Corey Phillis, Metropolitan Water DistrictAnna Sturrock, U.C. DavisRachel Johnson, NOAA FisheriesPeter Weber, Lawrence Livermore National Laboratory

Otolith Chemistry Reveals the Diverse Rearing Habitats of Winter-Run ChinookSalmon

10-year winter-run otolith study spanning hydroclimatic regimes

1. Where do the successful winter-run rear as juveniles?

2. Are both fry and parr migrants represented in the adult population (based on otolith size)?

• Where do fry rear?

3. Are there differences in size at freshwater exit associated with juvenile rearing habitat?

• Or escapement year?

3 Research questions

Q1: Where do the successful winter-run rear as juveniles?

I’m a winner!!

Q1: Where do the successful winter-run rear as juveniles?

I’m a winner!!

What do I have to do to be like that guy?

Federal Register Vol. 58, No.114: Designation of ESA critical habitat for Sacramento River winter-run Chinook, 6/16/1993

Our conceptual models assume juvenile rear in the Sacramento and Delta

Hendrix et al., Life cycle monitoring framework for Sacramento River winter-run Chinook salmon, 2014

Narrative model Life-Cycle Model

Is rearing in the Delta a viable strategy?

And if not the Delta, where?

Q1: Where do the successful winter-run rear as juveniles?

Most juveniles begin moving downstream as fry

Proportion of total catch

Fork length (mm) of winter-run juveniles at RBDD RST

fry (<55)

Min. size for acoustic tag (> ~85)

parr (>55)

Most juveniles begin moving downstream as fry

Proportion of total catch

Fork length (mm) of winter-run juveniles at RBDD RST

fry (<55)

Where do these fry go to rear?

Sr isotopes discriminate habitats

· ·. r in the otoliths record outmigration

., Sr provides geographic data

., North-south gradient ~ 87Srf86Sr otolith = 87SrJB6Sr water

''What's in th1e water is in the otolith''

D Upper Sac. R .

D Lower Sac. R. & Delta

15] SF Bay Estuary

Pacific Ocean

San Francisco

Bay

• 188 otoliths (2007-2009 n = 29, 91, 68)

• Individuals assigned to 1 of 5 habitats:• Sacramento River (Keswick to Freeport)• American River• Northern Tributaries (e.g. Mill, Deer, Battle Creeks)• Delta or Feather River • “Habitat X”

• Detection limit for rearing in a habitat ~20 days

Individuals were assigned to juvenile rearing habitats

Strontium isotopes in otoliths record juvenile life-history

High Sr-isotope ratio and low Sr concentration hallmark of American River rearing

{b) American River 0.7,0

______ ,.. __ Rive k Loeatia Sr oonoo tration

AmericafJ RiLr'f.Jf Gold£:

9o 0.709 Gate Bay

UJ 0.708 Chipps m - 73 95% C.l. ~ ~SIMld

Dofra

en 0.707 - - - - - - - - - - - - - - -1'-- J

" ~fl-1\1.!1 t aJ J

aJ R ) "iri,;lHD b.i!Dt I

- ,75 I

0.706 r'oopor J

.... .- -- --- - -- --Sacramento River ... fR. 1'1- . I iJ 1 QLlrl·l~ 1 ,..:!-1fJ.!

0.705 - 567 ®dding .:: •.t.f].r:~ , .. i .1,-o.:ato

~---- -----------------.,.,__,_ ___ .,... ____ ..... ____ ,__

~1orthorn

0.704

200 300 400 500 SOO 700 ,BOO 000

Distance rom otolith core (~m)

Rearing in the Northern tribs indicated by Sr-isotope ratio lower than Sac R. minimum

(c) orth ern Trib·u tari es 0.710 Loeatia Sr oonoo trn.tion

Al11a.rica.n R · 1'

0 Gold£:

9o 0.709 Gate

UJ Bay

0.708 Chipps m 73 95% C.l. ~ ~SIMld

Dclr:a

en D.7C7' - - - - - - - - - - - - - - -1'-- J

" ~fl-1\1.!1 t aJ J

aJ R ) "iri,;lHD b.i!Dt I

175 I

D.1DI r'oopor J

.... .- -- --- - -- --... f R . 1'1- ' I iJ 1 QLlrl·l~ 1 ,..:!-1fJ.!

0.705 567 ®dding .:: •.t.f].r:~ , .. i .1,-o.:ato

D.704

200 300 400 500 SOO 700 ,BOO 000

Distance rom otolith core (~m)

Delta rearing is likely, but difficult to discriminate isotopically from Feather River

0.709

0.708

0.707

0.706

0.705

0.704

{d) De~ ta or Feather R~ver

i

L • • - • •

... -

Bay

Do/ra

ather Ri'WJr

Sacramento RiiiCt

200 300 400 500 SOO 700 ,BOO 000

0

73

567

Distance rom otolith core (~m)

Loeatia

Gold£: Gate

Chipps ~SIMld

®dding

Sr oonoo tration

9o 95% C.l.

" ~fl-1\1.!1 t aJ R ) "iri,;lHD b.i!Dt

---------- .......... ---

J

J

I

I

J

45-65% of adults reared in non-natal habitats as juveniles

Q2: Are both fry and parr migrants represented in the adult population?

Spatial diversity in rearing strategies

Temporal diversity in rearing strategies?

fry (<55mm)

parr (55-75 mm)

smolt (>75 mm)

leave earlier

leave later

Otolith radius

Fork length

Zabel et al., 2010

Otolith radius is a suitable proxy for body length, but it varies by ESU

***Currently no established relationship for SWRC ESU***

Fork length ~ f(Otolith radius + ESU)

Lots of variation in migration timing between individuals

Body size was estimated at exit from the natal rearing habitat

Natal rearing exit size

Fry migrate to non-natal rearing habitats

Freshwaterexit size

Q3: Are there differences in size at freshwater exit associated with juvenile rearing habitat?

Size at freshwater exit is conserved across rearing habitats…

…But freshwater exit size differs across years

10-year winter-run otolith study spanning hydroclimatic regimes

Q1: Where do the successful winter-run rear as juveniles?

A1: Winter-run rear in the Sacramento and Delta. But they also use non-natal habitats

Q2: Are both fry and parr migrants represented in the adult population?

A2: Yes, and the non-natal habitats are used successfully by fry

Q3: Are there differences in size at freshwater exit?

A3: Freshwater exit size is conserved across rearing habitats, but can vary between years

In summary:

Lessons from t'h:e Ocean for Integrating Science in Policy Decisions Steve Gaines, Dean, Bren School of Environmental Science and Management at UCSB

The Scientific C allenges of Establishing Appropriate Baselines for Watershed Restoration Daniel Schindler, Harriet Bullitt Endowed Chair in Conservation, School of Aquatic and Fishery Sciences, University of Washington

Ecosystems are not static. They are reshuffling in response to

physical and biological drivers.

Populations are resilient when there are options to reshuffle into

For winter-run, non-natal rearing habitats are some of those options

Incorporate non-natal rearing habitats into our conceptual models

Narrative model Life-Cycle Model

Non-natal habitats represent options for fish

But they also represent management options

Conservation Value

Stak

ehol

der V

alue

scenarios in critical habitat onlyscenarios that include non-natal habitat

efficiency frontier

Non-natal habitats represent options for fish

But they also represent management options

Conservation Value

Stak

ehol

der V

alue

scenarios in critical habitat onlyscenarios that include non-natal habitat

efficiency frontier

Acknowledgements

Otolith samplesUSFWS & Livingston Stone FH staff

Otolith preparation & analysesJustin Glessner & George Whitman

FundingCALFED(!!!)

Delta Science Program MWD

YearOctNovDecJanFebMarApr

MayJunJul

AugSep

1993 2016

Fremont weir overtopping event

http://www.cbr.washington.edu/sacramento/data/alert_weirs.html

Timing and duration of Yolo Bypass inundation varies year-to-year

YearOctNovDecJanFebMarApr

MayJunJul

AugSep

1993 2016

Fremont weir overtopping event

http://www.cbr.washington.edu/sacramento/data/alert_weirs.html

Yolo bypass is rarely accessible when fry need rearing habitat

2007 2008 2009

RBDD RST

Knights Landing RST

Date cumulative catch exceeded ~80% at:

Chipps Island Trawl

del Rosario et al., 2013