Harbor seal-steelhead interactions under
variable survival conditions in Puget Sound
Megan Moore, Barry Berejikian, Steve Jeffries1
Northwest Fisheries Science Center
1/ Washington Department of Fish and Wildlife
Nisqually (W)
Puyallup (W
)
Puyallup (H
)
Green (W)
Green (H)
Skagit (W
)
Skagit (H)
Surv
ival P
robabili
ty (
%)
0
20
40
60
80
100
Skokomish (W)
Skokomish (H)
Dewatto (W
)
Hamma (H)
Duckabush (H)
Big Beef C
reek (W)
0
20
40
60
80
100
Freshwater
Marine
Surv
ival P
robabili
ty (
%)
Puget Sound
Hood Canal
Moore et al. 2015. MEPS
Tag
Hydrophones
Steelhead survival in Puget Sound
Travel time (days)
0 5 10 15 20
Dis
tance fro
m S
trait o
f Juan
de F
uca 0
50
100
150
200
Big Beef Creek
Green River
Nisqually River
Skagit River
Skokomish River
Juan de Fuca
Admiralty Inlet
Central Puget Sound
Hood Canal Bridge
Deception Pass
Puget Sound steelhead average travel times 2006-2009
3
Steelhead migrate rapidly through Puget Sound
Identifying potential predators
From: Pearson et al. (WDFW)
Likely predators
Harbor seal
Double-crested & Brandt’s cormorants
Caspian terns
Harbor porpoise
Common murre
Why start with harbor seals?
Jeffries et al. 2003. J. Wildl. Manage. 5
1. Increases in abundance coinciding with
decline in steelhead survival/abundance
2. Opportunistic feeders
3. Preferred prey species declines in Puget
Sound (pollock, cod, hake, rockfish, herring,
others)
4. Known to eat steelhead smolts elsewhere Lower Columbia River
San Lorenzo River, CA
Puntledge River, BC
Straight of Georgia
Seals as mobile ‘receivers’ • 12 Packs deployed
• Vemco VMT Tag-hydrophone
• Wildlife Computers Splash Tag
• Vhf transmitter
Orchard Rocks
2014-6 packs
Colvos Rocks
2014- 6 packs
1. Stationary steelhead tags detected
repeatedly at harbor seal haulouts
2. Higher proportions of stationary
tags and total detections in Central
Puget Sound where mortality was
most acute
3. Tag detection patterns near
haulouts consistent with harbor seal
movements
2014 Summary
-1.0
0.0
1.0
2.0
3.0
4.0
Berejikian et al. 2016. Mar. Ecol. Prog Ser.
6 seals packs
recovered
5 seals packs
recovered
1) Increase sample sizes and spatial coverage
2) Incorporate systematic mobile tracking
3) Estimate predation rate based on:
• Tag deposition at haulouts
• Deposition probability: Osterback et al. 2013; Hostetter et al. 2015)
• Harbor seal spatial distribution and abundance
• Steelhead smolt abundance
4) Construct hierarchical, spatially explicit models to assess
predation risk (similar to Ward et al. 2012 Cons. Lett. 5:37-47)
2016 Objectives: Estimate predation rate
8 – Nisqually, Eagle, Gertrude
4 – Orchard Rocks
4 – Colvos Rocks
9 2006 2008 2010 2012 2014 2016
RM
-JD
F s
urv
ival estim
ate
(%
)
0
10
20
30
40
50Nisqually Steelhead Smolt Survival
2014 2016
Seal packs recovered (analyzed) 11 16 (11)
Nisqually 0 3 (3)
Eagle/Gertrude 0 5 (4)
Orchard/Blakely 5 4 (3)
Colvos 6 4 (1)
Number of fish detected by seal VMT
Nisqually wild steelhead 30/95 =33% 63/104=60%
Squaxin hatchery coho salmon -- 60/100=60%
2014 2016
12
Historical fluctuations and recent observations of Northern Anchovy in the Salish Sea William Duguid1, Jennifer Boldt2, Lia Chalifour1, Douglas Hay3, Dayv Lowry4, Skip Mckinnell5,
Jessica Qualley1, Todd Sandell4, Matthew Thompson2, Kelly Young6, and Francis Juanes1
2016
2005
1969
1947
1940
2006 2008 2010 2012 2014 2016
RM
-JD
F s
urv
ival estim
ate
(%
)
0
10
20
30
40
50Nisqually Steelhead Smolt Survival
13
2014
• Survival through Central Puget Sound was low and a substantial
number steelhead tags were found stationary at Central Puget Sound
haulouts (Orchard/Blakely Rocks) .
2016
• Survival through Central Puget sound was high and no stationary tags
were detected at Orchard Rocks
• Abundant anchovy perhaps buffering predation on migrating smolts
may explain high survival/low predation
Summary
14
Acknowledgements
Iris Kemp
Katy Doctor
Jeff Atkins
Jed Moore
Tom Friedrich
Walker Duvall
Dennis Lucia + Hickson crew
Matt Klungle
Devin West
Chris Frazier
Lars Swartling
Martin Chen
Paul Herschberger
Jake Gregg
Ashley Mackenzie
Mallory Wilmot
Dyanna Lambourn
Josh Oliver
Brian Murphy
Austen Thomas
James Hackett
Nisqually Estuary
Eagle Island
