Dear Diana
inflation of the swim bladder is frequently stopped by a micron thin film of
oil on the water surface.  are you skimming the surface dust/oil film off
the tanks.  You can also use tissue paper but it is not as good.   arrange
an air jet to blow the surface water into a floating ring with a small
section cut out.  The air should blow the surface film in and then slowly
rotate the liquid inside the ring so that the oil is kept concentrated in
the centre.  The air is best blown by a very fine jet - use a fine plastic
tube- heat and stretch to a almost needlike point.  This air jet will now
remove all the scum from your surface water and I hope will reduce your
mortality dramatically.

regards

steve

At 01:09 PM 4/19/00 -0600, you wrote:
>     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
>     Fish Biologist
>     Columbia Environmental Research Center
>     USGS-BRD
>     4200 New Haven Rd.
>     Columbia, MO 65201
>     (t) 573 876 1902
>     (f) 573 876 1896
>     (e) [log in to unmask]
>
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Dr. Steve Oakley,      Shell Prof. of Environmental Science,
Institute of Biodiversity & Environmental Conservation,  Universiti Malaysia
Sarawak, 94300 Kota Samarahan, Sarawak, Malaysia  [log in to unmask]
Fax  082 671903  Tel 082 671000 x 254 or 257

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