Respiration In Fishes

[Fella]

Is there a set equation for the respiration of fishes? I can't find one online. Is there one that can generalise for all fish? Are there seperate equations for those that have labyrinth organs etc?

 

[andywg]

Hmm, both of my text books are somewhat quiet on any equation. They spend most of their time dealing with osmoregulation at the gills, rather than the oxygen uptake.

 

[Bignose]

What kind of equation are you looking for? Specifically, what do you want the equation to describe? This is just the engineer in me talking, but there can be many different kinds of equations describing respiration... do you want to know how much oxygen a fish needs (as a function of its size, for example), or the rate at which oxygen is taken up? The efficiently of which the fish uses the oxygen? How quickly a fish breathes? How quickly the blood flows through its gills? How quickly the oxygen diffuses into the blood and the carbon dioxide diffuses out?

If you can be more specific about what you exactly want, I can probably find something.

 

[Fella]

sorry, it was really vague, i apologise.

Essnetially, respiration in humans is



Glucose + Oxygen = Carbon Dioxide + Water + Energy

C6H12O6 + 6O2 = 6CO2 + 6H2O + Energy



What would it be in fish? What i basically want to know, is how much, if any ammonia is produced in the respiration of fishes, and if so, what other bi products are created. I have zero knowledge of this, so as much guidance as possible would be great. Preferably with little chemistry.

 

[Bignose]

I am 99% sure that is the same chemical reaction. I think that is the basic reaction used by all oxygen consumers. There are others that are used when oxygen levels are low or in oxygen-free environments, even sometimes used by fish like the ones that live in Arctic waters, but that is the same one used by all life forms that take up oxygen.

The ammonia production comes from the digestion of food. The breakdown of proteins into amino acids and then into ammonia. Ammonia is said to "respire" because the large majority of ammonia leaves the fish's body through the gills (most fishes it is over 75%). However, the ammonia doesn't come into play in the use of oxygen to convert sugars into energy. It isn't brought up as often, because it isn't anywhere as imminently deadly as ammonia, but fish respire carbon dioxide, too. That is the by product of their oxygen use, not ammonia.

Edited to change "lungs" to "gills" Hah, lungs! what the dip was I writing when I put that down!

 

[The-Wolf]

I have read that the amount of ammonia produced by fish is 80% respiration and 20% by waste products (erm, the rear end)
I don't have time to search for the reference right now

 

[steelhealr]

I would have to agree with bignose on his post, however, we must remember that many animals exist on other substrates beside glucose. I would have to agree that basic energy equation is the same. As for excretion, just an old post. SH

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