Before you read this story blaming the universal bogeyman ‘climate change’ for the decline in yellow perch, it might be a good idea to listen to what the fishermen and other researchers have to say:
Scientists studying the lake and fishery say there are numerous reasons why. They include changing water quality and clarity and the effects of recent warming trends. Yellow perch are a cool-water species.
Recent study findings, however, also suggest that Lake Erie’s booming white perch population has had more of an impact than previously thought. They prey voraciously on tiny yellow perch.
“The numbers are staggering,” said Stuart Ludsin, an associate professor of evolution, ecology and organismal biology at Ohio State University. Ludsin has been studying the lake and its fishery for 20 years.
“There are between 46 million and 106 million predators in the western basin of Lake Erie. In just 24 hours they can consume between 32 million and 189 million yellow perch larvae. That is an enormous number.
“We don’t have that broken down by how much each eats, but I can tell you that white perch make up 90 percent of the predators. It is the most abundant predator in the lake. Period.”
Walleyes and white bass also prey on larval yellow perch. Even adult yellow perch will “cannibalize” their own young, according to Ludsin, but nothing approaches the volume that white perch eat. His evidence was found in white perch stomachs.
Full story in Michigan Outdoor News: Increasing white perch affecting Erie’s yellows
Also, this EPA report on Yellow Perch in Lake Erie doesn’t mention climate change or global warming at all. They do have this graph, which has an interesting peak in 1979, one of the coldest winters for Lake Erie ever, so it appears that there is some sensitivity to temperature, but it seems more weather than climate related. I agree that temperature is a factor, but this looks to be more of a case of weather, not climate.
![yellow-perch[1]](https://wattsupwiththat.files.wordpress.com/2015/07/yellow-perch1.gif)
And according to the Michigan Outdoor News article, the predators got a kick-start in the 1980’s:
“In the 1980s we had a series of four very warm winters. That allowed the small adult population of white perch to survive and get off several very strong year-classes. The white perch population then exploded,” Ludsin said.
And the EPA article from 2009 says:
There also may be an inverse relationship between the peak walleye abundance periods (late 1980s-early 1990s, and more recently since 2003) with yellow perch abundance. When walleye abundance is very high, it appears that yellow perch abundance declines and probably is due to predation (Thomas 2006).
So it seems predation is the dominate factor, followed by weather, and I’m betting the “climate change” angle was thrown in to grab headlines. Some scientists, like fishermen, know what bait to use to reel in the big ones.
From Ohio State University: Climate change threatens one of Lake Erie’s most popular fish
Short, warm winters spell trouble for young yellow perch
![435[1]](https://wattsupwiththat.files.wordpress.com/2015/07/4351.jpg?quality=83)
COLUMBUS, Ohio – Research has suggested yellow perch grow more rapidly during the short winters resulting from climate change, but a new study shows warmer water temperatures can lead to the production of less hardy eggs and larvae that have trouble surviving these early stages of life in Lake Erie.
The research also showed that yellow perch don’t adjust spawning to match earlier spring-like temperatures. This poses a problem if the hatchlings’ main food source, zooplankton, does make a temperature-based adjustment because supplies may be low by the time larvae are ready to feed.
“If not enough food is available, the larvae will grow slowly and be vulnerable to predators like invasive white perch,” said Stuart Ludsin, principal investigator of the study and an associate professor of evolution, ecology and organismal biology at The Ohio State University.
On average, eggs produced in long, cold winter conditions in a lab experiment were 30 to 40 percent larger and their hatching success was between two- and four-fold better than the smaller eggs produced under warm, short winter conditions.
The survival problem could help explain why yellow perch numbers in Lake Erie have been low since 2003, and stand at only about half of the average fish population recorded during its heyday in the 1960s and ’70s.
“There are a lot of factors that can help explain why yellow perch numbers are low in Lake Erie. The warmer winter temperature clearly is an important one,” said Ludsin, also co-director of Ohio State’s Aquatic Ecology Laboratory. “For management agencies, there is no easy fix to this problem.”`
The study is published in the journal Nature Communications.
Ludsin first saw a relationship between warmer winters and reductions in the annual abundance of juvenile yellow perch in Lake Erie while working on his dissertation at Ohio State more than 15 years ago. He has spent much of his career working with Lake Erie fishery managers to try to explain why yellow perch numbers have fluctuated so dramatically over the past four decades.
For this study, the researchers combined long-term fisheries assessment data, a lab experiment and fieldwork to gauge the effects of warmer winters on one of Lake Erie’s most popular fish among commercial and recreational anglers.
Yellow perch live on the bottom of Lake Erie, where water temperatures are about 40 degrees Fahrenheit (4 degrees Celsius) during the winter, said lead author Troy Farmer, a postdoctoral fellow at Auburn University who completed this work as a graduate student at Ohio State.
The scientists collected wild yellow perch from the lake with the help of state and federal biologists. In the lab, the scientists exposed different groups of fish to historic cold winter conditions or to warmer temperatures that have been recorded in more recent years.
Farmer said a long winter in the lab featured 107 days of water temperatures below 42 degrees Fahrenheit (5 degrees Celsius), which represented the average winter duration over the past 25 years. Under short winter conditions in the lab, the temperature remained under 42 degrees Fahrenheit for only 52 days, mimicking the length of the winter recorded in 1999.
“Our temperature treatments represented environmentally relevant conditions that are already being experienced by fish populations in Lake Erie,” Farmer said.
Females exposed to warm, short winter conditions produced just as many eggs as their counterparts experiencing a long winter, but egg quality differed: They were smaller and didn’t hatch as well, and eggs that did hatch produced unusually small larvae.
Yellow perch also don’t show signs of adapting to warmer temperatures by fully adjusting when they spawn, Ludsin said. In both the lab and the field, the researchers observed that females continued to spawn in the historically typical months of April and May even when air temperatures reached the 80s in March in 2012.
“In lots of cold-blooded species, we find that as spring occurs earlier, the timing of reproduction will also move forward,” Ludsin said. “Walleye are a great example. In the record short winter of 2012, walleye moved their spawning period up by several weeks. With yellow perch, we didn’t see that.”
The supply of zooplankton that yellow perch larvae eat can peak early along with warm weather. If food is scarce at the time eggs hatch, larvae will grow slowly and remain vulnerable to invasive white perch, a key predator in Lake Erie.
“If we didn’t have that predator in the lake, the larvae that actually hatch after a warm winter might be able to survive just fine. But having short winters lead to low-quality larvae is a big disadvantage because of the risk of getting eaten,” Ludsin said.
The research doesn’t explain the biological mechanisms behind these reproduction problems for yellow perch.
“Yellow perch might have an inability to adjust their spawning to take advantage of those warm temperatures when they occur,” he said. “Is there something hard-wired in them, like some physiological limitation, or an effect of temperature on hormones? We just don’t know.
“It could be that we’ll have to wait for adaptation to occur because there is no obvious quick fix. And, other ongoing stressors like nutrient pollution that causes low-oxygen zones and harmful algal blooms in Lake Erie don’t help the situation,” Ludsin said.
Ludsin also is principal investigator on a state-funded study looking at potential human health concerns associated with eating yellow perch and walleye caught from areas of Lake Erie affected by harmful algal blooms.
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The yellow perch study was funded by the Federal Aid in Sport Fish Restoration Program, administered jointly by the U.S. Fish and Wildlife Service and the Ohio Division of Wildlife, the Great Lakes Fishery Commission’s Fishery Research Program, a Norman S. Baldwin Scholarship from the International Association for Great Lakes Research and a Presidential Fellowship from Ohio State.
The Ohio State research team also included co-authors Elizabeth Marschall, chair of evolution, ecology and organismal biology and co-adviser with Ludsin on Farmer’s graduate work, and Konrad Dabrowski of the School of Environment and Natural Resources.
Many predators, including man…
Mike Durkalec is an aquatic biologist with Cleveland Metro Parks. He ticks off other issues worrying him and fellow fishermen along the Rocky River.
“Some of those would include runoff of phosphorous in particular from agricultural areas, it has caused harmful algae blooms,” says Durkalec. “Non-native species is another one. One big one that affects this particular fishery is the sea lamprey, a non-native species of parasitic fish that does have an effect on the sport fish that these anglers are pursuing.”
Trout Unlimited says annually, an estimated 450,000 people fish the Ohio waters of Lake Erie.
http://www.ideastream.org/news/shale-development-biggest-threat-lake-erie
White perch came up through the canals. They used to be known as white bass when I was a kid. In Lake Champlain they appeared about 20 yrs ago. Now lake trout, which spawn heavily in this lake, never get past the fry stage. Yellow perch are still very strong in this lake, but we don’t gill net them here the way they do, or did when I lived there, on Lake Erie.
I have fishfinder images of schools of them that look like a whale. One time I stopped the boat after seeing a school about 40 ft down that was 15 feet thick and we fished for them with a three fly rig and brought up over a hundred of them three at a time til we got bored. We drifted about a half mile at a time and never got off the school. Fortunately you can eat them, but they don’t taste as good as yellow perch. And yellow perch are *not* a cool water fish, they are considered garbage fish in warmer waters because of parasites, but they can grown there fine.
The only lakes where yellow perch are considered ‘undesirable’ are lakes where they’re overpopulated and severely stunted. Any lake where you can catch decent sized yellow perch they’re considered highly delectable and very desired.
I’ve lived up and down the East coast and am currently living in a ‘warm water’ state.
White perch are also very delectable, very much similar to their cousins the white bass and striped bass. White bass and white perch are two different species that can interbreed with fertile hybrids; unlike most white bass x striped bass crosses which are sterile.
Both white and yellow perch make for excellent fried fish dinners.
White perch and white bass are two totally different fish.
Perched on the brink.
Following up on GamegetterII’s and dp’s comments above:
Yellow perch are a schooling fish during much of the year and targeting the larger adults means finding the school those fish are in, often out in deep open water; making it tough fishing for the shore bound angler.
Fisherpeople learned long ago that yellow perch gathering for spawning was one of the best times for shore bound anglers and requires fishing during spring thaw near or under the edge of the ice and in the same area till shortly after ice-out. Ice edge fishing is one of the first indications that yellow perch spawn during certain temperature conditions, an early spring vs late spring doesn’t matter to the fish.
From the ‘Outdoor News research announcement’;
Hallelujah! They found yellow perch dna in the white perch’s stomach! Oddly there wasn’t any sign of yellow perch, so immediately the researchers ruled out all possibilities but the preferred bias.
What if!? The yellow perch dna came from the digestive tracts of white perch consumed small fish that do prey on yellow perch larvae and minnows. Just because the researchers found something does not indicate in any way how that material got there, assumptions only pander to their bias.
From “NAS – Nonindigenous Aquatic Species”:
From their preferred native range, I seriously doubt that white perch ‘favor’ warm water.
Looks like another false assumption by the researchers.
A very odd assumption and statement by the researchers regarding a topic they did not investigate.
What is very odd, several of the online references to Lake Erie reference how much cleaner the water of the lake is. Some attributed the clean water to the influence of EPA, most attributed the cleaner waters to the invasive ‘zebra mussel’.
Well, there is a ‘duh’ finding.
What is very disturbing is the discussion regarding one river, Maumee river in Toledo, Ohio. What about all of the other rivers around Lake Erie? No mention about other rivers leaves us with the disturbing thought that this research was very narrow and very locale restricted; but there appears to be little restriction regarding attribution to all of Lake Erie.
From “Great Lakes Perch Boom” article posted April, 2014 (as mentioned by dp, above)
In the same article are some notes regarding factors leading to ‘reduced’ yellow perch recruitment affecting yellow perch populations. A major impact to yellow perch larvae;
Another noted impact that curtailing had beneficial results;
Ludsin finishes his announcement with;
Notice that ‘viable’ adjective? A description that is intended to convey a meaning of ‘less viable’ eggs at other times, yet there was no investigation into egg viability, nor is there supporting ‘lack of egg viability’ true research brought into the article.
Again there is that sole locality point reference indication just how limited the research truly was.
No mention of the various state DNR departments around the Great Lakes that have online information regarding the current health of the yellow perch fishery.
Lots of unproven or unverified assumptions makes this research another less than definitive confirmation bias piece of cr@p.
This is the most current thing I could find quickly for Ohio.
http://wildlife.ohiodnr.gov/fishing/fishing-forecasts-and-reports/the-fish-ohio-report
You’d think the limit would be lower based on the paper.
Historic Lake Erie water temperature, °F, max/normal/min for July 16 between 1927-2012: 76/71/64.
Optimum temperature range for Yellow Perch: 66–75°F.
Current Lake Erie temperature: 68°F.
There are factors other than predation that could have an effect, but I don’t think climate change is responsible for agricultural runoff and the failure of Detroit’s sewage treatment system.