Ojibwe Lifeway: Fishing (“niibin”- summer)

Ojibwe man spear fishing, ca. 1900.

In this unit you will investigate impacts of a warming climate on cold and coolwater fish species in Wisconsin and in Ceded territories are lands transferred from tribes to the federal covernment by treaty. Ceded Territory of the Lake Superior Ojibwe. This area includes the northern portions of Wisconsin, Minnesota, and Michigan. Fishing is an important source of food for the Lake Superior Ojibwe and a cultural practice protected by treaty rights. As you work through this unit, think about how climate change is affecting the sustainability of these fish species and how it could also affect the activities and traditions you enjoy.

Key species: Cold and coolwater fish (giigoonh) species including brook trout (na-may-kose), lake trout (chinamekos), walleye (ogaa), northern pike (ginoozhe), and muskellunge (maashkinoozhe)

Possible climate change stressors: Higher air and water temperatures, shorter winters, less ice cover, droughts, increased storm events and flooding

Impacts include: Rising water temperature, habitat and spawning area destruction, replacement by warmwater non-game fish, increase in invasive species, increase in toxic algae blooms


  • Understand why fish and the harvest of cold and coolwater fish species, especially walleye, are important to the Ojibwe culture both historically and today.
  • Identify habitat conditions needed to sustain healthy cold and coolwater fish populations.
  • Identify specific climate change stressors that could impact the sustainability of coolwater and coldwater fish species based on an evaluation of scientific climate change trends and Evidence that you can see, feel, or experience based on what you observe around you. place-based evidence.
  • Identify at least three fish species that would benefit from a warming climate and three species that could be harmed; and explain how climate change could affect each species.
  • Develop and test a hypothesis to determine how these climate change stressors are affecting ecosystems and cultures.
  • Implement a service learning project to educate others about how to reduce climate change impacts.


Fish species within Wisconsin and the Ceded Territory are divided into three major groups depending on the water temperature and oxygen requirements they need to sustain their populations.

Coldwater Fish Species: This category of fish includes the brook trout, a Wisconsin native, and the brown trout which was introduced in Wisconsin in 1883. Coaster brook trout is a native brook trout that is being re-introduced in streams along Wisconsin’s Lake Superior shore.

Coolwater Fish Species: Walleye pike, northern pike, and muskellunge are included in this category. These species historically and today are important as The use of plants and animals to provide food, shelter, medicines, and livelihood subsistence fish for the Ojibwe people, as well as being prized by recreational anglers.

Warmwater Fish Species includes game fish such as large and smallmouth bass, crappie, bluegill, and many nongame forage fish such as minnows and suckers.

Many invasive fish, like carp, are adapted to survive and even thrive in a wide A geographical area where an animal normally lives range of water temperature conditions and very low oxygen levels. Because they are not native to the Lake Superior ecosystems, there are no natural predators here to help keep their numbers in check. With these advantages, invasive fish species can out compete native fish and take over aquatic environments.

What About Lake Superior’s Fishery?
Lake Superior is a coldwater fishery that includes native lake trout and whitefish. Coho and chinook salmon were introduced in lake the 1960’s. These coldwater species are important to recreational fishers, as well as tribal and non-tribal commercial fishers. Lake trout and whitefish can also be found in deep, cold inland lakes.

Lake Superior’s large mass of cold water, averaging a chilly 40 º F, may help buffer coldwater fish species from warming conditions. Despite this, the average summer surface water temperature of Lake Superior has increased by about 3.5°C over the past three decades, with shallow coastal areas warming the most. GLIFWC fisheries biologists believe that Lake Superior coldwater fish will have decreased growth rates as the climate warms. This is due to “bio-energetics” which refers to the energy flow among living systems within the Lake. As water in Lake Superior warms, coldwater fish eat more. Due to Lake Superior’s naturally low levels of nutrients, there will be less for these fish to consume and therefore their growth rates will slow.

Warming Lake Superior water also means more impacts from invasive species that can tolerate higher water temperatures. Impacts from the invasive sea lamprey which prey on native lake trout are on the rise with these warmer water temperatures.


Source: "Effects of Climate Change on the Fish and Fisheries of the Great Lakes Basin", Brian Schuter
Water temperature and the level of dissolved oxygen are critical for survival of cold and coolwater fish species. The colder the water, the more oxygen it can hold.

Coldwater fish species, like brook trout, lake trout, and whitefish are very sensitive to changes in water temperature and environmental conditions. They grow best in chilly water between 50's and 60 º F that does not exceed 71 º F. Coldwater fish can only survive in water with high dissolved oxygen levels of 5 ppm (parts per million) or greater. Dissolved oxygen levels below 2-3 ppm are lethal. Habitats that provide these conditions include Lake Superior and its coldwater tributary streams, spring fed streams, and lakes that have a constant supply of cold water.

Coolwater fish species can survive in slightly warmer water between 60-70 º F, but temperatures above 88 º F are lethal. Compared to coldwater species, these fish can survive in water with slightly less oxygen, but need at least 4 ppm. Dissolved oxygen levels around or below 2 ppm are lethal.

Water temperature is important for spawning. The spawning migration of walleye begins soon after the ice goes out, at water temperatures of 38 - 44º F and reaches a peak when water temperatures are 42 - 50º F. Spawning generally occurs

between mid-April and early May. Northern pike spawn as soon as the ice begins to break up in the spring when temperatures are between 34 and 40º F. Optimum spawning temperature for muskellunge is about 55º F.

Habitats that provide these conditions include deeper inland lakes, Great Lakes coastal wetlands, and coolwater rivers.

Warmwater fish grow best in bathwater temperatures between 80-95 º F, depending on the species. Because warmwater holds less dissolved oxygen, these species are adapted to needing less oxygen to survive and grow. Warmwater fish species can get by with minimal levels of dissolved oxygen between 2-3 ppm. Dissolved oxygen levels of 0.5-1 ppm are lethal. Habitats that provide these conditions include inland lakes and rivers and shallow coastal wetlands.

Invasive fish species, such as the common carp, like water temperatures around 73 º F, but can tolerate water temperatures as high as 95 º F and very low oxygen levels. Unlike most fish, they survive under the ice, with very low oxygen levels that would kill other fish. New invaders, such as the bighead carp and silver carp, are threatening the Great Lakes ecosystems.


Walleye: Present throughout Wisconsin and the Ceded Territory.

Northern Pike: Widely distributed throughout Wisconsin (except in the unglaciated area of southwestern Wisconsin) and throughout the Ceded Territory.

Muskellunge: Northern Wisconsin and Ceded Territory lakes and rivers.

Walleye: Present throughout Wisconsin and the Ceded Territory.

Brook Trout: The Lake Superior Basin and northern Wisconsin is recognized for its abundance of coldwater streams which are home to brook trout and coaster brook trout. In Wisconsin, there are over 10,000 miles of classified trout streams.

Lake Trout: Lake trout are native to the Great Lakes area, New England, and Canada. In the Lake Michigan waters of Wisconsin, they live in the outer half of Green Bay and along the entire Lake Michigan shoreline.

Use this “fish map” to explore the current distribution of walleye and other Wisconsin fish species.

Climate Related Issues

Rising Air and Water Temperatures: Air temperature has a direct effect on water temperature. Brook trout are expected to take the hardest hit if Wisconsin’s climate warms. Climate models predict up to 95% of brook trout habitat across Wisconsin could be lost if the average annual summer air temperature increased just over 5 º F. Warmer air temperatures will warm streams to levels that threaten trout survival. Hotter days also mean less soil moisture, more The process where water becomes vapor and enters the atmosphere evaporation, and less groundwater recharge to replenish water levels in streams and lakes.

Intense Rainfall Events: Intense heavy rainfall events can flood fish spawning areas washing away nesting areas and fish eggs, or covering them with sediment and silt, reducing fish reproduction. Although climate change models indicate more overall rainfall, especially as rain falling during winter, the forecast is that there will not be enough precipitation to balance the higher rate of The process where water becomes vapor and enters the atmosphere evaporation due to higher summer temperatures. Summer lake and stream levels are predicted to be lower. This will impact the amount and quality of aquatic habitats available for fish.

Drought: More frequent, localized periods of extreme drought will dry up wetlands that provide water to streams and lakes and provide habitat for insects and amphibians that provide food for fish. Stream flow and lake levels will be lower. Important aquatic habitats and vegetation within the shallower The nearshore area of a lake where sunlight can penetrate to the lake bottom littoral zone that provide spawning, feeding, and resting areas could be reduced or eliminated.

Shorter Winters, Less Ice Cover: Shorter winters result in more The process where water becomes vapor and enters the atmosphere evaporation and water loss from rivers and lakes. Why? Because ice on a lake blocks the The process where water becomes vapor and enters the atmosphere evaporation of water from its surface. Early “ice-out” of lakes means species like walleye are spawning earlier. Fish populations could be negatively affected if baby fish, called “fry,” hatch before the food that they depend on is available. If an earlier ice-out has walleye hatching before conditions are just right, the fry might not make it.

Invasive Species: Many invasive fish species, such as the common carp, goby, and Asian carp can tolerate warmer, oxygen poor water. With no natural predators and high reproductive rates, these invasives can replace native species stressed by climate change.

Toxic Algae Blooms: Warmer water temperatures favor outbreaks of blue-green algae which can be toxic to livestock, pets, and humans. Blue green algae blooms are extremely unusual in Lake Superior because the water is usually very low in nutrients and cold. However, the floods in June, 2012 flushed nutrients and sediment from the land into the lake. Combined with exceptionally warm weather and water, conditions were right for the algae to multiply. Lake Superior experienced a rare blue-green algae outbreak.

Something is Fishy in Upper Clam Lake!

Up until 2005, Upper Clam Lake was one of Wisconsin’s best manoomin (wild rice) lakes. It supported up to 300 acres of lush rice and yielded approximately 3000 pounds of rice per year. By 2006, there was no reported harvest of rice from the lake. Aerial images taken in 2010 showed that only 60 acres of sparse wild rice were left. The wild rice had all but disappeared! What happened? Could climate change be a cause?

Let’s take a closer look. Upper Clam Lake supports a population of bluegill, other panfish and game fish, along with invasive carp. Carp are vegetarians and eat aquatic plants, including wild rice. Bluegills and other panfish eat carp eggs and normally help keep the carp population in balance. Bluegills, other panfish, and carp are all warm water fish and can survive in lakes with warming temperatures.

In 2005, biologists discovered that the carp population exploded in Upper Clam Lake, at the same time the population of bluegills and other panfish died off. This left the carp with no controls on their population. Their numbers exploded. Some researchers suspect that a The suffocation of fish due to low dissolved oxygen levels in lakes during the winter winterkill in 2007 could have caused a massive die off of bluegills. The mystery is that no The suffocation of fish due to low dissolved oxygen levels in lakes during the winter winterkills have been reported in Upper Clam Lake.

Without the bluegills to keep their numbers in check, the carp population in Upper Clam Lake is increasing. They are eating up the wild rice beds. Researchers discovered that very few manoomin seeds now remain in the lake bottom, so the rice cannot re-establish itself.

Because carp eat so much vegetation, they may also reduce the hiding places young bluegills need to survive, further reducing the chance for the bluegills to recover.

Today Upper Clam Lake has little to no wild rice. This lake demonstrates how natural resources are interconnected. What happens to one resource, affects the sustainability of other resources.

Click here to investigate the full story