Non-native Species Introduced to the Great Lakes Region Interrupt

the Natural Balance

Zebra Mussel

• This clam-like organism attaches itself to the bottom of ships, piers, and water intake pipes

• Multiplies quickly• Competes with other organism in consuming

plankton and algae… it is a consumer!• Can cut feet when walked on…ouch!• Controlled by cleaning boating and fishing gear.

Also by raking and cleaning shallow water and beaches

Ruffe

• The yellow perch and white fish are greatly disrupted by this predator

• It competes with other, more desirable fish

• 3-6 inches long

• Not desirable for food because of sharp top fin

Quagga Mussel

• This mussel is related to the zebra mussel

• Interrupts the natural balance of the ecosystem in a similar manner

Round Goby

• This predator fish came from the Black and Caspian Seas

• Feeds mainly on bivalves (clam-like organisms)

• Can see in the dark

• Fishermen and women leave them out to die when caught

Spiny Water Flea

• Small consumer that competes with young fish for food

• May have entered the Great Lakes waterways by ballast water from ships

• Controlled by not dumping water from one lake into another

• Cleaning boating and fishing gear after use

In the picture below, eggs are in the sac on the back of the water flea.

Sea Lamprey

• Larger parasite that interrupts the natural balance of the Great Lakes

• Can kill up to 40 pounds of fish in 12 to 20 months

Betsie River 2009

Dam on Betsie River where salmon jump to lay eggs up

stream

U.S. Department of Sea Lamprey Control workers catching

lamprey

Barriers are set to help control sea lamprey from entering

waterways.• When sea lamprey are caught, some are

killed

• Some males are sterilized, transported and reintroduced to the St Mary’s River where they hope that sterile males will mate with females producing no offspring.

Eurasian Watermilfoil

• Water plant that entangles boats and other water recreation vehicles

• Crowds out other water plants

• Expensive to get rid of-up to 1,000,000 per lake

• Eurasian watermilfoil is a producer!

Purple Loosestrife

• A lovely producer that inhabits wetlands, marshes and ditches

• Thought to have been brought by settlers to grow in gardens

• Creates a monosystem as it interrupts the natural balance

• Natural foods have been eliminated by its intrusion

Emerald Ash Borer

• Larva bores under ash tree bark

• Trees cannot transport nutrients

• Ash trees die

• Controlled by not transporting firewood and not planting ash trees

Ecosystems are always changing.

Some changes are sudden and dramatic like forest fires, oil

spills, and volcanoes.

Some changes occur slowly through stages over time.

Cattails

• What was one major population before the purple loosestrife?

• What other populations of this community may have changed?

• How might this ecosystem change in 50 years? A hundred years?