The Influence of Hatchery Rearing on Tucannon River

Spring Chinook

Michael Gallinat

WDFW

Purpose of this talk…• Provide a quick background on hatchery

management of Tucannon Spring Chinook.

• Describe the influence of hatchery rearing on selected phenotypic traits.

• Inform you about the latest cutting edge advancements in fisheries phenomenon and ask really deep philosophical ?’s.

• Describe our latest attempts to improve survival of our hatchery fish & possible genetic implications.

Quick Background…

LSRCP Mitigation Program

• Hatchery mitigation was for 48% loss (1,152) through the dams with the remaining 52% (1,248) expected to be self-sustaining.

• Mitigation was to be accomplished by the annual release of 132,000 smolts with an assumed SAR of 0.87%.

• Evaluation program was established in 1985 to monitor the success of the program in achieving the mitigation goal.

• First smolts (derived from wild Tucannon brood) were released in 1987.

• Since 1989, the hatchery broodstock has consisted of both H & N origin fish (strive for 50:50 ratio).

• The stock was listed as “Threatened” under the ESA in 1992.

HatcherySpawners

NaturalSpawners

Integrated ProgramIntentional gene flow between hatchery and natural components:

effectively there is a single population

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Return Year

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mb

er o

f S

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HatcheryNatural

Hatchery Mitigation Goal = 1,152

• Relatively stable runs from 1985-1993 (mean = 550 fish)

• Between 1994-1999 the average run declined to 196 fish (range 54-351)

Captive Broodstock Program

Purpose/Goal

• To artificially boost broodstock numbers over the course of one generation (5 brood years – 1997-2001) and supplement the population through a bottleneck situation.

• Captive broodstock were selected from the hatchery supplementation program (HxW, HxH, and WxW parents) with a progeny release goal of 150,000 smolts @ 15 fpp.

With the captive brood program we can now look at three levels of hatchery

influence on the same stock…

• Captive Brood - extreme influence.

• Hatchery-origin - partial influence.

• Natural-origin - minimal influence.

Nature NurtureVersus

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Percent

Age 2 Age 3 Age 4 Age 5

Captive Brood Hatchery Natural

Age at Maturation (M & F Combined)

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Percent

Age 2 Age 3 Age 4 Age 5

Captive Brood Hatchery Natural

Age at Maturation (M & F Combined)

Mean Fork Length (cm)M

ean

Fork

Len

gth

(cm

)

CB4 H4 N452

56

60

64

68

72

Age 4 Female Spawner Fork Length

Mean Egg Size (g)

Mea

n E

gg S

ize

(g)

CB4 H4 N40.22

0.23

0.24

0.25

0.26

0.27

Egg Size

Mean Fecundity (# eggs/female)

Mea

n Fe

cund

ity

CB4 H4 N41600

2000

2400

2800

3200

3600

Fecundity

Index of Relative Fecundity

“Normally”

= Fecundity ÷ Body Weight

Modified Index of Relative Fecundity

= Fecundity ÷ Fork Length

Index of Relative Fecundity (Fecundity/Fork Length)

Mea

n R

elat

ive

Fecu

ndity

CB4 H4 N430

34

38

42

46

50

Relative Fecundity

Maybe they just allocate/partition it differently?

Maybe Hatchery fish = Natural fish??

Index of Reproductive Effort

= Fecundity x Egg Wt.

Mean Reproductive Effort (fecundity x egg wt.)

Mea

n R

epro

duct

ive

Effo

rt

CB4 H4 N4410

510

610

710

810

Index of Reproductive Effort

Gallinat’s Phenomenon

Phenomenon whereby hatchery-origin fish are able to divert more energy than natural-origin fish in producing larger eggs due to a readily available food supply and protected hatchery environment.

These larger eggs result in overall lower fecundities at size compared to naturally-reared fish.

What does this mean in the big picture?

Productivity might be lower with a higher composition of hatchery-origin

fish in the run…

Is this a “bad” thing…hatchery fish that are less fecund?

Might not be “bad”…if based on DNA analysis they are genetically the same…might actually be preserving genes with

the hatchery program!

Would just have to use natural fish equivalents in comparisons.

SAR's for the 2000-2003 BY's (2003 BY incomplete)

Mea

n S

AR

CB Hatchery Natural0

0.3

0.6

0.9

1.2

1.5

Smolt-to-Adult Returns

0.87 SAR

SAR's for the 1985-2002 BY'sM

ean

SAR

Hatchery Natural0

0.5

1

1.5

2

2.5

Smolt-to-Adult Returns

0.87 SAR

Yikes!!

• Based on the current average hatchery SAR of 0.22% (well below the original goal of 0.87%) the program would need to produce over 500,000 smolts annually to meet the hatchery mitigation goal of 1,152 returning hatchery adults.

How can we increase survival? (Thereby mining less broodstock from the river….)

• Emphasis change from quantity to quality!

What are some of the methods to do this?

• Exercise Experiments?

• “Nature’s” Rearing?

• Increase Smolt Size?

Reciprocal X Model

Survival

FPP

Prediction Limit

Confidence Limit

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40r 2 = 0 .8 2 ; P < 0 .0 1

S u rv iv a l f ro m R M IS (C W T ) D a ta b a s e …

What have other studies found?

00.5

11.5

22.5

3

3.54

4.5T

otal

% S

urvi

val

20 12.9 8 7 6.2 5.8 5Fish Per Pound

White River Spring Chinook Survival vs. Size at Release

(Appleby and Keown 1995)

Size at Release Study (06-08 BY’s)

• 9 fpp (“large” size) vs. 15 fpp (“small” size)

• CWT + VIE (blue & purple)

• 2,500 PIT tags in each group

• If there’s no difference in survival then it’s more cost effective to rear the “small” fish.

• If the “large” fish have significantly higher SAR’s - than we may be able to collect fewer broodstock from the river in the future.

What might the results tell us?

Q: Isn’t having a larger number of jacks/precocials a bad thing?

…and that’s exactly what will happen if we release larger hatchery smolts.

Todd Pearsons (WDFW) asked…

“Are you experiencing what we see in the Yakima?”

You have to look closer…

“I just see a bunch of small wild fish…”

“We have to capture them??…”

How does Todd’s crew catch them?

• Underwater angling.

• Pooper Scooper????

I DON’T THINK SO!!!!!!

A cast net!

Our current record is 11 in one cast.

Wild Mature Size Range 68-127 mm

DNA-based parentage assignment study from the Cle Elum

spawning channel (Yakima River)

Interesting Study…

So Are Jacks Bad? Philosophical ?’s…

• Don’t large numbers of jacks indicate good survival and tend to foreshadow good/strong runs?

• Precocial males are a characteristic of spring Chinook populations – if the hatchery environment just causes it to be expressed without changing the population’s genetic structure - why worry about it?

• May actually even increase genetic diversity!

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Percent

Age 2 Age 3 Age 4 Age 5

Captive Brood Hatchery Natural

Age at Maturation (M & F Combined)

•Our natural-origin fish aren’t replacing themselves for the most part so why do we want to imitate them?

•The environment has changed from what they adapted/evolved for…

•Dams/Global Warming/Ocean Dead Zones/Loss of Estuary Habitat/Predator Changes/Forage Changes/etc., etc.

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Brood Year

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urn/

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NaturalHatchery

Replacement Line

• If it’s genetically caused wouldn’t we see more jacks in the natural population…since we limit the number of jacks brought into the hatchery?

• Large natural-origin jack runs don’t tend to follow large natural-origin jack runs.

• And…aren’t increased numbers of females what we’re really after anyway?

Fish Management Dilemma…

• If we actually achieve increases in our hatchery fish survival it could decrease our Proportionate Natural Influence (PNI) below 50%.

HatcherySpawners

NaturalSpawners

PNI is a Function of the Gene Flow Rates Between the Two

Environments

pNOB

pHOS

pNOB = proportion of broodstock consisting of natural-origin fish

pHOS = proportion of fish spawning naturally consisting of hatchery-origin fish

pHOSpNOB

pNOBPNI

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pNOB

pHOS

PNI =.5

PNI =.6

PNI =.7

PNI =.8

PNI =.9

Effect of pNOB and pHOS on Proportionate Natural Influence

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pNOB

pHOS

Effect of pNOB and pHOS on Proportionate Natural Influence

“Golden Triangle of Genetic Goodness”

Key HSRG Guidelines for (Properly) Integrated Programs

• PNI must exceed 50%.

• For populations of special concern – natural influence should exceed 70%.

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pNOB

pHOS

PNI =.5

PNI =.6

PNI =.7

PNI =.8

PNI =.9

Effect of pNOB and pHOS on Proportionate Natural Influence

Catch-22…

• We might be able to reach the LSRCP mitigation goal but at the expense of not being in the “Golden Triangle of Genetic Goodness”.

• We can be in the “Golden Triangle of Genetic Goodness” (as we currently are) but at the expense of not reaching the LSRCP mitigation goal.

In Conclusion

• While hatchery and natural-origin Tucannon spring Chinook are derived from the same endemic stock and considered genetically the same (based on our analysis to date)…

• hatchery-origin fish natural-origin fish! But just because it’s different doesn’t necessarily make it bad if genetically the same.

• Going to take experimentation/innovation to increase hatchery fish survival.

And…

• Fish management will need to decide what level of risk it is willing to accept from the hatchery program.

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Return Year

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Hatchery

Natural

Hatchery Mitigation Goal = 1,152