Life-cycle models for the diverse and plastic Oncorhynchus mykiss:

challenges and opportunities

Neala Kendall*§, Rich Zabel§, and Tom Cooney§

*Washington Department of Fish and Wildlife §NOAA Fisheries, Northwest Fisheries Science

Oncorhynchus mykiss life history tactics and population dynamics

• Life history strategies influenced by environmental and

anthropogenic factors

• Life-cycle models used to better understand strategies,

evaluate population dynamics spatially and temporally

Jonny Armstrong John McMillan

Purpose of a life-cycle model

• Questions to answer using the model:

– Is anadromy expected to persist into the future?

– Under what environmental conditions will O. mykiss

be resident or anadromous?

– What life history stages represent population

“bottlenecks?”

– What patterns of anadromy and residency will we see

given different freshwater habitat mitigation actions?

Decision to smolt

O. mykiss life cycle models

Freshwater Ocean

Growth

Maturation

Decision to return & spawn

Natural mortality

Migration to ocean as steelhead

trout

Mature fish

Maturing fish

Mature fish

Modified from Theriault et al. 2008

Growth

Maturation

Spawning

Natural mortality

Maturing fish

Mature fish

Mature fish

Immature fish

Immature fish

Spawning migration

Fishing and

natural mortality

Ocean migration

Mortality

Natural mortality

Immature fish

Mature fish

Existing models to help

1. Yakima River, WA anadromous/resident O. mykiss abundance and reproductive success life-cycle models (I. Courter & C. Frederiksen et al.)

2. Anadromy/residency and smolt age decision for O. mykiss (originally developed for CA populations; Satterthwaite et al. 2009, 2010)

3. Chinook and O. mykiss life-cycle matrix models for Interior Columbia River basin (but only anadromous component; ICTRT and Zabel 2007)

Yakima River O. mykiss life-cycle models

Cross-Ecotype

Exchange

Capacity

Fecundity

Flow

Habitat Area

(PHABSIM & 2D modeling)

Anadromous

Spawners

Resident

Spawners

Freshwater SurvivalMarine Survival

Body Size

Growth

(bioenergetics)

Temperature

Food Supply

Territory Size

(competition)

Abundance

Fry

Environmental

Conditions

Reproductive

Success

Survival

Courter et al. 2009

• Use freshwater food

supply, flow, and

temperature to predict

fish growth, survival,

capacity, and reproductive

success by life history

tactic

Model predictions

Anadromous Resident

Courter et al. 2009

Anadromy/residency life-cycle model for O. mykiss

• Based on fish emergence date, freshwater growth,

survival, fecundity, and overall fitness

• Predict maturation/residency and smolt age decision

Satterthwaite et al. 2009, 2010

Maturation decision smolting decision

Model predictions

• Predict maturation/

residency and smolt

age decision

Satterthwaite et al. 2009, 2010

Gro

wth

rate

(m

m/d

ay)

Emergence date

Maturity of age-0 females

mature

wait, smolt at age 0

mature

wait, smolt at age 1

O. mykiss matrix models for Interior Columbia River basin

• Steelhead-only life-cycle model

• Beverton-Holt functions to include density-dependent survival in freshwater

• Components (adjusted in different “scenarios”):

– Downstream survival (based on hydropower corridor passage)

– Estuary and early marine survival (based on climate conditions)

– Later marine survival

– Harvest, upstream survival

– Overwinter survival in fw

ICTRT and Zabel 2007, Zabel et al. 2013

Interior Columbia River basin populations

• Rapid River (Little Salmon River)

• Potlatch River

• Catherine Creek

• Umatilla River

• Toppenish Creek

• Naches River

• Satus Creek

• Upper Yakima River

Photo: John McMillan

Example model run—Umatilla River

20 40 60 80 100

0

1000

2000

3000

4000

5000

6000

sp

aw

ne

rs.r

aw

[, , 3

]P

op

ula

tio

n a

bu

nd

ance

Years into the future

50 fish

• Abundance decreased over time for Yakima River

basin and Umatilla River populations

• Abundance increased over time for Potlatch

River, Catherine Creek, & Rapid River populations

Model predictions (under baseline scenarios)

• Changes in habitat, upriver survival, and estuary/early ocean conditions resulted in largest spawner abundance changes

• Changes in habitat resulted in greatest changes in quasi-extinction probability

• Changes in harvest rates resulted in smaller abundance and extinction probability changes

Model predictions (under varying scenarios)

Population-specific model predictions under various scenarios—Umatilla River

Survival through the hydropower corridor

Po

pu

lati

on

ab

un

dan

ce

afte

r 1

00

ye

ars

Estuary and early marine survival

Survival through the hydropower corridor

Habitat (overwinter/ prespawning survival)

Population-specific model predictions under various scenarios—Umatilla River

Later marine survival

Estuary and early marine survival

Estuary and early marine survival

Harvest rate

Po

pu

lati

on

ab

un

dan

ce

afte

r 1

00

ye

ars

Future work

• Combine ICTRT and Zabel matrix model with Courter & Frederiksen et al. freshwater habitat conditions determinants and Satterthwaite et al. model of anadromy/residency decision

Photos: John McMillan

Habitat considerations need to be incorporated

• First establish fish-specific side of the life-cycle model

• Then incorporate freshwater habitat considerations into model

• Understand how habitat changes (climate change and human modifications including restoration) may affect abundance and viability

Incorporating habitat restoration into the models

• Develop landscape-to-habitat functional relationships

• Develop habitat-to-fish relationships

• Model habitat quality (e.g., flow and temperature) and quantity using land-use and geomorphic characteristics to estimate fish capacity and survival

Bartz et al. 2006, Scheuerell et al. 2006, Beechie et al. 2006

Acknowledgements • National Research Council Postdoctoral Fellowship Program

• Interior Columbia TRT life-cycle modeling group

• Ian Courter (Mt. Hood Consulting), Chris Frederiksen (Yakama Nation), Ethan Crawford (WDFW), ODFW La Grande office, Brett Bowersox (IDFG), and others who supplied data

Photo: John McMillan

• NOAA Northwest Fisheries Science Center

• WDFW, especially Erik Neatherlin, Jeremy Cram, Andrew Murdoch, and Thomas Buehrens

Questions?

Oncorhynchus mykiss: one (two?) cool fish

Photo: John McMillan

Oncorhynchus mykiss: one (two?) cool fish

• Very diverse life history including migration tactics (“partial migration”)

• Valuable recreational and commercial fisheries

• Many natural populations have declined in abundance and

life history diversity over the past century, are ESA listed

Photos: Jonny Armstrong

Population-specific model predictions under various scenarios—Umatilla River

Habitat (overwinter/prespawning survival)

Po

pu

lati

on

ab

un

dan

ce

Estuary and early marine survival

Later marine survival