeong> ong>andong> human interventions will interact

to determine cumulative impacts ong>ofong> CC on fish. One means ong>ofong>

exploring the potential consequences ong>ofong> complex events is to

develop simulation models that account for explicit interactions.


Questions

Fisheries ong>andong> Oceans Pêches et Océans

Canada Canada Canada


FWMT is a coupled-set ong>ofong> 4 biophysical models ong>ofong> key relationships among ong>climateong>, fish

ong>andong> water that interact with a 5 th water-management rules model used to predict

consequences ong>ofong> water management decisions for fish ong>andong> other water users. FWMT

song>ofong>tware allows system users to explore water management decision impacts in near

“real-time” (current-mode), historic intervals (retrospective-mode) or future intervals

(prospective-mode) given data on water supplies, ong>climateong> ong>andong> fish population state(s).

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