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Evaluating Local Lobster Population Dynamics with Geo-referenced Trap Arrays, Mark-recapture Methods & Seabed Mapping. Richard A. Wahle 1 Michael J. Dunnington 1 Kerrie O’Donnell 2 , Nate Geraldi 2 Allen Gontz 3 , Michael C. Bell 4 1 Bigelow Laboratory for Ocean Sciences - PowerPoint PPT Presentation
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Evaluating Local Lobster Population Dynamics with Geo-referenced Trap Arrays, Mark-recapture Methods & Seabed Mapping
Richard A. Wahle 1 Michael J. Dunnington 1 Kerrie O’Donnell 2, Nate Geraldi 2
Allen Gontz3, Michael C. Bell 4
1 Bigelow Laboratory for Ocean Sciences2 The Island Institute, Rockland, ME3 University of Maine, Orono4 CEFAS, Lowestoft, Suffolk, UK
-68.844-68.842
-68.84-68.838
-68.836-68.834
-68.832
44.022
44.024
44.026
44.028
44.03
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
-68.844-68.842
-68.84-68.838
-68.836-68.834
-68.832
44.022
44.024
44.026
44.028
44.03
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
Overview• Background• Proof of Concept Study: Integrating
mapping, trapping, mark-recapture– Dunnington et al. (NZJMFR 2005)– Geraldi et al. (CJFAS 2009)
• Application: Disposal Impact Study– O’Donnell et al. (MEPS 2007)
Seabed (Post-settlement) Processes
- movements & mortality
JUVENILECRYPTIC
disperse / migrate
emerge
ADOLESCENTS
ADULT(SPAWNERS)
LARVAE
hatch
POSTLARVAEtransport
Water column (Pre-settlement) Processes - larval drift & death
Long-term Vision
Linking Life Stage-specific Abundance Estimates
• Seabed Mapping
• Geo-Referenced Trap Arrays
• Jolly-Seber Multiple Mark-Recapture Method
Abundance, Gains & Losses
Movement & Growth
Proof-of-Concept Project Make Traps a Better Tool by Integrating Methodologies
Validating Trap-based Mark-Recapture Methods2001
2-4 Weeks – No 2-4 Weeks – No Research TrappingResearch Trapping
3 Hauls in 10 d3 Hauls in 10 d
3d 3dTrap Trap Trap
3 Hauls in 10 d3 Hauls in 10 d
Trap Trap Trap
Dive SurveysDive Surveys Dive SurveysDive Surveys
Sampling Schedule
Etc. …..Etc. …..
N
Validating Trap-based Mark-Recapture Methods2001
Rockland Harbor
Vinalhaven
Penobscot Bay
Analysis
• Mark-recapture based vs Diver-based estimates of abundance
Diver Surveys by Substrate
Substrate Mapping
Population Estimate
Research Trap Catch
Mark-RecaptureAnalysis
Validating Trap-based Mark-Recapture Methods2001
Analysis
• Mark-recapture based vs Diver-based estimates of abundance
Diver Surveys by Substrate
Substrate Mapping
Population Estimate
Research Trap Catch
Mark-RecaptureAnalysis
Validating Trap-based Mark-Recapture Methods2001
0
5
10
15
20
25
30
6/20/01 7/20/01 8/20/01 9/20/01 10/20/01 11/20/01 12/20/01
Lo
bs
ters
/Tra
p
Sublegal
Legal
Substratebadscanblankcobbleledgesediment
# Research traps
##
# # ## # #
## # # # # #
#
# # ## #
# # #
# ## # # #
##
# # # ##
## #
# # # # # # # #
# ## # #
## #
# # ##
## # #
#
#
#
#
#
0.2 0 0.2 0.4 Kilometers
Substrates from Side Scan Sonar
0
5
10
15
20
25
30
6/20/01 7/20/01 8/20/01 9/20/01 10/20/01 11/20/01 12/20/01
Lo
bs
ters
/Tra
p
Sublegal
Legal
Catch per Trap (+/- 1SE)
Geo-referenced Catch Patterns 2001All Lobsters Catch Per Trap
-68.844 -68.842 -68.84 -68.838 -68.836 -68.834 -68.832
44.022
44.024
44.026
44.028
44.03
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
June 20, 2001
-68.844 -68.842 -68.84 -68.838 -68.836 -68.834 -68.832
44.022
44.024
44.026
44.028
44.03
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
June 21, 2001
-68.844 -68.842 -68.84 -68.838 -68.836 -68.834 -68.832
44.022
44.024
44.026
44.028
44.03
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
June 22, 2001
-68.844 -68.842 -68.84 -68.838 -68.836 -68.834 -68.832
44.022
44.024
44.026
44.028
44.03
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
July 6, 2001
-68.844 -68.842 -68.84 -68.838 -68.836 -68.834 -68.832
44.022
44.024
44.026
44.028
44.03
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
July 9, 2001
-68.844 -68.842 -68.84 -68.838 -68.836 -68.834 -68.832
44.022
44.024
44.026
44.028
44.03
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
July 12, 2001
-68.844 -68.842 -68.84 -68.838 -68.836 -68.834 -68.832
44.022
44.024
44.026
44.028
44.03
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
July 27, 2001
-68.844 -68.842 -68.84 -68.838 -68.836 -68.834 -68.832
44.022
44.024
44.026
44.028
44.03
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
July 30, 2001
-68.844 -68.842 -68.84 -68.838 -68.836 -68.834 -68.832
44.022
44.024
44.026
44.028
44.03
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
August 2, 2001
-68.844 -68.842 -68.84 -68.838 -68.836 -68.834 -68.832
44.022
44.024
44.026
44.028
44.03
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
August 24, 2001
-68.844 -68.842 -68.84 -68.838 -68.836 -68.834 -68.832
44.022
44.024
44.026
44.028
44.03
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
August 27, 2001
-68.844 -68.842 -68.84 -68.838 -68.836 -68.834 -68.832
44.022
44.024
44.026
44.028
44.03
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
August 30, 2001
-68.844 -68.842 -68.84 -68.838 -68.836 -68.834 -68.832
44.022
44.024
44.026
44.028
44.03
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
September 21, 2001
-68.844 -68.842 -68.84 -68.838 -68.836 -68.834 -68.832
44.022
44.024
44.026
44.028
44.03
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
September 24, 2001
-68.844 -68.842 -68.84 -68.838 -68.836 -68.834 -68.832
44.022
44.024
44.026
44.028
44.03
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
September 27, 2001
-68.844 -68.842 -68.84 -68.838 -68.836 -68.834 -68.832
44.022
44.024
44.026
44.028
44.03
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
October 29, 2001
-68.844 -68.842 -68.84 -68.838 -68.836 -68.834 -68.832
44.022
44.024
44.026
44.028
44.03
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
November 1, 2001
-68.844 -68.842 -68.84 -68.838 -68.836 -68.834 -68.832
44.022
44.024
44.026
44.028
44.03
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
November 5, 2001
-68.844 -68.842 -68.84 -68.838 -68.836 -68.834 -68.832
44.022
44.024
44.026
44.028
44.03
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
December 20, 2001
Analysis
• Mark-recapture based vs Diver-based estimates of abundance
Diver Surveys by Substrate
Substrate Mapping
Population Estimate
Research Trap Catch
Mark-RecaptureAnalysis
Sublegal Lobster Densities (+/- 1 SE)
0
0.05
0.1
0.15
6/20/01 7/20/01 8/20/01 9/20/01 10/20/01 11/20/01 12/20/01
Lo
bste
rs/m
2
Cobble
Ledge
Sediment
Legal Lobster Densities (+/- 1 SE)
0
0.01
0.02
0.03
0.04
0.05
6/20/01 7/20/01 8/20/01 9/20/01 10/20/01 11/20/01 12/20/01
Lo
bste
rs/m
2
Substratebadscanblankcobbleledgesediment
# Research traps
##
# # ## # #
## # # # # #
#
# # ## #
# # #
# ## # # #
##
# # # ##
## #
# # # # # # # #
# ## # #
## #
# # ##
## # #
#
#
#
#
#
0.2 0 0.2 0.4 Kilometers
Substrates from Side Scan Sonar
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
6/20/01 7/20/01 8/20/01 9/20/01 10/20/01 11/20/01 12/20/01
Esti
mate
d A
bu
nd
an
ce
Tag Sublegal
Diver Sublegal
Tag Legal
Diver Legal
0
5
10
15
20
25
30
6/20/01 7/20/01 8/20/01 9/20/01 10/20/01 11/20/01 12/20/01
Lo
bs
ters
/Tra
p
Sublegal
Legal
Validating Trap-based Mark-Recapture Methods2001
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
6/20/2001 7/20/2001 8/20/2001 9/20/2001 10/20/2001 11/20/2001 12/20/2001
Est
imat
ed A
bund
ance
Tag Sublegal
Tag Legal
Sublegal Daily Gains and Losses (+ 1 SE)
-0.01
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
07/27/01 08/24/01 09/21/01 10/29/01 12/20/01
Pro
po
rti
on
Gains
Loss
Legal Daily Gains and Losses (+ 1 SE)
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
07/27/01 08/24/01 09/21/01 10/29/01 12/20/01
Pro
po
rti
on
Gains
Loss
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
6/20/01 7/20/01 8/20/01 9/20/01 10/20/01 11/20/01 12/20/01
Est
imat
ed A
bu
nd
ance
Tag Sublegal
Diver Sublegal
Tag Legal
Diver Legal
Diver-based & Mark-recapture-based Abundance (+/- 95% C.I.)Sublegal Lobster Densities (+/- 1 SE)
0
0.05
0.1
0.15
6/20/01 7/20/01 8/20/01 9/20/01 10/20/01 11/20/01 12/20/01
Lo
bste
rs/m2
Cobble
Ledge
Sediment
Legal Lobster Densities (+/- 1 SE)
0
0.01
0.02
0.03
0.04
0.05
6/20/01 7/20/01 8/20/01 9/20/01 10/20/01 11/20/01 12/20/01
Lo
bste
rs/m2
Diver-based Pop Density EstimatesSublegal Daily Gains and Losses (+ 1 SE)
-0.01
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
07/27/01 08/24/01 09/21/01 10/29/01 12/20/01
Pro
po
rtio
n
Gains
Loss
Legal Daily Gains and Losses (+ 1 SE)
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
07/27/01 08/24/01 09/21/01 10/29/01 12/20/01
Pro
po
rtio
n
Gains
Loss
Mark-recapture –based Gain & Loss Estimates
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
6/20/01 7/20/01 8/20/01 9/20/01 10/20/01 11/20/01 12/20/01
Est
imat
ed A
bu
nd
ance
Tag Sublegal
Tag Legal
Mark-recapture-based Abundance Estimates (+/- 95% C.I.)
Tagged 10,000 Lobsters
Validating Trap-based Mark-Recapture Methods2002
2001
Rockland Harbor
Vinalhaven
N
Rockland Harbor
Vinalhaven
N
2002
2002
2001
Validating Trap-based Mark-Recapture Methods2002
Browns Head
Sheep Ledges
Carvers Harbor
Dogfish Island
0
5
10
15
20
25
30
35
40
45
0
10
20
30
40
50
60
2001 2002
Dis
tanc
e pe
r da
y (m
)
(a)
(b)
(c)
Year
SedimentCobbleLedge
Movements Within ArrayTagged & Recaptured in Research Traps
Lobster first tagged on
Movements Beyond ArrayTagged in Research Traps. Recaptured in Commercial Traps
Commercial Recaptures Dist per Day from Initial Substrate (+/- 1SE)
0
0.5
1
1.5
2
2.5
2001 2002
Lo
g D
ista
nce
per
Day
(m
)
Soft Substrate
Hard Substrate
A.
B.
A.
B.
APPLICATION: Impact of Dredge Disposal on Lobster & Crab
“DG” Buoy
C1 T C2
Maine
Penobscot Bay
RocklandHarbor
North H
aven
Vinal-
haven
A.
B.
C. C1 T C2
Maine
Penobscot Bay
RocklandHarbor
North H
aven
Vinal-
haven
A.
B.
C.
Disposal Area
“DG” Buoy
C1 T C2
C1 T C2(b)
C1 T C2
BEFORE
C1T C2C1 T C2
AFTER
C1 T C2
BeforeAfter
DISPOSAL BEGINS
11/1/02 11/5/02 11/8/02
11/12/02 11/15/02 11/22/02
11/26/02 12/4/02 12/11/02
12/16/02 12/19/02
C1 C2T C1 C2T C1 C2T
C1 C2T C1 C2T C1 C2T
C1 C2T C1 C2T C1 C2T
C1 C2T C1 C2T
DISPOSAL BEGINSDISPOSAL BEGINS
11/1/02 11/5/02 11/8/02
11/12/02 11/15/02 11/22/02
11/26/02 12/4/02 12/11/02
12/16/02 12/19/02
C1 C2TC1 C2T C1 C2TC1 C2T C1 C2TC1 C2T
C1 C2TC1 C2T C1 C2TC1 C2T C1 C2TC1 C2T
C1 C2TC1 C2T C1 C2TC1 C2T C1 C2TC1 C2T
C1 C2TC1 C2T C1 C2TC1 C2T
LobsterResponse
11/5/02 11/8/02
11/12/02 11/15/02 11/22/02
11/26/02 12/4/02 12/11/02
12/16/02 12/19/02
DISPOSAL BEGINS
C1 C2T C1 C2T
C1 C2T C1 C2T C1 C2T
C1 C2TC1 C2T C1 C2T
C1 C2TC1 C2T
12/19/02
DISPOSAL BEGINSDISPOSAL BEGINS
C1 C2T C1 C2T
C1 C2T C1 C2T C1 C2T
C1 C2TC1 C2T C1 C2T
C1 C2TC1 C2T
11/5/02 11/8/02
11/12/02 11/15/02 11/22/02
11/26/02 12/4/02 12/11/02
12/16/02
C1 C2T C1 C2T
C1 C2T C1 C2T C1 C2T
C1 C2TC1 C2T C1 C2T
C1 C2TC1 C2T
CrabResponse
All Traps
-1
0
1
2
3
C1 T C2
Pro
po
rtio
nal C
han
ge
Ca
tch
per
Hau
l
Lobster
Crab
C1 T C2
Pro
po
rtio
na
l Ch
an
ge
Cat
ch
p
er H
aul
*
-1
0
1
2
3
C1 T C2
*
Pro
po
rtio
na
l Ch
an
ge
Cat
ch
p
er H
aul
C1 T C2
(a) All Traps
(b) Central Traps
All Traps
-1
0
1
2
3
C1 T C2
Pro
po
rtio
nal C
han
ge
Ca
tch
per
Hau
l
Lobster
Crab
C1 T C2
Pro
po
rtio
na
l Ch
an
ge
Cat
ch
p
er H
aul
*
All Traps
-1
0
1
2
3
C1 T C2
Pro
po
rtio
nal C
han
ge
Ca
tch
per
Hau
l
Lobster
Crab
C1 T C2
Pro
po
rtio
na
l Ch
an
ge
Cat
ch
p
er H
aul
*
-1
0
1
2
3
C1 T C2
*
Pro
po
rtio
na
l Ch
an
ge
Cat
ch
p
er H
aul
C1 T C2
-1
0
1
2
3
C1 T C2
*
Pro
po
rtio
na
l Ch
an
ge
Cat
ch
p
er H
aul
C1 T C2
(a) All Traps
(b) Central Traps
All Traps
CrabLobster p < 0.00001
p = 0.16
C1 T C2
Pro
po
rtio
na
l Ch
an
ge
Cat
ch
p
er H
aul
*
-1
0
1
2
3
C1 T C2
Pro
po
rtio
nal
Ch
ang
e C
atc
h p
er H
aul
*
Pro
po
rtio
na
l Ch
an
ge
Cat
ch
p
er H
aul
C1 T C2
(a) All Traps
(b) Central Traps
C1 T C2
Pro
po
rtio
na
l Ch
an
ge
Cat
ch
p
er H
aul
*
C1 T C2
Pro
po
rtio
na
l Ch
an
ge
Cat
ch
p
er H
aul
*
-1
0
1
2
3
C1 T C2
Pro
po
rtio
nal
Ch
ang
e C
atc
h p
er H
aul
*
Pro
po
rtio
na
l Ch
an
ge
Cat
ch
p
er H
aul
C1 T C2
-1
0
1
2
3
C1 T C2
Pro
po
rtio
nal
Ch
ang
e C
atc
h p
er H
aul
*
Pro
po
rtio
na
l Ch
an
ge
Cat
ch
p
er H
aul
C1 T C2
(a) All Traps
(b) Central Traps
Central Traps
p = 0.00008CrabLobster
p = 0.18
Response Summary
• Seabed mapping a critical tool for habitat-specific abundance estimates & impact assessment
• Trap-based catch rates highly correlated with abundance.
• M-R analysis a powerful tool in translating catch into abundance, gains, loss estimates.
• Longer time series more robust.
• Approach can be tailored for different spatial scales and time-frames.
• Potential use in MPA assessment and environmental impact studies.
Validating Trap-based Mark-Recapture Abundance Estimates with Dive Surveys
Summary:
Funding:
• Sea Grant
• US Army Corps of Engineers
• Island Institute
Industry:
• Walter Day, Vinalhaven Fishermen
Interns of 2001, 2002:
• Selena Kirby, Nick Sosin, Curt Brown, Shelly Tallack
Acknowledgements
Analysis
• Mark-recapture based vs Diver-based estimates of abundance
Diver Surveys by Substrate
Substrate Mapping
Population Estimate
Research Trap Catch
Mark-RecaptureAnalysis 0
10,000
20,000
30,000
40,000
50,000
60,000
6/24/02 7/8/02 7/22/02 8/5/02 8/19/02 9/2/02
Popu
latio
n Es
timat
e
Tag Sublegal
Tag Legal
Sublegal Daily Gains and Losses
-0.5
0
0.5
1
1.5
2
7/1 7/5 7/8 7/18 7/22 7/25 7/29 8/12 8/15 8/19 8/29 9/3
Pro
pro
rti
on
Gains
Loss
Legal Daily Gains and Losses
-0.5
0
0.5
1
1.5
2
7/1 7/5 7/8 7/18 7/22 7/25 7/29 8/12 8/15 8/19 8/29 9/3
Pro
po
rti
on
Gains
Loss
Validating Trap-based Mark-Recapture Methods2002
0
10,000
20,000
30,000
40,000
50,000
60,000
6/24/02 7/8/02 7/22/02 8/5/02 8/19/02 9/2/02
Po
pu
lati
on
Est
imat
e
Tag Sublegal
Diver Sublegal
Tag Legal
Diver Legal
Sublegal Lobster Densities (+/- 1 SE)
0
0.05
0.1
0.15
0.2
0.25
6/24/02 7/15/02 8/5/02 8/26/02
Lo
bste
rs/m
2
Cobble
Ledge
Sediment
Legal Lobster Densities (+/- 1 SE)
0
0.01
0.02
0.03
0.04
0.05
6/24/02 7/15/02 8/5/02 8/26/02
Lo
bste
rs/m
2
Catch per Trap (+/- 1 SE)
0
5
10
15
20
25
30
6/22/2002 7/13/2002 8/3/2002 8/24/2002L
ob
ster
s/T
rap
Sublegal
LegalCatch per Trap (+/- 1 SE)
0
5
10
15
20
25
30
6/22/2002 7/13/2002 8/3/2002 8/24/2002
Lo
bst
ers/
Tra
p
Sublegal
Legal
Carvers Harbor Sheep
Ledges
Browns Head
Dogfish Island
Sublegal Daily Gains and Losses
-0.5
0
0.5
1
1.5
2
7/1 7/5 7/8 7/18 7/22 7/25 7/29 8/12 8/15 8/19 8/29 9/3
Pro
pro
rtio
n
Gains
Loss
Legal Daily Gains and Losses
-0.5
0
0.5
1
1.5
2
7/1 7/5 7/8 7/18 7/22 7/25 7/29 8/12 8/15 8/19 8/29 9/3
Pro
po
rtio
n
Gains
Loss
Carvers Harbor
Sheep Ledges
Browns Head
Dogfish Island
Carvers Harbor
Sheep Ledges
Browns Head
Dogfish Island
Sublegal Lobster Densities (+/- 1 SE)
0
0.05
0.1
0.15
0.2
0.25
6/24/02 7/15/02 8/5/02 8/26/02
Lo
bste
rs/m
2Cobble
Ledge
Sediment
Legal Lobster Densities (+/- 1 SE)
0
0.01
0.02
0.03
0.04
0.05
6/24/02 7/15/02 8/5/02 8/26/02
Lo
bste
rs/m
2
Carvers Harbor
Sheep Ledges
Browns Head
Dogfish Island
Carvers Harbor
Sheep Ledges
Browns Head
Dogfish Island
0
10,000
20,000
30,000
40,000
50,000
60,000
6/24/02 7/8/02 7/22/02 8/5/02 8/19/02 9/2/02
Po
pu
lati
on
Est
imat
e
Tag Sublegal
Diver Sublegal
Tag Legal
Diver Legal
Estimated Population Size (+/- 95% C.I.)
Carvers Harbor
Sheep Ledges
Browns Head
Dogfish Island
0
10,000
20,000
30,000
40,000
50,000
60,000
6/24/02 7/8/02 7/22/02 8/5/02 8/19/02 9/2/02
Po
pu
lati
on
Est
imat
e
Tag Sublegal
Tag Legal
Estimated Population Size (+/- 95% C.I.)
Carvers Harbor
Sheep Ledges
Browns Head
Dogfish Island
Browns Head
Sheep Ledges
Carvers Harbor
Dogfish Island
Movements Within Array
0.0
0.2
0.4
0.6
0.8
1.0
0.0
0.2
0.4
0.6
0.8
1.0
Sediment Cobble Ledge
Pro
po
rtio
n o
f lo
bst
ers
(a)
(b)
Substrate
Different TrapSame Trap
2001
2002
• Efficient• Relatively inexpensive• Sample where divers & trawls can’t• Catch data – reflect basic patterns
Why Use Traps?
The Problem With Catch Data:• Don’t know how catch rates relate to abundance or dynamics.
• Not all traps are created equal.
• Lobstermen fish traps to catch lobsters.
