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Posts: 227
Location: New Brighton, MN | I saw on the local news last night, a story about Wisconsin lakes in general. It was claiming that due to the long, cold winter and high snowfall, that Wisconsin lakes would have low levels of oxygen, and expect some levels of fish to die as a result. Actual numbers of lakes/fish affected are yet unknown.
I don't think this past winter was anything too special. Snowfall was pretty close to normal. I can't believe that the oxygen levels would be out of the ordinary. They tied it to an informative story about VHS, which is good, but I wonder if this is just media hype to get our attention? Can anyone confirm/deny it? |
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Posts: 224
Location: Madison | a story about Wisconsin lakes in general.
Snowfall was pretty close to normal.
Not anything close to normal in Madison. Average snowfall is about 44" a season, record WAS 88" we are currently over 100" and more is falling outside right now. |
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Posts: 159
Location: Stevens Point, WI | True that, i know most places in the state are over 100" right now, with more on the way today. We fished a shallow lake a few weeks ago with some floating fish in it, and all the live ones were just under the ice with their backs up against the bottom of the ice. That doesn't look good. Yesterday i measured 36 inches of ice, and that's not normal for the end of March, either. At least not here. Some fish die somewhere every winter (more due to dying vegitation than snow, i think), but having a harsh winter will just increase numbers of dead fish on shallow lakes. |
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Posts: 16632
Location: The desert | 12gauge - 3/27/2008 11:50 AM
Some fish die somewhere every winter (more due to dying vegitation than snow, i think), but having a harsh winter will just increase numbers of dead fish on shallow lakes.
The decomposition of the dead plants is what is causing the lack of oxygen in the lakes. All the oxygen is sucked up by the decomposition process, the longer the ice is on the lake the longer the plants decompose and the more oxygen is removed from the system. The high level of snow and ice is hindering sunlight to get to the plants to start the 'growing' season, which gets photosynthesis going which puts oxygen back into the system. So the snow and dead vegitation go hand in hand. We need some spring conditions soon, winter sucks! |
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| Mike, what role do you see phosphorus/nitrogen concentrations playing in this? As I understand it, runoff from heavy snow pack washes a lot of phosphorous and nitrogen out of the soil and into the lakes, making them too fertile, which leads to a host of other issues as well. Is this going to be a bad year for watersheds in general, algae blooms, high bacteria counts, fish kills, etc? Or is that offset by the extra volume of water?
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Location: New Brighton, MN | Wow. I had no idea there was that much snow down south. My mistake. |
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Location: The desert | Jeff,
It could lead to some more fertile than normal waters, but I honestly am not really sure. I'll have to ask next monday in Water Chem as we are just getting to that area of study next week. I'll let you know what I find out. |
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Posts: 299
Location: Nowheresville, MN | The plants decompose whether there is snow or not. Snow and cloudy ice blocks light and phytoplankton decreases; = more respiration then photosynthesis. Some MN lakes winter-killed in January. In general, winter-kill is a normal event for lakes and a good thing for the fish populations in them. This referring to shallow lakes. I would only be concerned if it happened in a lake without a history of a kill.
Nutrients reach lakes in many ways, runoff being the biggest contributor. Definitely not offset by extra volume. Extremely difficult to get nutrients out once they get in. |
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| Rough fish species are normally the first fish to die off when the oxygen level decreases. I'm not sure how bad things are over there, but I haven't seen to much concern so far. Hope it's not too bad. |
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Posts: 158
Location: Burlington, WI | PointerPride,
Since you are studying biology (I think) I was wondering if you ever came across some data involving phosphorous levels in different types of water. i.e. inland lakes, rivers, or reservoirs. The reason I am asking is because I live on a private 24 acre lake where two different drain tiles from fields flow into the lake and also a ditch line eventually flows into the lake as well. I have access to testing the levels of phosphorous as I work in a lab that tests for that. I am curious to see how much PO4 is draining into the lake from the fields via fertilizers and manure. I know in the summer when it rains the algae blooms can get crazy. In comparison, a few years ago when we didn't have much rain the water was clearer than I had ever seen it before. I think that is a pretty good indication of what is going on, but I would still like to run some tests. Thanks. Thought I would ask.
Greg |
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Posts: 90
Location: ne53 | It has happened to a few of our smaller lakes here in Nebraska. |
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Posts: 299
Location: Nowheresville, MN | Derrys - 3/27/2008 6:35 PM Rough fish species are normally the first fish to die off when the oxygen level decreases. If you consider trout, walleye, LMB, sunnies and crappies rough fish!! You didn't ask me, but I'd bet you'd think twice about swimming in that pond after a rain event.
Edited by tfootstalker 3/27/2008 7:24 PM
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| I fished a lake for Bass that had supposedly froze out. I talked to a guy about it and I thought he said the Rough fish species die off first, but after thinking about it, I think the Game fish species would be the ones to die off first, so I believe you're right and he mis-spoke.
Oxygen deprivation, or Hypoxia, has also been linked to decreases in reproduction. In a study done a while back fish that were deprived of oxygen reproduced at a rate of 20% of what the fish in an oxygen-rich environment produced. So even if the "winter kill" isn't too bad, the effects of it can still be detrimental.
I'm currently working on a project dealing with Hypoxia and Muskies, so some of this information I'm finding is really interesting.
Good fishing.
Edited by Derrys 3/27/2008 7:55 PM
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Posts: 299
Location: Nowheresville, MN | Black bullheads are the last fish left in a lake. I didn't say anything about esocids. The jury is out on suckers, but is believed they can tolerate low oxygen (2 ppm). Tullibee, well, not a rough fish in my mind.
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Location: oswego, il | From what I have read, bullheads, perch and pike have low oxygen tolerance. I am not sure where muskies lie, bass do not tolerate low levels and shad die if you look at them kinda funny.
I think this winter was harder than normal and lots of snow to cover the ice. I bet ponds down here winterkilled. I think a good test for the winter up north would be irving and white birch lakes. They winterkill during bad winters. |
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Posts: 178
| This has been a VERY tough winter on fish in shallow, productive lakes in northern Wisconsin because the onset of ice and snow cover was early, and because the snow has remained at least a few inches thick atop the ice to date. What most folks don't realize is that it takes only a few inches of snow to absorb virtually ALL of the light of the wavelength needed by planktonic algae to photosynthesize and produce oxygen. So it doesn't matter if we have 4 inches of snow that lasts all winter or 100 inches of snow that falls sporadically. As long as there is at least a few inches of snow (or even extremely milky, opaque ice), there will be very little oxygen production occurring by planktonic algae under the ice. Under such circumstances, dissolved oxygen gets used up via the process described accurately above by Mike Bolinski. The dissolved oxygen disappears near the bottom first, where there is more organic material for bacteria to consume. In a chronic winterkill lake, the last refuge of dissolved oxygen occurs just beneath the ice. That's where the fish will be until the snow melts and light penetrates. If winter lasts too long, most of the fish will die under the ice. The shallower the lake and the more dead organic matter (muck) on the bottom, the greater the risk that oxygen depletion will cause a fish kill before the long winter ends.
Dave Neuswanger
Fisheries Team Leader, Upper Chippewa Basin
Wisconsin DNR, Hayward |
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Posts: 84
| Well I was just walking out around Shabonnah in Illinois today the ice is finally off. There were 8 to 14 inch dead gizzard shad everywhere. Hundreds of them, maybe thousands. A few walleye and to my count 8 muskies up to about 45 inches. The smallest was about 36". Never saw any other species. The gizzard shad where the most predominant by far and then muskies second. I was only able to walk about a quarter of the lake, so who knows how many died. I have never seen this many dead fish on that lake ever. No matter which direction the wind was blowing there were dead fish on the shore.
Rick |
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| Heard about this a few weeks ago and never thought much of it..until last week, we targeted a few lakes with inlet creeks coming from other lakes and went to check out the shallow water by the mouth of the creek. We did some of the best fishing all year for 3 days straight. Limits of nice eater gills perch and crappies, hundreds of fish caught and released....Caught more walleyes in 3 days that we did on our best day of early ice flowage fishing, 90% were legal size with a few smaller ones, caught too many northerns for my liking..lot of nice ones though. Also saw 2 of the biggest muskies I've seen all winter (haha) it may have been the same one but it was 2 days apart and this fish's head was wider than an 8inch hole and it's fins were the size of some of the gills we were getting..All this while fishing not more than 5 inches under the bottom of ice, with about 19" of ice. Talk about nuts. Thinking about heading back out there today but 2 days ago we were literally cornered into our spot by 25 other vehicles. The early bird gets the worm...dumb friends sleeping in.
Fish swarm to oxygen in these conditions I've always heard..so I'm assuming that the levels are really low in a lot of our shallower lakes. |
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Location: oswego, il | Rick, I was out there. not only were there dead shad everywhere, there were dying shad everywhere. Then there were shad just sitting there like they were going to die. You could hit them with the rod tip, my boat partner even scooped an upright shad out of the water and chucked it at me. They were everywhere. Anytime I have seen this situation with dead, not rotten shad and dying shad, there is not a musky to be had. Why chase a meal if you don't have to.
I did not see any dead muskies but talked to a guy who seen one. Seen a big dead bass and a couple carp.
This also begs the question about oxygen levels. When does the oxygen recover? When the ice melts? Runoff? Higher water temps? |
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Posts: 178
| Folks, it's worth noting here that gizzard shad die sometimes even when there are no problems with low dissolved oxygen. They are intolerant of prolonged cold, so long winters are particularly hard on them. That's why you don't see them further north. Massive overwinter mortalities of gizzard shad occur routinely in the northern part of their range. I just thought it would be worth distinguishing them from other species that may be seen dead under the ice or at ice-out.
Dave Neuswanger
Fisheries Team Leader, Upper Chippewa Basin
Wisconsin DNR, Hayward |
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Posts: 20248
Location: oswego, il | Dave, I would agree with that. I used to fish pool 13 on the mississippi alot and remember seeing thousands od dead shad along the banks in the early spring. A biologist told me at some point they stop eating during prolonged winter, digest their internal organs and die. I am going to assume that that the reason for that is that plankton are not avaiable to eat. |
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Posts: 720
| This may be a stupid question then. Do lakes with more fertile characteristics like the Madison chain have more of a potential for winter kill than say a Canadian sheild lake?
Dave |
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Posts: 2894
Location: Yahara River Chain | Hunter4 - 3/31/2008 7:49 AM
This may be a stupid question then. Do lakes with more fertile characteristics like the Madison chain have more of a potential for winter kill than say a Canadian sheild lake?
Dave
I would guess yes as there is more biological activity going on in the Madison Chain than most Canadian Lakes and therefore that activity takes up Dissolved Oxygen and then DO depletion is greater. But because of sizes of most of the Madison Chain (and current) it is not likely to have much winterkill, however, in smaller lakes - very much so. |
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Posts: 84
| Todd
I was back out there yesterday with the boat fishing and saw alot of dying pan fish as well. The majority of the dead muskies were down by the dam. I also saw one in east bay. I know long cold winters create shad die offs. But this is alot larger than usual. I am more concerned about all the dead game fish.
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