Integrated Pest Management of Invasive Fish:Common Carp

Peter W. Sorensen, Przemek Bajer & Lab

University of MinnesotaDept. of Fisheries, Wildlife, and Conservation Biol.

This Talk

Invasive Fish Integrated Pest Management The sea lamprey Introduction to the common carp Integrated, sustainable control An hypothesis and approach An example in North American Midwest Questions?

The world’s ‘worst’ invasive fishes

North America

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Conventional Control Toxins/ draw-downs/ trapping (mass mortality)

Often unsustainable, damaging (nontargeted) Often not possible (ex. Asian carp)

RotenoneTFM

Integrated Pest Management (IPM)Control of a species using a collection of techniquesthat target specific biological attributes in an economically, socially and ecologically viablemanner that is sustainable over the long-term.

-Specialized biochemistry and physiology-Mechanistic behaviors and life histories-Short generation times

Integrated control of fish(2 species)

The sea lamprey

Sea lamprey invasion triggered collapse of the Great Lakes fisheries…

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1930 1940 1950 1960 1970 1980 1990Year

wild lake trout - MI

Lake Superior

lampreyenter lake

?

Herculean Searchfor larvicide

• 6000+ compounds tested• 3-trifluoromethyl-4-nitrophenol (TFM ) found

Early focus on barriers

Life History

Deployment of Lampricides

$1.5 million for treatments each year

$3 million assessment

Search for an integrated program

New Poisoning Techniques New barriers

Sterile males??

??

New traps

Population Models

Summary: Sea Lamprey Control

1. Complex mix, designed to enhance TFM2. An open system but a simple and ‘unusual’

creature.3. A qualified success Many native fish have returned BUT Costs high TFM is still the backbone.

The common carp-a teleost-oviparous-long-lived-physiologically resilient

A fish from shallow seas in central Asia…

Invasion Perpetuated by Man

Catholic Church

The Romans

U.S. Fish Commission-stocking Australia

Fish farming

Global but especially damaging in a few places

Adult carp destroy habitats and water quality

Algae bloom

Plantsdecline

Nutrients (N, P)

‘Bio

logi

cal p

ump’ X

Shading

Uprooting

200410 kg/ha

2006100 kg/ha

2008250 kg/ha

Damaging to Plants, Waterfowl and Fish

Carp Biomass

Hennepin-Hoper Lakes, IL after carp invasion

Extant Control Techniques-Mix of unselective removal & exclusion techniques-Expensive, usually unsustainable

- VARIABLE RESULTS

Rotenone

Adult seining

Water Draw-downs

Electrical Barriers

Seining

Drawdowns

Carp seperation cages

Integrated Carp Managementin Tasmania

A Closed population in a sensitive lake with low biodiversity

Monthly carp captures from Lake Crescent February 1995 - November 2003

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Total of 7753 carp removed and processed. Population estimates

than 20 females remain

‘Judas males’ to capture aggregations

Spawning sabotage using traps and lime

10 years, 2 million dollars

Now down to few females…

Adult removal and spawning sabotage

Summary: Carp in Tasmania

Simple, clever combination A closed system with sensitive species Qualified success Suppressed but not extirpated No poisons used What if they are introduced again Very expensive

Overarching goal:‘To develop biologically and economically sound

plans for controlling carp in MN lakes over the long-term by exploiting its life history*’

* not known!

Integrated Control of Carp inMinnesota , 2005-

Initial Sub-Objectives 1.Do carp use pheromones, and might they be useful?

2.Do carp have specific aggregate for spawning or other reasons and might they be targeted?

3. Is carp abundance attributable to specific factors that might be targeted (population dynamics*)?

* Models but shockingly little data!

1. PheromonesChemical signals that pass between organisms of the same species (Karlson & Luscher 1959, Sorensen & Wyatt 2000).

O

OH

O

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OS

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OHßOH

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O

O

Female PGF pheromone attracts carp to traps in the field (Li & Sorensen)

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n nu

mbe

r of f

ish

in th

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nge

(+SE

)

Distance from a trap (m)

ImplantBlank

P = 0.01

Mean distance from a trap• Implant: 28.97 ± 2.80 m (N = 27)• Blank: 38.54 ± 2.19 m (N = 12)P < 0.01

COOH

OH

OH O

Sorensen and Li, unpublished

2. Spawning, can it or other aggregations be sabotaged?

Radio-tracking 80 adult carp during spawning season in a system of interconnected lakes and marshes

Weak spawning site preferences (and strong propensity to migrate and then return)

Spawning sabotage not reasonable

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Bajer & Sorensen (2010)

Aggregations in Winter(targetable?)

3. Why are there so many carp? (and can we do something about it)

Numbers

Ages

LakeSamplingsessions Marked Recaps

Population Estimate(95% CI)

Biomass(kg/ha)

Dutch 11 2088 122 13,312 (11,300 – 16,100)

371*

Echo 13 929 72 5,666(4,605 - 7,361 )

326

Susan 11 361 15 4,459(5,700-3,661)

307

ABUNDANCE

*150 kg/ha is considered damaging

Recruitment: highly sporadic in MN

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Num

ber o

f car

pSusan & Marsh winterkill

? ?

Marsh winterkills

Marsh winterkills

Marsh winterkills

Rem

oval

of c

arp

and

BH

Bajer and Sorensen; Biol Invasions 2009

Why winterkill?Lakes that winterkill are unstable, lack predators that otherwise eat carp eggs and larvae….

Summer-time unstable nursery habitats(Australia)

Test-1: Carpsim shows winterkill can explicitly explain the densities we measure

YOY carp presentNo YOY carp present

> 200 / net

> 130 / net

Test-3: When we stock lakes with fertilized carp eggs, eggs are eaten in normoxic lakes

but NOT normoxic lakes (PB)%

Sur

viva

l to

hatc

h da

y

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Open Control Coarse mesh

normoxic

hypoxic

A Model of Invasiveness

Riley

Susan Marsh

Recruits?R

ecruits?

Nursery

Adult Refuge

Adult Refuge

Bajer and Sorensen 2010

Integrated Carp Control in MN

I. Diagnosis problem and establish goals

II. Treat carp based on Population Dynamicsa. Remove a critical number of adultsb. Suppress recruitment (and/or spawning)c. Suppress emigration (if necessary)

III. Monitor and Model

IV. Adapt

A ‘Typical’ Example:Riley Creek Chain of Lakes

http://www.bwsr.state.mn.us/publications/WD_Guidebook/RileyPurgatory.pdf

RICE MARSH

ANN

SUSAN

RILEY

Lucy

1. Targeted removal of adult carp: Judas fish2008 – population estimated: 4,181 carp (Lake Susan)

January 2009 – Judas fish 3278 removed (78%)

January 2010 183 removed

April 2010 138 removed (at the carp barrier) 590 remain in the lake (15% of original)

2. ‘Monitoring’ fish movement (with an aim to controlling recruitment)

Construct simple ($100) fish gate to ensure no carp movement

3. Monitor and Suppress RecruitmentAerate nursery, encourage game-fish, monitor

RESULTS: Carp Abundance

So far, effective + no signs of recruitment…

Carp movement is predictable and stoppable

Date

4.1.20

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4.7.20

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Carp Pike TemperatureDepth (cm)

Rain event

Results: Aquatic vegetation recovered

Before removalAfter removal

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Results: Water clarity improvements in L. Susan

Before removal

Sources: MPCA, UofM

2010

1. Three components (at present):-recruitment, immigration, adult removal

2. Works well in moderate sized, semi-closed lakes3. A success (so far):

- Large sustainable drop in carp density- Substantial increase in water quality- No poisons- Affordable- Well received

4. Could be improved and expanded… (barely touched)5. The common carp system is suitable for experiments

Integrated Pest Management in Minnesota

SUMMARY:

1. IPM can work! 2. It likely must focus on recruitment, density

dependence.3. It will be situation specific (species, locale, scales)4. Solid biological foundation is still needed5. Modeling is useful esp. if good data exists6. It can /should set the stage for more sophisticated and

diverse techniques such as genetic control.

FUNDING

Riley Purgatory Bluff Creek Watershed DistrictRamsey Washington Metro Watershed District

Test-2: ‘We’ now often find age-0 carp in hypoxic lakes, but never in normoxic lakes (PB)

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Normoxic N=13

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age

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E) c

atch

per

trap

net

Removal of carp in Lake Riley 94% population removed using Judas fish on 3/5/10

Recruitment following winterkill is common(ex. Lake Echo)

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TREATING: Riley Chain of Lakes

Population*

MORTALITY!

Immigration* Emigration

SpawningHatchingEgg sac resorption

Growth

Prevent/ control winterkill to enhance predation*

monitor

* = Monitor

Recruitment*

2) However, not all carp need be removed?(to improve water quality)

Is 100 kg carp /ha a threshold for severe

damage in shallow lakes?Bajer et al. 2009

L. Susan!

?

Hennepin Hoper Lakes, IL, USA

Lake Keller (refuge lake with Bluegills)

RESULTS:- eggs ‘disappear’ within 3 days (prior to hatch)- 1000’s of eggs in bluegill sunfish guts

- SUMMER: No young carp found in Lake

Bluegill Predationin Lake Keller

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Keller Lake Trap Catch

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Population Dynamics!

Population

Mortality

Recruitment*

Immigration Emigration

* Survival of fertilized eggs to adulthood

SpawningHatchingEgg sac resorbtion

Growth

A dashed line signifies intermittency

1. Remove a critical targeted number of adult carp

Tracked carp aggregation in January under ice n corner Seined and removed 3278 carp, over 20,000 lbs (78% of population) Biomass reduced from 307 lbs/acre to 90 lbs/acre

Winter seining – Lake Susan

Reduction in carp biomass

Wat

er q

ualit

yTurbid water

Clear water

Many ways to control abundance(the best will address the local situation)

Population

MORTALITY

Recruitment*

Immigration Emigration

SpawningHatchingEgg sac resorbtion

Growth

Winter 2008/2009:-78% of the population in Lake Susan- 35% of population from Lake Riley

Winter/summer 2009, repeat at critical level:- Ongoing

1. Remove Critical Number of Adult Carp

2008/2009: Temporary ($100) barriers to stop spawning carp moving into winterkilled marsh (other fish passed)

2. Control winterkill effects, Phase I:

Monitoring Temp Barrier

Life HistoryEggs

???

??????

2. They move: Approximately 1/3 of adult carp move in/out wetlands to spawn (ex. Riley-Susan-Marsh)

Study lakesStudy lakes

Echo

Dog

Dutch

Susan, Rice Marsh, Riley

Olfaction plays a critical role in carp sexual behavior

Monitored for 1 hr

N = 7 pairs

Spawning activity

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Nose-plugged Sham control

Male carp treated

# sp

awni

ng a

ct /

min

(mea

n +S

E)

P < 0.01

Study 1 Hypothesis: The abundance of age-0 carp will

be higher in hypoxic lakes which have lower density of predatory fishes that forage on carp eggs and larvae

Study Design – step 2 Mortality of carp eggs determined in 2 normoxic and 2

hypoxic lakes

2-4 Carp spawning areas located in each lake Carp eggs attached to yarn floats In each area we placed:

8 in open water (fish + invertebrates) 4 in coarse mesh bags (invertebrates only) 4 in fine mesh controls Counted daily until hatching

Diet of native fishes examined in one normoxic lake

Invasive Species ‘an alien [nonnative / exotic / introduced] species whose introduction does or is likely to cause economic or environmental harm

or harm to human health’

(President Clinton’s - Executive Order 13112)