bering sea crab: 2019/20 season...review of tacs bering sea crab: 2019/20 season adf&g...
TRANSCRIPT
Review of TACs
Bering Sea Crab:
2019/20 Season
ADF&G presentation to BSAI crab industry, 9 Oct 2019
Join by teleconference:
Call in #: 1-800-315-6338
Access code: 48618421
Outline
• Introduction
• PIBKC
• PIRKC
• SMBKC
• BBRKC
• Tanner
• Intermission
• snow
2
2019/20 TAC Summary
Details follow…
3
OFL ABC TAC
(mill lb) (mill lb) (mill lb)
0.0026 0.0020 0
(total catch) (total catch) (directed fishery closed)
1.90 1.43 0
(total catch) (total catch) (directed fishery closed)
0.10 0.08 0
(total male catch) (total male catch) (directed fishery closed)
7.50 6.00 3.80
(total catch) (total catch) (retained catch)
63.62 50.89 0 (EBT), 0 (WBT)
(total catch) (total catch) (directed fishery closed)
121.00 96.80 34.02
(total catch) (total catch) (retained catch)
Bering Sea Tanner crab
Bering Sea snow crab
Fishery
Pribilof blue king crab
Pribilof red king crab
St. Matthew blue king
Bristol Bay red king crab
TAC: Annual catch target for the directed fishery, set to prevent exceeding the ABC for that stock. Limits legal sized males, but must consider all sources of mortality to ensure the ABC is not exceeded.
ABC: Level of annual catch that accounts for scientific uncertainty and is set to prevent the OFL from being exceeded.
In practice ABC limits mortality of ALLmale and female crabs regardless of size, from all sources of fishery mortality (i.e. retained catch, bycatch in directed and nondirected crab fisheries, and groundfish fisheries).
OFL: Level of fishing mortality that jeopardizes the capacity of a stock to produce the maximum sustained yield on a continuing basis.
Cat
ch
0
10-20% buffer
Overfishing Level (OFL)Federal Government
Acceptable Biological Catch (ABC)Federal Government
Total Allowable Catch (TAC)State of Alaska
Below ABC
4
•Steady State
•Cyclical
•Irregular
•Spasmodic
• How can we account for all this change over time??
• Potential different realities create challenges in
estimating population abundance
Population Trends
5
Population AbundanceSurveys: bottom trawl yields area-swept estimates• Net mensuration: net width x tow length = area-swept• Crab catch / area-swept → density → expand to total area• Survey-based abundance indices (i.e., area-swept estimates)
– Sampling error, survey selectivity, summer snap-shot
Stock Assessment Models: quantitative predictions about crab populations
• Length-based analysis: reduces uncertainty in annual abundance estimates
• Can account for gear selectivity, natural mortality, growth, etc• Lots assumptions that goes into them:
– Growth– Male maturity – Natural mortality– Etc
6
A size class that gets larger from one year to the next suggest sampling error, not that more crab were born and immediately were in that size class.
Example of
Sampling Error
7
Example of Sampling Error
• The survey fails to detect portions of the population.
• Survey estimates of newshell female snow crab were 125 million in 1999, yet estimates of oldshell mature females was nearly 1,000 million in 2000.
• Estimates of oldshellfemales should be at or below levels of newshell females the year prior.
From 2019 NOAA Tech Memo
8
Stock Assessment
Growth
Recruitment
Movement
Death (mortality)
Survey DataCatch data
Stock StatusFishing limits
Research
Abundance Index
9
Federal Crab Stock Assessment Process
NMFS Crab SurveyIndustry survey
Population Models (CPT)
Initial OFLs and ABCs
NPFMC (SSC)
Technical Review
Public Input
Final OFLs and ABCs
ADF&G TACs
ResearchFishery Data
10
FMP 8.2.2. Total Allowable Catch and Guideline Harvest Level
The FMP authorizes the State to set preseason TACs and GHLs under State regulations………
The State will take into account the following factors, to the extent information is available, in developing harvest strategies or setting TACs and GHLs:
(1) whether the (Annual Catch Limit) ACL for that stock was exceeded in the previous year;
(2) stock status relative to the OFL and ACL;
(3) estimates of exploitable biomass;
(4) estimates of recruitment;
(5) estimates of thresholds;
(6) market and other economic considerations;
(7) additional uncertainty; and
(8) any additional factors pertaining to the health and status of the stock or the marine ecosystem.
Additional uncertainty includes:
(1) management uncertainty (i.e., uncertainty in the ability of managers to constrain catch so the ACL is not exceeded, and uncertainty in quantifying the true catch amount) and
(2) scientific uncertainty identified and not already accounted for in the ABC (i.e., uncertainty in bycatch mortality, estimates of trends and absolute estimates of size composition, shell condition, molt status, reproductive condition, spatial distribution, bycatch of non-target crab stocks, environmental conditions, fishery performance, fleet behavior, and the quality and amount of data available for these variables).
11
Life Cycle
C. Leroux
12
Kingdom: Animalia
Phylum: Arthropoda (“Arthro”=jointed, “pod” =foot or leg )
Subphylum: Crustacea
Class: Malacostraca
Order: Decapoda (“Deca”=10, “pod”=foot or leg)
Infraorder
BrachyuraAnomura
Crabs
13
Biology: Anomurans vs. Brachyurans
Anomurans (king crabs)
• No terminal molt– Females molt yearly
– Males may molt
• No sperm retention– Males must be present at
fertilization
• Podding behavior• Patchy distribution
• Could impact survey precision
Brachyurans (snow, Tanner)
• Terminal molt (oldshell)– Females
– Males
• Sperm retention– Males not present at
fertilization
– Complicates our understanding of mating dynamics and reproductive potential
14
Groups considered in TAC setting
Mature males: generally thought of as “currency” of the population. Exploitation rates scaled to MMB or TMBMature females: represent an important component of the reproductive potential of the populationLegal males: a size intended to allow at least one opportunity for mating before potential removal by fisheryIndustry preferred males: often larger than the legal size. Group of individuals targeted by the fishery.
15
1. “Area Swept” estimates………..raw area-swept; male maturity defined by size
cut-off, female maturity defined by abdomen shape
2. “Model observed” estimates……. model estimates of area-swept, defining
male and female maturity within the model using maturity curves informed by
morphometric data using historic chela height data and female abdomen shape
3. “Model survey” estimates…………. interprets what the area-swept estimates
“should have been”, attempting to correct for survey sampling error
4. “Model population” estimates………the fitted line that applies a survey
selectivity curve by sex and size, attempting to correct for trawl efficiency (Q)
…….estimates of the underlying population….. “the population estimate if all
crabs in the line of the survey trawl net were caught”
• Q = proportion of animals in trawl path captured
Abundance estimates in TAC setting
16
• These estimates can differ greatly• In any given year we don’t know what estimate is closer to the true
population size• Resulting TAC can vary depending on what set of estimates is used
FMP 8.2.2. Total Allowable Catch and Guideline Harvest Level
The FMP authorizes the State to set preseason TACs and GHLs under State regulations………
The State will take into account the following factors, to the extent information is available, in developing harvest strategies or setting TACs and GHLs:
(1) whether the ACL for that stock was exceeded in the previous year;
(2) stock status relative to the OFL and ACL;
(3) estimates of exploitable biomass;
(4) estimates of recruitment;
(5) estimates of thresholds;
(6) market and other economic considerations;
(7) additional uncertainty; and
(8) any additional factors pertaining to the health and status of the stock or the marine ecosystem.
Additional uncertainty includes:
(1) management uncertainty (i.e., uncertainty in the ability of managers to constrain catch so the ACL is not exceeded, and uncertainty in quantifying the true catch amount) and
(2) scientific uncertainty identified and not already accounted for in the ABC (i.e., uncertainty in bycatch mortality, estimates of trends and absolute estimates of size composition, shell condition, molt status, reproductive condition, spatial distribution, bycatch of non-target crab stocks, environmental conditions, fishery performance, fleet behavior, and the quality and amount of data available for these variables).
17
2016
2017
2018
2013
2019
2015 2014
2019
Environmental uncertainty
Sea ice extent was at record low in 2018
Sea ice extent on April 29 of each year using data from the National Snow and Ice Data Center (NASA Earth Observatory, Joshua Stevens)
21
Ecosystem status
report card
Erin Fedewa, NOAA scientist
• Environment and ecosystem is changing rapidly
• Must be considered in management decisions
Outline
• Introduction
• PIBKC
• PIRKC
• SMBKC
• BBRKC
• Tanner
• Intermission
• snow
22
23
Pribilof Blue King Crab
Federal 2019/20 Status
Stock estimated at 6% of BMSY in 2018/19
Stock projected at 4% of BMSY in 2019/20
• biomass must be above 25% of BMSY for directed fishery opening
ABC = 2,000 lb total catch
OFL = 2,600 lb total catch
State harvest strategy (5 AAC 34.918)
•Stock threshold for opening fishery:•13.2-million pounds total (male and female) mature biomass @ survey for 2
consecutive years
•10% exploitation then applied to mature male abundance
2018 estimate for total mature biomass @ survey:
• 0.50-million pounds (NMFS area-swept estimate)
2019 estimate for total mature biomass @ survey:
•1.35-million pounds (NMFS area-swept estimate)
→Stock is below state threshold for a fishery opening
Pribilof Blue King Crab
24NOAA survey area-swept
0
20
40
60
80
100
120
140
197
5
197
61
977
197
8
197
91
980
198
11
982
198
3
198
41
985
198
6
198
71
988
198
9
199
01
991
199
2
199
31
994
199
51
996
199
7
199
81
999
200
0
200
12
002
200
3
200
42
005
200
6
200
72
008
200
92
010
201
1
201
22
013
201
4
201
52
016
201
7
201
82
019
Bio
mas
s (m
illio
n lb
)
Mature males (≥ 120 mm CL)
0
20
40
60
80
100
120
140
197
5
197
61
977
197
8
197
91
980
198
11
982
198
3
198
41
985
198
6
198
71
988
198
9
199
01
991
199
2
199
31
994
199
51
996
199
7
199
81
999
200
0
200
12
002
200
3
200
42
005
200
6
200
72
008
200
92
010
201
1
201
22
013
201
4
201
52
016
201
7
201
82
019
Bio
mas
s (m
illio
n lb
)
Mature females (≥ 100 mm CL)
Pribilof Blue King Crab
Closed areas to protect stock from overfishing in 2019/20
25
Closed to commercial crab
fisheries to protect BKC
Metrics for opening portions of the
closure area:
• BKC spatial distribution in past 2-years
• Bycatch rates in recent fisheries
High risk of exceeding OFL (2,600
lbs): Observer numbers are
expanded to entire fishery
Pribilof Red King Crab
Federal 2019/20 Status
ABC = 1.43 mill lb, including bycatch mortality of males and females in all fisheries
OFL = 1.90 mill lb
State harvest strategy: no harvest strategy in regulation, some harvest in
the 1990s with BKC
26
0
10
20
30
40
50
60
70
80
90
100
19
75
1976
19
77
1978
19
79
1980
19
81
1982
19
83
1984
19
85
19
86
1987
19
88
1989
19
90
1991
19
92
1993
19
94
1995
19
96
1997
19
98
1999
20
00
20
01
2002
20
03
2004
20
05
2006
20
07
2008
20
09
2010
20
11
2012
20
13
2014
20
15
20
16
2017
20
18
2019
Bio
mas
s (m
illi
on
s lb
)
Mature males (≥ 120 mm CL)
0
5
10
15
20
25
30
35
40
19
75
19
76
19
77
19
78
19
79
19
80
19
81
19
82
19
83
19
84
19
85
19
86
19
87
19
88
19
89
19
90
19
91
19
92
19
93
19
94
19
95
19
96
19
97
19
98
19
99
20
00
20
01
20
02
20
03
20
04
20
05
20
06
20
07
20
08
20
09
20
10
20
11
20
12
20
13
20
14
20
15
20
16
20
17
20
18
20
19
Bio
mas
s (m
illi
on
s lb
)
Mature females (actual maturity)
Pribilof Red King Crab
TAC = 0
• Poor precision of abundance estimates
• Little sign of recruitment to stock
• Concerns for bycatch of blue king crabs remains
very high• Pribilof blue king crab OFL= 2,600 lb (bycatch
mortality only)
The same concerns since 1999
27
Outline
• Introduction
• PIBKC
• PIRKC
• SMBKC
• BBRKC
• Tanner
• Intermission
• snow
28
St. Matthew Blue King Crab
Federal 2019/20 Status
Stock estimated at 33% of BMSY in 2018/19
• Below MSST (50% BMSY), hence SMBKC is
“overfished”
• Federal control rule: biomass must be 25% of BMSY
for directed fishery opening
Stock projected to be at 31% of BMSY in 2019/20
• Federal rebuilding plan will be developed in coming
year(s)
ABC = 0.08-mill lb (80,000 lb) total male catch (male only
assessment model)
• including bycatch mortality of males in all fisheries
OFL = 0.10-mill lb total male catch 29
30
0
1
2
3
4
5
6
7
8
9
10
19
78/7
91
979
/80
19
80/8
11
981
/82
19
82/8
31
983
/84
19
84/8
51
985
/86
19
86/8
71
987
/88
19
88/8
91
989
/90
19
90/9
11
991
/92
19
92/9
31
993
/94
19
94/9
51
995
/96
19
96/9
71
997
/98
19
98/9
91
999
/00
20
00/0
12
001
/02
20
02/0
32
003
/04
20
04/0
52
005
/06
20
06/0
72
007
/08
20
08/0
92
009
/10
20
10/1
12
011
/12
20
12/1
32
013
/14
20
14/1
52
015
/16
20
16/1
72
017
/18
20
18/1
9
Mill
ion
lbSt Matthew BKC Harvest
St. Matthew Blue King Crab: State harvest strategy (5 AAC 34.917)
Stock threshold for opening fishery:
• Survey abundance of mature-sized males (M) = 50% of 1978-2012 average
Exploitation rate on mature-sized males (M):
• 5%, when M = 50% of 1978-2012 average
• Increases linearly up to 10% with increasing M, up to the 1978-2012 average
• 10%, when M ≥ 1978-2012 average
• Harvest capped at 25% of legal male abundance (L) at time of survey
31
0%1%2%3%4%5%6%7%8%9%
10%11%12%13%14%15%
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 110% 120% 130% 140% 150%
Exp
loit
ati
on
ra
te o
n M
M/MAVG:1978-2012
Harvest strategy: exploitation rate on M
M = mature-sized male (males ≥ 105 mm CL)
MAVG:1978-2012 = average of annual M estimates for 1978-2012
L = legal-sized male (males ≥ 120 mm CL) abundance
32
Two surveys: NOAA bottom trawl survey and
ADF&G pot survey
For population
abundance estimates,
models use:
• NMFS area swept
bottom trawl
abundance data
• ADF&G pot survey
CPUE
33
0
2
4
6
8
10
12
14
19
78
19
79
19
80
19
81
19
82
19
83
19
84
19
85
19
86
19
87
19
88
19
89
19
90
19
91
19
92
19
93
19
94
19
95
19
96
19
97
19
98
19
99
20
00
20
01
20
02
20
03
20
04
20
05
20
06
20
07
20
08
20
09
20
10
20
11
20
12
20
13
20
14
20
15
20
16
20
17
20
18
20
19
Ab
un
dan
ce (
mill
ion
cra
b)
Mature males (≥105 mm CL)
NOAA survey area-swept
34
0
2
4
6
8
10
12
14
19
78
19
79
19
80
19
81
19
82
19
83
19
84
19
85
19
86
19
87
19
88
19
89
19
90
19
91
19
92
19
93
19
94
19
95
19
96
19
97
19
98
19
99
20
00
20
01
20
02
20
03
20
04
20
05
20
06
20
07
20
08
20
09
20
10
20
11
20
12
20
13
20
14
20
15
20
16
20
17
20
18
20
19
Ab
un
dan
ce (
mill
ion
cra
b)
Legal males (≥120 mm CL)
NOAA survey area-swept
35NOAA survey area-swept
36
ADF&G
pot survey
results0
2
4
6
8
10
12
14
16
18
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016
2018
CP
UE
Total males
All 96
02468
10121416182022242628
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016
2018
CP
UE
Legal males (≥ 120 mm CL)
84 inside 12 outside All 96
1995–2017 pooled♂ CPUE
2018 ♂ CPUE
pot-only survey area
0%
10%
20%
30%
40%
50%
60%
70%
1992 1995 1998 2001 2004 2007 2010 2013 2016 2019
% M
ale
s in
12
insh
ore
sta
tio
ns
Pot Survey Year
Legal males (≥120 mm CL) Mature males (≥105 mm CL)
37
2004–2017 pooled♀ CPUE
2018 ♀ CPUE
pot-only survey area
0%
20%
40%
60%
80%
100%
1992 1995 1998 2001 2004 2007 2010 2013 2016 2019% F
em
ale
s in
12
insh
ore
sta
tio
ns
Pot Survey Year
Total females
38
2016
2017
2018
20132015 2014
Cold pool in
2018 did not
cover historical
SMBKC
distribution
2019/20 St Matthew BKC fishery closed
TAC = 0
– Declared “overfished” in 2018 + 2019 assessment
• Federal rebuilding plan in development: will likely include
directive to close directed fishery until it is declared
rebuilt
• Ultimately limited by ABC: 80,000 lb
• Need to closely monitor bycatch in snow crab and
groundfish fisheries
– Below model-based threshold for opening fishery
– Trawl survey data shows some weak signs of
recruitment
40
St. Matthew BKC Bycatch
• ABC = 80,000 lb• Possible bycatch in snow crab fishery
• Observer data expanded to entire fishery• Potential impact to snow crab fishery (potential area closure)
41
Outline
• Introduction
• PIBKC
• PIRKC
• SMBKC
• BBRKC
• Tanner
• Intermission
• snow
42
Bristol Bay Red King Crab
Federal 2019/20 Status•ABC= 6.00-mill lb total catch
• including bycatch mortality of males and females in all
fisheries
• based on a 20% buffer on OFL
•OFL = 7.50-mill lb total catch
43From 2019 SAFE
Figure 4 from 2019 SAFE. Comparison of survey legal male abundances
and catches per unit effort for Bristol Bay red king crab from 1968 to 2019.
2019 SAFE
• CPUE variable • CPUE in past 2 seasons
below average for rationalized years
0
5
10
15
20
25
30
35
40
0
5
10
15
20
25
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019
CP
UE
Har
vest
(m
illio
n lb
)
BBRKC
Harvest CPUE mean CPUE
44
2018/19 observations from BBRKC fleet
• Continued increase in average weight since 2016/17 season.– 7.10 lbs in 2018/19, 6.84 lbs in 2017/18, 6.7 lbs in
2016/17. – Captains commenting that they are fishing the same
group of crab as last year, which are a year older and year heavier.
– General concern from captains about the increase in average weight.
• Several vessels reported having to move gear off large masses of female crab where pots were catching as many as 200 females.
45
46
0
5
10
15
20
25
30
35
40
45
50
197
519
76
197
719
78
197
919
80
198
119
82
198
319
84
198
519
86
198
719
88
198
919
90
199
119
92
199
319
94
199
519
96
199
719
98
199
920
00
200
120
02
200
320
04
200
520
06
200
720
08
200
920
10
201
120
12
201
320
14
201
520
16
201
720
18
201
9
Ab
un
dan
ce (
mill
ion
cra
b)
Legal males (≥ 135 mm CL)
Survey area-swept
Model estimates
47
0
10
20
30
40
50
60
70
80
901
975
197
61
977
197
81
979
198
01
981
198
21
983
198
41
985
198
61
987
198
81
989
199
01
991
199
21
993
199
41
995
199
61
997
199
81
999
200
02
001
200
22
003
200
42
005
200
62
007
200
82
009
201
02
011
201
22
013
201
42
015
201
62
017
201
82
019
Ab
un
dan
ce (
mill
ion
cra
bs)
Mature male abundance
Survey area-swept
Model estimates
48
0
20
40
60
80
100
120
140
160
197
51
976
197
71
978
197
91
980
198
11
982
198
31
984
198
51
986
198
71
988
198
91
990
199
11
992
199
31
994
199
51
996
199
71
998
199
92
000
200
12
002
200
32
004
200
52
006
200
72
008
200
92
010
201
12
012
201
32
014
201
52
016
201
72
018
201
9
Ab
un
dan
ce (
mill
ion
cra
bs)
Mature female abundance
Survey area-swept
Model estimates
threshold
Fishery "off switch": 8.4 million crabs
49NOAA survey data
NOAA survey data
Bristol Bay red king crab (female)
Carapace length (mm)
Ab
un
da
nce
(m
illio
ns)
1
2
3
4
5
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
145
150
155
160
165
170
175
180
185
190
195
200
201635
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
145
150
155
160
165
170
175
180
185
190
195
200
2019
2015
1
2
3
4
5
2018
1
2
3
4
5
2014 2017
Shell condition
Soft & molting New - hard Old Very old
50
Bristol Bay Red King Crab
2019 survey results:
Survey distribution, crab nm-2 station
51
Legal males
Mature females
Bristol Bay Red King Crab
State harvest strategy (5 AAC 34.816)1. Stock threshold for opening fishery:
•8.4-million mature-sized females (females ≥ 90 mm CL), and
•14.5-mill lb of effective spawning biomass (ESB)
2. Exploitation rate on mature-sized (≥120-mm CL) male abundance:
•10%, when ESB <34.75-mill lb
•12.5%, when ESB is between 34.75-mill lb and 55.0-mill lb
•15%, when ESB ≥55.0-mill lb
3. Harvest capped at 50% of legal male abundance
•ESB = effective spawning biomass•F = mature-sized female (females ≥ 90 mm CL) abundance•M = mature-sized male (males ≥ 120 mm CL) abundance •L = legal male (males ≥ 135 mm CL) abundance•W = expected average weight of landed legal males
2019 length-based analysis (LBA) estimates for determining fishery opening,
computing TAC (area-swept estimates for comparison):
52
Avg wt 2018/19 Fishery = 7.104
Parameter Estimate 95% CI
ESB (millions of lb) 28.009 (-) (-) (-)
F (millions of crab) 10.613 (8.81 - 12.418) 8.587 (+/- 3.156)
M (millions of crab) 5.345 (4.39 - 6.232) 5.008 (+/- 1.633)
L (millions of crab) 4.006 (3.2 - 4.757) 2.887 (+/- 2.887)
W (lb) (-) (-) 6.846 (-)
Area-swept
LBA Estimate
(NMFS-AFSC)
State harvest strategy (5 AAC 34.816) - Results for 2019/20
1. Stock above threshold for opening fishery
• F = 10.613-million > threshold = 8.4-million (ADF&G LBA estimate)
• ESB = 28.009-mill lb > threshold = 14.5-mill lb (ADF&G LBA estimate)
2. Exploitation rate on mature-sized male abundance (M)
• ESB is between 14.50 mill lb and 34.75-mill lb
→ 10% exploitation rate on estimated mature male abundance
3. TAC computation according to state harvest strategy:
•10% exploitation rate applied to estimated mature-sized male abundance
•5.345-million mature-sized males (ADF&G LBA estimate)
•(0.10)x(5.345-million) = 0.535-million crabs
•Check: 50% cap on harvest of legal males
•4.006-million legal males (ADF&G LBA estimate)
•(0.5)x(4.006million) = 2.003-million crabs > 0.535-million crabs
→Compute TAC on harvest of 0.535-million legal males, assuming 2018/19 fishery avg wt (7.104 lb) = 0.535 x 7.104
TAC = 3.797 million lb53
0
5
10
15
20
25
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
/06
2006
/07
2007
/08
2008
/09
2009
/10
2010
/11
2011
/12
2012
/13
2013
/14
2014
/15
2015
/16
2016
/17
2017
/18
2018
/19
2019
/20
Mil
lio
n lb
Historical TACs
3.797
54
01
23
45
BBRKC discard mortalityD
iscard
mort
alit
y (
mill
ion lb)
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
Estimation method
Subtraction
LNR
2018 absolute value
of discard mortality
was relatively low,
but the TAC was
also low (~4 mill lb)
55
0.0
0.1
0.2
0.3
0.4
0.5
BBRKC discard mortality ratelb
bycatc
h m
ort
alit
y p
er
lb r
eta
ined c
atc
h
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
Estimation method
Subtraction
LNR
High discard
rate in 2018
56
Bycatch in groundfish fisheries
0
200
400
600
800
1000
1200
1400
197
61
977
197
81
979
198
01
981
198
21
983
198
41
985
198
61
987
198
81
989
199
01
991
199
21
993
199
41
995
199
61
997
199
81
999
200
02
001
200
22
003
200
42
005
200
62
007
200
82
009
201
02
011
201
22
013
201
42
015
201
62
017
201
8
Byc
atch
mo
rtal
ity
(t)
Groundfish
P cod
pots
57
Bristol Bay Red King Crab: Total mortality @ TAC and ABC
58
Mortality
Assumptions (million lb)
Assume max mortality in groundfish fisheries, 94/95-18/19 = 0.51
Expected mortality in Tanner crab fishery 0.00
Subtotal 0.51
Remaining for directed (incl. bycatch mort), mill lb (ABC-Subtotal) = 5.49
Assume maximum (lb discard mort)/(lb retained) in directed fishery, 05/06-18/19 = 0.212
Maximum total mortality = (remaining for directed)/(1+0.212) = 4.53
• Max mortality in GF fisheries since 1994/95 occurred in 2018/19
• Max discard mortality rate in directed fishery in rationalized years occurred in
2018/19
• Given these assumptions, our proposed TACs should be low enough to
allow sufficient discard and bycatch mortality (i.e., 3.797 < 4.53)
2016
2017
2018
2013
2019
2015 2014
2019
Is there enough room between TAC and ABC to account for
environmental uncertainty?
0
5
10
15
20
25
30
2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019
AB
C (
mill
ion
lb)
TAC vs ABC
TAC ABC-TAC (buffer between TAC and ABC) 60
61
0
5
10
15
20
25
30
2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019
AB
C (
mill
ion
lb)
ABC components
BBRKC TAC BBRKC Test fishery Directed discard
Tanner bycatch Groundfish mortality ABC- total fish mort.
Trends – Outlook: 2019 stock assessment recruitment trend
62Zheng and Siddeek 2019, 2019 SAFE
63
Ecosystem status
report card
Erin Fedewa, NOAA scientist
Environmental uncertainty• Increasing temps• Changing ecosystem: shifts in
predators, competitors
Overall Outlook
• Continued downward trajectory for ESB, M, F, L
• Low estimated recruitment
• Length frequencies discouraging, no strong pulses of small crabs in system
64
Trending towards thresholds
0
5
10
15
20
25
30
35
40
4520
00
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
Ab
un
dan
ce (
mill
ion
cra
bs)
Mature female abundance
Fishery "off switch": 8.4 million crabs
65
0
5
10
15
20
25
30
35
40
45
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
Ab
un
dan
ce (
mill
ion
cra
bs)
Mature female abundance
Fishery "off switch": 8.4 million crabs
Trending towards thresholds
-20.0%
-18.0%
-16.0%
-14.0%
-12.0%
-10.0%
-8.0%
-6.0%
-4.0%
-2.0%
0.0%2013 2014 2015 2016 2017 2018 2019
Perc
ent
dec
reas
e fr
om
pri
or
year
% decrease from previous year
Average = -13%
66
Trending towards thresholds
0
10
20
30
40
50
60
70
8020
00
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
Bio
mas
s (m
illio
n l
bs)
Effective spawning biomass (ESB)
Fishery "off switch": 14.5 million lbs
67
Effective spawning biomass: biomass estimates of mature female abundance and the number of females which males can mate with at a given size (i.e., mature females reduced by the number of males at size)
Trending towards thresholds
0
10
20
30
40
50
60
70
80
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
Bio
mas
s (m
illio
n l
bs)
Effective spawning biomass (ESB)
Fishery "off switch": 14.5 million lbs
-16.0%
-14.0%
-12.0%
-10.0%
-8.0%
-6.0%
-4.0%
-2.0%
0.0%2015 2016 2017 2018 2019
Perc
ent
dec
reas
e fr
om
pri
or
year
% decrease from previous year
Average = -11.5%
68
State harvest strategy thresholds
• Based on mature females:– S-R relationship: expected number of recruits as a
function spawner abundance• Poorly fitting for most BSAI crab stocks, but decent for BBRKC
using historical data
– Thresholds: minimum abundance “that allows sufficient recruitment so that the stock can eventually reach a level that produces MSY”
• Current S-R plot:– Current thresholds are low bars, if anything they could
be more conservative– Falling below state thresholds will likely be
accompanied by falling below federal threshold for being declared “overfished” (i.e., less than MSST)
69
Outline
• Introduction
• PIBKC
• PIRKC
• SMBKC
• BBRKC
• Tanner
• Intermission
• snow
70
Bering Sea Tanner Crab
Federal 2019/20 Status
ABC = 50.89-mill lb total catch
• Including bycatch mortality of males and females in all fisheries
• Set with 20% “buffer” on OFL (i.e., ABC = 0.8*OFL)
OFL = 63.62-mill lb total catch
71From 2019 SAFE Intro chapter, Model M19F03
72
0
5
10
15
20
25
30
35
40
45
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
Mill
ion
lbs
Historical TACs
73
East and west combined
2018/19 WBT observations from
the fleet
• Observed vessel CPUE ranged from 9 to 91.5.
• Captains reported slow fishing in November (after finishing RKC), but fishing improved for vessels that waited to fish until February/March (after finishing BSS).
• Fishing was spotty in general compared to 2017/18 season.
74
75
2019: 93% oldshell
2019: 96% oldshell
EAST
WEST
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0
5
10
15
20
25
30
35
200
5
200
6
200
7
200
8
200
9
201
0
201
1
201
2
201
3
201
4
201
5
201
6
201
7
201
8
201
9
Per
cen
t o
ldsh
ell
Ab
un
dan
ce (
mill
ion
cra
b)
5-inch males EAST of 166
Abundance Percent oldshell
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0
5
10
15
20
25
30
200
5
200
6
200
7
200
8
200
9
201
0
201
1
201
2
201
3
201
4
201
5
201
6
201
7
201
8
201
9
Per
cen
t o
ldsh
ell
Ab
un
dan
ce (
mill
ion
cra
b)
5-inch males WEST of 166
Abundance Percent oldshell NOAA survey area-swept
76
0
2
4
6
8
10
12
newshell oldshell
Bio
mas
s (m
ill lb
)
5 inch males WEST of 166
2019 survey area-swept
0.45 mill lb
10.58 mill lb
77
Pribilof Islands Closure Area
78
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
20
00
20
01
20
02
20
03
20
04
20
05
20
06
20
07
20
08
20
09
20
10
20
11
20
12
20
13
20
14
20
15
20
16
20
17
20
18
20
19
Perc
ent
of
5-i
nch
mal
e Ta
nn
er c
rab
ava
ilab
le t
o f
ish
ery
(Ou
tsid
e P
IBKC
clo
sure
are
a)5-inch males west of 166 W
~50% of the 5-inch crab available to fishery
79NOAA survey area-swept
0
100
200
300
400
500
600
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
Bio
mas
s (m
illio
n lb
s)5 inch males
All EBS
East 166
West 166
802019 NOAA survey
81
Recruits starting to enter larger size classes?
82NOAA survey area-swept
83
84NOAA survey area-swept
Tanner crab all EBS (female)
Carapace length (mm)
Ab
un
da
nce
(m
illio
ns)
10
20
30
40
50
0 510
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
145
150
155
160
20160 5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
145
150
155
160
2019
2015
10
20
30
40
50
2018
10
20
30
40
50
2014 2017
Shell condition
Soft & molting New - hard Old Very old
85
86
Mature female biomass
Within threshold range
Below threshold Above threshold
Fishery Closed
Males above
100% ave
Males below
100% ave
Fishery Closed
Fishery ClosedTAC = (B/BAVG – 1) x
(0.9) x CMSY
TAC = (B/BAVG) x (0.9) x CMSY
TAC = (0.9) x CMSY
fem
ales
mal
es Males above
100% ave
Males below
25% ave
Males 25%-100% ave
87
0
50
100
150
200
250
19
751
976
19
771
978
19
791
980
19
811
982
19
831
984
19
851
986
19
871
988
19
891
990
19
911
992
19
931
994
19
951
996
19
971
998
19
992
000
20
012
002
20
032
004
20
052
006
20
072
008
20
092
010
20
112
012
20
132
014
20
152
016
20
172
018
20
19
Bio
mas
s (m
illio
n l
b)
Mature female biomass
Threshold: 12.12 mill lb2019 error band: 6.027 – 14.985 mil lb
88
Mature female biomass
Within threshold range
Below threshold Above threshold
Fishery Closed
Males above
100% ave
Males below
100% ave
Fishery Closed
Fishery ClosedTAC = (B/BAVG – 1) x
(0.9) x CMSY
TAC = (B/BAVG) x (0.9) x CMSY
TAC = (0.9) x CMSY
fem
ales
mal
es Males above
100% ave
Males below
25% ave
Males 25%-100% ave
0
50
100
150
200
250
300
350
4001
97
51
97
61
97
71
97
81
97
91
98
01
98
11
98
21
98
31
98
41
98
51
98
61
98
71
98
81
98
91
99
01
99
11
99
21
99
31
99
41
99
51
99
61
99
71
99
81
99
92
00
02
00
12
00
22
00
32
00
42
00
52
00
62
00
72
00
82
00
92
01
02
01
12
01
22
01
32
01
42
01
52
01
62
01
72
01
82
01
9
Bio
mas
s (m
ill l
b)
Mature males EAST of 166 W
89
1982-2016 avg: 47.54 mill lb
2019 estimate: 14.06 mill lb 30% of long-term average
NOT above 100% long-term
average, cannot open fishery
EAST
0
20
40
60
80
100
120
140
160
180
2001
97
51
97
61
97
71
97
81
97
91
98
01
98
11
98
21
98
31
98
41
98
51
98
61
98
71
98
81
98
91
99
01
99
11
99
21
99
31
99
41
99
51
99
61
99
71
99
81
99
92
00
02
00
12
00
22
00
32
00
42
00
52
00
62
00
72
00
82
00
92
01
02
01
12
01
22
01
32
01
42
01
52
01
62
01
72
01
82
01
9
Bio
mas
s (m
ill l
b)
Mature males WEST of 166 W
90
1982-2016 avg: 42.39 mill lb
2019 estimate: 21.63 mill lb 51% of long-term average
NOT above 100% long-term
average, cannot open fishery
WEST
TAC = 0 for east and west
• Mature and legal portions of the population
are down relative to last year
• State harvest strategy: MMB is below
threshold for opening fishery in both areas
– MMB 30% and 51% of long-term average for
east and west
• 5 inch males are 93% and 96% oldshell
– Only 0.45 mill lb newshell in the west, of which
approximately 50% is in the PI closure area
91
…Looking ahead
• State Tanner crab harvest strategy revision currently in progress• Simplify and evaluate the utility of including female control rule
– Consider variety of scenarios ranging from no female consideration to full female consideration
– Address “on/off” switches• Management strategy evaluation (MSE)
– ADF&G, BSFRF, UW, NOAA scientists, and super-computers– Considering 13 harvest strategy scenarios– Project the population forward 100 years under different
harvest strategy scenarios– Evaluate results via conservation and economic performance
metrics• ADF&G/industry recommended harvest strategy to BOF in March
2020
92
93
Model
estimates
• Immature
crab on
increasing
trend
94
Highest estimated
recruitment since the 70s!
95
Ecosystem
status report card
Erin Fedewa, NOAA
Environmental uncertainty• Increasing temps• Changing ecosystem: shifts
in predators, competitors
Tanner crab outlook
• Mature females are still in a declining trend, but there is a strong cohort population, which has carried forward from the 2017 cohort ….hope for the future
• East: portion of large male crab is senescing but weak sign of recruits in the 75-100 mm size class
• West: portion of large male crab is senescing but strong sign of recruits across juvenile cohorts– Years from reaching legal size
– Hope for the future
• Expect continued declines in legal male abundance next year
96
Intermission:Snow crab next
97