Jeremy S. Collie Joseph Langan, and Joseph Zottoli ... · Long-term Changes in the Fish Community...
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Long-term Changes in the Fish Community of Narragansett Bay Jeremy S. Collie Joseph Langan, and Joseph Zottoli Graduate School of Oceanography University of Rhode Island
Transcript of Jeremy S. Collie Joseph Langan, and Joseph Zottoli ... · Long-term Changes in the Fish Community...
Long-termChangesintheFishCommunityofNarragansettBay
JeremyS.CollieJosephLangan,and
JosephZottoliGraduateSchoolofOceanography
UniversityofRhodeIsland
Outline
v IntroductiontotheGSOfishtrawlsurveyvObjectivesandsamplingmethods
vHowhastheNarragansettBayfishcommunitychanged?v IndividualSpeciesAbundanceandBiomass
vSpeciesGroups
vWhyhastheNarragansettBayfishcommunitychanged?
vPhenology:timingoftheseasonalmigration
vComparisonwithneighboringestuaries
vWhatwillthefuturebring?
GraduateSchoolofOceanographyFishTrawlSurvey
Objectives:v Monitortheseasonalmovementoffishandinvert-ebrates inNarragansettBay
v Understandtheannualandlong-termvariationinthefishcommunity
v Examinehowthechangingenvironmenteffectsfishpopulations
http://www.gso.uri.edu/fishtrawl
URI/GSO
TheGSOFishTrawl– SamplingMethods
WhaleRock
FoxIsland
v Onceperweeksince1959v Over2800samplingeventsv 2sitesinNarragansettBay
v Inner Bay (Fox Island)v Outer Bay (Whale Rock)
v Hydrographicprofilesv Temperaturev Salinityv Dissolved oxygen
v Abundance,weightandsizeoffishandinvertebrates
ChangesinSpeciesCompositionbySpeciesGroup
1959 1966 1973 1980 1987 1994 2001 2008 2015
Demersal Invertebrate Pelagic Squid
0.00
0.25
0.50
0.75
1.00Fox Island (Inner Bay)
Year
Pro
porti
on o
f cat
ch
ChangesinSpeciesCompositionbySpeciesGroup
1959 1966 1973 1980 1987 1994 2001 2008 2015
Demersal Invertebrate Pelagic Squid
0.00
0.25
0.50
0.75
1.00Fox Island (Inner Bay)
Year
Pro
porti
on o
f cat
ch
1959 1966 1973 1980 1987 1994 2001 2008 2015
Whale Rock (Outer Bay)
TimeTrendsinAbundanceofTop25Species
ButterfishLong finned squidLady crabAlosa spp.Cancer crabScupFourspot flounderStriped searobinLobsterSpider crabSummer flounderBluefishLittle skateWeakfishAtlantic HerringRed HakeTautogSilver HakeHorseshoe crabSea starWinter flounderNorthern searobinWindowpaneLonghorned sculpinCunner
-0.2 -0.1 0.0 0.1 0.2
Rate of increase
0.01 1 100
Fox IslandProportional change
1960 1980 20000
100
200300
Winter flounder
1960 1980 20000123456
Tautog
1960 1980 20000
50
100
150
Silver Hake
1960 1980 20000
102030405060
Lobster
1960 1980 20000
100200300400500
Cancer crab
1960 1980 20000
50100150200250300
Long finned squid
1960 1980 200002468
1012
Summer flounder
1960 1980 20000
100200300400500
Scup
1960 1980 20000
100200300400
Butterfish
Year
Ann
ual m
ean
catc
h pe
r 30-
min
tow
Commonspecies Fox Island (Inner Bay)Whale Rock (Outer Bay)
CommunityMetrics
200
400
600
800
1000
1960 1970 1980 1990 2000 2010
Mea
n ca
tch
per t
ow
Total Numbers
1960 1970 1980 1990 2000 2010
13
14
15
16
17
18
19
Spring-Summer SST
Tem
pera
ture
(°C
)
11
12
13
14
1960 1970 1980 1990 2000 20101960 1970 1980 1990 2000 2010
Year
Inner Bay (Fox Island)
Pre
ferre
d te
mpe
ratu
re (°
C)
10.0
10.5
11.0
11.5
12.0
12.5
13.0
1960 1970 1980 1990 2000 2010
Outer Bay (Whale Rock)
Pre
ferre
d te
mpe
ratu
re (°
C)
Fox Island (Inner Bay)Whale Rock (Outer Bay)
SpeciesCompositionbyTemperaturePreference
1959 1966 1973 1980 1987 1994 2001 2008 2015
15-30 13-15 10-13 7-10
0.00
0.25
0.50
0.75
1.00Fox Island (Inner Bay)
Year
Pro
porti
on o
f cat
ch
Temperature preference in °C
SpeciesCompositionbyTemperaturePreference
1959 1966 1973 1980 1987 1994 2001 2008 2015
15-30 13-15 10-13 7-10
0.00
0.25
0.50
0.75
1.00Fox Island (Inner Bay)
Year
Pro
porti
on o
f cat
ch
1959 1966 1973 1980 1987 1994 2001 2008 2015
Whale Rock (Outer Bay)
Temperature preference in °C
TotalBiomassbySeason
1995 2000 2005 2010 20150
500
1000
1500
2000
2500
3000
biomass$Year
Inner Bay (Fox Island)
1995 2000 2005 2010 2015
1000
2000
3000
4000
biomass$Year
Outer Bay (Whale Rock)
Year
Bio
mas
s (u
nit?
)
Winter (November to April)Summer (May to October)
Total consumer biomass is increasingly concentrated in the summer months.
ComparisonwithOtherEstuaries
Bell et al. (2014) ICES Journal of Marine Science
Winter flounder Summer flounder
TheBostonGlobe13November2007 WaterColumn:
v Lessalgae(chlorophyll)v Moreconsumption
-Pelagicfishandinvertebrates
SeaFloor:
v Lessfood(algae)tosupportdemersalfishv Competitionforlimitedresources
-BenthicInvertebrates
SummaryandConclusions
v Totalabundanceandbiomassoffishandinvertebrateshasremainedfairlyconstant;
v Speciescompositionshiftedfromfishtoinvertebratesandfrombenthictopelagicspecies;
v Temperatureincreasedby~2°Csince1959;v Thepreferredtemperatureofthefishcommunityhasincreasedtokeeppacewiththewatertemperature;
v Totalconsumerbiomassisincreasinglyconcentratedinthesummermonths;
v Speciesphenologyisshiftingevenmorethantemperaturewouldsuggest.
TheFuture…
v Continuedchangesinfishdistributionandutilizationofprimaryproduction
v Emergingfisherytargetspecies- PelagicSpecies:Butterfish,Scup,Squid- BenthicInvertebrates:JonahCrab,Whelk,BlueCrab- WarmWaterSpecies:BlueCrab,Spot,Croaker
TimingoftheSeasonalMigration
Summer flounder arrives earlier and stays later, occupying cooler temperatures.
Questions?
