fish topping..why?

[Dunk Fairley]

OK, I possibly should get out more on the social side. But seeing as most of my friends are anglers anyway, I may as well go fishing, where I'll often meet them on the bank.

 

Apart from that, I don't really sign up to the commercialisation of good will that happens around new years eve. It seems like an excuse for someone to make lots of money.

[peter mccue]

I can't go along with the cleaning of gills theory for one good reason, my pond is crystal clear & very well oxygenated by means of a strong stream flow & a waterfall. The Carp simply have nothing to clog their gill filaments with, yet they still top & occasionally crash out mainly on an evening.

 

I suppose it could be a parasite infestation that pushes them into leaping, but again as far as I can see there is no problems with my fish.

 

I like the oxygen buzz idea & maybe along with that it's a fit of energy release, it goes quite nicely with the timing of the leaping activity early evening just when they're getting active.

 

However just to put a spoke in that, I watched Gudgeon one afternoon on a gravel glide that was too pacey to have any silt on it & must have been supersaturated with oxygen, plus the pace of the glide must have cost them some energy just maintaining station, but they still flipped themselves out of the water every now & then.

 

Ah God knows why they do it, but why ever they do I think it's a sign of fit healthy fish.

[aero]

fish crash or roll on the top to get more air into there swim bladder so it takes less energy to swim shallower. I asked my lectuer today in lesson.

[Newt]

Aero - your instructor had it right if he/she specified Cyprinids (minnows and carp) .

 

Cyprinids (minnows and carp) have a physostomous swim bladder, which means there is an open connection between the esophagus and the swim bladder, allowing adjustment of buoyancy by letting air in/out through the digestive tract. Similar to clupeids, salmonids, ictalurids, and other older species. So gulping and belching air is a thing they will do.

 

But based on the fact they can also go to some depth (caught at 60 feet that I know of) I wonder if their swim bladder is a mixed one and partily Physostomous as well so they can not only gulp and belch air but can also move it in and out of the swim bladder thru disolved gasses in the blood. Anybody have a clue if this might be the case? If there are species who use both mechanisms?

[poledark]

Dick Walker used to reckon that the carp were having a muscle spasm trying to excrete, probably accounts for some of the "leaping about", another reason is that ........no I won't go down that road

 

 

Den

[poledark]

Dick Walker used to reckon that the carp were having a muscle spasm trying to excrete, probably accounts for some of the "leaping about", another reason is that ........no I won't go down that road

 

 

Den

[brad]

aero that sounds good to me,your right though ive always been told "there cleaning there gills"

[Dunk Fairley]

So if they are getting their swim bladder ready to swim near the surface, why do they do it when they are obviously feeding on the bottom?

[Newt]

Dunk - I suppose the reason is that carp abide by the law.

 

As a fish swims deeper into the water, the pressure increases. According to Boyle's Law, a fixed amount of gas will provide less buoyancy at greater depths.

 

This means that a fish must increase the quantity of gas in the swim bladder. This prevents the swim bladder from compressing due to the increase in pressure at greater depth.

 

So, and contrary to what you would first think, they need more air to establish neutral buoyancy if they are to be feeding off the bottom than if they plan to stay on or near the surface.

[wunnus]

Duh?

Does that mean we can safely say the carp is trying to stay on the bottom when we see them splashing the surface?

 

I sense a breakthrough here.