The presence of epibiotic barnacles, starfish size and mussel size had
a significant effect on predator feeding rates under certain conditions as
shown by the significant interaction among all three factors (Table 2;
Fig. 2). There was no significant difference between predation rates on
unfouled mussels and cleaned mussels across all treatments. Post-hoc
tests revealed that the effect of fouling on feeding rates was dependent
on starfish size (Table 2; Fig. 2). The feeding rate on fouled mussels was
lower than that of unfouled mussels for medium sized starfish feeding
on large mussels with the presence of barnacles reducing the feeding
rate from a mean of 0.45 ± 0.10 per day to 0.13 ± 0.07. Large starfish
feeding on small mussels also showed a similar trend towards a reduced
feeding rate on fouled compared to unfouled mussels with a mean feeding
rate of 0.76 ± 0.30 and 0.26 ± 0.21 respectively. For all remaining