NATURES (Project 199105500) Natural Rearing Enhancement System Resource Enhancement and Utilization Technologies Division Northwest Fisheries Science Center.

NATURES

(Project 199105500)

Natural Rearing Enhancement System

Resource Enhancement and Utilization Technologies DivisionNorthwest Fisheries Science CenterNational Marine Fisheries Service

2725 Montlake Boulevard E.Seattle, Washington

Goals

• Increase postrelease survival

• Minimize morphological and behavioral divergence from wild fish

Summary of Major Results Achieved

• Seminatural raceway habitat– Induced wild-like behavior and coloration– Increased instream survival

• Predator avoidance conditioning– Increased instream survival– Increased predator recognition

• Ecological interactions– Improved competitive ability– Reduced behavioral divergence

• Feeds– Improved foraging skills

• 12 published papers

Objectives

1. Evaluate the independent and interactive effect of NATURES seminatural raceway habitat variables on chinook salmon smolt-to-adult survival.

2. Evaluate the effect of NATURES predator avoidance conditioning on chinook salmon smolt-to-adult survival.

3. Quantify the effects of hatchery steelhead reared in NATURES and conventional environments on the growth, survival, condition, and emigration of naturally-reared steelhead and chinook salmon.

4. Determine the effects of NATURES rearing on the behavioral development of juvenile steelhead and the effects of competition with naturally-reared salmonids.

Address RPA 170-173, and 184

Carson NFH Experiments (Obj. 1 & 2)

• Seminatural Raceway Habitat

• Predator Avoidance Conditioning

Experiment evaluating the independent and interactive effects of NATURES Seminatural Raceway Habitat

StructureNo structure

No substrate

Cover No coverNo cover No cover

No structure

Cover Cover

Structure

Substrate

No cover Cover

Eight rearing treatments

Substrate

No structure

No substrate No substrate

Structure

Substrate

No cover No cover

No structure No structure No structure

No substrate No substrate

Cover Cover

Structure Structure Structure

Substrate Substrate

No cover Cover No cover Cover

Full factorial experimental design

T1 T2 T3 T4 T5 T6 T7 T8

Seminatural Raceway Habitat Experiment

Response variables• Growth• Health• Cryptic coloration• Brain development• Predation bioassay• Instream survival• Smolt-to-adult survival

Predator Avoidance Conditioning Experiment

Rearing treatments• No antipredator conditioning

• Antipredator conditioning

Response variables• Instream survival

• Smolt-to-adult survival

The effects of NATURES rearing environments on ecological interactions between naturally and hatchery-reared steelhead (Obj. 3 & 4).

Rationale:• Ecological interactions between wild and

hatchery-reared salmonids have been implicated in stock declines.

• NATURES rearing affects competitive ability and agonistic behavior (Berejikian et al. 2000, 2001).

Experimental Facilities

Quasi-natural stream(40 x 6 m)

Behavior observationflumes

How do hatchery rearing environment and stocking density affect interactions with

naturally-reared steelhead parr?

• Stock conventional and NATURES steelhead parr at different densities with naturally-reared steelhead and chinook parr.

• Evaluate habitat use, agonistic behavior, feeding, growth, survival, and dispersal of naturally-reared steelhead parr.

Expected Results• Determine the combination of seminatural raceway

habitat components that maximize smolt-to-adult survival.

• Determine if predator avoidance conditioning increases smolt-to-adult survival.

• Quantify effects of NATURES-reared steelhead on the growth, survival, and dispersal of natural steelhead and chinook parr.

• Quantify effects of NATURES-reared steelhead on the habitat use, behavior, and feeding of natural steelhead and chinook parr.