Photo: Carey Smith, Pacific Coast Joint Venture, Vancouver, WA

Wetland Recovery and Salmon Population Resilience:

A Case Study in Estuary Ecosystem Restoration

Daniel L. Bottom NOAA NW Fisheries Science Center, Newport, OR

Kim K. Jones, Trevan J. Cornwell, Staci Stein Oregon Department of Fish and Wildlife, Corvallis, OR

Lance A. Campbell

Washington Department of Fish and Wildlife, Olympia, WA

From Reimers 1973

• Fry migrants

• Yearling migrants

• Subyearling migrants

• Subyearling migrants (mid summer)

• Subyearling migrants (late summer/fall)

Life history diversity in Chinook salmon

• Stream rearing (~1 ½ years) • Ocean rearing (~1 ½ years)

Conventional life history of Coho salmon

High Diversity

Reduced Diversity

Resilience of Salmon with Diverse Life Histories

Salmonid Response

Environmental variability

Photo: Carey Smith, Pacific Coast Joint Venture, Vancouver, WA

Objective

• Juvenile habitat use and performance within the estuary (residency, foraging success, growth)

• Population response within the basin (life history diversity, production, resilience)

Determine whether recovery of tidal wetlands in Salmon River estuary has benefited Chinook and coho salmon, as indicated by:

• Chinook salmon study (1998 – 2005) • Coho salmon study (2008 – 2011) • Pre-hatchery survey (1975-77)

Salmon River Research

Salmon River Basin

• 195 km2 watershed

• Estuary area 800 ha

• Head of tide ~ Rkm 6.5

• Fish hatchery at Rkm 8

• Estuary protection: Cascade Head Scenic Research Area (1974)

Reference

1987 1996

1978

Salmon River Estuary Marsh Restoration

>175 ha restored

2011

Life-cycle perspective:

• Juvenile abundance in streams (coho)

• Migration from watershed

• Estuary habitat use, movement, timing and CPUE, growth

• Adult returns (spawner surveys)

• Life history reconstruction: − juv, adult otoliths − PIT tags (coho) − Survival (coho)

Sampling at estuary mouth to collect ocean-bound juveniles

Reconstruct life histories of juveniles and adults from otolith chemistry

Life History Variation in Juvenile Salmon

• Strontium indicator of salt-water entry

• Back-calculated size at estuary entry based on otolith:fish size relationship

• Growth rates from daily increments

1975

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1976

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1977

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Lower estuary Mid estuary Upper estuary 75' seine (1977) Upper estuary 125' seine (1977)

2000

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2002

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Lower estuary Mid estuary Upper estuary

Chinook life history diversity has expanded with increased estuary rearing opportunity

E Fry ER<30d

E Fry ER>30d

Spring Migrant ER<30d

Spring Migrant ER> 30d

Summer Migrant ER<30d

Summer Migrant ER>30d

Fall Migrant ER< 30d

Fall Migrant ER> 30d

Early Fry

Spring

Summer Summer

Fall

Size at Estuary Entry (mm) Emergent Fry < 45 Spring (MAM) 47 – 64 Summer (JJA) 55 – 96 Fall (SON) 97 – 109

Life histories of outmigrating juvenile Chinook

(adapted from Volk et al. 2010)

Juvenile Life Histories of Returning Adult Chinook

Run Year 2004 (n=145)

Run Year 2005 (n=85)

Size at Estuary Entry (mm FL)

• All 4 migrant types contributed to surviving adults

• 25 – 40% of spawners were spring fry migrants that were rare or absent when the marshes were diked

(L. Campbell unpubl. data)

PIT Array, Smolt Trap

Coho Population Studies Salmon River 2008-2011

Jones et al. 2014

CPUE upper Salmon R. estuary

yearling

subyearling

• Yearlings in upper estuary in the spring

• 27% of tagged yearlings used 96 Marsh (2010)

• Contrary to the conventional coho life history, subyearlings reared in estuary wetlands

• Fry entered in spring; parr were present late fall and winter

Juvenile coho use of upper estuary and wetlands

Diverse juvenile coho life histories in Salmon River

Yearling Fry Nomad Parr

Juvenile Migrant Type

Rearing Environment

Stream and Tidal Fresh

Estuary

Ocean

(Jones et al. 2014)

Juvenile Life Histories of Returning Adult Coho

• 20-35% of returning adults had reared in the estuary • Estuary life histories were absent when marshes were diked • Estuary restoration has increased coho life history diversity as

well as production

Yearling Nomad Fry Parr

Estuary rearing types

(Jones et al. 2014)

Coho life history diversity has expanded with increased estuary rearing opportunity

(Jones et al. 2014)

Lessons from Salmon River

• Restoring estuary habitat has enhanced life history expression in both Chinook and coho salmon

• Coho that leave natal streams as subyearlings are not lost to the population but use the estuary

• Estuary life histories linked to restored wetlands contributed 25-40% of adult Chinook and 20-35% of adult Coho produced in Salmon River

• Life history diversity (and the habitat opportunities that support it) is fundamental to the productivity as well as the resilience of salmon populations

Case Studies in Salmon Resilience