increasing aeration and a fast water flow I have found strengthens larvae.  lowering the water level to facilitate the surface also helps. Breeding the largest possible stock insures health as well as a rich green algae growth in hatching tank. I've observed numerous times clinging half way on the algae surface as if resting and latter continuing for the surface.

Stamatis VARSAMOS wrote:

> A 13:09 19/04/00 -0600, vous avez écrit :
> >     Fish-sci list members:
> >
> >     We are attempting to study the effects of various chemicals on
> >     bluegill survival to approximately 20 days post hatch.  However, we
> >     are experiencing near 100% mortality (in controls) at about 11 days
> >     after hatch (25C).  Mortality seems to be due to lack of swim bladder
> >     inflation and switch from endogenous to exogenous nutrition (we are
> >     feeding marine rotifers).  We have tried and are continuing to try
> >     various things to improve the situation but so far, no luck.  Do any
> >     of you have procedures that might get us at least 50% control
> >     survival?  Any suggestions/insight would be greatly appreciated.
> >
> >     Thank you in advance.
> >
> >     Diana Papoulias
>
> Hello,
>
> more info on your rearing conditions and setup might help us in
> understanding what is going wrong.
> Anyway, in sea bass and sea bream larval rearing, mortality due to swim
> bladder malfunction (lack of inflation) was significantly reduced by
> removing from the surface of the water in the rearing tanks, the oil film
> introduced by the feeding (rotifers or artemia).
> Hope it helps
> cheers
>
> ps: By the way, can you see any preys (rotifers) in the intestin of the
> larvae?
>
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