Keri L. Stepanek Maine Department of Marine Resources January 8, 2014
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Results from the Maine-New Hampshire Inshore Trawl Survey: Potential Prey and Predators of Atlantic Salmon Keri L. Stepanek Maine Department of Marine Resources January 8, 2014
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Results from the Maine-New Hampshire Inshore Trawl Survey: Potential Prey and Predators of Atlantic Salmon. Keri L. Stepanek Maine Department of Marine Resources January 8, 2014. Survey Goals. - PowerPoint PPT Presentation
Transcript of Keri L. Stepanek Maine Department of Marine Resources January 8, 2014
Results from the Maine-New Hampshire Inshore Trawl Survey: Potential Prey and Predators of Atlantic Salmon
Keri L. StepanekMaine Department of Marine Resources
January 8, 2014
Survey GoalsTo provide a long-term fisheries-independent
data base on the distribution and relative abundance of marine resources in the near shore Gulf of Maine.
To gather biological information (age at length, sexual maturity, food habits, and habitat use).
To consistently provide data that is valued by both industry members and scientists
To foster collaborative research between scientists and the fishing industry
F/V Robert Michael – Downeast 54’ commercial fishing vessel
Flagg Research Trawl – modified shrimp net, 2” mesh, 1” liner in cod end
20 minute straight tows, 2.5 knots (~0.8 nm)Stratified random design (95 random sites, 20
fixed stations) – target of 115 tows per surveyBiannual surveys, spring and fall
Survey Operations
Data Indices of AbundanceDistribution MapsCatch at LengthCatch at Age (Otoliths Backlogged)MaturitySex RatiosFood HabitsTemperature and Salinity Profiles
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Maine-New Hampshire Inshore Trawl Survey Sites#0 Fall 2012
Spring 2013
Fall 2012 Sept. 24 – Oct. 26 99 sites warmest fall since survey inception (11.30 C)Spring 2013 May 6 – June 6 113 sites
Occurrence of Prey Species
Atlantic herringAlewifeBlueback herringRainbow smeltSilver hakeButterfishPandalid shrimp
Atlantic Herring
Spring average total number ~140,000
Range of 3 to 38 cm total central length
Mean length 12.9 cm
%,%,%,%,%,
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%,All HerringQuantity
%, 1 - 25
%, 26 - 500
%, 501 - 1000
%, 1001 - 5000
%, 5001 - 11916
Spring 2013 Atlantic Herring Number Per Tow
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2009
2010
2011
2012
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%,All HerringQuantity
%, 1 - 25
%, 26 - 500
%, 501 - 1000
%, 1001 - 5000
%, 5001 - 11916
Herring <15 cmQuantity
1 - 25
26 - 500
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5000+
Spring 2013 Atlantic Herring Number Per Tow
AlewifeSpring average total number ~13,900
Range of 5 to 30 cm total central length
Mean length 11.2 cm
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All AlewivesQuantity
%, 1 - 25
%, 26 - 500
%, 501 - 1000
%, 1001 - 5000
%, 5001 - 10078
Spring 2013 Alewife Number Per Tow
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
0255075
100125150175200225250275
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Number
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Kilo
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%,%,%,
All AlewivesQuantity
%, 1 - 25
%, 26 - 500
%, 501 - 1000
%, 1001 - 5000
%, 5001 - 10078
Alewives <15 cmQuantity
1 - 25
26 - 500
501 - 1000
1001 - 5000
5000+
Spring 2013 Alewife Number Per Tow
Blueback HerringSpring average total number ~1,700
Range of 8 to 30 cm total central length
Mean length 12.4 cm
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All BluebackQuantity
%, 1 - 10
%, 11 - 50
%, 51 - 250
%, 251 - 500
%, 501 - 668
Spring 2013 Blueback Herring Number Per Tow
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
05
101520253035404550
0.000.250.500.751.001.251.501.752.002.252.50Num
berWeight
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tow
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All BluebackQuantity
%, 1 - 10
%, 11 - 50
%, 51 - 250
%, 251 - 500
%, 501 - 668
Blueback <15 cmQuantity
1 - 10
11 - 50
51 - 250
251 - 500
501+
Spring 2013 Blueback Herring Number Per Tow
Rainbow SmeltSpring average total number ~960
Range of 4 to 25 cm total central length
Mean length 13.6 cm
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All SmeltQuantity
%, 1 - 10
%, 11 - 20
%, 21 - 30
%, 31 - 40
%, 40 - 56
Spring 2013 Rainbow Smelt Number Per Tow
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2002
2003
2004
2005
2006
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2009
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0
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40
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%,
All SmeltQuantity
%, 1 - 10
%, 11 - 20
%, 21 - 30
%, 31 - 40
%, 40 - 56
Smelt <15 cmQuantity
1 - 10
11 - 20
20+
Spring 2013 Rainbow Smelt Number Per Tow
Silver HakeSpring average total number ~30,500
Range of 4 to 46 cm total central length
Mean length 15.8
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All Silver HakeQuantity
%, 1 - 100
%, 101 - 250
%, 251 - 500
%, 501 - 1000
%, 1001 - 5280
Spring 2013 Silver Hake Number Per Tow
2001
2002
2003
2004
2005
2006
2007
2008
2009
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2013
0
100
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All Silver HakeQuantity
%, 1 - 100
%, 101 - 250
%, 251 - 500
%, 501 - 1000
%, 1001 - 5280
Silver Hake <15 cmQuantity
1 - 100
101 - 250
251 - 500
501 - 1000
1001+
Spring 2013 Silver Hake Number Per Tow
Spring 2013 Pandalid Shrimpkg_per_tow
1 - 10
11 - 20
21 - 30
31 - 40
Spring 2013 Shrimp Number Per Tow
Spring 2013 ButterfishQuantity
1 - 10
11 - 20
21 - 30
31 - 40
41 - 50
Spring 2013 Butterfish Number Per Tow
PredatorsAtlantic codMonkfishWhite hakeRed hakeSilver hakeSea Raven
$+$+
$+$+
$+$+$+
$+
$+$+
$+
$+
$+$+
$+
#* #*#*
#*#*
#*
#*
#*
#*
#*
Fall 2012 Cod >25 cmQuantity
$+ 1
$+ 2
$+ 3
Spring 2013 Cod >25cmQuantity
#* 1
#* 2
Atlantic Cod
$+$+
$+ $+
$+$+$+
$+$+ $+$+ $+ $+
$+
$+$+$+
$+
$+ $+ $+
$+
#*#*
#*#*
#* #*
#*#*
#* #*
Fall 2012 Monkfish >25 cmQuantity
$+ 1 - 2
$+ 3 - 4
$+ 5 - 6
$+ 7 - 8
$+ 9 - 10
Spring 2013 Monkfish >25 cmQuantity
#* 1
#* 2
#* 3
Monkfish
$+ $+ $+$+$+
$+
$+$+ $+
$+$+
$+$+
$+$+$+ $+
$+$+$+ $+ $+
$+$+
$+$+
$+$+
$+$+ $+
$+
$+$+
$+
$+$+$+$+
$+$+$+
$+$+
$+$+
$+
$+ $+$+$+
$+ $+$+
$+
#* #*#*
#*#*
#*#*
#*
#* #* #*#* #*
Fall 2012 White Hake >25 cmQuantity
$+ 1 - 5
$+ 6 - 10
$+ 11 - 25
$+ 26 - 50
$+ 51+
Spring 2013 White Hake >25 cmQuantity
#* 1 - 5
#* 6 - 10
#* 11 - 25
#* 26 - 50
White Hake
$+$+$+
$+$+$+$+$+$+
$+$+$+
$+$+$+
$+$+
$+
$+$+
$+$+$+ $+
$+$+ $+ $+$+$+
$+$+ $+
$+ $+ $+$+
$+
$+
$+$+$+
$+$+$+
$+$+ $+
#* #*#*#*
#*#* #*
#*
#* #*
#*#*
#*
#*#*
#*
#*#* #*#*
#*
#*
#*
#*#*#* #*
#* #*
#*
#*#*
#*#*#*
#*#*
#*
#* #* #*#*
Fall 2012 Red Hake >25 cmQuantity
$+ 1 - 10
$+ 11 - 25
$+ 26 - 50
$+ 51 - 100
$+ 101 - 150
Spring 2013 Red Hake >25 cmQuantity
#* 1 - 10
#* 11 - 25
Red Hake
$+$+$+
$+$+$+$+
$+$+$+$+$+$+
$+$+
$+$+$+$+$+
$+$+$+$+
$+$+$+ $+
$+ $+$+$+ $+
$+$+
$+$+ $+
$+
$+$+$+$+
$+$+$+
$+ $+$+$+
$+$+
#*#*#*
#*#*#*#*
#*#*#*#*
#* #*#*#* #*
#*#* #*
#*#*
#*
#*
#* #*
#*#*
#*#*#*
#*#*
#*#*#*
#*#*#* #*
#*#*
#*
#*#*#*#* #*#* #* #* #*#*
#*
#*
Fall 2012 Silver Hake >25 cmQuantity
$+ 1 - 25
$+ 26 - 50
$+ 51 - 100
$+ 101 - 250
$+ 251 - 575
Spring 2013 Silver Hake >25 cmQuantity
#* 1 - 25
#* 26 - 50
#* 51 - 100
#* 101 - 250
Silver Hake
$+
$+
$+
$+$+
$+
$+$+$+
#*#*#*
#*#* #*
#* #*
#*#*#*
#*Fall 2012 Sea Raven >25 cmQuantity
$+ 1 - 2
$+ 3 - 4
$+ 5 - 6
$+ 7 - 8
Spring 2013 Sea Raven >25 cmQuantity
#* 1 - 2
#* 3 - 4
Sea Raven
Summary Large abundance of forage species near
shore in spring months
Overall presence of large predators is sparse and further away from the shallows
