Megan Moore, Barry Berejikian, Steve Jeffries1

Northwest Fisheries Science Center

1/ Washington Department of Fish and Wildlife

Funding sources: Washington Department of Fish and Wildlife, Nisqually Indian Tribe, NOAA Northwest Fisheries Science Center

Survival of steelhead smolts through Puget Sound in relation to shifting

predator-prey relationships

Photo: John McMillan

Tag

Quantifying steelhead smolt survival

Hydrophone deploymentN = 40 (2014-2019)

Data from Moore et al. 2015. Mar. Ecol. Prog. Ser. 3

0.000.050.100.150.200.250.300.350.400.45

2006

2007

2008

2009

Estim

ated s

urviv

al thr

ough

Pug

et So

und

Migration year

Nisqually (PS) Green (PS)Skagit (PS) Skokomish (HC)Big Beef (HC) Average

Low and decreasing steelhead smolt survival in Puget Sound (2-week migration)

4

Seals as mobile ‘receivers’

12 Packs deployed• Vemco VMT Tag-hydrophone• GPS/archival tag• Vhf transmitter

Orchard Rocks2014-6 packs

Colvos Rocks2014- 6 packs

2014

• Stationary steelhead tags detected by seals at haulouts in Puget Sound

• Tag detection patterns consistent with harbor seal movements in Puget Sound (Welch et al. 2007; Berejikian et al. 2016) and estuaries (N = 12)

2014 - Evidence of predation in Puget Sound

-1.00.01.02.03.04.0

Berejikian et al. 2016. Mar. Ecol. Prog. Ser.

• Higher proportions of stationary tags and total seal-detected tags in Central Puget Sound where mortality was greatest

6

2016

5(5)

3(3)

4(3)

4(4)

200 smolts

• Similar approach 2014• 16 seals• Include South Puget Sound

10/17/2018 7

7

2016 – Substantial increase in steelhead survival20

06

2007

2008

2009

2010

2011

2012

2013

2014

2015

2016

2017riv

er m

outh

to J

DF

surv

ival

est

imat

e (%

)

0

10

20

30

40

50

Nisqually River steelhead smolt survival

8

55%Survival rate

34%Survival rate

2014 2016

70%Survival rate

83%Survival rate

69%Survival rate

71%Survival rate

Little evidence of seal predation in high survival year

9

Recent shifts in PS and HC steelhead early marine survival

0.000.050.100.150.200.250.300.350.400.45

2006

2007

2008

2009

2010

2011

2012

2013

2014

2015

2016

2017

Estim

ated s

urviv

al to

JDF

Migration year

Nisqually (PS) Green (PS) Skagit (PS)Skokomish (HC) Big Beef (HC) Average

What has caused the shift in steelhead smolt survival and apparent predation?

U.S. Department of Commerce | National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 10

- Change in steelhead smolt behavior

- Change in predator behavior/predation pressure

11

Travel time

Days from release

0 2 4 6 8 10 12 14

Kilo

me

ters

fro

m J

DF

0

50

100

150

200

250

Nisqually 2016Nisqually 2015Nisqually 2014

Rkm 19River MouthNAR

CPS

ADM

JDF

Top-down effects?

05

101520253035

Jan-

06Se

p-06

May-0

7Ja

n-08

Sep-

08Ma

y-09

Jan-

10Se

p-10

May-1

1Ja

n-12

Sep-

12Ma

y-13

Jan-

14Se

p-14

May-1

5Ja

n-16

Sep-

16Numb

er of

days

with

at le

ast 1

sig

hting

Whale Museum Data - transient sightings 2006 -2016Area 9

Area 13

Area 11

Area 10

Duguid et al. (2018) Deep Sea Research Part II, https://doi.org/10.1016/j.dsr2.2018.05.018

0.000

0.100

0.200

0.300

0.400

0.500

2005

2006

2007

2008

2009

2010

2011

2012

2013

2014

2015

2016

2017

Survi

val (p

ropo

rtion)

Nisqually steelhead early marine survival

Alternative prey hypothesisStrait of Georgia zooplankton

survey

Strait of Georgia Age-0 herring survey

Fraser River plume study

S. Strait of Georgia tow net

Skagit Bay tow net

Whidbey Basin town net

Central Puget Sound tow net

South Puget Sound tow net

Snohomish beach seine

Elwha beach seine

14

F=5.91, p = 0.051R2 = 0.496

F=11.97, p = 0.013R2 = 0.666

Close relationship between anchovy abundance and steelhead mortality rate

Anchovy data from Correigh Greene – Skagit Bay tow net survey

15Duguid et al. (2018) Deep Sea Research Part II,

https://doi.org/10.1016/j.dsr2.2018.05.018

Anchovy abundance regulated by temperature

Summary1. Significant changes in early marine survival 2. Evidence for predation by harbor seals in

Puget Sound inversely related to marine survival rates

3. Smolt behavior similar among years4. Variation in survival appears to be associated

with increased transient killer whale activity and anchovy pulses

Photo:Steve Jeffries

Acknowledgements

Salish Sea Marine Survival Project Steelhead WorkgoupMatt KlungleEric WardKaty DoctorJeff AtkinsJed MooreTom FriedrichWalker DuvallDennis Lucia + Hickson crewDevin WestChris FrazierLars Swartling

Iris KempDyanna LambournJosh OliverBrian MurphyAusten ThomasJames HackettSayre HodgsonChris EllingsRob EndicottMichael SchmidtErik Neatherlin

Many others!