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View Full Version : Fish Swim Bladders



Moose1am
04-23-2004, 01:33 PM
A while back I was trying to discuss how a fish's swim bladder was attached to the fish's stomach. I could not get a picture on the old forum but I was able to finally get this picture and hopefully it will post on this new forum.

This is also a test.

Note: The picture's memory requirements can be seen by right clicking on the picture and then left clicking on the properties item in the drop down list.

FalconSmitty
01-24-2005, 12:04 AM
These bladders are interesting. They hold air awhile after they die. Ever cleaned a fish and busted the air bladder.

Do they release and take in air to stay at certain depths? If they breathe with gills, why does it attach to the digestive tract?

thanks.
smitty

Moose1am
01-24-2005, 12:31 AM
Air can be released into a fish's air bladder though the capilaries that line the inside of the fish's air bladder. It's a slow process. Just like our lungs can release Carbon Monoxide, the fish's air bladder can exchange gases with the capilaries inside the swim bladder or air bladder. But we are more effecient at this since the surface area of our lungs is equal to the size of a NFL foot ball field. Our lungs are full of tiny aveoli that give us the large surface area. Fish's air bladders are smooth and they don't have a lot of surface area. Therefore the exchange of air from the capilaries to the air bladder is much slower. This is what the Ichythyology book said in summary. It goes into a lot more detail on how these things work but that is the gist of it.

Not all fish have the same setup inside them. I did read that some minnows for example have not air bladder at all. So not all fish have an air badder. Some fish today breath air still. I know that cat fish gulp air and can live for a long time out of water as compared to a bass for example. Lung fish can breath air though thier air bladders and walk around on mud flats. Mud skippers in India can survive out of the water for long periods of time.

Most fish breath though the gills. The oxygen is dissolved in the water and the gills can extract the oxygen out of the water and I suppose give off carbon dioxide to the water from the gills. That is the main way that fish get their oxygen today. Maybe the very early fish (Geologically speaking) needed air bladders to help them breath. I don't really know.

Why the air bladder is still attached to the stomach of some fish today I have no idea. LOL Good question though. Wish I could ask my old college professor this question as I have wondered about that myself.


Do they release and take in air to stay at certain depths? If they breathe with gills, why does it attach to the digestive tract?

thanks.
smitty[/QUOTE]

FalconSmitty
01-24-2005, 12:38 AM
Do the fish use the swim bladder to stay at certain depths?
thanks for the info. Is this why barometric pressure affects them easily?

Moose1am
01-24-2005, 01:54 AM
yes to first question

Most likely answer to second question. Although many other things can effect the fishs behaviour when the air pressure changes. Normally when we get a cold front coming though the clouds increase that day and decrease after the front passes. The air cools as the Cold Front approaches and that cools the shallow waters and this effects the fish too. And after the front passes the water is lite up by bright sunshine especially when there are no clouds in the sky. Lots of UV radiation UV A UVB will be hitting the water's surface. And UV rays can penetrate deeper into the water than long color waves of light such as reds.

I know that fish will hide from the light and stay closer to structure and in the shade or under a horizontal log. By going under the log they are shaded from the sun but I see no way that the log could protect them from an increase or a decrease in air or water pressure.

Just as the increased air pressure pushing down on the mercury's surface pushs the mercury up inside the sealed glass tube the same air pressure can push on the lakes surface and increase the water pressure in the water column. The pressure at 33 ft is about two Atmospheres. If you double the air pressure above you you would be at 2 Atmospheres.

You have 1 atmosphere of air pressure above you and 1 atmosphere of water pressure above you when you are at 33ft below the surface. The air pressure above you adds to the water's pressure. They combine to increase the pressure on you when you are at 33ft deep.

The fish can sense the increased water pressure around them I would think with their lateral lines. If they can detect a minnow swimming in the water and zero in on that minnow using the pressure waves that the minnow gives off as it swims then surely they can detect small increases in the water pressure around them. Whether the air pressure alone or the combiation of increasing air pressure and increased sunlight and colder water after the front passes by effects the fish is still unanswered.



Do the fish use the swim bladder to stay at certain depths?
thanks for the info. Is this why barometric pressure affects them easily?

crap-king
01-24-2005, 08:24 AM
Saw an apisode of Roland Martin,s Show a couple of weeks ago and he was catching Red Snapper over 200' deep and the bladders were poking out of their mouths where they came up to quick and he just took a knife an puntures the bladder and released the fish - he said the fish would be fine and they did swim off - I don't knoe if the bladder would work again or not

soundpainter
06-28-2006, 11:51 PM
Air can be released into a fish's air bladder though the capilaries that line the inside of the fish's air bladder. It's a slow process. Just like our lungs can release Carbon Monoxide, the fish's air bladder can exchange gases with the capilaries inside the swim bladder or air bladder. But we are more effecient at this since the surface area of our lungs is equal to the size of a NFL foot ball field. Our lungs are full of tiny aveoli that give us the large surface area. Fish's air bladders are smooth and they don't have a lot of surface area. Therefore the exchange of air from the capilaries to the air bladder is much slower. This is what the Ichythyology book said in summary. It goes into a lot more detail on how these things work but that is the gist of it.

Not all fish have the same setup inside them. I did read that some minnows for example have not air bladder at all. So not all fish have an air badder. Some fish today breath air still. I know that cat fish gulp air and can live for a long time out of water as compared to a bass for example. Lung fish can breath air though thier air bladders and walk around on mud flats. Mud skippers in India can survive out of the water for long periods of time.

Most fish breath though the gills. The oxygen is dissolved in the water and the gills can extract the oxygen out of the water and I suppose give off carbon dioxide to the water from the gills. That is the main way that fish get their oxygen today. Maybe the very early fish (Geologically speaking) needed air bladders to help them breath. I don't really know.

Why the air bladder is still attached to the stomach of some fish today I have no idea. LOL Good question though. Wish I could ask my old college professor this question as I have wondered about that myself.


Do they release and take in air to stay at certain depths? If they breathe with gills, why does it attach to the digestive tract?

thanks.
smitty[/QUOTE]

SwampHunter
06-29-2006, 12:18 AM
When we were growing up we were poor. We used fish air bladders for baloons.

Roberta
06-29-2006, 07:32 AM
>>> I did read that some minnows for example have not air bladder at all<<<

Moose, the darters and daces generally lack air bladders. When we do the electro-shock fish sampling with the MetroParks biologist in the local streams, one of our biggest jobs is scooping up these fish before they sink into the rocks. Chubs and "minnows" will float to the top, but the rainbow darters, black-nosed daces and related will sink like a rock. They normally use their pectoral fins to walk on the bottom in search of food. They are also good indicators of stream health.

BTW, Roland Martin killed the fish, whether he wants to admit it or not. - Roberta

Naixus
06-29-2006, 05:20 PM
Sharks don't have air bladder, this gives them the ability to change depth quickly when hunting for food. On the other hand, they have to keep swimming all their life, otherwise they would sink to the bottom of the ocean.

BTW, moose, the lungs release carbon dioxide, not monoxide.

ceb
06-29-2006, 06:02 PM
I think this answers most of the questions. The bladder retains its connection with the GI tract because they are of the same embryological origin, germ cell-line wise. Pretty interesting to read about the mechanism for gas exchange. There is actually glandular epithelium in the bladder that produces acid, which promotes the dissociation of oxygen from red blood cells. Though, I don't think this is going to help me catch more fish.

http://en.wikipedia.org/wiki/Air_bladder