St. Thomas Grouper Analysis

Carried out under STFA FundingJosh Nowlis, Ph.D. Stock Assessment Specialist

Data Sources

• Catch Reports (Snapper/Grouper) 1974-1999• Catch Reports (by Fishing Method) 1974-2012• Catch Reports (Grouper Landings) 1997-2012• Port Sampling (TIP) 1979-2012• STFA Studies (2005-6, 2006, 2008, 2010-2012)• Rick Nemeth’s Red Hind Bank Studies (2000-2012)• Olsen and LaPlace Nassau Grouper/Hind data

from 1974

Total St. Thomas Finfish Landingsby method

19741976

19781980

19821984

19861988

19901992

19941996

19982000

20022004

20062008

20102012

0

100000

200000

300000

400000

500000

600000

700000

800000

Diving Nets Line Fishing Traps

Tota

l Fin

fish

Land

ings

(lbs

)

St. Thomas Grouper Landings (Estimated and Reported

19741976

19781980

19821984

19861988

19901992

19941996

19982000

20022004

20062008

20102012

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

SEFSC Grouper Estimated Grouper

ACL

National Standard 198-623 (1) Conservation and management measures shall prevent overfishing while achieving, on a continuing basis, the optimum yield from each fishery for the United States fishing industry.

(28) The term "optimum", with respect to the yield from a fishery, means the amount of fish which–

(A) will provide the greatest overall benefit to the Nation, particularly with respect to food production and recreational opportunities, and taking into account the protection of marine ecosystems;

(B) is prescribed as such on the basis of the maximum sustainable yield from the fishery, as reduced by any relevant economic, social, or ecological factor; and

(C) in the case of an overfished fishery, provides for rebuilding to a level consistent with producing the maximum sustainable yield in such fishery.

St. Thomas Estimated Grouper Landings (and OFL/ACL)

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

Estimated Grouper LandingsReported Grouper LandingsOFLAdjusted ACLOriginal ACL E

sim

ated

Gro

uper

Land

ings

(lbs

)

R2 Reported and Estimated =0.486

Timing of ClosureSt. Thomas Grouper Landings by Month (1999-2006)

January

February

March

AprilMay

JuneJuly

August

September

October

November

December

0.0%

2.0%

4.0%

6.0%

8.0%

10.0%

12.0%

14.0%

16.0%

18.0%

20.0%

19992000200120022003200420052006Average

Red Hind Average TL

1970 1975 1980 1985 1990 1995 2000 2005 2010 2015240

260

280

300

320

340

360

380

Avg TLTota

l Len

gth

(mm

)

1982 Strong El Nino1986 Moderate El Nino1987 Moderate El Nino

STT Grouper Abundance Measures

1998 2000 2002 2004 2006 2008 2010 20120

0.2

0.4

0.6

0.8

1

1.2

1.4

Standardized Red Hind Bank Density

Red Hind Trap CPUE

Grouper Trap CPUE

Year

Rela

tive

Abun

danc

e)

Recommendations• Dr. Nemeth should be funded to carry out an annual survey

on the hind bank MCD. These normally take place in February to March.

• Following the survey, the results should be assessed and the OFL/ACL adjusted to account for variations in recruitment on the MCD.

• Fishermen should be involved in this review and adjustment process.

• The OFL should serve as the ACL guide.• The CFMC should not only insure funding for Dr. Nemeth’s

surveys but also establish a mechanism for review and adjustment (if required) of the ACL on an annual basis.

• We note that this approach is similar to the manner in which many fisheries are managed (e.g.. Salmon, Alaska King crab).

% Red Hind in TIP Grouper Samples

1984 1985 1986 1987 2004 2005 2006 2009 2010 2011 20120%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Nemeth January Hind Bank Census Results

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 20130

5

10

15

20

25

30>4131-4021-30<20

Year

Red

hind

Den

sity

(#/1

00m

2)

density by size class (Jan)

Nemeth Hind Bank Census

1998 2000 2002 2004 2006 2008 2010 2012 20140

5

10

15

20

25

30

# Transects

#/100 M2)

Max

Red

Hin

d/10

0 M

2

Nemeth Census vs Total Grouper Landings

5.00 10.00 15.00 20.00 25.00 30.0040,000

45,000

50,000

55,000

60,000

65,000

70,000

75,000

80,000

f(x) = 792.510903395033 x + 46485.5497383909R² = 0.460125608111071

Hinds/100 sq. m.

Grou

per L

andi

ngs (

lbs)

Impact of Survey Based St. Thomas Grouper OFL/ACL

20002001

20022003

20042005

20062007

20082009

20102011

2012

40,000

45,000

50,000

55,000

60,000

65,000

70,000

75,000

Survey Based OFLSurvey Based ACLReported Grouper LandingsCurrent OFLCurrent ACL

Grou

per L

andi

ngs (

lbs)

Proposal for Grouper Management• Funding for Nemeth to carry out annual MCD census at

appropriate sample size.• Incorporate current work by Nemeth/Appledorn to

improve precision of estimate.• Use results to calculate OFL annually.• Set ACL=OFL?• Close fishery when ACL/OFL exceeded.• Current effort for electronic reporting will enhance ability

for projecting landings.• Monitor Sizes by Port Sampling to assess impacts of

fishing pressure.

Advantages

• Does not guarantee that ACL will be exceeded.

• Precautionary in that when Nemeth census indicates low numbers ACL can be reduced.

• Advantage for fishermen in that when census indicates, ACL can be increased.

• Incorporates more information than simple average landings calculations.