Sunflower starfish
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| Sunflower Sea Star | ||||||||||||||
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| Pycnopodia helianthoides |
The sunflower sea star (Pycnopodia helianthoides) is a large predatory starfish with 15-26 limbs called rays. These stars grow up to an arm span of 1 m (3 ft.) in diameter.[1] The colour of the sunflower starfish ranges from bright orange, yellow, red to brown and sometimes to purple, with soft, velvet-textured bodies and 16-24 arms with powerful suckers.[1][2] Most sea star species have a mesh-like skeleton that protects their internal organs.[3] Easily stressed by predators such as large fish and other sea stars, they can shed arms to escape, which will grow back within a few weeks. They are part of the diet of the king crab.[3] Also, they can eat small pacific living fishes.
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[edit] Feeding
The sunflower sea stars are quick, efficient hunters, moving at a speed up to three meters per minute,[2] using 15,000 tube feet which lie on the undersides of the body.[1] They commonly hang around urchin barrens, as the sea urchin is a favourite food. They also eat clams, snails, abalone, sea cucumbers and other sea stars.[1] In Monterey Bay, California, they will feed upon dead or dying squid.[4] Although the sunflower sea star can greatly extend its mouth, for larger prey, the stomach can extend outside the mouth to digest prey, such as bivalves like abalone.[5] Their feeding behavior was filmed in the 2006 BBC nature documentary, Planet Earth.
[edit] Reproduction
Sunflower sea stars have separate sexes.[5] Sunflower stars breed from May through June. In preparing to spawn, they arch up using a dozen or so arms to hoist its fleshy central mass free of the seafloor and release gametes into the water for external fertilization.[5] The microscopic sea star larvae float and feed near the surface for two to ten weeks. After the larval period, the larva settles to the bottom developing as a planktonic form[5] and transforming into a juvenile sunflower sea star,[3] Juvenile sunflower stars begin life with five arms[4] The life span of most sea stars is 3–5 years.
[edit] Habitat
Sunflower sea stars are common in the Pacific from Alaska to Southern California,[1] and are largest in Puget Sound, British Columbia and Alaska.[3] They generally inhabit low subtidal and intertidal areas rich in seaweed[6] or kelp.[7] They do not venture into high- and mid-tide areas because the body structure is fleshy and requires water to support it.[8]
[edit] References
- ^ a b c d e Sunflower sea star - NOAA
- ^ a b Telnack, Jennifer. Intertidal Marine Invertebrates of the South Puget Sound. NW Marine Life.
- ^ a b c d Sunflowerstar. Scott Boyd's Emerald Sea Photography.
- ^ a b Monterey Bay Aquarium: Online Field Guide - Sunflower star. Monterey Bay Aquarium.
- ^ a b c d Sea stars and relatives Edmonds Discovery Programs, City of Edmonds, Washington.
- ^ North Coast Intertidal Guide: Seastars & Urchins. North Coast Intertidal Guide. Humboldt State University. Arcata, CA.
- ^ Sunflower Star. Channel Islands National Park. National Park Service.
- ^ Sunflower Star. North Island Explorer.
