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illumination levels were measured in three artificially illuminated tanks: a black tank, a white tank and a tank with black sides and white bottom, in order to test how well normal tank illumination in different tank types corresponds to natural illumination conditions for flrst feeding of marine fish larvae. Measurements were made with clear water and with algae added ("green water").The black tank had low wall and bottom illumination. The white tank had high wall and bottom illumination. The black walled white bottomed tank had low wall and high central and bottom illumination. Green water attenuated light substantially. The black tank seemed best suited to reproduce natural illumination conditions. The white tank was not suited. The black walled white bottomed tank had interesting properties, but species specific tests would have to be carried out to fme tune the reflective properties of the bottom. Green water seemed to be beneficial in all tests.

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Bergh, IZI., K.E. Naas, and T. Harboe. 1994. Shift in the intestinal microflora of Atlantic halibut (Hippoglossus hippoglossus) larvae during first feeding. Can. J. Fish. Aquat. Sci. 51 : 1899-1 903.Isolates of aerobic intestinal bacterial flora from unfed Atlantic halibut (Hippoglossus hippoglossus) larvae revealed a population dominated by nonfermentative rods of the Cytophag~Flexibacter/Flavobacteriurn group. Following the onset of feeding, the flora gradually changed towards a fermentative flora dominated by the Vibrio/Aeromowas group. This transition occurred faster in a group which was reared in water containing cultivated phytoplankton, in contrast with groups where the larvae were kept in filtered water. No major differences in the bacterial fiora of the tank water were found among the groups.Des isolats de flore intestinale aerobie provenant de iarves de fletan atlantique (Hippoglossus hippoglossus) non alirnentees ont revkle une population dorninee par des batonnets non ferrnentatifs appartenant au groupe Cytsphag~Flexibacter/F~avobacteriurn. AprPs le d&but de Ifalimentation, la flore s'est graduellement rnodifiee pour devenir une flore fermentative dominee par le groupe Vibrio/Aerornonas. Cette transition s'est produite plus rapidement chez un groupe qui a 6t6 kleve dans de I'eau renfermant du phytopiancton cultive, contrairement aux groupes dcsnt les larves csnt ete gardees dans de Ifeau filtree. On n'a observe aucune difference importante dans la flore bacterienne presente dans I'eau des bassins renfermant les divers grsupes.

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