Zooplankton Community Composition along a Longitudinal Gradient of Invasive Asian Carp Densities in

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Zooplankton Community Composition along a
Longitudinal Gradient of Invasive Asian Carp
Densities in the Illinois River
Anthony Erickson and Greg G. Sass Ph.D
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Background Information

• Silver and bighead carp were introduced into the
  Mississippi River watershed in the early 1970s.
• Silver and bighead carp are voracious
  planktivores.
• The introduction of these Asian carps pose a
  serious risk to native ecosystems.
• Most fishes rely upon plankton for sustenance
  during early life stages.
• Examples of a few planktivorus native fish
  species that may be under pressure from
  competition with Asian carps (Iron et al 2007).
• Bigmouth buffalo (Ictiobus cyprinellus)
• Paddlefish (Polyodon spathula)
• Gizzard shad (Dorosoma cepedianum)

www.tnfish.org
www.ohioriverfdn.org
www.museum.state.il.us
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Silver Carp
David Riecks UIUC/IL-IN Sea Grant
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Bighead Carp
David Riecks UIUC/IL-IN Sea Grant
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Silver and Bighead Carps

• silver carp
• Hypophthalmichthys molitrix
• Minimum Filtration Size 4µm
• Leaps from the water when disturbed, posing a
  threat to boaters.
• Has a ventral keel that runs all the way to the
  throat.
• Capable of consuming 2 to 3 times its body
  weight in plankton everyday (www.fws.gov).
• Can sustain itself on detritus.

• bighead carp
• Hypophthalmichthys nobilis
• Minimum Filtration Size 20µm
• Ventral keel runs from the anus to the base of
  the pelvic fins (Pflieger 1997.)
• Consumes a larger proportion of zooplankton than
  silver carp (Davis.)
• Will not leap when disturbed.

http//www.jjphoto.dk/fish_archive/a_intro12.htm
Pubs.usgs.gov
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Silver and Bighead carps cont.

• Both fish grow quickly enough that they out grow
  most natural predators in a short amount of time.
• Capable of hybridizing in the wild.
• Asian carps are capable of producing millions of
  eggs per spawn, and spawning may occur multiple
  times per season based on flood pulses and other
  cues.
• Asian carps are Cyprinids, which means they are
  essentially very large minnows.

• Gill Rakers- mechanism by which silvers and
  bigheads filter organic particulate matter.
• Silver carp gill rakers are fused together with
  a sponge like appearance.
• Bighead carp gill rakers appear striated, like
  fingers on a comb.

fisc.er.usgs.gov
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Zooplankton Facts

• Zooplankton Microscopic invertebrates
• Can be found in the worlds oceans and almost any
  freshwater habitat.
• Most zooplankton are filter feeders, feeding on
  bacteria and phytoplankton. Others are
  carnivorous and consume smaller zooplankton
  (www.srel.edu)
• Zooplankton can reproduce very rapidly. Some
  accounts state that they can increase population
  by 30 in one day of favorable conditions
  (www.srel.edu)

www.sea-ex.com
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Copepods
Most Common Zooplankron Observed
Cyclopoid
Rotifers
Cladocera
Daphnia
Brachionus
www.essentiallivefeeds.com
Harpacticoid
Cyclot.hp.infoseek.co.jp
www.wilsonlab.com
Bosmina
Keratella
Nas.er.usgs.gov
Calanoid
Microworld.ddo.jp
www.notcot.com
Conochilus
Sida
www.fredrikstad.kommune.no
Naupili
www.cladocera.de
Cyclot.hp.infoseek.co.jp
www.environmentalleverage.com
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Objectives

• Collect zooplankton samples and water quality
  data from 6 reaches of the Illinois River over a
  4 week period.
• Analyze zooplankton samples for species
  composition and zooplankton abundances.
• Analyze data from archived historical samples
  prior to Asian carp establishment
• Compare data from samples taken in the La Grange
  Reach summer of 2009 with pre-invasionarchived
  samples.
• Hypothesis Higher densities of Asian carp will
  have a negative influence on zooplankton
  density. Pre- invasion zooplankton densities and
  community composition will be different than
  post-invasion zooplankton populations in La
  Grange Reach

Nerissa Micheals
Electroshocking near Rm 121.1 Havana Il by INHS
I.R.B.S staff
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Field Methods
Dresden
Peoria

• Two filter sizes were used for this study 55µm
  and 20µm.
• 30 liters of river water were pumped through the
  55µm filter mesh sampled from the entire water
  column
• Same methods used for collection of 2009 samples
  as historical samples.
• Only one 20µm sample was taken at each site
  fromonly 3.6L of water.
• Samples were then preserved in 10 buffered sugar
  formalin for later analysis in the lab.
• Each sample was dyed with a Rose Bengal
  concentrate to make zooplankton more visible.

La Grange
Marseilles
Alton
Starved Rock
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Lab Methods

• A concentrate volume of 25-30 ml of water was
  made from the original sample.
• 5ml sub-sample vol. for 55µm samples
• 1.139 ml sub-sample vol. for 20µm samples (vol.
  req. to close Sedgwick-rafter counting cell.)
• 55µm samples were counted using a zooplankton
  counting wheel and 20µm were counted with a
  Sedgwick-rafter counting cell.
• Sub-samples were taken until at least 100
  zooplankton were enumerated.
• Total counted from sub-sample(s) is then
  extrapolated into a zoop./L estimate for each
  particular sample.

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La Grange Reach of Illinois River

• Bighead carp

• Silver carp

Silver carp catch increases exponentially from
1998 on
First Silver caught LTRMP (1998)
First Bighead caught LTRMP
Irons, Kevin
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Mean Zooplankton Concentrations
55µm Samples
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Community Composition of the Illinois River
6/2/09 7/1/09
Alton
La Grange
Peoria
Starved Rock
Marseilles
Dresden
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Pre-invasion La Grange VS. Post-Invasion
Archived Samples
La Grange 09
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Community Composition by Year La Grange Reach
1994
1995
1996
1997
1999
2009
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Large Bodied Zooplankton VS. Small Bodied.
Historical Comparison
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Results

• The lower 4 reaches of the Illinois River have a
  zooplankton community dominated by small bodied
  rotifers and copepod nauplii.
• The upper two reaches showed overall higher
  concentrations of large bodied cladocerans and
  copepods.
• Overall, the lower three reaches had
  significantly greater concentrations of
  zooplankton (t-test n 54 df 52 t 4.04 p
  lt 0.001).
• Peoria - 87.1 zoop/L
• La Grange 81.3 zoop/L
• Alton 80.3 zoop/L
• Dresden 49.8 zoop/L
• Marseilles - 50.9 zoop/L
• Starved Rock 34.3 zoop/L
• The archived samples (La Grange reach) had a
  greater mean zooplankton (161.7 Zoop/L)
  concentration in the late 1990s compared to 2009
  (81.3 Zoop./L).

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Results cont.

• Archived data showed a zooplankton community that
  changed over time.
• Dominant Zooplankton
• 1994 Copepods
• 1995 Cladocerans
• 1996 Copepods
• 1997 Copepods
• 1999 Rotifers
• 2009 - Rotifers
• All 20µm samples consisted of 99 rotifers.

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Discussion

• My data suggests that silver and bighead carps
  may be influencing Illinois River zooplankton
  populations.
• The lower three reaches had overall higher
  concentrations of zooplankton than the upper
  three reaches, which is in contrast to my
  hypothesis.
• Zooplankton community composition changed along a
  gradient of Asian carp densities.
• High Asian carp abundances Community dominated
  by small bodied zooplankton
• Lower Asian carp abundances Community with
  greater proportions of large bodied copepods and
  cladocerans, but still dominated by rotifers
• Pre-Asian carp invasion mean zooplankton
  concentrations were greater than post-Asian carp
  invasion mean zooplankton concentrations
  suggesting that Asian carps or other abiotic and
  biotic factors led to this decline.
• Pre-Asian carp invasion zooplankton community
  composition (all historic years analyzed) was
  dominated by large bodied copepods and
  cladocerans, whereas the post-invasion community
  is dominated by small bodied rotifers and copepod
  nauplii.

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Discussion cont.

• 1997 may be a transitional year where larger
  bodied zooplankton concentrations were negatively
  affected by Asian carps.
• Asian Carp may influence communities by consuming
  larger quantities of large bodied copepods and
  cladocerans.
• This may result in communities dominated by small
  bodied zooplankton.
• Changes in community composition in the archived
  samples among years may suggest that other
  abiotic and biotic factors besides Asian carps
  may influence zooplankton populations.
• A more comprehensive study of zooplankton
  community composition changes in the Illinois
  River is suggested.
• Future studies should test for zooplankton
  community and concentration changes at smaller
  spatial scales under more controlled conditions
  to isolate mechanisms (e.g. mesocosm).

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Acknowledgements

• I would like to thank NGRREC for offering me this
  opportunity, the entire staff at the I. R.B.S.
  for all of their support throughout my project,
  and special thanks to Lori Soeken-Gittinger,
  Blake Ruebush, Thad Cook, Eric Hine, Matt O
  Hara, Kevin Irons, Mike McClelland, Nick
  Bloomfield, Merril Foster, and Kyle Hopps for
  their assistance with my study.

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Questions?