Stock assessment of Summer flounder ( Paralichthys dentatus )
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Stock assessment of Summer flounder (Paralichthys dentatus) • Managed as a unit stock from New England to North Carolina • Maximum size & age fish in NEFSC SV and fishery samples: SV: 2005 - 76 cm FL age 14; 2011 - 82 cm age 11 Comm land: 2005 - 75 cm FL age 13; 2011 - 74 cm age 13 2010 - 82 cm age 12 • 50% mature age 1.0; average M = 0.25 • Commercial trawl fishery; recreational rod and reel fishery • Comm. landings ~60%; Comm. discards ~<5% • Rec. landings ~25%; Rec. discards ~10% • NEFSC SVs peaked in late 1970s, mid 2000s • Comm landings (and probably total catch) peaked in
description
Stock assessment of Summer flounder ( Paralichthys dentatus ). Managed as a unit stock from New England to North Carolina Maximum size & age fish in NEFSC SV and fishery samples: SV: 2005 - 76 cm FL age 14; 2011 - 82 cm age 11 - PowerPoint PPT Presentation
Transcript of Stock assessment of Summer flounder ( Paralichthys dentatus )
Stock assessment of Summer flounder (Paralichthys dentatus)
• Managed as a unit stock from New England to North Carolina
• Maximum size & age fish in NEFSC SV and fishery samples:SV: 2005 - 76 cm FL age 14; 2011 - 82 cm age 11Comm land: 2005 - 75 cm FL age 13; 2011 - 74 cm age
13 2010 - 82 cm age 12
• 50% mature age 1.0; average M = 0.25
• Commercial trawl fishery; recreational rod and reel fishery• Comm. landings ~60%; Comm. discards ~<5%• Rec. landings ~25%; Rec. discards ~10%
• NEFSC SVs peaked in late 1970s, mid 2000s• Comm landings (and probably total catch) peaked in late 1970s
Commercial Fishery Landings,Total Catch and NEFSC Spring Survey
Year
1940 1950 1960 1970 1980 1990 2000 2010
NEF
SC S
prin
g kg
/tow
0
1
2
3
4
Land
ings
, Cat
ch ('
000
mt)
0
5
10
15
20
25
30
NEFSC Spring SurveyCommercial Land Total Catch
Assessment history Summer flounder (Paralichthys dentatus)
• First comprehensive assessment: Chang and Pacheco (1975)Compilation of catch and surveys, tagging data Tag Fs ~0.3-9.6 for late 1950s-early 1960sSurvey Fs ~0.3-0.5 late 1960s-early 1970sUn-tuned VPA, S-R data (M = 0.20): MSY = 21 kmt
• Second comprehensive assessment: Fogarty (1981)Updated tagging Fs, YPR analysisFmax combined sexes ~0.20 (M= 0.20), MSY = ~20 kmt
• First analytical assessment (tuned VPA): 1990 SAW 11 "Overexploited and seriously depleted"; poor 1988 YCFmax = 0.23 (M=0.20)
Assessment history Summer flounder (Paralichthys dentatus)
• Subsequent SAW analytical assessments:1991 SAW 13, 1993 SAW 16, 1994 SAW 18, 1995 SAW 20,1996 SAW 22ADAPT VPA, YPR: generally found stock overexploited
(overfishing) and at low to medium biomass (overfished),Fmax = 0.23 (M=0.20; 1990 SAW 11)
• 1997 SAW 25: ADAPT VPA, new BRPs (YPR)Overexploited, medium abundance; Fmax = 0.24 (M=0.20)Subject to NRC review (NRC 2000)
• 1999 Amendment 12: SFA BRPsFMSY = Fmax = 0.24 (M = 0.20); BMSY = 153 kmtInitial Rebuild Deadline by 2006 (Amend 12)
• 1998, 1999 Updates: ADAPT VPA, new BRPs (YPR) Fmax = 0.26 (M = 0.20), BMSY = 106 Kmt
Assessment history Summer flounder (Paralichthys dentatus)
• 2000 SAW 31, 2001 Update: ADAPT VPA, retain 1999 BRPs Overfished (< ½ BMSY), Overfishing (F > FMSY)However, F lowest and B highest since the early-1980s
• 2002 SAW 25: ADAPT VPA, retain 1999 BRPs Overfished (< ½ BMSY), Overfishing (F > FMSY)
• 2003 Update: (Not Overfished, Not Overfishing)
• 2004 Update: (Not Overfished, Overfishing)
• 2005 SAW 41: ADAPT VPA, new BRPs (YPR) Not Overfished, Overfishing FMSY = Fmax = 0.276 (M = 0.20); BMSY = 93 kmt; NMFS reset rebuild deadline to 2010
Assessment history Summer flounder (Paralichthys dentatus)
• 2006 Update and NMFS S&T Review: ADAPT VPA, new BRPs (YPR)Not Overfished, OverfishingFMSY = Fmax = 0.28 (M=0.20); SSBMSY = 89 kmt; MSY = 21 kmt
• 2006 MSA Reauthorization: 3 yr extension to rebuild deadline to 2013
• 2007 Update: Overfished, Overfishing
• 2008 SAW 47: ASAP SCAA, new BRPS, average M = 0.25Not Overfished, Not OverfishingFMSY = F35% = 0.310 (M=0.25); SSBMSY = 60 kmt; MSY = 15 kmt
• 2009, 2010, 2011 Updates: Not Overfished, Not Overfishing
• 2011 Update indicated SSB rebuilt to just above 60 kmt in 2010
Summer Flounder Historical Retrospective 1990-2011 Stock Assessments
1980 1985 1990 1995 2000 2005 2010
Fish
ing
Mor
talit
y (F
)
0.0
0.5
1.0
1.5
2.0
2.5
Year1980 1985 1990 1995 2000 2005 2010
SSB
(000
s m
t)
0
15
30
45
60
75
Stock definition: Cape Hatteras to Maine
TaggingPoole (1962)Murawski (1970)Lux & Nichy (1981)Monaghan (1992)
Morphometrics and MeristicsWilk et al. (1980)Fogarty et al. (1983)
GeneticsJones and Quattro (1999): no subdivision at Cape Hatteras
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)55
)5
Summer flounder: 2012 update
• Data - Add 2011 fishery and research survey data to the 2008 SAW 47, 2009-2011 updated assessment models
• Data - Incorporate MRIP 2004-2011 estimates; adjust prior years by 2004-2011 average
• Projections - through 2013 to determine OFL
• Note that based on 2011 update, stock was declared rebuilt in 2010 (Nov 2011)
Stock definition: Cape Hatteras to Maine
TaggingPoole (1962)Murawski (1970)Lux & Nichy (1981)Monaghan (1992)
Morphometrics and MeristicsWilk et al. (1980)Fogarty et al. (1983)
GeneticsJones and Quattro (1999): no subdivision at Cape Hatteras
)5555
)55
)5
Assessment components
Fishery dependentNER (ME-VA) and NC commercial landingsCommercial discardsRecreational landingsRecreational discards
Fishery independentNEFSC trawl surveysState agency trawl surveys
Analysis: NFT ASAP SCAA, AGEPRO Projection
In 2010, 5,930 mt (13 million lb)In 2011, 7,511 mt (17 million lb)
Commercial Landings
Comm. Landings: MA to NC, out to edge of shelf
Mainly a mixed trawl fishery (>90% of landings)
Avg. ~10,000 mt (22 million lb) for 1955-60Avg. < 5,000 mt (11 million lb) for 1968-72Avg. ~13,000 mt (29 million lb) for 1974-87Under quotas, avg. 5,800 mt (13 million lb) for 1993-2009
During 1993-2009, 50% of total catch in weightIn 2010, 63% of total catch weightIn 2011, 67% of total catch weight
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
0
50
100
150
200
250
300
350
Summer Flounder Fishery Sampling Intensity
NEFSC Comm Land NCDMF Comm Land Comm Disc Rec Land Rec Disc Threshold
Year
Met
ric to
ns p
er 1
00 le
ngth
s
Commercial Landings at age
• NER 2008: 5% age 1, 16% age 2, 24% age 3, 55% age 4+• NER 2009: 5% age 1, 21% age 2, 29% age 3, 45% age 4+• NER 2010: 5% age 1, 16% age 2, 28% age 3, 51% age 4+• NER 2011: 2% age 1, 13% age 2, 32% age 3, 53% age 4+
• NC 2008: 1% age 1, 10% age 2, 25% age 3, 64% age 4+• NC 2009: 0% age 1, 9% age 2, 28% age 3, 63% age 4+• NC 2010: 1% age 1, 14% age 2, 33% age 3, 52% age 4+• NC 2011: 0% age 1, 12% age 2, 23% age 3, 65% age 4+
Commercial DiscardsEstimated as product of Observed rate (kg/df) and fishery effort from Vessel Trip Reports (VTR); assume 80% discard mortality
Since ~2000, Comm. Discards: 70% trawl, 30% scallop dredge2008: 73% trawl, 27% scallop dredge2009: 91% trawl, 9% scallop dredge2010: 86% trawl, 14% scallop dredge2011: 79% trawl, 21% scallop dredgeSince ~2000, About 500-700 mt, about 8-10% of comm. land.2008: 309 mt, about 8% of comm. land.2009: 118 mt, about 3% of comm. land.2010: 198 mt, about 3% of comm. land.2011: 126 mt, about 2% of comm. land.
Since ~2000, 5% of total catch in weight2008: 4% of total catch weight2009: 2% of total catch weight2010: 2% of total catch weight2011: 1% of total catch weight
Age comp 2008: 19% age 0 & 1, 18% age 2, 63% age 3+Age comp 2009: 14% age 0 & 1, 37% age 2, 49% age 3+Age comp 2010: 28% age 0 & 1, 31% age 2, 41% age 3+Age comp 2011: 13% age 0 & 1, 38% age 2, 49% age 3+
Commercial Discards• Observer/VTR estimate of landings: potential indication
of accuracy of discard estimate• Compare Observer/VTR estimate with Dealer reported• 1998: -28%, 1999: + 53%, 2000: +32%, 2001: -70%, 2002: +1%, 2003: -10%
• To date, no adjustment to the discard estimates
• 2008 SAW 47 WP1: Investigation of alternative estimation (SBRM: dflk/keptall) provided no improvement in precision or “accuracy” through 2003 – but recent bias suggests need to re-investigate change to SBRM method in next benchmark
• Over 1989-2003, no persistent pattern or bias evident - but 2004-2011 well below dealer report - recent bias?
• 2004: -36%, 2005: -55%, 2006: -72%, 2007: -77%, 2008: -65%, 2009: -74%, 2010: -56%, 2011: -81%
• 2010: 2,238 mt; 2011 2,543 mt
Recreational Landings
• Estimated by MRFSS: updated for 2000+ revisions
• Recreational Landings: mainly in state waters
• Under bag and size limits, avg. 4,500 mt for 1993-2009
• During 2002-2004, 36% of total catch in weight 2005: 34% of total catch in weight 2006: 42% of total catch in weight 2007: 43% of total catch in weight 2008: 41% of total catch in weight 2009: 31% of total catch in weight 2010: 24% of total catch in weight 2011: 23% of total catch in weight
Since ~2000, about 20% of rec. land.2008: 35% of rec land.2009: 50% of rec land.2010: 41% of rec land.2011: 42% of rec land.
Recreational Discards
Estimated by MRFSS: Assume 80% discard mortality (three 1999 studies)
Since ~2000, ~5-10% of total catch in weight2008: 14% of total catch in weight2009: 15% of total catch in weight2010: 10% of total catch in weight2011: 10% of total catch in weight
Recreational Catch at age
• Landings 2008: 1% age 1, 4% age 2, 19% age 3, 76% age 4+• Landings 2009: 1% age 1, 6% age 2, 25% age 3, 68% age 4+• Landings 2010: 1% age 1, 3% age 2, 16% age 3, 80% age 4+• Landings 2011: <1% age 1, 2% age 2, 14% age 3, 84% age 4+
• Discards 2008: 42% age 0&1, 27% age 2, 31% age 3+• Discards 2009: 47% age 0&1, 26% age 2, 27% age 3+• Discards 2010: 45% age 0&1, 26% age 2, 29% age 3+• Discards 2011: 28% age 0&1, 28% age 2, 44% age 3+
Recreational Catch
• MRIP to MRFSS 2004-2011 ratio
Landed number (A + B1): 0.97Landed weight (A + B1) : 0.99Discarded number (B2) : 0.96
• Use MRIP 2004-2011 landed weight and discarded weight in model
• Adjust prior years by 2004-2011 average MRIP to MRFSS ratio
• Final adjusted total fishery catch about 1% lower
Total Catch at age 2008: ~8.8 million fish
CL: NER 2.9 + NC 1.1 = 4.0 million (46%) CD: 0.3 million (3%) RL: 2.3 million (26%) RD: 2.2 million (25%)
2009: ~9.3 million fishCL: NER 3.5 + NC 1.4 = 4.9 million (53%)CD: 0.1 million (1%)RL: 1.9 million (20%)RD: 2.4 million (26%)
2010: ~10.0 million fishCL: NER 4.3 + NC 1.6 = 5.9 million (60%)CD: 0.3 million (3%)RL: 1.5 million (15%)RD: 2.2 million (22%)
2011: ~11.3 million fishCL: NER 5.9 + NC 1.4 = 7.3 million (64%)CD: 0.2 million (2%)RL: 1.8 million (16%)RD: 2.0 million (18%)
Year
1988 1992 1996 2000 2004 2008 2012
Met
ric to
ns
0
2000
4000
6000
8000
10000
12000
14000
Comm Land Comm Disc Rec Land Rec Disc
Components of the Summer flounder Total Catch
Summer flounder Total Catch Mean Weights at Age
Year1983 1986 1989 1992 1995 1998 2001 2004 2007 2010 2013
Mea
n w
eigh
t (kg
)
0
1
2
3
4
5
Age 0Age 1Age 2Age 3Age 4
Age 5Age 6
Age 7+
Research Surveys
NEFSC: Spring 1968-2012, Fall 1963-2011, Winter 1992-2007MADMF: Spring and Fall, Seine YOY 1978-2011RIDFW: Fall 1979-2011, Monthly Fixed 1990-2011CTDEP: Spring and Fall, 1984-2011
NJBMF: Apr-Oct, 1988-2011DEDFW: Annual, 1980-2011MDDNR: YOY, 1980-2011VIMS: YOY, Rivers 1980-2011VIMS ChesMMAP: 2002-2011VIMS NEAMAP: 2007-2011NCDMF: YOY, 1987-2011
NEFSC Trawl Surveys
Year1970 1980 1990 2000 2010
Sprin
g an
d Fa
ll kg
/tow
0
1
2
3
4
5
6
Win
ter k
g/to
w
0
5
10
15
20
25
30
Fall Offshore ALBSpring ALB Winter Spring HBB Fall HBB
MA and RI State Trawl Surveys
Year1975 1980 1985 1990 1995 2000 2005 2010
Num
ber/t
ow
0
1
2
3
4
5
6
MA Spr MA Fall RI Fall
CT State Trawl Surveys
Year1975 1980 1985 1990 1995 2000 2005 2010
Num
ber/t
ow
0
1
2
3
4
5
6
7
CT Fall CT Spr
NJ and DE State Trawl Surveys
Year1975 1980 1985 1990 1995 2000 2005 2010
NJ
Num
ber/t
ow
0
3
6
9
12
15
18
DE
Num
ber/t
ow
0.0
0.5
1.0
1.5
2.0
2.5
3.0
NJ DE
ChesMMap and NEAMAP Trawl Surveys
Year1975 1980 1985 1990 1995 2000 2005 2010
Che
sMM
ap N
umbe
r/tow
0
100
200
NEA
MAP
Num
ber/t
ow
0
1
2
3
4
5
ChesMMap NEAMAP Spr NEAMAP Fall
NEFSC and CT YOY Indices
Year1975 1980 1985 1990 1995 2000 2005 2010
NEF
SC N
umbe
r/tow
0.00
0.25
0.50
0.75
1.00
1.25
CT
Num
ber/t
ow
0.0
0.2
0.4
0.6
0.8
NEFSCCT
MA and RI YOY Indices
Year1975 1980 1985 1990 1995 2000 2005 2010
MA
num
ber/t
ow
0
25
50
75
100
RI n
umbe
r/tow
0.00
0.05
0.10
0.15
0.20
MARI
NJ and DE YOY Indices
Year1975 1980 1985 1990 1995 2000 2005 2010
DE
Num
ber/t
ow
0.00
0.15
0.30
0.45
0.60
0.75
NJ
num
ber/t
ow
0
1
2
3
4
5
6
DE NJ
MD, VIMS and NC YOY Indices
Year1975 1980 1985 1990 1995 2000 2005 2010
VIM
S N
umbe
r/tow
0
2
4
6
8
10
12
MD
, N
C N
umbe
r/tow
0
10
20
30
40
50
60
VIMS MD NC
ChesMMAP and NEAMAP YOY Indices
Year1975 1980 1985 1990 1995 2000 2005 2010
Che
sMM
AP N
umbe
r/tow
0
20
40
60
80
100
NEA
MA
P N
umbe
r/tow
0.0
0.3
0.6
0.9
1.2
1.5
ChesMMAPNEAMAP Fall
Summer flounder 2012 • With respect to 2008 SAW 47 BRPs
– Not Overfished: SSB2011 = 57,020 mt; 5% below Btarget = SSBMSY = SSB35% = 60,074 mt
– Stock was declared rebuilt in 2010 based on 2011 update(estimated at 60,238 mt in 2010)
– Not Overfishing: F2011 = 0.241; below FMSY = F35% = 0.310
– Recruitment in 2008: 47 million Recruitment in 2009: 47 million Recruitment in 2010: 32 million Recruitment in 2011: 26 million Average 1982-2011: 42 million
– Retrospective: recent is reversed compared to 2004 pattern;– Now underestimate SSB and overestimate F; – Tendency to overestimate recent R
Summer flounder 2012
– Estimate of 2009 year class is no longer large (initially was influenced by recent northern state [CT, RI, MA] and MD YOY indices, relatively large age 0 discards in 2009 rec fishery)
– Developing retro pattern in recruitment estimates, 2009 year class is now 48% lower than initial estimate in 2010;
– 2010 & 2011 year classes below average
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
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
Summer Flounder Assessment ComparisonMRIP: MRFSS ratio = 0.993
MRFSS MRIP
Year
SSB
(mt)
SSB (000s mt)0 25 50 75 100
Fish
ing
Mor
talit
y
0.00
0.25
0.50
0.75
1.00
1.25
1.50
F35% = FMSY = 0.310
0.5*SSB35% =0.5*SSBMSY = 30,037 mt
SSB35%=SSBMSY = 60,074 mt
19971998
1999 20002001
20022003 2004
20052006
2007 2008
2009 2010
2011
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
0
5,000
10,000
15,000
20,000
25,000
30,000
0.0
0.5
1.0
1.5
2.0
2.5
Total Catch and Fishing Mortality
Total Catch Fishing MortalityF35% = FMSY = 0.310
Year
Cat
ch (m
t)
F ( a
ges
3-7+
unw
eigh
ted)
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
0
20,000
40,000
60,000
80,000
100,000
Spawning Stock Biomass (SSB) and Recruitment (R)
R SSB
Year
SSB
(mt)
R (a
ge 0
, 000
s)
0 10,000 20,000 30,000 40,000 50,000 60,000 70,0000
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
90,000
Summer flounder S-R Datafor 1983-2011 Year Classes
SSB (mt)
R (a
ge 0
, 000
s)
50% CI = 0.228 - 0.254
50% CI = 54,440 - 59,822 mt
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
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
Summer Flounder Assessment Comparison
2008 SAW47 F2009 F2010 F2011 F2012
Year
SSB
(mt)
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
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
90,000
Summer Flounder Assessment Comparsion
2008 SAW47 F2009 F2010 F2011 F2012 Mean
Year
Rec
ruitm
ent (
age
0, 0
00s)
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
0.00
0.50
1.00
1.50
2.00
2.50
Summer Flounder Assessment Comparsion
2008 SAW47 F2009 F2010 F2011 F2012
Year
Fish
ing
Mor
talit
y (F
)
Summer flounder 2012• Short term projection for 2013 OFL (at FMSY = 0.310)
• Use 2008 SAW 47 BRPs; no explicit adjustment for retro (2006 S&T; Legault and Terceiro 2008 [GARM3 work])
• AGEPRO stochastic projection– resample 1982-2011 CDF of age 0 recruitment
• Note MSY = 13,122 mt of Total Landings + 1,510 mt Total Disc = 14,632 mt of Total Catch
• Specify Landings in 2012 = TAL = 10,238 mt; • Median Discards = 1,455 mt; median Total Catch = 11,693 mt • Median F2012 = 0.247, below FMSY• Median SSB2012 = 55,300 mt, below Btarget (SSBMSY)
Summer flounder 2012
• Specify F in 2013 = FMSY = 0.310
• Total Catch = 13,523 mt = Overfishing Limit (OFL)
Landings = 11,892 mt and Discards = 1,637 mt(note: independent medians so do not exactly total)
• Median SSB2013 = 52,843 mt, below Btarget (88% of SSBMSY)
