What is going on? Here are links to the news stories:

2 million dead fish in Maryland: http://www.todaysthv...36846&catid=288
100 thousand dead fish in Arkansas: http://www.todaysthv...?storyid=136401

The short answer is that this goes on all the time, except now there's a group panic on the internets because everything is connected to everything instantaneously. It has little or nothing to do with global warming, the alleged "end of the earth prophecy" of the Mayan calendar for 2012, the return of the aliens or too many people taking Justin Bieber seriously.

Fundulus is right, but I would still like to understand the ecological factors behind it. I've seen massive squirrel migrations, June beetles (Phyllophaga) invasions, etc. All of which I understand.

Could it be a food chain collapse, associated with weather changes? It seems rather rapid for that but not entirely ruled out. Just some wild guesses but perhaps the northern range of the river begins migrating south as food gets scarcer leading the a rapid cascade food chain collapse. Perhaps also a sudden temperature inversion. Perhaps even oxygen depletion when too many fish are grouped in the same river segment due to winter migrations. Pollutants would exacerbated that situation. It doesn't look like something that would be very difficult to investigate, especially in areas where it can be expected to some extent every year. I would begin with a lot of real time temperature monitors, over an extended period prior to a die off, and some fish finders to do some basic statistics on directional flow and volume of fish. Perhaps google maps can give some clues, or rule out others.

Still curious, even though it's not abnormal.

Fundulus is right, but I would still like to understand the ecological factors behind it. I've seen massive squirrel migrations, June beetles (Phyllophaga) invasions, etc. All of which I understand.

Could it be a food chain collapse, associated with weather changes? It seems rather rapid for that but not entirely ruled out. Just some wild guesses but perhaps the northern range of the river begins migrating south as food gets scarcer leading the a rapid cascade food chain collapse. Perhaps also a sudden temperature inversion. Perhaps even oxygen depletion when too many fish are grouped in the same river segment due to winter migrations. Pollutants would exacerbated that situation. It doesn't look like something that would be very difficult to investigate, especially in areas where it can be expected to some extent every year. I would begin with a lot of real time temperature monitors, over an extended period prior to a die off, and some fish finders to do some basic statistics on directional flow and volume of fish. Perhaps google maps can give some clues, or rule out others.

Still curious, even though it's not abnormal.

Being primarily one species and during this time of year it has to be cold shock. Happens in the Great Lakes with Alewives too. As is said that doesn't stop the media from makes something out of it it is not.

Nothing is going on but a natural phenomenon that is getting a rediculous amount of news coverage with highly speculative and misleading headlines. It happens EVERY YEAR!!!! Spot and croaker have a lower thermal tolerance somewhere around 37-39 F. The water temperatures in the middle Chesapeake Bay dropped drastically to below 36 F in the days leading up to the fish kill. There are several real time monitoring bouys of USGS and NOAA that clearly show this temperature drop. Their is nothing complex about this. Some fish stayed around too long as they do every year. There are tens upon tens of million more spot in the Chesapeake Bay. There is no real complex answer to this and all the end of days talk is making me pull my hair out.

Yes it's worthwhile to drum it in people heads that this kind of thing is normal. There are certain people that will operate off whatever mythology they choose though, regardless of the facts. There are even flat earthers still kicking, facts don't mean much to some people.

There is an often repeated official quote concerning the Arkansas River die off:
http://www.msnbc.msn...ws-environment/

Officials said 95 percent of the fish that died were drum fish — indicating that the likely cause of death was disease as only one species was affected.

I'm not sure how disease likely follows from single species die off. The 95% looks to me more like species specific susceptibility rather that "single" species effect. Drum are benthic zone feeders and are not likely as hardy as catfish. It was Keith Stephens of the Arkansas Game and Fish Commission making these statements, but test results will not be available till early next month.

Massive squirrel migrations followed by a die off, and all sorts of ecological cycles, are perfectly normal, but get strange reactions from people when it's witnessed. Curiosity about the ecological factors is no excuse for feeding the myths people sometimes want to attach to such events, but it remains a valid source of curiosity.

The common thread seems to be species that occur in very large tight groups, either schools of fish or flocks of birds. I don't know anything about drum but I do know the redwing black birds roost in gigantic, very tightly packed groups. Something that might cause a few birds to die and go unnoticed, instead kills large numbers. But what is it?

I'm not taking any of the nutty stuff seriously but I gotta admit no explanation sits quite right with me.

This is exactly what happened when VHS hit in Lake Erie (although there were more perch in the first strike - but I wouldn't expect that species to be prevalent in the Arkansas), and I'd reckon the temperatures in the south were about the same in Arkansas (40-50 degrees). Did anyone get a good look at the fish? Were there bloody spots in and around the eyes? I couldn't make it out from any of the pictures I saw.

And what were the species in the Maryland kill? The pic I saw looked like some type of Clupeiform, and they're quite prone to freeze kill in eutrophic systems when they ice over suddenly because it cuts off the exchange of oxygen - bacteria decomposing dead algae burn up all the O2 under the ice.

I'd have to see a whole lot more to say anything conclusively, but those kills mesh up quite well with other known problems.

Todd

They were primarily spot and croaker, both Scianids, that make southerly migrations like most sport/commercial fish towards the southern part of Chesapeake bay during the winter. Spot especially school very tightly. When you find hardbottom and hook into a spot, you can hook into a hundred in an hour. There were probably some Cluepids mixed in just because there are several species.

If anyone would like further evidence that our unusually cold climate in the southern half of the country take a look at the current national weather map. Central Tennessee averages 8-12" of snow a year. The current forecast is for 8-10"+ and this is at least the second snow storm of this size in the past two months. Manatees in Florida are dying at such a rate that power plants with hot water discharges that would normally be closed because of lack of seasonal demand are being paid by the state to operate so they discharge hot water for manatees to survive.

Being primarily one species and during this time of year it has to be cold shock. Happens in the Great Lakes with Alewives too. As is said that doesn't stop the media from makes something out of it it is not.

There must be an echo in here.

Yes it's worthwhile to drum it in people heads that this kind of thing is normal. There are certain people that will operate off whatever mythology they choose though, regardless of the facts. There are even flat earthers still kicking, facts don't mean much to some people.

There is an often repeated official quote concerning the Arkansas River die off:
http://www.msnbc.msn...ws-environment/


I'm not sure how disease likely follows from single species die off. The 95% looks to me more like species specific susceptibility rather that "single" species effect. Drum are benthic zone feeders and are not likely as hardy as catfish. It was Keith Stephens of the Arkansas Game and Fish Commission making these statements, but test results will not be available till early next month.

Massive squirrel migrations followed by a die off, and all sorts of ecological cycles, are perfectly normal, but get strange reactions from people when it's witnessed. Curiosity about the ecological factors is no excuse for feeding the myths people sometimes want to attach to such events, but it remains a valid source of curiosity.

Personally to call it disease is absolutely ignorant IHMO. Granted disease many times follows soon after a significant stressor, but this seems to be cold shock and happens too quickly for a facultative pathogen to be the culprit. From my experience facultative pathogens are bacterium and they don't act this quickly and so suddenly. Most bacteria also aren't at the full strength in cold water.

If anyone would like further evidence that our unusually cold climate in the southern half of the country take a look at the current national weather map. Central Tennessee averages 8-12" of snow a year. The current forecast is for 8-10"+ and this is at least the second snow storm of this size in the past two months. Manatees in Florida are dying at such a rate that power plants with hot water discharges that would normally be closed because of lack of seasonal demand are being paid by the state to operate so they discharge hot water for manatees to survive.

I'm not arguing or disageeing, just trying to understand.
I know it was cold and snowed but doesn't it take more than a few snow storms to plunge the temps quick enough and deep enough for mass fish kills?
Aren't these temprorate species that are exposed to some cold naturally most seasons?
What about the birds? Coincidence only goes so far.

Believe me, I'm not an end of world nut, nor do I suspect secret government missle tests or any other foolishness. Neither am I arguing to be difficult. I'm trying hard to wrap my mind around this and having trouble.

Personally to call it disease is absolutely ignorant IHMO. Granted disease many times follows soon after a significant stressor, but this seems to be cold shock and happens too quickly for a facultative pathogen to be the culprit. From my experience facultative pathogens are bacterium and they don't act this quickly and so suddenly. Most bacteria also aren't at the full strength in cold water.

I have to agree with you. Even the reason the fish and game guy gives seems to point more toward cold to me. I guess the test early next month will say more.

I'm not arguing or disageeing, just trying to understand.
I know it was cold and snowed but doesn't it take more than a few snow storms to plunge the temps quick enough and deep enough for mass fish kills?
Aren't these temprorate species that are exposed to some cold naturally most seasons?
What about the birds? Coincidence only goes so far.

Believe me, I'm not an end of world nut, nor do I suspect secret government missle tests or any other foolishness. Neither am I arguing to be difficult. I'm trying hard to wrap my mind around this and having trouble.

You can kill fish in water that's not too cold for them to live in just by changing the temperature too fast. That's why in aquariums we let the temperature equalize before dumping fish into a new aquarium. It's not just air temperature over a particular part of the river that chills the fish (or water) so fast. In a river situation you can easily have much colder water coming from upstream dropping temperature extremely rapidly as it moves downstream. If cold water is dumped in from a tributary then it will rapidly sink to deeper areas, as hot water (like air) will rise. The Drum were in fact bottom feeders, right where the cold water is going. Here's a little experiement you can do to demonstrate the effect:
http://www.explorato...watertrick.html

It's a lot like being out on a hike and getting caught in a "Blue Norther". It's not any fun... I got caught in one on the property in the Ozarks once, and in spite of the trees it was like the wind was blowing almost straight down, with over a 30 degree drop in temperature in under 10 minutes. Wind went from zero to over 30 mph real quick, so the wind chill made it far worse.

The more I think about it the more cold makes sense and even explains why Drum were primarily effected. Normal heat conduction (diffusion) in water when the temperature is dropping makes the deeper water more thermally stable, or cools slower. Due to the diffusion by the time it reaches the bottom. This is where the Drum will be feeding. However, the heat transfer is far different when you have much colder feeding a main channel from a tributary.

In effect, this much colder column of water from a tributary will effectively head straight to the bottom upon entering the main channel without any effective diffusion or mixing. The temperature difference, with cold on the bottom, actually slows heat diffusion exacerbating cold shock for the bottom dwellers. Just like the linked experiment above. Eventually the boundary layer between the temperature variance will diffuse. This would explain the 20 mile stretch in which the Arkansas fish kill occurred. Once this cold bottom column diffused sufficiently with the rest of the river water the cold shock kill would stop.

I'm just guessing, based on the physics, but makes a lot of sense to me.

I'm just guessing, based on the physics, but makes a lot of sense to me.

Thanks for the physics lesson.
I guess the past 40 years of catching fish through the ice of frozen ponds as I have done has defied science.

That's why in aquariums we let the temperature equalize before dumping fish into a new aquarium.

And thanks for the husbandry lesson. I guess four decades of fish keeping didn't learn me nuthin neither.

Unless the cold comes on extremely fast, the fish move to thermal refuge to avoid it.
I didn't think the weather was extreme enough to catch so many fish in so many different places away from the reach of warmer water.
This ain't the first cold winter to ever happen. How'd so many cold sensitive temperate species survive this long?

I think one possible explanation for many of these mass deaths is large numbers of somewhat cold-slowed fish entering hypoxic areas, and not being aware enough or able to leave before mass mortality. This could especially be true in a place like Chesapeake Bay which has any number of pollution problems.

One thing I learned after I made my last post was that the low end temp for spots is 39 F which is what the temp would be at the bottom in a stratified frozen pond without springs. If they were trapped in shallow water and could not reach deeper water for extended period of time, the water could drop below that temp [very shallow ponds, 3 foot deep or less, up here can freeze to the bottom which obviously kills all the fish].

One thing I couldn't find before I lost interest was just what the weather was in each of the places being reported.
Neither could I find any historical stories of birds falling dead en masse.

For historical accounts of mass bird and fish deaths, rains of frogs and fishes, etc., check out the collected work of Charles Fort from about a hundred years ago. Fort was an eccentric collector of news accounts of these anomalies which he published in a series of volumes. These accounts are largely true, at least in part. Much of Fort's work is available in inexpensive reproductions from Dover Press. These "Fortean" phenomena are where rational science seemingly meets craziness, although today many such phenomena can be explained by water spouts, etc. I think Fort did collect reports of such mass die-offs from the late 19th century, which reinforces my view (and that of others) that these are natural phenomena that occur at irregular intervals. Nowadays of course the Internets spread any such stories very quickly, which makes them loom larger in the collective view. I'll have to dig out my Fort volumes...

Thanks for the physics lesson.
I guess the past 40 years of catching fish through the ice of frozen ponds as I have done has defied science.



And thanks for the husbandry lesson. I guess four decades of fish keeping didn't learn me nuthin neither.

Unless the cold comes on extremely fast, the fish move to thermal refuge to avoid it.
I didn't think the weather was extreme enough to catch so many fish in so many different places away from the reach of warmer water.
This ain't the first cold winter to ever happen. How'd so many cold sensitive temperate species survive this long?

Your right, the last paragraph with rapid cooling is the key to getting a kill off. Your also right that the physics involved in normal freezes encountered when ice fishing wouldn't do it. There is nothing wrong with the science involved in the experience acquired from years of ice fishing. It remains perfectly valid. The question is how the usual conditions differ to produce the rapid benthic zone cooling needed to produce a kill off.

To get this rapid a cooling in the benthic zone the cold cannot come from surface cooling, no matter how cold the air temperature above is. This rapid cooling had to come from chilled water upstream, likely a tributary. Even with this cold water coming from upstream, if the cold water merely mixes with the warm water as it flows downstream it still fails, under all but the most extreme circumstances, to produce a kill off. The point of the physics involved then is how a cold tributary feeding into a warmer main channel will not result in an effective 'mixing' of that warm a cold water. Once mixing is accomplished the danger of a kill off is past.

In a laminar flow of warm and cold water, rather than merely mixing, the cold water will form a subchannel with much colder water at the bottom of the channel, much colder than surface water temperature sensors will indicate. The temperature transition across this boundary layer can have an intense temperature variance over just a few inches. Furthermore, this hydrodynamic boundary layer in a laminar flow will produce a boundary which resist effective mixing of the water across this boundary. This is why I said it explained a 20 mile length of river in Arkansas being effected, because eventually mixing does occur, which would end the kill off effect and the usual thermodynamics of the flow returns to normal.

So I wasn't berating or suggesting any lack of validity of the science gained through experience, I was merely trying to describe the circumstances under which the usual thermodynamics of the situation no longer applied. Much like a tornado or hurricane can't be described as just a warm front, a benthic zone cold flow can't be described as just cold water. A similar boundary layer separation exist inside and outside a hurricanes eyewall.

If this model of winter fish kills is correct, there are ways of greatly reducing these kill offs. The key is in the dynamics of laminar flows. Any turbulent flows in the river will tend to force mixing of the water, destroying the boundary layers that maintains non-mixing cold flows. Normal meandering in rivers tends to have this effect at bends in the river to some extent. A series of subsurface boulders, strategically placed to interfere with the flows created by previous boulders, could also have a significant mixing effect. Certainly, you wouldn't want to create any shipping hazards though. Also, tributaries with embankments that forced a significant portion of the water to exit into the main channel a few feet upstream after mixing begins would also force a lot of thermal mixing.

I'm not sure that preventing these kills is an ecologically advantageous idea though. Not only does it weed out a lot of weaker fish, it also provides a significant winter food sources for other birds and mammals.

One thing I learned after I made my last post was that the low end temp for spots is 39 F which is what the temp would be at the bottom in a stratified frozen pond without springs.

The particular fish kill model I was suggesting indicates that the bottom temperature could have been far colder. Not from local air temperatures, as you have noted from experience that would be essentially impossible, but from much colder water being feed into the system from upstream.