Which of the following are “exotic species”?

Wheat in Kansas

Steelhead trout in Lake Michigan

Bluegrass in Kentucky

Zebra mussels in Lake Erie

Steps to become an invasive species…..

Disperse from native range to somewhere else

Survive in new habitat

Reproduce in new habitat

Naturalize (establish permanent population)

Become a problem (immigrant vs invasive spp)

lag phase when not know if spp will become invasive

Some conditions can promote invasiveness

Vacant “niches”: ecosystems with few species

Escape from predators and competators

Disturbance of ecosystem

Consequences of invasion: Great Lakes case study

Ricciardi et al 2001

Great Lakes Introductions increase over time

Routes of introduction

Canals (sea lamprey) alewife

Ballast water importation zebra mussels spiny water flea goby ruffe

Aquaculture and aquarium trade and intentional release carp

The Sea Lamprey(Petromyzon marinus)

Primative (jawless) fish

Native to Atlantic Ocean

Adults predatory on large fish

Probably entered Great Lakes via the Hudson River and its artificial extension, the Erie Canal (opened to Lake Ontario in 1819)

Hudson

Erie Canal

Thereafter invasion quickened; found in Lake Huron in 1932, Lake Michigan in 1936, and Lake Superior in 1946.

Gained access to Lake Erie through Welland Canal around Niagara Falls (completed 1829), but not noted in Lake Erie until 1921

http://www.glfc.org/slft.htm

Lampreys devastated lake trout populations in Great Lakes

Removal of top predator allowed smaller fish such as alewife (also introduced through canals) to boom

Lamprey control (pesticide applied to juvenile form in streams)- continues today

Coho & Chinook salmon easier to grow in hatcheries than lake trout. These exotic species were heavily stocked

Euryhaline species Traveled through canals (maybe native to Ontario)

Alewife

Population expanded when lake trout died

Efficient zooplankton eater, changed zooplankton and contribute to decline of native fish (e.g. bloater)

Lake Trout

AlewifeBloater

Whitefish

Large zooplankton Small zooplankton

Sea LampreyPacific Salmon

Phytoplankton

Ballast-mediated species Introduction

uptake

transport

discharge

Water is used for ballast, but sediments accumulate too

Can contain resting stages or live animals

Dreissenid Mussels

Ponto-Caspian origin Ballast transport First found in Lake St. Clair

Adults attach to substrate Planktonic larvae High population density High filtration rate

History

Biology

http://www.earthwave.org/zmussel.htm

Zebra mussel covering hard substrate and spreading over soft sediment in Oneida Lake, NY

Total coverage of sediments in St Lawrence Seaway

Covering hard objects

2

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1975 1980 1985 1990 1995 2000

Sec

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zebra mussels

Increase in water clarity in Oneida Lake, NY

Bay of Quinte; S. Millard, DFO

Onieda Lake; CBFS

Lake Erken; P. Eklov, Uppsala U.

Naroch Lakes chain; L. Brulakova & A. Karatayev, Austin St. U.

Western Lake Erie; S. Ludsin

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Naroch Oneida Erie Erken Quinte N Quinte B Myastro Batorino

Lake

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ebra

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pre zebra musselpost zebra musselpre zebra mussel

Some species extremely long lived, > 100 yearsDo not mature for relatively long time ~> 10 years

Dreissena and Unionid Clams

Zebra mussels encrust unionid shells. Interference competition

Populations already hurt by water quality problems and dams

Native clams usually disappear w/ in 5 yr of zebra mussel introduction

http://www.miseagrant.org/ans/zoo.html

Bythotrephes

A native of Great Britain and northern Europe

Discovered in Lake Huron in 1984

Spread to all the Great Lakes and some inland lakes.

Native Daphnia spp.

http://ebiomedia.com/gall/classics/Daphnia/feature_main.html

short vs. long spine

big vs. small body

Feeds on smaller zooplankton in the Great Lakes

May be reducing food for native plankton and fish species

http://www.miseagrant.org/ans/zoo.html

http://ebiomedia.com/gall/classics/Daphnia/feature_main.html

Which would fish rather eat??

Round Goby

Eat zebra mussels

May compete with native darters or sculpins

May consume eggs of natives (lake trout)

http://www.miseagrant.org/ans/fish.html

http://www.miseagrant.org/ans/fish.html

Eurasian RuffeEuropean perch family

discovered in Duluth harbor in 1985.

Have spread around Lakes Superior and have established a population in Thunder Bay near Alpena, Michigan.

In some areas, explosive population growth and displace native species such as y.p. and emerald shiners

Sharp spines make them difficult for larger fish to eat

Aquaculture Releases

Carp European settlersfor food and fishingwell established population

Asian CarpSouthern fish farms

Knocking on the door: Asian carp

several species, accidentally released from aquaculture facility.

~ 40 mi from Lake Michigan.

Electrical barrier in place in Chicago.

http://www.glfc.org/fishmgmt/carp.asp

Economics of electrical barrier

Construction cost?

Maintenance cost?

Will it work?

MN proposing bubble and sound curtain

57% effective

Lake Trout

AlewifeBloater

Whitefish

Large zooplankton Small zooplankton

Sea LampreyPacific Salmon

Phytoplankton

Zebra mussels

goby

Asian carp

Spiny flea

Benthic algae

Invasional Meltdown

Theory that suggests that current invasions may facilitate future invasions

Exotics don’t necessarily compete with one another, may make it easier for others to get in.

Compare to “biotic resistance” or “empty niche” theories described in reading

Prevention and Control

Prevent entry:

International trade treatiesInternational and interstate commerce

Examples: Garden plants, pets, aquarium fish, agricultural species

Shipping industry regulations

Examples: all GL species

Very difficult to predict which species will become invasive

How to decide which species cannot be imported

Eradication

Possible if detected early

Biology of species important, ex. it has slow dispersal or depends on few other spp. for survival

Long-term effort: funding for eradication program is not cut

Public support

Maintenance Control

Keep population at low level to avoid ecological damage

Some successful examples