denise
08-12-2008, 04:42 PM
Sea Stars (also called starfish) are a group of bottom dwelling, unusual looking creatures with five or more "arms". There are more than 2000 species of sea stars worldwide, in tropical waters all the way down to the cold deep trenches of the seafloor. Five-arm varieties are the most common (hence their common name), but species with 10, 20, and even 40 arms exist!
Starfish do not have a jointed movable skeleton, instead they have a hydraulic water vascular system that helps them to move from place to place. There are millions of tiny tube feet underneath their arms, which act like little suction cups, and are used for locomotion and feeding.
Sea stars favorite food items are oysters and clams. Sea stars have a unique, fascinating ability to consume prey outside their bodies! Using their tube feet, they pry open the clams or oysters shell, their stomach extends out of their mouth and squeezes inside the shell to engulf the prey item. The stomach then digests the prey, and withdraws back into the body. This allows starfish to hunt prey that is much larger than its mouth would otherwise allow.
http://www.scubadiver.cc/forums/gallery/files/1/4/2/0/tylerbhb_2.jpg
Hungry sea star eating a fish
Photo by Tyler Phillips
Sea stars are famous for their ability to regenerate lost limbs, and in some cases, their entire bodies. This is possible as most of their vital organs are located in their arms. If a sea star looses a limb, they simply regenerate a new one to replace it. However is a severed limb has a small part of the central body disk attached to it, a whole new sea star can regenerate!
Starfish are unique in the fact that, unlike most other animals, they do not have blood, but instead use sea water to pump around their bodies, to exchange gases. The have no central brain, their nervous system is spread through their arms. They have a simple eye at the end of each arm. This eye is only able to "see" differences of between light and dark, mostly useful in detecting movement.
http://www.scubadiver.cc/fishid/starfishkeveinblueheron.jpg
Cushion Sea Star, Oreaster reticulatus, off Blue Heron Beach
Photo Courtesy of Courtney Redfield
The cushion star is a thick-bodied species of sea star. Its color varies from brown to orange, red, and yellow. Its skin is covered with raised knobby spines. the cushion sea star can grow to more than 10 inches, and usually lives in sandy areas.
http://www.scubadiver.cc/forums/gallery/files/1/1/8/5/cushionseastarjoe_1.jpg
Cushion Sea Star, Oreaster reticulatus, off Blue Heron Beach
Photo Courtesy of Joe Stillman
http://www.scubadiver.cc/forums/gallery/files/1/1/8/5/bandedseastarjoe_1.jpg
Banded Sea Star, Luidia alternata, Blue Heron Bridge
Photo Courtesy of Joe Stillman
http://www.scubadiver.cc/forums/gallery/files/1/1/8/5/urchinandstarjoe_1.jpg
Pincushion Urchin and sea star, Venice Beach
Photo Courtesy of Joe Stillman
Starfish do not have a jointed movable skeleton, instead they have a hydraulic water vascular system that helps them to move from place to place. There are millions of tiny tube feet underneath their arms, which act like little suction cups, and are used for locomotion and feeding.
Sea stars favorite food items are oysters and clams. Sea stars have a unique, fascinating ability to consume prey outside their bodies! Using their tube feet, they pry open the clams or oysters shell, their stomach extends out of their mouth and squeezes inside the shell to engulf the prey item. The stomach then digests the prey, and withdraws back into the body. This allows starfish to hunt prey that is much larger than its mouth would otherwise allow.
http://www.scubadiver.cc/forums/gallery/files/1/4/2/0/tylerbhb_2.jpg
Hungry sea star eating a fish
Photo by Tyler Phillips
Sea stars are famous for their ability to regenerate lost limbs, and in some cases, their entire bodies. This is possible as most of their vital organs are located in their arms. If a sea star looses a limb, they simply regenerate a new one to replace it. However is a severed limb has a small part of the central body disk attached to it, a whole new sea star can regenerate!
Starfish are unique in the fact that, unlike most other animals, they do not have blood, but instead use sea water to pump around their bodies, to exchange gases. The have no central brain, their nervous system is spread through their arms. They have a simple eye at the end of each arm. This eye is only able to "see" differences of between light and dark, mostly useful in detecting movement.
http://www.scubadiver.cc/fishid/starfishkeveinblueheron.jpg
Cushion Sea Star, Oreaster reticulatus, off Blue Heron Beach
Photo Courtesy of Courtney Redfield
The cushion star is a thick-bodied species of sea star. Its color varies from brown to orange, red, and yellow. Its skin is covered with raised knobby spines. the cushion sea star can grow to more than 10 inches, and usually lives in sandy areas.
http://www.scubadiver.cc/forums/gallery/files/1/1/8/5/cushionseastarjoe_1.jpg
Cushion Sea Star, Oreaster reticulatus, off Blue Heron Beach
Photo Courtesy of Joe Stillman
http://www.scubadiver.cc/forums/gallery/files/1/1/8/5/bandedseastarjoe_1.jpg
Banded Sea Star, Luidia alternata, Blue Heron Bridge
Photo Courtesy of Joe Stillman
http://www.scubadiver.cc/forums/gallery/files/1/1/8/5/urchinandstarjoe_1.jpg
Pincushion Urchin and sea star, Venice Beach
Photo Courtesy of Joe Stillman