let’s prevent a flea circus: stopping minnesota’s invasion by … · hatch partial hatch 9...

Let’s Prevent a Flea Circus: Stopping Minnesota’s Invasion by Spiny Water Flea

Donn K. Branstrator (University of Minnesota Duluth) dbranstr@d.umn.edu; 218-726-8134

September 12, 2016

1 cm

Native

Believed vector - cargo ship ballast water from Baltic Sea.

First appearance in North America - 1980s in Great Lakes.

Non-native

Kerfoot et al. (2011)

Now spread to 150-200 inland lakes.

About 35 Minnesota lakes infested

Minnesota Invasion Timeline

Year

1990 1995 2000 2005 2010 2015

0

10

20

30

40

Cum

ula

tive n

um

be

r of

invaded lakes

6 of top 10 largest inland lakes

Presentation Outline

A) Bythotrephes biology

B) Management-relevant research on mitigating spread 1) What we know (completed project)2) What we don’t know (future project)

C) Management-relevant research on ecosystem impacts

Bythotrephes longimanus

1) Bythotrephes is neither a flea nor an insect.

Crustacean : Freshwater and marine group that includes crayfish and shrimp.

Freshwater Zooplankton: Small-bodied animal that lives in the open waters of lakes.

2) Bythotrephes’ long, stiff tail spine is a novelty among freshwater zooplankton in North America.

Fish < 10 cm body length have trouble eating Bythotrephes.

Larger fish eat Bythotrephes but the spine may slow gut passage and injure gut lining.

Cisco Stomach Photo by B. Clarke

3) Bythotrephes’ reproductive strategy is seasonally adaptive.

For most of the summer, females produce females through clonal (asexual) reproduction.

1-2 weeks to go from egg to egg

Stage 1 Stage 2 Stage 3

Gravid female A single female could theoretically colonize a new lake.

In the fall, females make males and mate with them. The result is a resting egg that lies dormant during winter months, and hatches the subsequent spring.

Phytoplankton

Bythotrephes

Planktivorous

Fish

Piscivorous

Fish

Herbivorous

Zooplankton

4) Bythotrephes is a carnivore that disrupts food webs at mid trophic levels; how does this cascade to

other trophic levels?

In lakes of Voyageurs National Park, herbivorous zooplankton biomass declined 40-60% after Bythotrephesinvaded (Kerfoot et al. 2016 ).

?

?

40-60%

A) Bythotrephes biology

B) Management-relevant research on mitigating spread 1) What we know (completed project)2) What we don’t know (future project)

C) Management-relevant research on ecosystem impacts

Bythotrephes longimanus

3-Step Firewall

Small and cryptic nature places premium on

drying

Harvest resting eggs (Sep-Oct) from wild-caught females.

1) Apply Stressor - 48 eggs per treatment (about 5,000 eggs over 3 years) – mimic a decontamination event

2) 4 month incubation simulating winter (dark, 3-4°C)

3) Temperature cue simulating spring overturn

4) Score hatching after 5 more months.

General Experimental Protocol to Test Drying and Other Stressors

Hatch

Partial hatch

9 months to complete an experimental

trial

Perc

enta

ge h

atc

h o

r part

ial hatc

h

0 15 25 35

2 weeks exposure

4 weeks exposure

Salinity (ppt)

control

control

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SalinityOcean water

concentration is non-lethal.

Hatch

Partial hatch

0

Chlorine (ppm)

Perc

enta

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atc

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h

1 hour

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data

controlcontrol

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data

5 mincontrolcontrol

controlcontrol

1 min

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data

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1 day

no

data

controlcontrol

Chlorination

Recipe strength on CLOROX container is

non-lethal.

Hatch

Partial hatch

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Perc

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Temperature (°C)

10 min

5 min

1 min

4 40 50

control

control

control

*

Heat

Hatch

Partial hatch

Implications for:

- Clean, drain, dry (50°C)

- Avian vectors (40°C body temperatures).

The lethal exposure is between 40-50 C for longer than 1 minute.

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Perc

enta

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atc

h o

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0 0 0.5 1 3 6 8 10 12 24

Drying time (hours)

2 4

Drying

Short-term drying works.Hatch

Partial hatch

We don’t know which recreational pathways pose the highest risk to overland transport.

Understanding the relative risks of angling equipment, watercraft hulls, anchors, versus live wells may improve the outreach message.

We don’t know if lake usage during different periods of day poses different risks of transfer.

Day versus night

0.03 0.06 0.09 0.12 0.150.03 0.06 0.09 0.12 0.15 0.03 0.06 0.09 0.12 0.15

0.03 0.06 0.09 0.12 0.15 0.03 0.06 0.09 0.12 0.15

2200 h

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Dep

th (

m)

0.00 0.03 0.06 0.09 0.12 0.15 0.03 0.06 0.09 0.12 0.15 0.03 0.06 0.09 0.12 0.15

1000 h 1400 h 1800 h

200 h

0.03 0.06 0.09 0.12 0.15

600 h

Number L-1

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0.00 0.03 0.06 0.09 0.12 0.15

Dep

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0.03 0.06 0.09 0.12 0.15 0.06 0.12 0.18 0.24 0.30

Number L-1

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0.03 0.06 0.09 0.12 0.15 0.03 0.06 0.09 0.12 0.15 0.03 0.06 0.09 0.12 0.15 0.03 0.06 0.09 0.12 0.15 0.03 0.06 0.09 0.12 0.15

Number L-1

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% Surface Irradiance

Stage 1

Stage 2

Stage 3

July 14-15

Increased Export Risk

August 27-28

September 2-3

Increased Export Risk

Increased Export Risk

Island Lake Reservoir, Duluth, Minnesota, 2004

A) Bythotrephes biology

B) Management-relevant research on mitigating spread 1) What we know (completed project)2) What we don’t know (future project)

C) Management-relevant research on ecosystem impacts

Bythotrephes longimanus

• Collect and section sediment core.• Date core sections (Lead-210).• Reconstruct past food web based on zooplankton subfossil remains.

What are the long-term impacts (magnitude and timing) of Bythotrephesinvasion on zooplankton, phytoplankton, and fish?

Paleolimnology

47.00

47.05

Longitude (oW)

Lat

itu

de

(oN

)

92.20 92.15 92.10

1

2

N

3

4

1 km

°

In 2009-2010 we studied sediment cores from Island Lake Reservoir, Duluth.

0

1000

2000

3000

4000

1970 1980 1990 2000 20100

1000

2000

3000

4000

Site 1

Site 2

Site 3

1970 1980 1990 2000 2010

Site 4

B. lo

ng

ima

nu

s a

ccu

mu

latio

n

rate

(sp

ine

s m

-2y

-1)

Estimated Year (210Pb)

Bythotrephes was first detected by anglers in 1990.

Bythotrephes was first present in the sediments in 1982.

Site 2

D. retrocurva

D. pulex

D. mendotae

1970 1980 1990 2000 2010

Daphnia

spp.

accum

ula

tion r

ate

(ephip

pia

m-2

y-1

)

Estimated Year (210Pb)

6000

4000

2000

0

Prey of Bythotrephes shifted in species composition but not until Bythotrephesreached a carrying capacity (about 15 years post-invasion).

Phytoplankton

Bythotrephes

Planktivorous

Fish

Piscivorous

Fish

Herbivorous

Zooplankton

How do changes wrought by Bythotrephes cascade to higher and

lower trophic levels in Minnesota lakes, and what is the timing of these events?

MAISRC funded paleolimnology project collaborative with the Minnesota DNR (fish data).

Study lakes:Kabetogama *Infested 2007Mille Lacs *Infested 2009Leech *Non-infested Winnibigoshish *Non-infested

?

?

AcknowledgementsAshley BeranekMeghan BrownDan EngstromKatie HeimgartnerLeif HembreMarte KitsonAmy MyrboEuan ReavieDoug RickettsLyle ShannonMike SorensenMatt TenEyck