Fishes of Wisconsin: Attack of the Clones

Happy Fish Fry Day! Once again fish is on the menu here at the CFL blog (and just about every restaurant in Wisconsin). Today we’re continuing the epic slog through all of the images on the Fishes of Wisconsin poster and we’re sticking with small plates. In fact, it’s a two-course deal. Introducing, the finescale dace and the northern redbelly dace.

Photo: Marilyn Larsen

Photo: Marilyn Larsen

Many anglers many know finescale dace (Chrosomus neogaeus) and northern redbelly dace (Chrosomus eos) as relatively hardy kinds of bait fish, which likely has readers of this blog groaning “Not again! TWO tiny fishes? Didn’t we have a boring little minnow last time?”

Photo: Marilyn Larsen

Photo: Marilyn Larsen

 

Well, yes, yes we did.

But the fact that no one came to the defense of the bullhead minnow’s reputation doesn’t discount the following facts:

  1. Dace aren’t minnows.
  2. Minnow” does NOT mean “little fish.”
  3. When it comes to reproduction, when the finescale dace meets a northern redbelly dace, something crazy happens.

Continue reading

At Home in the Water, “Condemned” to Life on Land

This essay originally appeared in the Lakeland Times in Minocqua, Wisconsin. Carol is an Aquatic Invasive Species expert and outreach specialist with the CFL and Wisconsin DNR.

by Carol Warden

Carol Warden for a short stay in her favorite element. Photo courtesy: Carol Warden

Carol Warden for a short stay in her favorite element. Photo courtesy: Carol Warden

Throughout my life I’ve been surrounded by water. Whether it was lakes, rivers or the sea, the water and I have had an intimate relationship. I remember thinking as a child, “These fish are so lucky; they never have to get out of the lake. They get to swim all day. How do they breathe underwater and what’s stopping me from doing it?”

A fish depends on oxygen just like we do except fish breathe oxygen that is dissolved in water. Instead of having lungs to breathe, a fish has gills. Lungs and gills have the same purpose; they both supply the body with oxygen.  Unlike human lungs that sit inside our bodies, gills of a fish are on the outside of their bodies. They sit right behind the mouth on both sides of the fish like where an ear is on our head. On some fish, the gills curve from the eye to the mouth. On other fish like sharks, the gills look like slits from a knife on the side of their bodies.

Most fish can open their mouths and let water in then when they shut their mouths the water is forced out past their gills and the gills absorb the dissolved oxygen in the water. Other fish, like tuna, don’t have the best system to force this water out and so they have to swim continuously so water is constantly passing over their gills.

Courtesy: University of Maryland Extension

Courtesy: University of Maryland Extension

Gills are very delicate, almost paper-like structures that depend on the buoyancy of water to remain open. The fragile gills will collapse if the fish is taken out of the water because air doesn’t have the same density and buoyancy water has to keep the gills open and functioning. This is why a fish cannot live outside the water. Gills also have much more surface area proportionate to their bodies than our lungs do proportionate to our bodies. This added surface area allows the fish to be very efficient at removing oxygen from water. Since water only holds a fraction of oxygen air does, it is important for fish to be really efficient breathers. Some fish can remove up to 85 percent of dissolved oxygen from the water that passes over their gills.

Carol feeds her lungs the oxygen they need via the compressed air of a scuba tank. Photo courtesy: Carol Warden

Carol feeds her lungs the oxygen they need via the compressed air of a scuba tank. Photo courtesy: Carol Warden

Alas, I will never be able to join the fish and swim all day. Gills are great for air and water exchange while our human lungs are only adapted to exchanging air. If our lungs were on the outside of our bodies like fish, we would lose too much water from our bodies because we don’t have the constant replenishment of moisture like fish do living in water. The same is true for a fish out of water. Even if their gills did not collapse, they would eventually lose too much water from their bodies to survive. They require a constant flow of water over their gills to absorb dissolved oxygen and to keep their gills moist. Also, our lungs do not have enough surface area to pull out the amount of oxygen from water that we humans require to live. I’m condemned to a life on land.

Fish Fry Day: Bass Set to Win, Walleye Lose Under Warming Projections

We interrupt the “Fishes of Wisconsin” challenge to be bring you this report from former CFL graduate student/post doc, Gretchen Hansen. Published yesterday in the journal Global Change Biology. For more, check out this amazing website

FOR IMMEDIATE RELEASE

Contact: Gretchen Hansen; Minnesota DNR, Gretchen.hansen@state.mn.us, 651-259-5245

Climate change predicted to change sport fish communities in Midwestern lakes

MADISON, WISCONSIN—Climate change is predicted to alter sport fish communities in Midwestern lakes, according to a new study that related water temperature to suitability for walleye and largemouth bass in over 2,100 Wisconsin lakes.

Walleye. Photo: Gretchen Hansen

Walleye. Photo: Gretchen Hansen

Walleye populations have been declining and largemouth bass populations have been increasing in lakes across Wisconsin for the past 30 years. These changes are cause for concern for many anglers and policy makers; freshwater fishing in Wisconsin is valued at over $1.5 billion, and walleye are the preferred species for many anglers.

Researchers identified characteristics of lakes where walleye or largemouth bass were most likely to thrive. Both species were strongly influenced by water temperature; walleye populations thrived in cooler, larger lakes, while largemouth bass were more abundant in warmer lakes.

“Generally this means that lakes that are best for walleye are not the best for largemouth bass, and vice versa” said study author Gretchen Hansen, former Wisconsin DNR Research Scientist currently with the Minnesota DNR. “Going forward, we predict that many Wisconsin lakes are going to become more suitable for largemouth bass, and less suitable for walleye”. Continue reading

Fishes of Wisconsin: Help Us Prove That Bullhead Minnows Aren’t Boring

Happy Fish Fry Day, the weekly holiday where our fair state (always) puts fried fishes on the menu and we here at the CFL (sometimes) put fishes on the blog. Summer’s drawing to a close and it’s time to resume our “Fishes of Wisconsin” challenge.

Without further ado, I give you – the bullhead minnow.

Bullhead minnow illustration on the Fishes of Wisconsin poster. Photo: Marilyn Larsen

Bullhead minnow illustration on the Fishes of Wisconsin poster. Photo: Marilyn Larsen

Houston, we have a problem. We once promised to prove to you that each Wisconsin fish is amazing in its own right. But, well…it’s really hard to find something all that interesting about a bullhead minnow.

Pimephales vigilax is one of four of the pimephales species, generally referred to as the bluntnose minnows as a whole, but also including the “bullhead,” “fathead” and (winner of the most flattering pimephales nomenclature) the “slim” minnow.

The native range of the bullhead minnow includes streams and rivers of the Mississippi River Basin, tributaries of Lake Michigan and Lake Huron and even the Rio Grande, where they prefer shallow, silty habitat and eat lots of aquatic insects. But, given their affinity as bait for fishermen, they’ve managed to move into unconnected waters throughout the years via bait buckets. The USGS map below illustrates this perfectly in the form of the red splotches far outside of the bullhead minnow’s home range.

US auto-generated map

And that, dear reader, is where the trail runs cold. We have nothing more to report on the bullhead minnow. So, in a first for this blog, we are asking you, our reader, to submit any sort of trivia, picture, anecdote or story into this narrative – what makes a bullhead minnow cool? Help us keep the streak alive and fill our comments section with tales of the majesty of this lowly minnow and we will update accordingly.

And, again, Happy Fish Fry Day!

 

 

Yahara Watershed to Star on Wisconsin Public Television – Sept. 1st

by Jenny Seifert

The future of the Yahara Watershed takes center stage in a new documentary born of a partnership between the UW-Madison’s Water Sustainability and Climate project (WSC) and Wisconsin Public Television (WPT). Called “Yahara Watershed: A Place of Change,” the show will debut on Thursday, September 1st at 7:30pm on WPT.

Will technological advances save the Yahara watershed? Illustration: John Miller

Will technological advances save the Yahara watershed? Illustration: John Miller

Nearly five-years in the making, the thirty-minute documentary features the research conducted by the WSC project team (Steve Carpenter and Corinna Gries from the Center for Limnology are two of the six principal investigators on the project) which is studying the impacts of changes in climate and land-use on freshwater resources and other natural benefits in the Yahara Watershed.

The show focuses on challenges related to the co-existence of agriculture and urban life in the region, as well as an innovative way of investigating what these challenges and their potential solutions could mean for the future of its water and people.

“Having WPT integrated into our WSC project from the beginning has allowed us to showcase interdisciplinary research from a perspective that differs significantly from our traditional reporting of research in scientific journals,” says Christopher Kucharik, lead principal investigator for the WSC project and a professor of agronomy and environmental studies at UW-Madison.

As this map shows, land in the Yahara Watershed is used for all sorts of purposes, from agriculture to development to public open space. Managing the area for these mixed uses is a challenge.

As this map shows, land in the Yahara Watershed is used for all sorts of purposes, from agriculture to development to public open space. Managing the area for these mixed uses is a challenge.

The partnership sprouted fortuitously through a personal connection just as the research team was assembling the proposal for the National Science Foundation grant they eventually received. While no one knew exactly how the documentary would unfold at the time, the end result is a critical component of the project’s outreach portfolio.

“This affords us a unique opportunity to reach a much broader audience through a storytelling lens,” says Kucharik.

The partnership also serves WPT’s mission to contextualize issues affecting Wisconsinites and improve the public understanding and application of that knowledge, explains Christine Sloan-Miller, executive producer of news and public affairs at WPT.

“Since water science affects us all, and climate science is rapidly becoming the most pressing area of study for the future, it was a natural partnership opportunity. Our job is to shine light on the relevant issues to enable a wider, more well-informed dialogue,” says Sloan-Miller.

Click here for additional air times.

Giant, Fishy Poster = Happy Fish Fry Day!

Nearly all of the Freshwater Fish of North America in one poster via Pop Chart Labs.

Nearly all of the Freshwater Fish of North America in one poster via Pop Chart Labs.

We’re going to admit that we still favor the more life-like illustrations of the gigantic “Fishes of Wisconsin” folder but, well, you have to give props to biodiversity! Presenting the Freshwater Fish of America, perhaps the only fish-related poster you will ever need. (Excepting that Wisconsin one, of course!) Details about the poster are here.

Happy Fish Fry Day!

What Can Snails Tell Us About Water Quality?

Pete McIntyre

Pete McIntyre

For the past 20 years, biologist Pete McIntyre has traveled to Africa’s Lake Tanganyika, Earth’s second-largest freshwater lake by volume, to study freshwater snails found nowhere else in the world. McIntyre, a professor with the University of Wisconsin-Madison, explains why these snails are important and what they tell us about pollution in the lake.

Q: First off, why study snails?

A: The snails of Lake Tanganyika are very diverse by freshwater snail standards. They’re interesting biologically, but we can also use them as sentinels for change in the environment. Unlike fish, they’re stuck at the bottom of the lake. So if some aspect of the environment changes, they’re also stuck with whatever bad things happen to the system.
Snails are painted bright shades of nail polish so they're easier to locate after they've been put back into Lake Tanganyika. Photo: Ellen Hamann

Snails are painted bright shades of nail polish so they’re easier to locate after they’ve been put back into Lake Tanganyika. Photo: Ellen Hamann

Guest Post: Focus on Phosphorus Control to Improve Water Quality

by Steve Carpenter

Summer is the season for unsightly and toxic blooms in lakes, and 2016 has been a banner year, with major blooms in Florida, Wisconsin’s Lake Petenwell, and other Wisconsin lakes, including those in Madison. The blooms of cyanobacteria produce toxins that threaten human health, like the bloom in Lake Erie that shut down Toledo’s water supply in 2014.

An algae bloom in Lake Erie is capture via satellite photo. Toledo sits on the far western shore of the lake. Photo: NOAA

An algae bloom in Lake Erie is capture via satellite photo. Toledo sits on the far western shore of the lake. Photo: NOAA

What’s more, many cyanobacteria float and form scums that accumulate, rot on beaches, and cause fish kills.

These severe blooms amplify the urgency behind a statement issued today by Canadian and American scientists, myself included, for governments around the world to focus on a proven solution — that is, we must control phosphorus to decrease the intensity and frequency of harmful algal blooms.

A mid-October algae (or phytoplankton) bloom shows up on the Lake Mendota shoreline. Photo: Sam Oliver

A mid-October algae (or phytoplankton) bloom shows up on the Lake Mendota shoreline. Photo: Sam Oliver

Readers of this blog know that phosphorus inputs to lakes and reservoirs, which come from agricultural and urban runoff, are the main driver of blooms, and that phosphorus reduction is the key to improving water quality. Some government agencies, however, have lost sight of this basic fact of lake management.

Recently, some scientists and managers have argued for the control of nitrogen and phosphorus at sewage treatment plants. In response, the European Union has required the removal of both nitrogen and phosphorus from sewage effluents, and in 2011 the US EPA announced that it would be “partnering” with states to control both phosphorus and nitrogen. New Zealand imposed a nitrogen-loading cap on the watershed of its largest lake, Lake Taupo, but failed to define a limit for phosphorus loading. Continue reading

Summer Intern Reflects on the Trout Lake Experience

We had the pleasure this summer to welcome Anna Krieg to a summer spent living, working and playing in Wisconsin’s Northwoods. To say the lake-studded landscape was new to the Arizona resident would be an understatement. We think we made a positive impression, anyway! Here is Anna’s recap of her time up at the CFL’s Trout Lake Station. 

by Anna Krieg

On August 4th, undergraduates gathered in the Juday Conference Room at Trout Lake Station to present their independent projects to an audience of Trout Lake Staff, Center for Limnology faculty, and the people who generously sponsored their summer work. Dom Ciruzzi, a graduate student at UW-Madison, spoke about his experiences this summer as the Graduate Student Fellow where he was saddled with the not-so-simple task of mentoring the undergraduates through their independent projects. I was asked to speak on behalf of the undergrads about the undergraduate experience at Trout Lake Station and these are my thoughts:

(From left to right) Maggie Sobolewski, Brandon Debraska, Keith Lyster, Emily MacParlane, Dom Ciruzzi, and Luke Maillefer presented at the Fellows Luncheon on August 4th. Photo: Anna Krieg

(From left to right) Maggie Sobolewski, Brandon Debraska, Keith Lyster, Emily MacParlane, Dom Ciruzzi, and Luke Maillefer presented at the Fellows Luncheon on August 4th. Photo: Anna Krieg

The undergraduate experience at Trout Lake is unique; I don’t believe there is any other place quite like it. Every undergrad that works here has a different perspective on this experience, on what makes Trout Lake Station special. From those who have been here every summer of their undergraduate career to those who have only experienced one Trout Lake summer, some common themes have arisen to explain the phenomenon that is Trout Lake. This station is a place to grow and change without fear, it is a place where academic and professional goals are developed and solidified, and it is a place which fosters a community that every undergrad who comes through needs in one-way or another.

Summer 2016 undergrads enjoy sunset on Trout Lake Station's pier. Photo: Anna Krieg

Summer 2016 undergrads enjoy sunset on Trout Lake Station’s pier. Photo: Anna Krieg

This summer, I had the privilege of being the Outreach and Communication Intern; Continue reading

Lake Tanganyika Fisheries Declining from Global Warming

by Mari N. Jensen and Adam Hinterthuer

FOR IMMEDIATE RELEASE – The decrease in fishery productivity in Africa’s largest lake is a consequence of global warming rather than just overfishing, according to a report to be published this week in the Proceedings of the National Academy of Sciences.

Local fishers on Lake Tanganyika. Photo credit: Saskia Marijnissen.

Local fishers on Lake Tanganyika. Photo credit: Saskia Marijnissen.

 

Lake Tanganyika, situated mainly between Tanzania and the Democratic Republic of the Congo, was already becoming warmer in the late 1800’s – the same time that abundance of fish began declining, the team found. The lake’s algae – fish food – also started decreasing at that time. However, large-scale commercial fishing did not begin on Lake Tanganyika until the 1950s.

The new finding helps illuminate why the lake’s fisheries are foundering, said the study’s lead author, Andrew S. Cohen, a geoscientist at the University of Arizona.

“Some people say the problem for the Lake Tanganyika fishery is ‘too many fishing boats,’ but our work shows the decline in fish has been going on since the 19th century,” Cohen said. “We can see this decline in the numbers of fossil fish going down in parallel with the rise in water temperature.”

Ben Kraemer and his group of volunteer limnologists prepare to head out on Lake Tanganyika. Photo: Ben Kraemer

Ben Kraemer and his group of volunteer limnologists prepare to head out on Lake Tanganyika. Photo: Ben Kraemer

The fact that Lake Tanganyika’s fishery has been in decline since before commercial fishing began, says Ben Kraemer, a graduate student at the University of Wisconsin’s Center for Limnology, is at the “heart of this study.” Lake Tanganyika yields up to 200,000 tons of fish annually and provides about 60 percent of the animal protein for the region’s population.

Kraemer has spent a large portion of the last several years in Tanzania researching temperature changes and fishery impacts. “The fish are not just a huge protein source for people, they’re also a huge part of the livelihood and income of people involved in the fishing trade,” he says.

While Kraemer and the paper’s other authors acknowledge that overfishing is one cause of the reduction in catch, they suggest sustainable management of the fishery requires taking into account the overarching problem that as the climate warms, algae – which is the basis for the lake’s food web – will decrease.

And it won’t just be fish food that decreases, but fish habitat as well. In fact, the warming of the lake has reduced the suitable habitat for many species by 38 percent since the 1940s, the team found.

“The warming surface waters cause large parts of the lake’s floor to lose oxygen, killing off bottom-dwelling animals such as freshwater snails,” Cohen said. “This decline is seen in the sediment core records and is a major problem for the conservation of Lake Tanganyika’s many threatened species and unique ecosystems.”

In tropical lakes, increases in water temperature reduce the mixing between the oxygenated top layer of the lake and the nutrient-rich but oxygen-free bottom layer of the lake, Cohen said. Fewer nutrients in the top layer mean less algae and therefore less food for fish.

Pete McIntyre

Pete McIntyre

Those rising temperatures also mean less space for fish, says Pete McIntyre, a professor at the UW-Madison Center for Limnology and another of the paper’s co-authors. In fact, based on instrumental records of oxygen in the lake water, the study’s researchers calculated that since 1946 the amount of oxygenated lake-bottom habitat decreased by 38 percent.

That’s because, unlike temperate lakes in North America, the oxygen in a deep tropical lake like Lake Tanganyika doesn’t go all the way down to the bottom. Instead, says McIntyre, there’s a “floor” within the water column and, beneath that floor, there is no more oxygen in the lake. Over the last 150 years, that floor has been rising in Lake Tanganyika.

“Whether you’re a snail living on the bottom, or a fish swimming in the middle of the lake, you have less oxygenated habitat to operate in than you used to,” says McIntyre.

This shrinking habitat is reflected in cores the team of scientists took from Lake Tanganyika’s bottom sediments. The remains of fish, algae, molluscs and small arthropods are preserved in the annual layers of sediment deposited in the bottom of Lake Tanganyika. By examining cores from the bottom of the lake, the team reconstructed a decade-by-decade profile of the lake’s biological history going back 1,500 years.

The team found that as the lake’s temperature increased, the amount of fish bits, algae and molluscs in the layers of sediment decreased.

You can think of the story playing out in Lake Tanganyika like a play, says McIntyre, “It’s not that the cast is changing, it’s that the amount of stage they have to work with is being reduced. That means fewer fish for people to catch and less habitat to support viable populations of the amazing diversity of life in Lake Tanganyika.”

“We know this warming is going on in other lakes,” adds Cohen. “It has important implications for food and for ecosystems changing rapidly. We think that Lake Tanganyika is a bellwether for this process.”

The study’s authors are Andrew S. Cohen, University of Arizona, Elizabeth Gergurich, now at the University of Oklahoma in Norman; Benjamin Kraemer and Peter McIntyre of the University of Wisconsin, Madison; Michael McGlue of the University of Kentucky in Lexington; James M. Russell of Brown University in Providence, Rhode Island; Jack D. Simmons, now at Weston Solutions, Inc. in Austin, Texas; and Peter W. Swarzenski, now at the International Atomic Energy Agency of Monaco.

The National Science Foundation, the Lake Tanganyika Biodiversity Project, the U.S. Geological Survey, the Society of Exploration Geophysicists Foundation, the Packard Foundation and the Nature Conservancy funded the research.

* This release is a modified version of the original version written by Mari N. Jensen at the University of Arizona.

Researcher contact:

Peter McIntyre

University of Wisconsin – Center for Limnology

pmcintyre@wisc.edu

+1-734-890-3416

Ben Kraemer

University of Wisconsin – Center for Limnology

Ben.m.kraemer@gmail.com

Andrew S. Cohen

University of Arizona

cohen@email.arizona.edu

After July 16: +1-520-621-4691

James Russell

Brown University

james_russell@brown.edu

+1-401-863-6330