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Blue Crab Update to LivRaw. Derek M. Orner NOAA Chesapeake Bay 4 November 2005. Trends in Blue Crab: Mature Females. GOAL: To protect the health of the blue crab stock and maintain the spawning stock at a sustainable level. - PowerPoint PPT Presentation
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Blue Crab Update to LivRaw
Derek M. OrnerNOAA Chesapeake Bay
4 November 2005
CHESAPEAKE BAY PROGRAM - ENVIRONMENTAL INDICATORS
TRACK 2: LIVING RESOURCE INDICATORCBP 8/23/05
Trends in Blue Crab: Mature Females
GOAL: To protect the health of the blue crab stock and maintain the spawning stock at a sustainable level.
STATUS: Mature female abundance has been below the long-term average for seven straight years and eleven of the past twelve years. Abundance declined in 2004 after trending upwards for three straight years from an historic low in 2000.
Sources: MD Department of Natural Resources, Virginia Institute of Marine Science, Academy of Natural Science, NOAA CBSAC.
Spawning Stock Abundance
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
1968
1971
1974
1977
1980
1983
1986
1989
1992
1995
1998
2001
2004
Spaw
ning
Fem
ale
Inde
x
Average
VIMS Trawl &Calvert Cliffs
VIMS Trawl,Calvert Cliffs &
MD Trawl
VIMS Trawl, Calvert Cliffs,MD Trawl &
Winter Dredge
CHESAPEAKE BAY PROGRAM - ENVIRONMENTAL INDICATORS
TRACK 2: LIVING RESOURCE INDICATORCBP 6/22/05
Trends in Blue Crab: Juveniles
GOAL: Manage blue crabs to conserve the Baywide stock, protect its ecological value and optimize the long-term use of the resource.
STATUS: It appears that recruitment continued to improve in 2004. The number of juvenile blue crabs entering the Chesapeake Bay population has stayed within ‘normal’ bounds for 12 straight years.
Sources: MD Department of Natural Resources, Virginia Institute of Marine Science, NOAA CBSAC.
Age O (<60mm) Indices
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
1968
1971
1974
1977
1980
1983
1986
1989
1992
1995
1998
2001
2004
Juve
nile
Inde
x
Average
VIMS Trawl &Calvert Cliffs
VIMS Trawl,Calvert Cliffs &
MD Trawl
VIMS Trawl, Calvert Cliffs,MD Trawl &
Winter Dredge
CHESAPEAKE BAY PROGRAM - ENVIRONMENTAL INDICATORS
TRACK 2: LIVING RESOURCE INDICATORCBP 6/22/05
0
20
40
60
80
100
120
1956
1959
1962
1965
1968
1971
1974
1977
1980
1983
1986
1989
1992
1995
1998
2001
2004
Land
ings
(mill
on p
ound
s)
Trends in Blue Crab: Commercial HarvestGOAL: Manage blue crabs to conserve the Baywide stock, protect its ecological value and optimize the long-term use of the resource.
STATUS: The 2004 harvest of approximately 60 million pounds is below the long term average and near historic lows. The 2004 fishing mortality rate did not exceed the overfishing threshold but is above the target.
Sources: Landings - National Marine Fisheries Service, NOAA.. Fishing Mortality Rate - Chesapeake Bay Stock Assessment Committee (CBSAC), unweighted average of 4 surveys.
Chesapeake Bay Blue Crab Landings
00.20.40.60.8
11.21.41.61.8
2
1956
1959
1962
1965
1968
1971
1974
1977
1980
1983
1986
1989
1992
1995
1998
2001
2004
Leng
th-B
ased
F Threshold: Not to be exceeded
Target: Safe Harvest Level
Average Fishing Mortality Rate
Adopted Control Rule -Blue Crab fisheries
From: Miller et.al. Stock Assessment of the Blue Crab in Chesapeake Bay 2005
http://hjort.cbl.umces.edu/crabs/Assessment05.html
From: Miller et.al. Stock Assessment of the Blue Crab in Chesapeake Bay 2005
From: Miller et.al. Stock Assessment of the Blue Crab in Chesapeake Bay 2005
Current AR 1999 -2005 Planned AR 2006+
WDS – harvest relationship
From: Miller et.al. Stock Assessment of the Blue Crab in Chesapeake Bay 2005
Blue Crab Distribution
Winter 2001/2002Winter 1990/1991From: Miller et.al. Stock Assessment of the Blue Crab in Chesapeake Bay 2005
From: Miller et.al. Stock Assessment of the Blue Crab in Chesapeake Bay 2005
