SSC Report to CFMC 150 th CFMC Meeting held August 12-13, 2014 SSC Meeting held August 5-7, 2014.
STFA/SCCFA/CFMC Spiny Lobster Project
description
Transcript of STFA/SCCFA/CFMC Spiny Lobster Project
STFA/SCCFA/CFMCSpiny Lobster Project
David Olsen, STFAJosh Nowlis, Bridge Environment
Daryl Bryan, STFA
Funded by Caribbean Fishery Management Council
Virgin Islands Spiny Lobster Landings
19741976
19781980
19821984
19861988
19901992
19941996
19982000
20022004
20062008
20100
20,000
40,000
60,000
80,000
100,000
120,000
140,000
160,000
St. Croix ACL= 107,307 lbs
St. Thomas/St. John ACL= 104,199 lbs
Year
Land
ings
(lbs
)
Landings by Method
19741977
19801983
19861989
19921995
19982001
20042007
2010
-
20,000
40,000
60,000
80,000
100,000
120,000
140,000
160,000
St. Thomas Spiny Lobster Landings
Other
Traps
Diving
Lbs.
19751978
19811984
19871990
19931996
19992002
20052008
2011
0
20,000
40,000
60,000
80,000
100,000
120,000
140,000
160,000
St. Croix Spiny Lobster Landings
Diving
Traps
Other
Lbs.
# Lobster Trips by Island (1974-2006)
19741976
19781980
19821984
19861988
19901992
19941996
19982000
20022004
2006
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
18,000Virgin Islands Lobster Trips
St. Thomas Lobster Trips
St. Croix Lobster Trips
Tags and Recaptures
# Trips
# Tagged
# Project Recaptures
# Non-Project Recaptures # Kept
St. Croix 92 1,507 46 9 12St. Thomas 210 4,709 319 43 155
% of Lobster by CL (Complete Trips)
0%
5%
10%
15%
20%
25%
30%
35%
ST. CroixSt. Thomas
Minimum Legal CL
Average VI Lobster CL (1974-2012 from DFW Port Sampling)
19711981
19831985
19871989
19911993
19951997
19992001
20032005
20072009
20112012
90
95
100
105
110
115
St. Thomas/St. JohnSt. Croix
Cara
pace
Leng
th (m
m)
St. Croix Size of LobsterTraps vs Diving
Anova: Single Factor
SUMMARY
Groups Count Sum Average Variance
Traps 990 105,236 106.30 220
Diving 2,451 262,190 106.97 250
ANOVASource of Variation SS df MS F
P-value F crit
Between Groups 319 1 319 1.32 0.251 3.844
Within Groups 833,276 3,439 242
Total 833,596 3,440
St. Croix Recruitment Pulse?
80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 1750
20
40
60
80
100
120
140
2002
2007
Carapace Length (mm)
# Lo
bste
rs
Recruitment Pulse?
80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 1750
20
40
60
80
100
120
140
2002
2007
2012
Carapace Length (mm)
# Lo
bste
rs
Recruitment Pulse?St. Croix Size Class Frequencies
19811982
19831984
19851986
19871988
19891990
19911992
19931994
19951996
19971998
19992000
20012002
20032004
20052006
20072008
20092010
20112012
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%<105 mm CL
105-115 mm CL
116-125 mm CL
>125 mm CL
Recruitment Pulse?St. Thomas/St. John Size Class Frequencies
19711980
19811983
19841985
19861987
19881991
19921993
19942004
20052006
20072008
20092010
20112012
20122013
0%
10%
20%
30%
40%
50%
60%
<105 mm CL
105-115 mm CL
116-125 mm CL
>125 mm CL
Monthly St. Thomas Lobster Landings
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0.0%
2.0%
4.0%
6.0%
8.0%
10.0%
12.0%
14.0%
2000 2001 2002 2003
2004 2005 2006 2007
2008 2009 2010 2011
Average
Monthly CPUE/# Trips
Sep 2012
Oct 2012
Nov 2012
Dec 2012
Jan 2013
Feb 2013
Mar 2013
Apr 2013
May 2013
Jun 2013
Jul 2013
Aug 2013
Sep 2013
Oct 2013
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
20
22
24
26
28
30
32
LT CPUE
Lobster Trips/Month
Pro
ject
Lobs
ter C
PUE
(lbs/
trap
hau
l)
Lobs
ter T
rips/
Mon
th
Peak Wind Period
Short/Berried SeasonalitySe
p-12
Oct
-12
Nov
-12
Dec-
12
Jan-
13
Feb-
13
Mar
-13
Apr-
13
May
-13
Jun-
13
Jul-1
3
Aug-
13
Sep-
13
Oct
-13
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
Shorts CPUE
Berried CPUE
Shor
t Lob
ster
s/Tr
ap H
aul
Berr
ied
Lobs
terT
rap
Haul
Summary of Coral World Tag Retention Study
• 45 lobsters were installed at Coral World between July and October 2013. To date there have been 9 molts with no tag loss.
• In the mean-time we have tagged an additional 10 (<45 mm) small Coral World lobsters. 6 of these molted and 4 lost their tags.
• The smallest lobster tagged in the field was 51 mm CL.
• We do not think tag loss is much of an issue.
STFA Lobster Landings (% of Total Lobster Landings)
2,003.00 2,004.00 2,005.00 2,006.0080,000
90,000
100,000
110,000
120,000
130,000
140,000
150,000
75%
80%
85%
90%
95%
100%Total Lobster LandingsSTFA Lobster LandingsSTFA % of Total
Lobs
ter L
andi
ngs (
lbs)
0 15 30 45 60 75 90105
120135
150165
180195
210225
240255
270285
300315
330345
3600
5
10
15
20
25
30
35
40
45
Days at Large
Freq
uenc
yDays at Large
Summer Recaptures
Winter Recaptures
Mortality Calculation• Von Bertalanffy growth equation .
• Solve for (t) for carapace length.
• This provides the age for each size class in the size frequency distribution so that total mortality (Z) can be calculated as the difference in numbers from the size class bin at full recruitment and the size class bin containing L
Where: is the number of fish at time (t) and (t-1)andZ is the rate of total mortality.
Total Mortality (Z) Calculated from TIP Data
19711981
19831985
19871989
19911993
19951997
19992001
20032005
20072009
2011
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
St. Thomas Moving average (St. Thomas)
St. Croix Moving average (St. Croix)
Tota
l Ann
ual M
orta
lity
(Z)
Estimated Spiny Lobster Growth
0 5 10 15 20 25 30 350
50
100
150
200
250
300
Age
Cara
pace
leng
th (m
m)
L∞ =244.9 mmK=0.361W∞ =15.6 lbs
01224364860728496108120132144156168180
0 1224 3648 6072 8496 108120 132144 156168 180
Fishing mortality rate
Size
at fi
rst c
aptu
re (m
m ca
rapa
ce le
ngth
)
St. Thomas St. Croix
Yield Per Recruit
Comparison Between Annual Fish Trap Hauls(St. Thomas CCR Reports and Fishermen Interviews)
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 20070
50,000
100,000
150,000
200,000
250,000
300,000
350,000
400,000
450,000
500,000
CCR Reports Fishermen Interviews
Year
Tota
l Ann
ual T
rap
Hau
ls
Traps/Day Hauled in St. Thomas (TIP, Historic and Adjusted CCR Data Compared to Current SEFSC Data)
1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 20150
20
40
60
80
100
120f(x) = NaN x + NaNR² = 0
SEFSC Data Adjusted CCR
TIP VIERS
MRAG MARFIN
Trap
Hau
ls/D
ay
STT Stock Health Indicators
1975 1980 1985 1990 1995 2000 2005 20100
0.5
1
1.5
2
2.5
Trap CPUE Divers CPUE
Year
Rela
tive
CPU
E va
lue
1975 1980 1985 1990 1995 2000 2005 2010707580859095
100105110115120
Avg Length Minimum size Size at 50% Maturity
Year
Cara
pace
Len
gth
(mm
)
Summary of Status: St. Thomas• On St. Thomas, landings increased gradually from the mid-1980s to peaks of just over
136,000 lbs in 2003 through 2006, followed by decreased landings following this period.
• During this time of historically high catches, the stock showed no consistent signs of decline in catch per unit effort or in the average size of catch.
• The average size of catch itself remained well above the minimum size limit and the size at first maturity.
• As such, catches of 130,000 lbs a year appear to be sustainable. Current OFL is 115,776 lbs.
• Ongoing catch reporting and port sampling allow us to watch for future signs of overfishing, and would allow for the opportunity to adjust catches downward if necessary.
STX Stock Health Indicators
1975 1980 1985 1990 1995 2000 2005 20100
0.5
1
1.5
2Trap CPUE
Divers CPUE
Year
Rela
tive
CPUE
val
ue
1975 1980 1985 1990 1995 2000 2005 2010707580859095
100105110115120
Avg Length Minimum size Size at 50% Maturity
Year
Cara
pace
Leng
th (m
m)
Summary of Status: St. Croix• On St. Croix, landings grew dramatically starting in the mid-1990s to a
peak of over 155,000 lbs in 2008. Catches have exceeded 135,000 lbs most years since 2005 to 2011
• Indicators of health provide conflicting information. Whereas catch per unit effort has consistently increased since 2003, the average size of catch has mostly declined since 2007, with particularly dramatic drops in 2011 and 2012. The Carapace Length value in 2012 was close to the minimum size limit and size at first maturity, indicating lobster were being caught just as they grew to legal size and were capable of contributing new lobsters to the population.
• Given the data sources (port sampling versus self-reporting) and problems with assessing diving effort, the size information should probably receive greater consideration than catch per unit effort.
• While the size information is no guarantee that the stock is in poor condition, it does raise concerns about the current catch levels.
• Catches of 100,000 to 120,000 lbs were sustained in the early 2000s and may be a suitable quota, pending ongoing monitoring of this stock. Current OFL is 119,230 lbs.