can fisheries under catch shares better track management targets ?
DESCRIPTION
Can fisheries under catch shares better track management targets ?. Michael Melnychuk, Tim Essington, Olaf Jensen, Trevor Branch, Ana Parma, John Pope, Tony Smith, Jason Link, Selina Heppell, Steve Martell . Pew Charitable Trusts Webinar November 3, 2011. - PowerPoint PPT PresentationTRANSCRIPT
Michael Melnychuk, Tim Essington, Olaf Jensen, Trevor Branch, Ana Parma, John Pope, Tony Smith,
Jason Link, Selina Heppell, Steve Martell
Can fisheries under catch shares
better track management targets ?
Pew Charitable Trusts WebinarNovember 3, 2011
0
25
50
75
100
125
150
175
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000N
umbe
r of c
atch
sha
re fi
sher
ies
Year of catch share implementation
0255075
100125150175 South America
South Africa
Europe
U.S. W coast/Alaska
U.S. E coast
Canada W coast
Canada E coast
Australia
New Zealand
0255075
100125150175
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
Year of catch share implementation
Year of fishery development
Catch shares → Allocation of quota to individuals such that competition among individuals is reduced
Ŷ Catch shares
Ŷ Partial catch shares
Ŷ Quota only
Ŷ Effort regulations
0 50 100 150
Benthic fishBethopelagic fish
Pelagic fishReef-associated fish
Invertebrates
Number of stocks in analyses
0
30
Alaska, U.S.
0
30
Australia
0
30
60New
Zealand
0
30
East coast Canada
0
30
West coast Canada
0
30
Europe
0
30
SouthAfrica
0
30
South America
0
30
Northeast & mid-Atlantic coast, U.S.
0
30
S. Atlantic coast & Gulf
of Mexico, U.S.
0
30
West coast U.S.
ŶC
atch
sha
res
ŶP
artia
l cat
ch s
hare
s
ŶQ
uota
onl
y
ŶE
ffort
regu
latio
ns
050
100
150
Ben
thic
fish
Bet
hope
lagi
c fis
hP
elag
ic fi
shR
eef-
asso
ciat
ed fi
shIn
verte
brat
es
Num
ber o
f sto
cks
in a
naly
ses
030
Ala
ska,
U
.S.
030
Aus
tralia
03060N
ew
Zeal
and
030
Eas
t coa
st
Can
ada
030
Wes
t coa
st
Can
ada
030
Eur
ope
030
Sou
thA
fric
a
030
Sou
th
Am
eric
a
030
Nor
thea
st &
m
id-A
tlant
ic
coas
t, U
.S.
030
S. A
tlant
ic
coas
t & G
ulf
of M
exic
o, U
.S.
030Wes
t coa
st
U.S
.
2000 – 2004
Do catch share fisheries better track management targets than fisheries not under catch shares ?
targets: annual quota (C/Q)exploitation rate target (F/Ftarget)
biomass target (B/Btarget)
Hypotheses:
Adherence to targets: catch shares > quota only > effort controls
Strength of response: C/Q > F/Ftarget > B/Btarget
0.02
0.03
0.04
0.05
0.06
0.07
1980 1985 1990 1995 2000 2005
0.5
0.75
1
1.25
1.5
1980 1985 1990 1995 2000 2005
Target F
F
FF
: Fta
rget
4 metrics:
Mean
SD(target)
Minor exceedance
Major exceedance
0 1 2 3 4 5 6 70
2040
6080
100
0 1 2 3 40
2040
6080
100
0 1 2 3 4 5 6 705
1015202530
0 1 2 3 405
1015202530
0 1 2 3 4 5 6 70
10
20
30
40
0 1 2 3 40
10
20
30
40
0 2 4 60
20406080
100
0 1 2 3 40
20406080
100
0 2 4 605
1015202530
0 1 2 3 405
1015202530
0 2 4 60
10
20
30
40
0 1 2 3 40
10
20
30
40
Summary of response variables
C/Q
n = 259 stocks
F/Ftarget
n = 172
B/Btarget
n = 205
Freq
uenc
y
0 2 4 60
20406080
100
0 1 2 3 40
20406080
100
0 2 4 605
1015202530
0 1 2 3 405
1015202530
0 2 4 60
10
20
30
40
0 1 2 3 40
10
20
30
40
Mean C/Q Mean F/Ftarget Mean B/Btarget
Variables of interest
Catch control type
Other covariates accounted for:
Region
Taxonomic/habitat-
association
Year of fishery
development
Average catch
Lmax
Propensity for being under catch
shares
Responses Predictors
3 ratios with management targets:
Catch/quota
F/Ftarget
B/Btarget
4 metrics:
Mean
SD(target)
Minor exceedance
Major exceedance
X
-6 -4 -2 0-6 -4 -2 0-3 -2 -1 0-3 -2 -1 0
Catch sharesPartial catch shares
Quota only
Average catch
Development year
Lmax
Propensity score
Mean C/Q SD(target C/Q) Small overages (10%)
Large overages (25%)
Mean C/Q SD(target C/Q) Minor (10%) overages
Major (25%) overages
C/Q analysis
Catch sharesPartial catch shares
Quota only * *
-6 -4 -2 0-6 -4 -2 0-3 -2 -1 0-3 -2 -1 0
Catch sharesPartial catch shares
Quota only
Average catch
Development year
Lmax
Propensity score
Mean C/Q SD(target C/Q) Small overages (10%)
Large overages (25%)
Coefficient estimate
-3 -2 -1 0 1-3 -2 -1 0 1-1.5 -1 -0.5 0 0.5-1.5 -1 -0.5 0 0.5
Catch sharesPartial catch shares
Quota onlyEffort control
Average catch
Development year
Lmax
Propensity score
Mean F/F ref SD(target F/F ref)Minor overfishing
(10%)Major overfishing
(50%)
Catch sharesPartial catch shares
Quota onlyEffort regulations
Mean F/Ftarget SD(target F/Ftarget)Minor (10%)
over-exploitationMajor (50%)
over-exploitation
-5 -3 -1 1-5 -3 -1 1-1.5 -1 -0.5 0 0.5-1.5 -1 -0.5 0 0.5
Catch sharesPartial catch shares
Quota onlyEffort control
Average catch
Development year
Lmax
Propensity score
Mean F/F referenceSD(target F/F reference )
Minor overfishing (10%)
Major overfishing (50%)
*-3 -2 -1 0 1-3 -2 -1 0 1-1.5 -1 -0.5 0 0.5-1.5 -1 -0.5 0 0.5
Catch sharesPartial catch shares
Quota onlyEffort control
Average catch
Development year
Lmax
Propensity score
Mean F/F ref SD(target F/F ref)Minor overfishing
(10%)Major overfishing
(50%)
-3 -2 -1 0 1-3 -2 -1 0 1-1.5 -1 -0.5 0 0.5-1.5 -1 -0.5 0 0.5
Catch sharesPartial catch shares
Quota onlyEffort control
Average catch
Development year
Lmax
Propensity score
Mean F/F ref SD(target F/F ref)Minor overfishing
(10%)Major overfishing
(50%)
F/Ftarget analysis
Coefficient estimate
-3 -2 -1 0 1-3 -2 -1 0 1-1.5 -1 -0.5 0 0.5-1.5 -1 -0.5 0 0.5
Catch sharesPartial catch shares
Quota onlyEffort control
Average catch
Development year
Lmax
Propensity score
Mean B/B ref SD(target B/B ref)Minor depletion
(10%)Major depletion
(50%)
Catch sharesPartial catch shares
Quota onlyEffort regulations
Mean B/Btarget SD(target B/Btarget)Minor (10%)
depletionMajor (50%)
depletion
-3 -2 -1 0 1-3 -2 -1 0 1-1.5 -1 -0.5 0 0.5-1.5 -1 -0.5 0 0.5
Catch sharesPartial catch shares
Quota onlyEffort control
Average catch
Development year
Lmax
Propensity score
Mean B/B ref SD(target B/B ref)Minor depletion
(10%)Major depletion
(50%)
Coefficient estimate
B/Btarget analysis
Summary
• Compared to non-catch shares, catch share fisheries had:
• less variability in C/Q
• less frequent (major) overfishing
• Effects of both quota management and catch shares
• Catch shares are one of many possible tools that can be used to help meet
management objectives
• Next step: what particular aspects of catch share systems tend to lead
to the outcomes we’ve observed ?
Thank you:
Data collection: Kate Stanton, Rachel Finley, Jordan Watson
Funding: Lenfest Ocean Program
RAM Legacy database: Dan Ricard and all contributors
Interviews: U.S. – Alaska: J. DiCosimo, J. Heltzel, M. Fina, S. Hare, S. Kelley, J. Regnart; U.S. – W Coast: J. DeVore, M. Burner, C. Niles, I. Stewart; U.S. – NE/Mid-Atl. Coast: C. Legault, T. Chute, D. Hart, J. Idoine, G. Shepherd, B. Beal, N. Meserve, K. Taylor, B. Spear, D. Boelke, T. Hoff, K. West, J. McNamee; U.S. – SE Coast/G. Mexico: J. McGovern, P. Hood, A. Strelcheck, S. Gerhart, J. Kimmel, J. Smith; Canada – W Coast: A. Keizer, B. Ackerman, W. Li Ou, P. Ridings, J. Rogers, J. Schweigert, E. Wylie, M. James; Canada – E Coast: P. Cahill, V. Docherty, J. Hansen, D. Coffin, M. Baker, D. Ball, H. Bishop, J. Buie, S. Campana, G. Chouinard, J. Conlin, P. Couillard, A. Frechet, J. Gaudette, C. Hendry, P. Koeller, M. LeCouffre, L. Legere, D. Lemelin, B. Lester, C. MacDonald, B. Morin, M. Moriyasu, D. Pezzack, D. Roddick, A. Rumbolt, T. Siferd, J. Simon, S. Smith, G. Stevens, H. Stone, C. Waters, R. Federizon; Europe: J. Sigurjónsson, J. Horwood, B. Deas, A. LeGarrec, C. Olesen, M. Anderson, M. Welvaert, G. van Balsfoort, P. Breckling, N. Holdsworth; Australia: C. Dichmont, N. Klaer, G. Tuck, S. Wayte, S. Auld, S. Gaddes, S. Koh, S. Weekes, B. Taylor, K. Crosthwaite, T. Ward, C. Gardner; New Zealand: D. Foster, D. Sykes, G. Clement; Argentina: J. Hansen, A. Giussi, M. Renzi; South Africa: A. Brandao, D. Butterworth, S. Halloway, S. Johnston, C. de Moor, R. Rademeyer, G. Maharaj, R. Bross, A. Badenhorst.
0.0 0.5 1.0 1.5 2.0
0
10
20
30
40
0
1
2
3Catch shares
0.0 0.5 1.0 1.5 2.0
0
10
20
30
40
0
1
2
3Partial catch shares
0.0 0.5 1.0 1.5 2.0
0
10
20
30
40
0
1
2
3Quota only
0 1 2 3
0
10
20
30
40
0
2
4
6
8Catch shares
0 1 2 3
0
10
20
30
40
0
2
4
6
8Partial catch shares
0 1 2 3
0
10
20
30
40
0
2
4
6
8Quota only
▬ Alaska, U.S.
▬ West coast, U.S.
▬ West coast, Canada
▬ East coast, Canada
▬ Europe
▬ Australia
▬ New Zealand
▬ Other
Probability density
Mean C/Q SD(target C/Q)
Catch/quota ratios
n = 130
n = 41
n = 88
▬ F
requ
ency
0 1 2 3 4 5 6 70
5
10
15
0.0
0.5
1.0
1.5Catch shares
0 1 2 3 4 5 6 70
5
10
15
0.0
0.5
1.0
1.5Partial catch shares
0 1 2 3 4 5 6 70
5
10
15
0.0
0.5
1.0
1.5Quota only
0 1 2 3 4 5 6 70
5
10
15
0.0
0.5
1.0
1.5Effort control
0 1 2 3 40
5
10
15
0.00.51.0
1.52.02.5Catch shares
0 1 2 3 40
5
10
15
0.00.51.0
1.52.02.5Partial catch shares
0 1 2 3 40
5
10
15
0.00.51.0
1.52.02.5Quota only
0 1 2 3 40
5
10
15
0.00.51.0
1.52.02.5Effort control
▬ Alaska, U.S.
▬ West coast, U.S.
▬ NE & mid-Atl., U.S
▬ Europe
▬ New Zealand
▬ Other
Probability density
Mean F/Ftarget SD(target F/Ftarget)
0 2 4 6024681012
0. 00. 51. 0
1. 5Cat ch s hare s
0 2 4 6024681012
0. 00. 5
1. 01. 5Par tial catch sh ares
0 2 4 6024681012
0. 00. 5
1. 0
1. 5Quo ta o nly
0 2 4 6024681012
0. 0
0. 51. 0
1. 5Effor t co ntrol
0 1 2 3 40510
15
0.00.51.0
1.5Cat ch share s
0 1 2 3 405
1015
0.00.5
1.01.5Pa rtial catch sh ares
0 1 2 3 405
1015
0.00.5
1.0
1.5Qu ota o nly
0 1 2 3 40
51015
0.0
0.51.0
1.5Effor t co ntrol
F/Ftarget ratiosn = 54
n = 24
n = 67
n = 27
▬ F
requ
ency
▬ Alaska, U.S.
▬ West coast, U.S.
▬ West coast, Canada
▬ NE & mid-Atl., U.S.
▬ Europe
▬ Australia
▬ New Zealand
▬ Other
▬ F
requ
ency
Probability density
Mean B/Btarget SD(target B/Btarget)
B/Btarget ratios
0 1 2 3 402468
1012
0.0
0.5
1.0
1.5Catch shares
0 1 2 3 402468
1012
0.0
0.5
1.0
1.5Partial catch shares
0 1 2 3 402468
1012
0.0
0.5
1.0
1.5Quota only
0 1 2 3 402468
1012
0.0
0.5
1.0
1.5Effort control
0 1 2 30
5
10
15
20
0
1
2Catch shares
0 1 2 30
5
10
15
20
0
1
2Partial catch shares
0 1 2 30
5
10
15
20
0
1
2Quota only
0 1 2 30
5
10
15
20
0
1
2Effort control
0 1 2 3 402468
1012
0.0
0.5
1.0
1.5Catch shares
0 1 2 3 402468
1012
0.0
0.5
1.0
1.5Partial catch shares
0 1 2 3 402468
1012
0.0
0.5
1.0
1.5Quota only
0 1 2 3 402468
1012
0.0
0.5
1.0
1.5Effort control
0 1 2 30
5
10
15
20
0
1
2Catch shares
0 1 2 30
5
10
15
20
0
1
2Partial catch shares
0 1 2 30
5
10
15
20
0
1
2Quota only
0 1 2 30
5
10
15
20
0
1
2Effort control
0 1 2 3 402468
1012
0.0
0.5
1.0
1.5Catch shares
0 1 2 3 402468
1012
0.0
0.5
1.0
1.5Partial catch shares
0 1 2 3 402468
1012
0.0
0.5
1.0
1.5Quota only
0 1 2 3 402468
1012
0.0
0.5
1.0
1.5Effort control
0 1 2 30
5
10
15
20
0
1
2Catch shares
0 1 2 30
5
10
15
20
0
1
2Partial catch shares
0 1 2 30
5
10
15
20
0
1
2Quota only
0 1 2 30
5
10
15
20
0
1
2Effort control
0 1 2 3 402468
1012
0.0
0.5
1.0
1.5Catch shares
0 1 2 3 402468
1012
0.0
0.5
1.0
1.5Partial catch shares
0 1 2 3 402468
1012
0.0
0.5
1.0
1.5Quota only
0 1 2 3 402468
1012
0.0
0.5
1.0
1.5Effort control
0 1 2 30
5
10
15
20
0
1
2Catch shares
0 1 2 30
5
10
15
20
0
1
2Partial catch shares
0 1 2 30
5
10
15
20
0
1
2Quota only
0 1 2 30
5
10
15
20
0
1
2Effort control
n = 67
n = 28
n = 82
n = 28
Catch share propensity scores
• Controls for non-random application of catch share “treatments”
• Logistic regression:
CS ~ Region + Habitat + avCatch + devYear + Lmax
• Use estimated coefficients to predict probability of each fishery
being under full catch shares during 2000–2004
• Use propensity scores as covariates in subsequent analyses
0 0.25 0.5 0.75 1
Canada-West coastAustralia
New ZealandSouth Africa
Canada-East coastSouth America
EuropeU.S.-Alaska
U.S.-NE/mid-Atl. U.S.-West coast
U.S.-S. Atl. /G. Mex
0 0.25 0.5 0.75 1
Benthopelagic fishInvertebrates
Benthic fishPelagic fish
Reef-associated fish
0 0.25 0.5 0.75 1
Catch sharesPartial catch shares
Quota onlyEffort control
Catch share propensity scores
Average propensity score
Region
Habitat
Catch control
0
0.2
0.4
0.6
0.8
1
0 5 10 15
Pro
pens
ity s
core
ln(average catch during 2000-2004)
Alaska
US W coast
Can W coast
Can E coast
US NE coast
US SE /GoMex
Europe
S. Africa
S. America
Australia
New Zealand
Propensity score matching
0
0.2
0.4
0.6
0.8
1
0 5 10 15
Pro
pens
ity s
core
ln(average catch during 2000-2004)
Can W coast
Australia
New Zealand
S Africa
Can E coast
S America
Europe
Alaska
US NE coast
US W coast
US SE /GoMex
● Actual full CS
X Actual non-CS
-1 -0.5 0 0.5
Propensity score matching
Mean C/QSD(target C/Q)
Minor (10%) overagesMajor (25%) overages
Mean F/Ftarget
SD(target F/Ftarget)Minor (10%) overfishingMajor (50%) overfishing
Mean B/Btarget
SD(target B/Btarget)Minor (10%) depletionMajor (50%) depletion
-1 0 1
Mean C/QSD(target C/Q)
P(C/Q > 1.1)P(C/Q > 1.25)
Mean F/FMSYSD(target F/FMSY)
P(F/FMSY > 1.1)P(F/FMSY > 1.5)
Mean B/BMSYSD(target B/BMSY)
P(B/BMSY > 1.1)P(B/BMSY > 1.5)
2.5th %ile 97.5th %ile
Grand mean of:
ResponseCS – ResponseNon-CS
Mean difference of response variable
0
0.2
0.4
0.6
0.8
1
1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2
0
0.2
0.4
0.6
0.8
1
1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2
0
0.2
0.4
0.6
0.8
1
0.10.20.30.40.50.60.70.80.91
Proportion of stocks in some undesirable state
Pro
babi
lity
of e
xcee
danc
e
C/Q
F/Ftarget
B/Btarget
(OK) (Bad)
Ŷ Catch shares
Ŷ Partial catch shares
Ŷ Quota only
Ŷ Effort regulations
0 50 100 150
Benthic fishBethopelagic fish
Pelagic fishReef-associated fish
Invertebrates
Number of stocks in analyses
0
30
Alaska, U.S.
0
30
Australia
0
30
60New
Zealand
0
30
East coast Canada
0
30
West coast Canada
0
30
Europe
0
30
SouthAfrica
0
30
South America
0
30
Northeast & mid-Atlantic coast, U.S.
0
30
S. Atlantic coast & Gulf
of Mexico, U.S.
0
30
West coast U.S.
0
0.2
0.4
0.6
0.8
1
1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2
Pro
babi
lity
of e
xcee
danc
e
'OK' 'Bad'F/Freference
-6 -4 -2 0-6 -4 -2 0-3 -2 -1 0-3 -2 -1 0
Catch sharesPartial catch shares
Quota only
Average catch
Development year
Lmax
Propensity score
Mean C/Q SD(target C/Q) Small overages (10%)
Large overages (25%)Mean C/Q SD(target C/Q)
Minor (10%) overages
Major (25%) overages
Fixed effect
coefficients(full model)
C/Q
Catch sharesPartial catch shares
Quota only
Average catchDevelopment year
Lmax
Propensity score
-3 -2 -1 0 1 2-3 -2 -1 0 1 2-1.5 -1 -0.5 0 0.5-1.5 -1 -0.5 0 0.5
Alaska, U.S.West coast U.S.
West coast CanadaEast coast Canada
EuropeSouth Africa
AustraliaNew Zealand
Other
Benthic fishBenthopelagic fish
Pelagic fishReef-associated fish
Invertebrates
-3 -2 -1 0 1 2-3 -2 -1 0 1 2-1.5 -1 -0.5 0 0.5-1.5 -1 -0.5 0 0.5
Alaska, U.S.West coast U.S.
West coast CanadaEast coast Canada
EuropeSouth Africa
AustraliaNew Zealand
Other
Benthic fishBenthopelagic fish
Pelagic fishReef-associated fish
Invertebrates
Random effect
conditional modes
* *
-3 -2 -1 0 1 2-3 -2 -1 0 1 2-1.5 -1 -0.5 0 0.5-1.5 -1 -0.5 0 0.5
Alaska, U.S.West coast U.S.
West coast CanadaNE & mid-Atl., U.S.
EuropeNew Zealand
Other
Benthic fishBenthopelagic fish
Pelagic fishReef-associated fish
Invertebrates
-3 -2 -1 0 1 2-3 -2 -1 0 1 2-1.5 -1 -0.5 0 0.5-1.5 -1 -0.5 0 0.5
Alaska, U.S.West coast U.S.
West coast CanadaNE & mid-Atl., U.S.
EuropeNew Zealand
Other
Benthic fishBenthopelagic fish
Pelagic fishReef-associated fish
Invertebrates
-3 -2 -1 0 1-3 -2 -1 0 1-1.5 -1 -0.5 0 0.5-1.5 -1 -0.5 0 0.5
Catch sharesPartial catch shares
Quota onlyEffort control
Average catch
Development year
Lmax
Propensity score
Mean F/F ref SD(target F/F ref)Minor overfishing
(10%)Major overfishing
(50%)F/Ftarget
Catch sharesPartial catch shares
Quota onlyEffort regulations
Average catchDevelopment year
Lmax
Propensity score
Mean F/Ftarget SD(target F/Ftarget)Minor (10%)
over-exploitationMajor (50%)
over-exploitation
Fixed effect
coefficients(full model)
Random effect
conditional modes
-5 -3 -1 1-5 -3 -1 1-1.5 -1 -0.5 0 0.5-1.5 -1 -0.5 0 0.5
Catch sharesPartial catch shares
Quota onlyEffort control
Average catch
Development year
Lmax
Propensity score
Mean F/F referenceSD(target F/F reference )
Minor overfishing (10%)
Major overfishing (50%)
-3 -2 -1 0 1-3 -2 -1 0 1-1.5 -1 -0.5 0 0.5-1.5 -1 -0.5 0 0.5
Catch sharesPartial catch shares
Quota onlyEffort control
Average catch
Development year
Lmax
Propensity score
Mean B/B ref SD(target B/B ref)Minor depletion
(10%)Major depletion
(50%)B/Btarget
Catch sharesPartial catch shares
Quota onlyEffort regulations
Average catchDevelopment year
Lmax
Propensity score
-3 -2 -1 0 1 2-3 -2 -1 0 1 2-1.5 -1 -0.5 0 0.5
Alaska, U.S.West coast U.S.
West coast CanadaEast coast CanadaNE & mid-Atl., U.S.
EuropeAustralia
New ZealandOther
Benthic fishBenthopelagic fish
Pelagic fishReef-associated fish
Invertebrates
-1.5 -1 -0.5 0 0.5 -3 -2 -1 0 1 2-3 -2 -1 0 1 2-1.5 -1 -0.5 0 0.5
Alaska, U.S.West coast U.S.
West coast CanadaEast coast CanadaNE & mid-Atl., U.S.
EuropeAustralia
New ZealandOther
Benthic fishBenthopelagic fish
Pelagic fishReef-associated fish
Invertebrates
-1.5 -1 -0.5 0 0.5
Mean B/Btarget SD(target B/Btarget)Minor (10%)
depletionMajor (50%)
depletion
Fixed effect
coefficients(full model)
Random effect
conditional modes
Filters applied
• Excluded oceanic sharks/tunas
• Excluded rarely targeted stocks
• Excluded stocks with catch shares or TACs established during 2000-2004
• Excluded stocks with missing time series data or reference points
• Excluded stocks whose assessments were not trustworthy (F, B only)
• Excluded stocks with >50% landings in recreational sector
• Excluded fisheries under moratorium 2000-2004 (C/Q, F only)
Sensitivity tests
• Removed propensity score covariate
• Excluded stocks whose Ftarget or Btarget reference points were estimated with Schaefer model
• Excluded ICES/NAFO-managed stocks
• Excluded stocks with C/Q < 0.5
• Excluded stocks under moratorium (biomass analyses)
• Considered only full catch share and quota-only categories
big reduction in sample
size
C/Q F/Ftarget B/Btarget
Catch shares 130 54 67
Partial catch shares 41 24 28
Quota only 88 67 82
Effort regulations ─ 27 28
Total 259 172 205
Number of stocks included in analyses after filtering
Mixed-effects model analysis
Y ~ (CControl + PS) + avCatch + devYear + Lmax + Region + Habitat
Y ~ (CControl + PS) + devYear + Lmax + Region + Habitat
Y ~ (CControl + PS) + avCatch + devYear + Region + Habitat
Y ~ (CControl + PS) + avCatch + Lmax + Region + Habitat
Y ~ (CControl + PS) + Region + Habitat
Y ~ Intercept + avCatch + devYear + Lmax + Region + Habitat
Y ~ Intercept + devYear + Lmax + Region + Habitat
Y ~ Intercept + avCatch + devYear + Region + Habitat
Y ~ Intercept + avCatch + Lmax + Region + Habitat
Y ~ Intercept + Region + Habitat
Catch control
included
Catch control
not included
Type of response variable :
Metric for each response variable :
Current catch to current quota
(C/Q)
Current exploitation rate to target
exploitation rate(F/Ftarget)
Current biomass to target biomass
(B/Btarget)
5-year meane.g. mean C/Q
Standard deviation around targete.g. SD(target C/Q)
Exceedance of minor undesirable thresholde.g. P(C/Q > 1.1)
Exceedance of major undesirable thresholde.g. P(C/Q > 1.25)