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How does tidal fluctuations effect starfish?
Question Date: 2007-03-26
Answer 1:

Starfish move using a water-vascular system, which depends on the hydraulics of moving muscles and water about and making suction. Their water system is open to the environment. As a result, they cannot move out of water - and at low tide, their food often is above the waterline.

Answer 2:

Starfish, also known as "sea stars" are not really fish at all.They don't swim. Instead, they use tube feet with little suckers on the end to walk around on rocks, sand and mud. They aren't fast, but those tube feet can pull really hard. For their size, they are very strong. One author compared their pulling to that of a human lifting a 1,000 pound weight with one hand. Their real talent, though, is keeping up a steady pull for a long time. Sea stars eat by crawling on top of clam-like animals such as mussels, pulling their shells apart, and eating the soft part of the animal inside.

Many sea stars live underwater all the time, so they're not affected by tides much. Some do live in the inter-tidal zone. When the tide comes in and the water covers their prey, they go to work. When the tide is low, they may stay in a pool waiting for the next tide. Sea stars have to stay fairly wet. They breathe through gills on their underside and they use a hydraulic (water powered) system to move their tube feet.You may see them out of the water sometimes, but if they stay out too long, they will die.

For some great pictures and explanations of the tide pools around Santa Barbara, go


Tide pools have a high concentration of animals compared to the open ocean. Why do you think so many animals are found in the intertidal zone?

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