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The Fish of Lake Superior

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9_15_14StudentResponse_lower

9_15_14StudentResponse_upper

 

The results of last week’s Cast YOUR Vote are in. Students have chosen that we should research the fish and animals of Lake Superior. There are 34 native fish species and a total of 88 fish species in this massive lake. “Native species” means a plant or animal that lives in the same place it is originally from, kind of like if you are still living in the same town you were born in.  There are many animals that live in and around the lake as well. There are so many fish and animals that I can’t tell you about all of them in this entry. I’ll share what I know about Lake Superior fish now. Next week, I’ll tell you about other animals that can be found in and around Lake Superior. You can use the links at the bottom of the page to learn more about the fish found in Lake Superior.

I have chosen four Lake Superior fish to tell you about: lake whitefish, sea lamprey, lake trout and lake sturgeon. This is just a small sample of fish in the lake, so I hope you will research even more fish that live here.

Lake Whitefish

People have been netting (and eating) whitefish for a long time. They are a fish that like to eat food from the bottom of the lake. They have small heads and are silver in color. A whitefish can grow to weigh as much as 20 pounds. They like to eat insects, freshwater shrimp, small fish and fish eggs. Over a million pounds of whitefish are harvested from Lake Superior each year.

Lake whitefish. Image source: http://en.wikipedia.org/wiki/Lake_whitefish#mediaviewer/File:Lake_whitefish1.jpg

Lake whitefish. Image source 

Sea Lamprey

Sea lampreys are not native to Lake Superior. They are an invasive species. An “invasive species” is a plant or animal that has been introduced to an environment and become a nuisance. Sea lampreys came from the Atlantic Ocean, through the St. Lawrence Seaway. The sea lamprey is a parasite. It grows to be about 8-12 ounces. It is a grayish-black fish that is long and skinny. It has a round mouth that looks like a suction cup, with many rows of teeth. Sea lampreys are kind of like vampires. They latch onto other fish and suck their blood. You can learn more about the sea lamprey here, in the Wilderness Library.

Sea Lamprey

Several lampreys attached to a Lake Trout. U.S. Geological Survey Image Source

 

Lake Trout

Lake trout are at the top of the food chain in Lake Superior. They live in deep parts of Lake Superior. They typically grow to be 7-12 pounds, but the biggest lake trout caught in Lake Superior was 63 pounds. Lake trout like to eat freshwater shrimp, other crustaceans, midsize fish and insects. Overfishing and an invasion of sea lamprey in the 1950s caused the lake trout population to drop.

Lake Trout. Image source

Lake Trout. Image source

Lake Sturgeon

Lake sturgeon are the largest fish in Lake Superior. They among the oldest fish in the lake too. Did you know that a lake sturgeon can live to be older than 100 years? This species of fish has also been around for a long time—about 150 million years. Lake sturgeon can grow to be 8 feet long and weigh over 300 pounds. They have tough skin with hard plates running along each side of their body. They have whisker-like barbels that help them search for food. They like to eat small things like crayfish, leeches, small fish and insects.

I hope you enjoyed learning about some of the fish found in Lake Superior.  Follow the links below to learn about more fish that live in the lake. What is your favorite fish? Do any of the fish found in Lake Superior live in a lake near you? Are there different fish near where you live? Are there any invasive species (like the sea lamprey) in the lakes and rivers near you?

 

Keep Exploring!

Amy

 

Resources

Fish in Lake Superior:

http://www.seagrant.umn.edu/fisheries/superior_fish_species

Lake Superior habitat:

http://dnr.wi.gov/org/caer/ce/eek/nature/habitat/lakesuperior.htm

Lake Superior food web:

http://www.glerl.noaa.gov/pubs/brochures/foodweb/LSfoodweb.pdf

The post The Fish of Lake Superior appeared first on Wilderness Classroom.

What do you want to learn about the world’s largest lake?

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Amy and I will spend the next two weeks sailing our 27 foot sailboat, Yemaya, across Lake Superior. Lake Superior is the largest freshwater lake in the world by surface area. (Lake Baikal in Russia is the biggest by volume.) Lake Superior holds over 3-quadrillion gallons of water and covers an area approximately the size of the state of Maine. It is a beautiful, and amazing place to explore, and a very important source of clean freshwater. You can learn more about Lake Superior on the Minnesota Sea Grant website.

 

http://www.seagrant.umn.edu/superior/facts

 

We need your help deciding what we should study while we are sailing on Lake Superior. We could focus on the lake and learn about how the lake was formed and other physical aspects of the lake. We could also study the fish and other animals that live in the lake, or we could focus on how people have used Lake Superior historically and how people use the lake today.

 

Please cast your vote and help us decide!

 

Yemaya sailing past Palisade Head on Lake Superior. Photo by Nate Ptacek

Yemaya sailing past Palisade Head on Lake Superior. Photo by Nate Ptacek

 

Note: There is a poll embedded within this post, please visit the site to participate in this post's poll.

The post What do you want to learn about the world’s largest lake? appeared first on Wilderness Classroom.

How much garbage do we produce? (part 1)

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One of our goals during our paddle from the Boundary Waters to Washington DC is to reduce the amount of garbage that we produce, especially plastic waste. Before we start trying to produce less garbage we need to figure out how much garbage we produce now. According to the Environmental Protection Agency, the average American produces between 4 and 4.5 pounds of garbage each day.

We need you to help us figure out the best way to measure the amount of garbage we produce. Should we weight it, measure the volume, sort it and by type of garbage and record the weight or volume of each type? Please tell us how you think we should measure our garbage and why. Make a comment below or send us an email to share your answer.

Keep Exploring!

Dave

The post How much garbage do we produce? (part 1) appeared first on Wilderness Classroom.

Glaciers and Climate Change

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While our trip is now over and we’re back home in Minneapolis, we are catching up on a final post or two about our experiences in the Arctic, in Svalbard, Norway, where we were about 800 miles from the North Pole.

On our return flight to Minneapolis, we flew over the southern part of Greenland, and were treated to a crystal clear day and a truly incredible sight.  The blinding whiteness of the Greenland ice cap, stretching as far to the north as the eye can see.  And then glaciers, everywhere, flowing down the mountainous coast of Greenland and into the sea.   We also saw several glaciers when we were in Svalbard, and got quite close to a few of them.

Greenland ice cap

Greenland ice cap

Glacier flowing into the sea, Greenland

Glacier flowing into the sea, Greenland

What are glaciers?

Glaciers are slow rivers of ice that flow from higher elevations to lower elevations, typically moving at speeds of about 3 feet per day, though some can move as much as 70-100 feet per day.  They are formed by snow at higher elevations being compacted into ice, and then by the weight of the new ice pushing older ice down a mountain slope.  When looking at a glacier it appears fixed and unmoving.  But get close to it, and you can hear and see that it is not.  Especially if the glacier ends in the ocean or a body of water, as you approach, you’ll see bits of ice floating all around.  Within earshot, you’ll hear what sounds like creaking and moaning.  These sounds are created by the slow movement of the glacier, by the ice pushing against itself and the ground below.  Occasionally what sounds like thunder will ring out, as chunks of the glacier break off and crash into the sea below, in a process called calving.

Jamie & Jason with Nordenskold Glacier, Svalbard

Jamie & Jason with Nordenskold Glacier, Svalbard

Kayakers approaching Esmarck Glacier, Svalbard

Kayakers approaching Esmarck Glacier, Svalbard

Jamie standing on some ice from Harriet Glacier (behind her), Svalbard

Jamie in front of Harriet Glacier, Svalbard

Here’s a link to a video of the largest glacial calving ever filmed.

Where are glaciers?

Glaciers require cold temperatures to form, and so are often found in places with high elevations as well as in high latitudes closer to the North and South poles.  On our trip we saw glaciers in Svalbard, but also learned about the problems changes in glaciers are causing in much warmer places, like Peru (look at our post about Arequipa).

Glaciers are alive… and sick

Glaciers can seem alive, with the sounds they make and because they are constantly in a state of flux, either growing or shrinking.  Glaciers grow when new ice at the top of a glacier is created faster than ice at the bottom is melting.  With the impacts of climate change, the vast majority of glaciers in the world are now getting smaller.  When a glacier gets smaller it is said to retreat.

Retreating Boulder glacier in Colorado, red line shows where it was in 1985 By User:Peltoms (Wikipedia) (http://en.wikipedia.org/wiki/Image:Bouldert.jpg) [see page for license], via Wikimedia Commons

Retreating Boulder glacier in Colorado, red line shows where it was in 1985
By User:Peltoms (Wikipedia) (http://en.wikipedia.org/wiki/Image:Bouldert.jpg) [see page for license], via Wikimedia Commons

We met some researchers in Svalbard who had been researching the same glacier for over 15 years.  Al Werner, of Mount Holyoke College and the Co-Director of Svalbard Research and Education for Undergraduates (REU), told us of when he first met the Linné Glacier, and how now, not only is it retreating, but it is also losing height.  He said it was almost like taking the plug out of an air mattress.

Climate change is being caused by the increasing amounts of greenhouse gases people are putting in the air.  The most common greenhouse gas is carbon dioxide, which primarily comes from the burning of fossil fuels, like oil, gasoline, coal, and natural gas.  Greenhouse gases act like a blanket around the earth, and the increase in greenhouse gases is making the earth warmer.  The actual temperature changes in degrees can seem pretty small (about 1-3 degrees Fahrenheit in average air temperatures for example), but small changes like this can have big impacts.  The melting of glaciers can be impacted both by the warmer air and warmer oceans.

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Who cares?

Besides the fact that glaciers are incredibly beautiful, as glaciers melt, the water from them eventually runs into the oceans.  And over time, this raises sea levels around the world, so far since 1850 sea levels are about 8 inches higher.  With more water from melting glaciers (there are other factors but this is likely the main one), sea levels are forecast to rise 1-6 feet by the end of the century.  This may not seem like much, but according to a study done by the Institute for Demographic Research at the City University of New York, almost 1 in 10 people in the world live near the coast at elevations less than 30 feet above sea level.  Higher sea levels will make it difficult for these people to live where they do.  Some land will be underwater, but also rising sea levels increase flooding, especially as surges and waves from storms start from a higher level.

What can we do?

In order to stop climate change, we need to reduce the amount of fossil fuels that we burn. People can help by driving less, driving cars that use less gas, and using less energy at home or work — like turning off lights, TVs, and computers when they’re not being used.  People can also use other sources of energy like solar power and wind power.  Planting more trees and preserving forests and grasslands can also help as trees and plants convert carbon dioxide to oxygen

 

Study Guide Questions

1. True or False, glaciers are made of ice that never moves

2. How are glaciers made?

3. True or False, most glaciers in the world are shrinking, or retreating.

4. What is it called when part of the front of a glacier breaks off and falls into the sea?

The post Glaciers and Climate Change appeared first on Wilderness Classroom.