Mark Bevelhimer wrote:
(big snips)

Hi Mark,

> > I realized I couldn't keep my reputation as the list's resident fish
> > biologist (actually one of two that I'm aware of) without a more complete
> > answer so I did a little more research on this fascinating topic. ;-)  See
> > below.

Hey, who's the second one? :)

> Did a quick Google on 'do fish fart' and from the first link that came up:
>
> "...However, the sand tiger shark, Carcharias taurus, gulps air into its
> stomach at the surface, then discharges it out the back door to attain the
> desired depth."
>
> > The entire post is worth reading
> > http://www.straightdope.com/columns/001110.html
> > Be sure to check out the response from Dr. Krejsa.

Yup. Seems to me, by what he says, that fish tend to infuse any gas
they accumulate into their swim bladders and then, perhaps, excrete it
from their gills (I'm saying this badly).

I'm relieved to know, therefore - sort of, that I simply have not
recognised/seen gas discharges in fish as others might have. It gives
me back just a little faith in my own powers of observation.

However what it also does is to again put into conjecture my
observations of that shark I saw? Having thought abut it at length
over some two days, I'm pretty convinced that I saw it heading UP.

Cheers,

Christian
--
"Menopause". Is that a contradiction in terms? CG