fish, marine mammals don't get bent
- Thread starter merkin
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
I have heard of salmon getting bent near a dam because the water had higher than normal concentrations of inert gas than the normal water of the river. Normally, the gas concentrations are uniform in water, but not at damn due to the water falling over the dam...wonder if this happens near waterfalls too.
I found a similar link... http://www.columbiapower.org/content/tgp.html
This explains it really well too:
For every 10 m down into the water column that a gas bubble is driven, there is an increase of 1 A pressure (the weight of 10 m of water is about the same as the entire atmosphere). Consequently, as gas dissolves into the water from that gas bubble it enters at high pressure and this increases the quantity and pressure of the dissolved gases in the water. [An Example] This is termed supersaturation. If a fish is swimming at the same depth (pressure) as that at which the dissolution occurred the gas pressure in the fish's blood is high, as well. This is not a problem as long as the fish stays at that depth, however, if the fish swims upward the hydrostatic pressure decreases and since the solubility remains constant the amount of gas the water can hold decreases and the excess gas is released as bubbles. Bubbles of gas in a fish's blood can quickly lead to fatal embolisms. This condition is called "gas bubble disease". Human divers can suffer from the same disease, but it is called "the bends". The deadly bubbles are usually not oxygen, but nitrogen. Gas supersaturation can occur below dams where the bubbles are driven deep into a plunge pool or are entrained under pressure in the turbines or passageways. It can also occur in the plumbing of hatcheries in ground water.
Note: supersaturation can only occur when gas goes into solution at pressure, if gas goes into solution at the surface (1 A) then it can be flow down to great depths without a change in gas pressure.
Breath hold divers don't generally get bent either. It's the breathing of compressed air (air under pressure, either in a cylinder or as explained above) that causes the problems.
Fish are a different story since they don't "breath hold", but marine mammals are analogous to free divers (I think). Perhaps a marine biologist will come along shortly...
Fish like red snapper can end up with a distended swim bladder when brought up from the bottom.
Generally they get cranked up so fast the bladder ends up sticking out of the mouth.
The recommended solution to this (provided the fish is too small to keep) is to rupture the bladder so it can deflate and release the fish.
There are mixed reports as to whether or not the fish survives this.
TwoBit
Generally they get cranked up so fast the bladder ends up sticking out of the mouth.
The recommended solution to this (provided the fish is too small to keep) is to rupture the bladder so it can deflate and release the fish.
There are mixed reports as to whether or not the fish survives this.
TwoBit
<Having a funny mental image of O-ring all decked out in his dive gear standing on the side of a road with his thumb out waiting to get picked up by a marine biologist>
Make sure she is cute before sending her my way though, ok?
Even some mammals stay down for times that are crazy long - maybe I'm wrong, but I'm not sure breath divers is a correct analogy in those circumstances.
Wishful thinking, but I haven't met too many cute marine biologist yet (n=3)...
Wishful thinking, but I haven't met too many cute marine biologist yet (n=3)...
Does lips like a red snapper and teeth like a trigger fish count as cute? <wondering if I am on my way to my first thread hi-jacking?>
BillP
Senior Member
Howdy merkin:
This topic comes up periodically. A search of the archives yielded a few threads that you might find helpful. You might find it interesting to take a look at:
http://www.scubaboard.com/showthread.php?s=&threadid=1734&highlight=whale
http://www.scubaboard.com/showthread.php?s=&threadid=3094&perpage=15&display=&pagenumber=1
and
http://www.scubaboard.com/showthread.php?s=&threadid=20030&highlight=bove
HTH,
Bill
Similar threads
