Kyle Young (Aberystwyth University) Stocking and catches in England and Wales

7/22/2019 Kyle Young (Aberystwyth University) Stocking and catches in England and Wales

1/72

Acknowledgments

&Disclaimer


2/72

A long history

A mature debate


3/72


4/72

Gravel finding

Redd digging

Mate choosing

Male competition

Timed emergenceStream rearing

Territorial

Drift feeding

Slow growing

Predator avoiding

Raceway ripening

Egg stripping

Random mating

Milt squirting

Free emergencePond rearing

Schooling

Search foraging

Fast growing

Predator free

egg size/number

emergence time

behaviour

body size/shape/colour

energy allocation

life history

FITNESS

PHENOTYPE


5/72

Crespi & Fulton 2004

Pacifictrout

Pacific

salmon

charr

Atlanticsalmon,trout

crazy

relatives

Atlantic salmon steelhead


6/72

Hood River, Oregon


7/72

Science 2007(318):100-103

Generations in captivity

Reproductive

Success

Relative

to wild fish


8/72

PNAS 2012:238-242

Number of adults produced by

wild broodstock bred in the hatchery

Average number

of adults produced by

theiroffspring

breeding in the wild


9/72

year after year

but so what?


10/72

CJFAS 2011:511-522

94 POPULATIONS

32 steelhead, 26 coho, 36 chinook

?

STOCK

RECRUITMENT


11/72

Proportion hatchery spawners

Population

productivity

recruits/spawner

the impact of hatchery fish from wild typehatchery

brood-stocks was no less adversethan hatchery fish

from traditional, domesticated brood-stocks

The Catch-22of stocking

steelhead

coho, chinook


12/72

Stocking damages salmon populations

So why do it?

STOCK

RECRUIT

MENT

DEGRADATION + STOCKING

HABITAT DEGRADATION

PRISTINE

Reisenbichler 1997


13/72

Angling...

STOCK

RE

CRUITM

ENT


HABITAT DEGRADATION

PRISTINE

?


14/72

62 rivers,15 yearseach with a Conservation Limit (eggs)

42 rivers with at least

one stocking event

between 1995-2009

adultsat time 1

adults

at

time 2

Atlantic salmon steelhead


15/72

FIRST CONTROL FOR:-region

-Conservation Limit

-year

-net fisheries

THEN ASK:

Does MEAN rod catch go up

with MEAN stocking effort?

Does ANNUAL rod catch go up

with ANNUAL stocking effort?

DOES STOCKING IMPROVE

ROD CATCHES?


16/72

-1

1

0

2 40 6 8 10

Mean total stocking effort (% CL)

Meanrod catch

NO: STOCKED CATCHMENTSDO NOT HAVE HIGHER ROD CATCHES


17/72

FOR 42 STOCKED CATCHMENTS

DOES ANNUALSTOCKING EFFORT

AFFECT ANNUALROD CATCH?

Correlation coefficient varies -1 to 1

stocking effort

subse

quentcatch

r= -0.80

r= 0.80

r= 0


18/72

Correlationwith annual

rod catch

Type of annual stocking effort

-1

1

0

Total YOY Parr Smolt

42 38 29 18

NO: ANNUAL STOCKING EFFORT IS NOTRELATED TO ANNUAL ROD CATCH


19/72

Do rivers with positive annual

correlations have improved mean

rod catches?

BONUS QUESTION


20/72

-1

1

0

Annual correlation

total stocking effort -v- rod catch

-1 10

Catch-22 Take 2

Meanrod catch


21/72

The damage from stocking is not

balanced by detectable fishery benefits

STOCK

RE

CRUITM

ENT


HABITAT DEGRADATION

PRISTINE


22/72

When do the benefits

balance the damage?...


23/72

blank


24/72

artificial breeding programmes should be used only as a

last resort when populations face imminent extirpation

Neff et al. 2011

Lande 2002

TO RESCUE SMALL POPULATIONS


25/72

Levins 1969, Young 1999

= mp(1-p)ep,dp

dt

dp

dt= 0, p*= 1-e/m

p= proportion occupied

m= migration rate from

occupied patches

e= extinction rate of

occupied patches

TO RESCUE FRAGMENTED METAPOPULATIONS


26/72

TO PROTECT WILD POPULATIONS FROM ANGLERS


27/72

Rand et al. 2012

TO SUPPORT LARGE COMMERCIAL FISHERIES

Palm et al 2012


28/72

Statements from the (100 delegate) workshop

1. Releases should not be performed in wild salmon rivers

with viable populations.

Palm et al. 2012


29/72

we summarized 266 peer-reviewed papers that were

published in the last 50 years, which describe empirical

case studies on ecology and genetic of hatchery stocks

and their effects on stock enhancement

results suggest that negative effects of hatchery rearingare not just a concern but undeniably present

scientific data supporting the positive effect on stock

enhancement are largely missingat this moment

2010


30/72

1. consider stocking only for populations

at imminent risk of extirpation AND

protected by no-harvest regulations

2. review/revise/revoke legally mandatedmitigationstocking programmes

3. promote and support alternative activities

for anglers to contribute to salmon & sea troutconservation efforts

Where the status of wild salmon

is a management priority

KNOWLEDGE, COMMUNICATION, COURAGE


31/72

Levin et al. 2001

hatchery programmes that produce increasingly higher numbers

of fish may hinder the recovery of depleted populations

Chilcote et al. 2003

removal rather than addition of hatchery fish may be themost effective strategy to improve productivity and resilience

Blanchet et al. 2008supportive breeding programmes do not meet the criteria

necessary to ensure preserving the genetic and ecological

integrity of wild populations


32/72

blank

Atl ti l l 101


33/72

Atlantic salmon ecology 101anadromous, semel(itero)parous

5,000Marine

density

independent

survival

500

Freshwater

densitydependent

survival

100

50

2

# time 1

#time2

# time 1

#time2

1-4 years

1-4 years


34/72

1991

THE 4 Hs

Harvest, Hydropower, Habitat, Hatcheries


35/72

Rand et al. 2012


36/72


37/72

Horrero et al. 2012

The estimated cost of each salmon caughtwas higher than4000.


38/72

River Spey stocking under review

1.1 million fry released annually

120,000 annually

In 2009 stocking contributed:

43/8626 rod caught fish = 0.5%

2,791 per rod caught fish*

*1.1m/5000 = 220 females = 440 adults = 44 fish removed from fishery!

http://www.asfb.org.uk/river-spey-stocking-under-review/


39/72

Many complex processes

Two simple principles

ECOLOGICAL

Predation

Predator attraction

CompetitionParasites

Diseases

EVOLUTIONARY

Genetic drift

Founder effects

Genetic bottlenecksInbreeding depression

Relaxed selection

Artificial selection

Modified selectionOutbreeding depression


40/72

1. ADDING INDIVIDUALS TO A POPULATION

REDUCES POPULATION GROWTH RATE

Wilson & Bossart 1971

K = carrying capacity


41/72

IN ATLANTIC SALMON


42/72

IN ATLANTIC SALMON

Einum & Nislow 2010

eggs/nest

survivalrate

tofry

Hindar et al. 2010

Stockeggs/m2

Recuitment

adultsx103PRODUCTIVITY

K

STOCK RECRUITMENT IN ATLANTIC SALMON


43/72

Hindar et al. 2010Stockeggs/m2

R

ecuitment

adultsx103

PRODUCTIVITY K

STOCK-RECRUITMENT IN ATLANTIC SALMON

2 ADDING MISMATCHED PHENOTYPES REDUCE


44/72

2. ADDING MISMATCHED PHENOTYPESREDUCE

POPULATION GROWTH RATE MORE

HATCHERIES CREATE MISMATCHED PHENOTYPES
http://people.rit.edu/rhrsbi/GalapagosPages/Map.html


45/72

HATCHERIES CREATE MISMATCHED PHENOTYPES

Redd digging

Mate choosing

Emergence timingStream rearing

Territorial

Drift feeding

Slow growing

Predator avoiding

Egg stripping

Random mating

Free emergencePond rearing

Schooling

Search foraging

Fast growing

Predator free

natural selection

PHENOTYPEegg size/number

emergence time

behaviour

metabolism

body size/shape

energy allocation

life history

F

ITNESS

relaxed selection

stocking

AND FISH THAT ARE LESS FIT IN THE WILD


46/72

18 studies, 1977-2008, NMFS 2009

AND FISH THAT ARE LESS FIT IN THE WILD

Relat

iveReprodu

ctiveSucce

ss

Generations in Captivity

vs

P di A l i


47/72

Pedigree Analysis

e.g. river spey


48/72

A multi generation reciprocal transplantexperiment

ENVIRONMENT

FTINESS

lineages favoured by artificial selection in the hatchery


49/72

offspring produced by

wild broodstock in the hatchery

o

ffspringproducedbytheir

offspring

inthewild

lineages favoured by artificial selectionin the hatchery

do poorly under natural selectionin the wild

adaptation to the hatchery environment


50/72

Generations in hatchery

Fitnessinhatc

hery

(numberofadultsp

roduced)

adaptation to the hatchery environment

occurs in a single generation

Christie et al. 2011

And the effect lasts.wild broodstock produce crap grandkids


51/72

Araki et al. 2009

p p g

parental [grand parental] historyRelativeRe

productiveS

uccess

males females

?


52/72

-1 1 20

log10(Conservation Limit x 106eggs)

Catch Per License Day

0

0.25

0.5

0

1

2

3

4

Total rod catch (log10

)

ANGLER CATCH STATISTICS 1995-2009

-1 1 20

MEAN STOCKING EFFORT 1995 2009


53/72

N

umberofcatchments

0

5

10

Years with stocking

1 5 10 15

0

20

30

10

Total stocking effort (% CL)

0 5 10 20

Fry stocking effort (% CL) Parr stocking effort (% CL) Smolt stocking effort (% CL)

0

20

30

10

00

20

30

10

0

20

30

10

5 10 20 0 0.2 0.4 0.6 0.8 1 5 0 0.2 0.4 0.6 0.8 1 5

00 1 52 3 4 6

Total stocking effort (log10+1)

20

30

10

MEAN STOCKING EFFORT 1995-2009

STOCKED CATCHMENTS


54/72

2 40 6 8 10

-0.2

0.2

0

-1

1

0

2 40 6 8 10

Catchment mean total stocking effort (% CL)

Mean rod catch Mean CPLD

STOCKED CATCHMENTS

DO NOT HAVE BETTER FISHING



55/72


DOES ANNUALSTOCKING EFFORT

AFFECT ANNUALANGLER CATCH STATS?

Correlation coefficient varies -1 to 1

stocking effort

subsequentcatch r= -0.80 r= 0.80r= 0

ANNUAL STOCKING EFFORT IS NOT


56/72

-1

1

0

C

orrelation

with

annualcatch

statistic

Type of annual stocking effort

Total YOY Parr Smolt Total YOY Parr Smolt

42 38 29 18 42 38 29 18

ANNUAL STOCKING EFFORT IS NOT

RELATED TO ANNUAL CATCH STATS

rod catch CPLD


57/72

Mea

nlog10

(rod

catch)

-1

1

0

Annual correlation

stocking effort -v- rod catch

-1 10

r = -0.48, P= 0.002

Catch-22 Take-2

genetic drift: change in the genetic composition of a population due


58/72

genetic drift:change in the genetic composition of a population due

to chance or random events. One of four (natural/sexual selection,

mutation, migration) principle mechanisms of evolution.

ALWAYS OPERATES. Only important in small populations.

founder effect: populations founded by only a few individuals will have


59/72

founder effect: populations founded by only a few individuals will have

lower, and non-representative, levels of genetic diversity than the original

population

0

population bottleneck: occurs when population size is small for at least


60/72

population bottleneck: occurs when population size is small for at least

one generation, genetic drift can result in a loss of genetic variation.


61/72

inbreeding depression: reduced individual/population fitness as a result of breeding

among related individuals. The risk increases in small population sizes

outbreeding depression: offspring from crosses between individuals


62/72

outbreeding depression: offspring from crosses between individuals

from different populations have lower fitness than offspring from crosses

between individuals from the same population:

1. retards local adaptation

2. breaks down coadapted gene complexes


63/72


64/72

to promote and open discussion of their merits and risks


65/72

-1 1 20

log10(Conservation Limit x 106eggs)

Catch Per License Day

0

0.25

0.5

0

1

2

3

4 Total rod catch (log10)

WHICH OBSERVATIONS HAD STOCKING?

-1 1 20


66/72

Kostow 2012


67/72


68/72

Chilcote 03

Proportion wild fish

Productiv

ity

recruits/spawner

slope of

SR curve


69/72

Hilborn & Eggers 2000, 2001; Neff et al. 2011

year

runsize

stocked


70/72


71/72


72/72

Stocking in E & W does not

appear to improve angling(the ONLY good answer)

And so againwhy do it?

Kyle Young (Aberystwyth University) Stocking and catches in England and Wales

Documents

Transcript of Kyle Young (Aberystwyth University) Stocking and catches in England and Wales