teach.GLIN.net
GLIN Daily News About GLIN
AboutEnvironmentHistory/CultureGeographyPollutionCareers/BusinessTeachers' Corner
water photo
What's New?

Students learn about Lake Superior at MTU’s Water Festival
ABC 10 - Ishpeming, MI (10/23)
Over 1,000 students from across the Copper Country made their way to the Great Lakes Research Center on the Michigan Tech campus for the third annual Water Festival. The event is designed to offer students engaging Lake Superior-based content.

New stewardship programs aim to teach students how to care for Great Lakes
Upper Peninsula Second Wave (10/15)
The Upper Great Lakes Stewardship Institute is the newest among several regional hubs across Michigan with the goal to educate students on good environmental stewardship for the Great Lakes and their watersheds.

TEACH Calendar of Events
What's going on in your neighborhood this month? Meet other people and learn together at recreational and educational events! Our new dynamic calendar is updated daily with current educational events.
Great Lakes Fish and Fishing

4 | More familiar species...and some foreign transplants

Smallmouth Bass. Click for larger image. Bass, Smallmouth (Micropterus dolomieui)
A plucky gamefish that gives a good "fight" on hook and line, smallmouth bass are considered to have a superior flavor and texture. See also: Largemouth Bass.

Lake Herring (Coregonus artedii)
The Herring fishery in the Great Lakes has suffered dramatic reductions in its population as a result of overfishing and habitat destruction.

Lake Whitefish (Coregonus clupeaformis)
Cited as the most important commercial fish in lakes Ontario and Huron, there have been more than $5 million in catches from these two lakes in a single year. Whitefish are also a critical component of the Lake Michigan commercial fishery, and a popular sport fish in all of the Great Lakes.

Muskie. Click for larger image. Muskellunge, or muskie/musky (Esox masquinongy)
This fish is legendary for its size. The largest one caught was 65 inches (164 cm) in length and weighed more than 70 pounds (32 kg)! The muskie was named the official Wisconsin state fish in 1955 and remains one of the most desired trophy fish in the Great Lakes region.

Northern Pike. Click for larger image. Northern Pike (Esox lucius)
This is a well known species in the Great Lakes and makes up a small, but significant, proportion of the commercial harvest.

Pumpkinseed (Lepomis gibbosus)
Pumpkinseeds, or similar species such as the blue gill or sunfish, are common in the Great Lakes basin and usually one of the first species caught by children.


Related site: The bluegill sunfish: A cross dressing fish!

Rock Bass (Ambloplites rupestris)
The rock bass isn't really a bass--it's a member of the sunfish family--but it is associated with rocky habitat. Found in all the Great Lakes, this species is often under-rated as a sport fish.

Walleye. Click for larger image. Walleye (Stizostedion vitreum)
In peak years, walleye accounted for half of the value of the Lake Erie commercial fishery. Sometimes referred to as the "glassy-eyed" fish, the walleye can be distinguished from the sauger (a similar species) by the absence of black dots on the first dorsal fin, and the absence of dark side blotches and saddle marks, as well as several other traits.

Yellow Perch (Perca flavescens)
Easily caught by fishers of all ages, the Yellow Perch is one of the more easily recognized fish of the Great Lakes! This species typically grows to a length of 10 inches (25 cm).

Non-native and endangered species

Invasive species and their impacts on the native fishery
Many commonly known Great Lakes fish, including chinook and coho salmon and rainbow trout, are actually non-native species that have been introduced to the lakes, either accidentally or intentionally.

When a species is introduced into a new habitat it lacks natural controls on its population; predators, and competitors are absent and prey don't know how to avoid them. Without these natural controls, populations of introduced species often explode. Examples of such introduced aquatic species in the Great Lakes include carp, zebra mussels, sea lamprey, goby and ruffe.

Perhaps one of the most notable accidental introductions was that of the sea lamprey (Petromyzon marinus) to the majority of the Great Lakes, between 1936 and 1946. This large, parasitic lamprey feeds on commercially important species such as whitefish and lake trout. Lamprey victims either die, or are no longer valuable because of the ugly scars left behind by the lamprey's "suction-like" mouth. The sea lamprey continues to be a problem in the Great Lakes and is the focus of much research.

Related sites:
Sea Lamprey control, Great Lakes Fishery Commission
GLIN Sea Lamprey in the Great Lakes Region
The Sea Lamprey: No bones about it!

The most serious problems that introduced, non-native species cause are competition and hybridization. Competition for food and habitat is difficult to prove, but is believed to be the cause of population declines of native fish in some situations. Hybridization results when an introduced species mates with a native species producing hybrid offspring. If native species are rare, they are more likely to encounter, mate and reproduce with the invading species than with their own species. This can ultimately lead to the extinction of the native species.

Related TEACH module:
Non-native invasive species in the Great Lakes

At risk species...
Several once commercially important fish, such as the cisco and the blue pike, have become extinct while populations of non-native invasive species have increased. The first fish to feel the pressure of the commercial fishery was the Atlantic salmon. By 1860, overfishing and loss of prime spawning habitat caused this popular, high-value fish to become endangered in the Great Lakes. Despite restocking efforts, today the Atlantic salmon is believed to be extinct.

Lake Sturgeon researchers. Click for larger image.The once common lake sturgeon is also very rare today. The lake sturgeon was once so abundant in the Great Lakes that it was considered a nuisance. However, advances in the smoking and processing industries created a market for smoked sturgeon meat and caviar. Sturgeon were then overfished, and by 1900 populations could no longer support a commercial fishery. Today, these immense fish -- sometimes up to 6 feet (1.8 meters) in length -- are very rare in deep waters of the Great Lakes.

Related sites:
About the Lake Sturgeon
Great Lakes Lake Sturgeon Page

Threats to species are everywhere. In the United States alone, 37 percent of freshwater fish species are threatened or have become extinct.

The Committee on the Status of Endangered Wildlife (COSEWIC) in Canada and the Fish and Wildlife Service in the United States determine the status of species, subspecies and separate populations suspected of being at risk from extinction. Species are categorized as follows:

  • Vulnerable: A species particularly at risk because of low or declining numbers, small range or for some other reason, but not a threatened species.

  • Threatened: A species likely to become endangered if the factors affecting its vulnerability are not reversed. Note: Great Lakes deepwater sculpin (Myoxocephalus thompsoni) is currently listed as threatened in Canadian waters.

  • Endangered: A species threatened with imminent extinction or extirpation throughout all or a significant portion of its range.

  • Extirpated: A species no longer existing in the wild, but occurring elsewhere.

  • Extinct: A species formerly indigenous that no longer exists anywhere.

Some extinct Great Lakes fish species
These species no longer exist on Earth!

    Blue pike (Stizostedion vitreum glacum)
    Formerly found in lakes Erie and Ontario
    Declared extinct in 1983

    Deepwater cisco (Coregonus johannae)
    Formerly found in lakes Huron and Michigan
    Extinct in 1960s

    Harelip sucker (Lagochila lacera)
    Formerly seen in clear streams of the upper Mississippi Valley, and the Lake Erie and Ohio drainage basins
    Not seen since 1900

    Longjaw cisco (Coregonus alpenae)
    Formerly found in lakes Erie, Huron and Michigan
    Declared extinct in 1983

    Shortnose cisco (Coregonus reighardi)
    Formerly found in lakes Huron, Michigan and Ontario
    No individuals collected since 1985


Graphics: Bass, muskie, pike and walleye, copyright ©Joseph Tomelleri; Dr. Nancy Auer and lake sturgeon researchers, Michigan Technological University, Houghton, Mich.

1 | 2 | 3 | 4 | 5 | 6 | 7   next page