19. How do predators feed on the crown-of-thorns starfish?

Each of the predators mentioned above have different ways of overcoming the spiny defenses of the crown-of-thorns starfish in order to feed on it. The shrimp (Hymenocera picta) attacks the less protected tissues underneath by turning the starfish over. As this animal is only about 10 cm in length it has difficulty in doing this to large starfish. Most of the fish predators have horny plate-like scales and very strong, sharp teeth which enable them to attack (and take bites out of!) crown-of-thorns starfish with apparent immunity.

One of the most well-known of predators, the giant triton (Charonia tritonis), is most adept at feeding on both large and small crown-of-thorns starfish. The triton uses its rather primitive foot to restrain the starfish and then inserts its proboscis (ie. trunk-like feeding organ) inside the animal to feed on its soft tissues (eg. gonads, caeca) (see Fig. 9). Often the starfish will escape from the triton by leaving behind that part of its body which is being held (eg. arms). Small starfish are normally ingested whole by the triton. After the meal has been concluded the spines and other skeletal material normally are regurgitated.

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