Hurricanes and fish kills?

[Barnacle Bill]

When a hurricane comes in on one of the gulf states do you have problems with fish kills? When we had our last one (Isabel) we had a major fish kill. But what I noticed was there were very few dead crappie. A lot of shad, bream and what really surprised me was catfish. Nothing very big unless the bigger ones didn't float to the top yet. A few months later we were catching some of the biggest crappie I've seen come out of that river in a long time. I'm guessing that the kill is caused from all the salt water getting dumped in there causing the brackish water to get too salty.

[kygorski]

When a hurricane comes in on one of the gulf states do you have problems with fish kills? When we had our last one (Isabel) we had a major fish kill. But what I noticed was there were very few dead crappie. A lot of shad, bream and what really surprised me was catfish. Nothing very big unless the bigger ones didn't float to the top yet. A few months later we were catching some of the biggest crappie I've seen come out of that river in a long time. I'm guessing that the kill is caused from all the salt water getting dumped in there causing the brackish water to get too salty.

I'm not anywhere near salt water, but late last summer, in conjunction with a storm on the gulf, our lake here in Ky rose 18 ft in just several days, there was alarge fish kill because of the temp. switch, and the disruption of the thermacline, also the federal fish hatchery lost all its fish because of the water temp change.

[Moose1am]

If there is a sudden influx of salt water into those rivers it can kill fresh water fish it the salt content gets too high. Not sure how far inland or upriver the salt water can go.

As for rainfall killing fish in the summer time you might think about what's in the rain water more than the temp of the rain water. Rain water contains Carbonic Acid which forms with the rain drops fall though an atmosphere full of carbon dioxide gas. Carbonic Acid will form naturally this way. You can take a beaker and fill it with water that has a pH of 10 and then blow though a straw into the beaker with your breath and drop the pH of the water in the beaker immediately down to below a pH of 7. This is due to the high concentration of carbon dioxide in one's exhaled air.

Also there are many power plants that emit lots of sulfur into the air. This SO2 gas forms when coal with inorganic or organic sulfur in the coal is burned. Some coals have as much as 10% sulfur in them here in the midwest. These are high sulfur coals. The SO2 combines with H2O and forms H2SO4 which is sulfuric acid. The sulfuric acid mist can travel over 500 miles from Southern IN where I live and be deposited on the tops of the Smokey Mountains in North Carolina and beyound.

It's been documented that trout raised in fish ponds along the Eastern USA have died after a rainstorm that deposited rain water with a very low pH. The rain water fell into these small swimming pool sized trout farm waters and drop the pH of the water and this is what killed the trout.

I wonder if you live in Eastern KY?

Most lakes in Western KY have plenty of limestone along the lake bottom and in the watersheds and this limestone will neutralize any low pH rain water and act as a buffer to keep the pH of the lakes water from changing too quickly

If you have access to a pH meter you can collect some rain water and see what the pH of that rain water is. I did this a few times and found that the water falling in Evansville,IN back in 1977 had a pH of 4.3. That is very low and that water was full of acid.

Acid can come from other sources too. Nitrogen is found in fuel of many types and when that fuel is burned at high temps it's oxidized and NOX forms. NOX is a symbol that is used to denote NO2 and NO gas which react so quikly with each other that we use NOX to describe the combination of the two gases. Both are highly corrosive and mixed with water vapor and other chemicals in the air form Nitric Acid which you don't want to mess with. If you look out over the horizon at dawn or dusk and see a redish brown color in the sky that is due to the NOX in the atmosphere and the sunlight coming in at a low angle to the earth and traveling though more of the earths atmosphere at that time of the day. When you fly over a major city and look down you can sometimes see the brown haze that forms a dome over the entire city.

NOX comes from cars, trucks, trains and planes as well as power plants.

The combination of NOX and H2SO4 in the atmosphere can drop the pH of the rain 1000 times below it's normal pH levels.

Summer time thunderstorms rain water coming from very high up in the cold atmosphere should have colder water and it should drop the temp of a lake when it enters the lake. Cold water holds more dissolved oxygen which is good for the fish. Unless the rain water is washing something off the land into the water I don't know how it could kill the fish. Fish can easily drop down or up to find the right water temp and dissolved oxygen content. Now if the lake is very small then it might experience a large temp swing. But if thunderstorms kill fish we would see a lot more fish kills. Thunderstorms are a natural phenomia and fish have learned to live though them over the years. You could say that fish evolved along with thunderstorms. But the phenomia of air pollution due to the industrial revolution is a new thing to the fish and they are still trying to adapt to man's pollution.

I would think that heating of the water would drive the O2 out of the water and that could kill the fish.

I am sure about the pH being a main cause of fish kills especially on Canadian Shield Type lakes that lack the Limestone in the ground that neutralized the acid rain. Acid rain and it's causes and effects have been studied thoroughly.

I know that the smokey mountains lakes much aquatic life due to the acidity of the rain water that falls there these days. Only some sections like Abrams creek have enough limestone in the stream beds to help neutralize the acid rain that falls on the smokey mountains. The upper parts of the mountains are all igneous rock and there is very little sedimentary rock like limestone in the upper parts of the Smokey Mountains. Most of the acid rain water that falls on the upper reaches stays acidic and the aquatic organisms can't survive in acidic water. So there are few bugs for the trout to eat up there. Also low pH water makes it hard for the trouts eggs to hatch or the fry to survive.

If you want to kill your minnows or fish in an aquarim just change the pH of the water by 1.0 pH units/hr and see what happens. Often when you setup an aquarium at home the pH of the tap water has to be tested to see what it is. Then chemicals Acids or bases must be added to the tap water to set the waters pH to 7.0 or somewhere close to 7.0. Different fish may require different water pH's. But a pH of 7.0 is neutral.. neither acidic or basic.

Most freshwater fish prefer a neutral pH in their water. Waters with pH's below 5.0 can't sustain many fish and waters with pH's above 10 won't harbor many fish either. Keep the pH levels between 6 and 8 and your fish will do much better.

The waters I fish (strip pits that have not been reclaimed) are full of all kinds of minerals left over from the coal mining. There is a lot or Iron in the water. I talked to a chemist the other day and asked him what could cause the pits' water to have a high pH. He told me that it may be because of the excess IronOxides in the water. I thought it might be due to the excess limestone in the overburden where the coal was removed. It's more likely caused by both. But the water's pH is around 8.5 or so which is on the basic side. This is why the fish don't grow too well in these waters IMHO. I could be wrong but this is my best guess as to the slow growth rates of the crappies.

We have one pit that is more nautural and is not the result of coal being removed from the pit. The water in this pit has much lower conductivity and I bet that it's pH is closer to 7. This natural lake has many lilly pads growing in the shallow waters and it's very fertile. I caught a nice big brim out of this lake the other night.

Water quality is the key to keeping the fish alive and healthy whether it's in an aquarium or in a lake or river.

I'm not anywhere near salt water, but late last summer, in conjunction with a storm on the gulf, our lake here in Ky rose 18 ft in just several days, there was alarge fish kill because of the temp. switch, and the disruption of the thermacline, also the federal fish hatchery lost all its fish because of the water temp change.