The effect of ration and spatial distribution of feed on survival, growth, and competition was
studied in juvenile red-claw crayfish in the laboratory. Groups of 60 juveniles were raised for 27
days in each combination of ration and spatial distribution: feed being provided once a day or
once in 4 days, spatially dispersed or clumped. Aggressive interactions among juveniles were
recorded on the 12th day, both prior to and following feed administration. The final weight was
much higher when the crayfish were fed once a day compared with once in 4 days, but the
respective survival was lower. The latter was explained by increased cannibalism due to higher
moulting frequency. The effect of spatial distribution of feed on growth and survival was
marginal. However, this factor affected competition for feed. This was revealed by the sharp
increase in frequency of aggressive interactions following feed insertion, observed only in the
groups where the feed was clumped. Ration had no influence on competition. The weak
association between feed competition and both survival and growth is discussed.