Unit 3: Invasive Species

Criteria

Must be non-native to the ecosystem, AND whose introduction causes or is likely to cause economic, environmental, or human health harm.

Lionfish

Native to Carribean; now in Georgia and Florida; outcompeting native species; hunting competitions to control population.

Nutria

Native to S. America; spread mostly through South US; hunting competitions.

Northern Snakehead (Fish) 

Spread to Maryland; moved across land and ponds. 

Burmese Python

Released pet; predominant everglade predator; hunting challenge.

Brown Tree Snake

Big problem in Guam; eating all the native birds.

Great Lakes and Invasive Species 

SOOOO many invasive species; easy or them to move between lakes via channels.

Lamprey

Tanking native trout population.

Accidental releases…

Aquaculture (brown trout); aquarium trade (oriental whitefish) 

Transportation

Navigation channels (alewife); ballast dumping (zebra mussels)

Range Expansion

White perch

Zebra Mussels 

Latch onto hard substrate; quaga new species and can latch onto anything; clog pipes; move when boats are moved 

Zebra Mussels Biological Impacts

Planktonic larvae, high filtering rate, attach to hard surfaces.

Round Goby

Benthic, voracious (eats zebra mussels), spawn multiple times a year, males guard nest, move offshore in winter.

Ballast Dumping Impacts

Motted Sculpins (Calumet Harbor); Logperch (St. Clair River); Sturgeon Eggs (St. Clair); Zebra Mussels (all over); Invertebrates (Calumet) 

Main Concerns with Invasive Species

Impact on native species and mobilization of toxic materials from sediments.

Bioaccumulation

Materials that accumulate in organisms as a result of feeding.

Biomagnification 

Materials that are concentrated at higher levels in the food chain. 

Zebra Mussels and toxins…

Zebra mussels accumulate toxins from filtering water which kills animals that eat them; can make its way up into human food.

Polychlorinated Biphenyls (PCBs)

Family or organic contaminants, more important impact on Great Lakes fish; industry release, sediment release, and tributes; can cause human developmental issues and immune system problems.

Chicago Waterways 

Lots of attention is being paid to the Chicago Waterways that dump into the lake, so Jumping Carp don’t make their way into the Great Lakes. Electric barrier is working.