AQUATIC EXOTICS

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Exxon Valdez Oil SpillValdez, Alaska 1989

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“By the end of the 21st century, biological invasions will

become one of the most prominent ecological issues on Earth.”

OTA Report (1993)

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• > 4,500 species established

• > 205 species arrived since 1980

• 59 might cause damage

• Control costs will approach $100 billion

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OTA Report

Infestations Are Increasing

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Interrupt the Pathways

Shipping and barge traffic Aquaculture and public stocking Wild bait harvest Recreational boats Live bait Nursery trade and aquascaping Aquarium and pet trade

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Great Lakes Exotics

• Purple loosestrife• Zebra mussel • Quagga mussel• Spiny waterflea• Fishhook waterflea

• Eurasian ruffe• Round goby• Alewife • Trout and salmon

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Eurasia 77

Atlantic 18

Asia 12

Mississippi 7

Pacific/Southern U.S. 7

Unknown 18

Total: 139

Where Did They Come From?

8(data taken from Mills et al. 1993)

Ships 41

Unintentional release 40

Multiple 27

Unknown 14

Deliberate release 11

Canals 5

Railroad/Highway 1

How Did They Get Here?

9(data taken from Mills et al. 1993)

% of Species

Plants (mostly marsh) 42

Invertebrates 21

Fish 18

Algae 17

Fish pathogens 2

What Are They?

10(data taken from Mills et al. 1993)

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Why Do Exotics Cause Problems?

Aggressive and prolific

Mature quickly

Leave behind diseases, parasites, predators, and competitors

The Good

The Bad

The Ugly

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The Good

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The Bad

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Adult Veliger

Can produce up to 1.6 M eggs/yr!

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Zebra mussel colony

Byssal

threads

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Impacts of Zebra Mussels

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• Feed by filtering particles from water• Each adult can filter 1 L water/day

Impacts of Zebra Mussels

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• Increase weed growth• Disrupt food webs

Clogged pipeClogged pipe

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Fouled boat

Impacts of Zebra Mussels

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Impacts of Zebra Mussels

Control costs in the Great Lakes = $120 million from 1989 - 1994

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Impacts of Zebra Mussels

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Spread as larvae and adults

Only 10 states with inland infested waters

Zebra Mussel

Distribution

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(WI, MI, MN, PA, IL, IN, OH, NY, CT, VT)

Lakes Erie, Ontario and Michigan

Ohio and Mississippi rivers

Quagga Mussel Distribution

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(WI, MI, IL, IN, OH, NY, CT, VT)

ID and Early Detection

Newly settled mussels feel like fine sand paper

Grow to look like coarse grains of pepper27

Cause serious damage

Industrial control is costly

No method of control in natural ecosystems

Preventing the spread is critical28

Rusty Crayfish

• Replaces native crayfish• Competes with fish• Raids fish nests• Eradicates aquatic plants 29

U.S

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Drainages with native populations

Drainages with introduced populations

Drainages with native populations

Drainages with introduced populations

• Anglers and commercial harvesters• Ballast water• Biological supply houses & schools• Life history facilitates spread

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Rusty Crayfish Spread

Rusty Crayfish ID

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• Can grow up to 8 in

• Rust spots on carapace

• Large gray-green/red-brown claws

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Rusty Crayfish

• No environmentally-friendly control method

• Preventing the spread is critical

Round Goby

• Small, strange-looking bottom fish

• Came from Eurasia in ballast water

• Considered a nuisance by anglers34

Round Goby Impacts

mottledsculpin

• Out-compete native species

• Quickly dominate local fisheries

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Round Goby Impacts

• Feed on lake trout and sturgeon eggs

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• Fused pelvic fins

Round Goby Identification

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Eurasian Watermilfoil

• Forms dense mats

• Replaces native plants

• Degrades food, shelter, and nesting sites for fish

• Limits swimming and boating 39

• Spreads by fragmentation

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Eurasian Watermilfoil

• Can be spread by recreational water users

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Eurasian Watermilfoil

U.S

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Adapted 1999 from USGS-Gainesville

States with nonnative recordsStates with nonnative records

Optimistic News

• Traditional control methods costly• Native weevil feeds on Eurasian watermilfoil

– Can cause stems to fall to lake bottom– Reduces canopy

4343

Predaceous zooplankton

Causes declines in native zooplankton– May impact fisheries

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Spiny Waterflea

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4646

Fishhook waterfleaFishhook waterflea

4747

Eurasian Ruffe

• Arrived in mid 1980s via ballast water

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• Spawn 2 – 3 times/season

• Mature rapidly

• Feed during day and night

Eurasian Ruffe

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Eurasian Ruffe Impacts

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• May compete with yellow perch

Predicted impacts of Great Lakes-wide infestation is

estimated at $105 million annually

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*

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White Perch

• Native to Atlantic coast

• Found in all Great Lakes

• Feed on zooplankton, invertebrates, and fish• Prefer shallow areas

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White Perch

• Easily confused with native white bass

• Transported to several inland lakes in Ohio

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white perch white bass

White Perch

• Can grow up to 10” long• Commonly stunted and undesired by anglers• Can have high levels of PCBs

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Threespine Stickleback

• Native to Hudson Bay, the Atlantic coast, and Lake Ontario

• Spread to lakes Superior, Michigan, and Huron

• Little known about potential impacts56

Threespine Stickleback

• May compete with native sticklebacks

• 3 or 4 spines on dorsal fin, respectively– Native sticklebacks have 5 or more spines

on dorsal fin

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Fourspine Stickleback

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Purple Loosestrife

• Perennial from Europe

• Invades moist areas

• Crowds out natives—reduces biodiversity

U.S

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Adapted 1999 from Biological Invasions by GLP

Good News!!

• 5 species approved for release

• Galerucella weevil– Feeds on leaves and growing shoots– Defoliates, reduces flowering, can kill plant

• Releases could reduce loosestrife by 80-90%60

We can make a difference!

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Three-State Exotic Species Boater Survey

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• How best to reach boaters

• Determine if boaters taking action

Source For Exotics Information

• Newspaper 92 81 84• Television 90 79 73• Magazine 75 67 74• Boat Launch 82 55 32

Minn Wisc Ohio

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How Effective Are The Following?

• Signs at Accesses 77 62 50• In Fish/Boat Regs 63 60 59• Brochures 61 57 58 • Inspection/Ed 63 52 48

Lowest Ranked • Laws 53 41 34• Road Checks 48 29 24

Minn Wisc OhioHighest Ranked

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What Influenced You Most?

• Out of “My” Lake 8888 7474 6363

• Personal Responsibility 82 63 56

• Signs at Access 68 47 31

• Prevent Property Damage 38 43 55

MinnMinn WiscWisc OhioOhio

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Why Didn’t You Take Precautions?

0 10 20 30 40 50

OhioWiscMinn

Not a Problem

Didn’t Boat in Infested Waters

Didn’t Know What To Do

Didn’t Have Time

It Won’t Help

Percent response 66

What Works?

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Survey Conclusions

• Boater education changes behavior

• Boaters believe it is important to prevent the spread of aquatic exotics

• Best information outlets are media, access signs, brochures, fishing and boating pamphlets

• Educational efforts must continue

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Education Works

Rate of inland lake zebra mussel infestations is slowing

Eurasian watermilfoil infestation rate has slowed

Eurasian ruffe have not spread to inland lakes

Round goby spread to inland waters is limited

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Prevent the Spread

• Know how to identify exotics

• Know which waters are infested

• Know the laws concerning prohibited exotics

• Learn the five simple steps to prevent spread

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Prevent the Spread

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BEFORE launching….. BEFORE leaving

1. Remove aquatic plants and animals.

2. Drain lake or river water.

3. Dispose of unwanted live bait.

4. Rinse equipment with high pressure or 104 F water.

OR

5. Dry everything for at least 5 days.

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Written and produced by

Doug Jensen and Jeff Gunderson

2001

With support from:

Editors: Glenn Kreag, Sharon Moen, Marie Zhuikov, and Pat Charlebois

Digital Production Coordinator: Debbie Bowen

Funding for this project was provided by a grant from the U.S. National Oceanic Administration to the National Sea Grant College Program through an

appropriation by Congress based on the National Invasive Species Act of 1996.