P. lividus from a cultured stock were weighed,
measured and placed into aquaria (Table 1). Six individuals
were placed into each of 20 aquaria. Initial
weights were not significantly different between aquaria
(One Way ANOVA, F=0.364, p=0.989). An initial
sample (n=12) was dissected at the beginning of the
experiment. Sea urchins from two aquaria (n=12) were
dissected after being fed Diet 1, the control diet with no
added carotenoids, for 4 weeks. The remaining 18 aquaria
were then randomly assigned one of six experimental
diets for eight weeks (n=3 aquaria/treatment).