Sea Stars

PEI has many interesting wild animals, but some of the most beautiful – and unusual – are Sea Stars, often called Starfish. The waters around PEI are home to at least five species, including the Common Sea Star (Asterias rubens) and Forbes Sea Star (A. forbesi).

It’s not hard to see where these invertebrates get their name: ask any kindergartener to draw a star, and you’ll get something that resembles this five-pointed shape. While our most common Sea Stars do have five arms, we have species with more than a dozen limbs, and you many come across our five-armed species with fewer than the allotted number of appendages.

Sea Stars are prey for all sorts of other marine animals including lobster, crabs, finfish, and other Sea Stars. As a defence, Sea Stars can shed an arm, leaving it behind to distract the enemy while the Sea Star escapes. The arm will slowly regenerate over the next year or so, temporarily leaving the Sea Star with four arms (or fewer, if the process happened more than once before the first arm had a chance to regrow).

This amazing regenerative capacity may have been behind a sudden increase of Sea Stars in Malpeque Bay in the early 1900s. Sea Stars are predators of shellfish – including mussels and oysters – and the Island’s oyster industry was just getting underway. In an effort to control these predators, it’s said that oyster fishermen would tear Sea Stars into four or five pieces to destroy them before tossing the pieces back in the water.

As long as part of a Sea Star’s central disk is attached, entire Sea Stars can regenerate from fragments, and so this action could well have resulted in propagation, rather than decimation, of the animals. In any case, by 1916, Sea Stars had increased from an uncommon curiosity to become second only to poaching as the biggest challenge to the oyster industry in Malpeque Bay.

Our two most common species, shown here, come in a range of colours but can be identified by their ‘madreporite’: a small disk on top of the star that regulates water flow. Common Sea Stars have a pale yellow madreporite (main photo), while that of Forbes Sea Star is orange (inset photo).

Sea Stars can often be found in tidal pools along the Island’s rocky shores; as with any wildlife, look but don’t touch (and never remove a live Sea Star from water). Just enjoy these interesting members of PEI Untamed!