** High Priority **

  The most compassionate way to blind the fish would be to block out the
light source or at least the visible wave lengths of light and observe the
fish using other wave lengths of the  radiant energy  spectrum.   An
infrared light source and  infrared goggles could be used for water
surface observations or sonar could be used to observe the entire water
column if the species is a good acoustic reflector (IE has a swim
bladder).  The down side of course is that this method may not be
practical or to costly and fish behavior may be effected by confinement,
etc.
                                                       James Stark
                                             Research Fisheries Biologist
                                    U.S. National Marine Fisheries Service