Sea cucumbers are “ spinous animals ”, members of the phylum Echinodermata and relatives of the seastars and sea urchins. All echinoderms are marine and closely all are bottom-dwellers. They are unique in having a 5-part body design and a water-vascular system of internal canals which provides hydraulic power for their many muscular tube feet .
Sea cucumbers differ from early echinoderms in having an elongate, cylindrical body with the mouth and anus at inverse ends. Because their soundbox is muscular and soft quite than spiny, sea cucumbers are sometimes confused with ocean slugs ( snail relatives that lack a outstanding shell ). An easily means to tell them apart is to look for a head. Sea slugs, like snails, have a head with centripetal tentacles. Sea cucumbers, like early echinoderms, lack a clear-cut “ mind ”. alternatively, the mouth end of a ocean cucumber is ringed by 5 feeding tentacles used in gathering food particles. Sea cucumbers either assemble detritus ( bits of plant and animal matter ) and bacteria from seafloor sediments or trickle particles from the water .
Sea cucumbers lack some features common in early echinoderms. The 5-part torso design you can see in seastars and even ocean urchins is harder to find in many sea cucumbers. Some ocean cucumbers have 5 rows of tube feet running the length of the consistency. But, in many ocean cucumbers, you have to look internally to see the blueprint — five muscle bands run the length of the body. A few sea cucumbers have 5 “ teeth ” around the anal orifice. These “ hindquarters teeth ” are not used in prey, but may protect the cucumber from parasitic pisces that tax shelter in the cucumber ’ sulfur body .
The skeleton and spines that are so big in other echinoderms are reduced in ocean cucumbers. alternatively of a rigid skeleton, sea cucumbers have a muscular torso well that contains only microscopic skeletal ossicles. The muscular body wall provides support, and thus does the water inside the cucumber ’ s large consistency cavity. This “ water system skeleton ” besides acts like a circulative arrangement.
Reading: Waikīkī Aquarium » Sea Cucumbers
Like other echinoderms, about all ocean cucumbers have tube feet. The suckered tube feet are important for both fastening and movement. In many species, the tube feet are all found on one side of the animal, providing greater clasp in wave-swept habitats. One group of sea cucumbers ( synaptid cucumbers ) lack tube feet all together and move by muscular waves which pass down the duration of the body ( peristalsis ). They are found in quiet-water habitats .
Sea cucumbers have some structures that other echinoderms don ’ metric ton ! A limited respiratory structure, called the respiratory tree, is derived from a branch of the sea cucumber lower digestive tract. Cucumbers obtain oxygen by pumping seawater in and out of the anus. The water that may drain from a ocean cucumber ’ south body is “ exhale ” water from the respiratory tree.
Sea cucumbers may lack spines and the protection of a rigid skeleton, but they have many different means of defense from predators. With easy, compromising bodies, they are able to crawl under rocks and into reef crevices. Some species have repellent or toxic chemicals in the skin that make them disgusting. Others eject sticky threads ( Cuvierian tubules ) from the anus — these threads entangle and immobilize electric potential predators and the cucumber crawl to safety. distillery early sea cucumbers can eject ( eviscerate ) separate of the digestive system as a defensive mechanism, regenerating lost parts later.
Like most echinoderms, ocean cucumbers reproduce sexually and many are broadcast spawners. Males release sperm and females release eggs into the body of water and fertilization is external. The resultant role is a barrel-shaped planktonic larva that drifts in plankton before settling to the seafloor and metamorphosing into a benthic ( bottom-dwelling form ). A few sea cucumber species retain the young and brood them until they emerge as crawling juveniles. Some species have besides been reported to reproduce by fission ( splitting in half ), a phase of asexual reproduction
There are more than fourteen species of sea cucumbers in Hawaii ’ s shallow waters, ranging in size from about 1 column inch ( 2.5 curium ) to 3 feet ( 0.9 molarity ). They occur in tide pools, on reefs, in bays and lagoons, and in deeper waters. Examples of common tidepool species are the black ocean cucumber ( Holothuria atra ), ash-grey cucumber ( Holothuria cinerascens ), banded ocean cucumber ( Holothuria pervicax ), and white-speckled ( rump-toothed ) ocean cucumber ( Actinopyga mauritiana ). In the quiet waters of Kāne ’ ohe Bay, the barbed ocean cucumber ( Ophiodesoma spectabilis ) is common. Sea cucumbers, in general, were known as loli by early Hawaiians, but only certain species were eaten. Sea cucumbers are highly prized as a dainty in many cultures including those of Asia, Pacific Islands, and Mediterranean Europe .
Sea cucumbers play an important function in reef “ recycling ”. They feed by gathering organic detritus and tied bacteria from the water or the sandpaper. They speed the dislocation of these bits of plant and animal debris — extracting energy for their own survival and recycling materials that seaweeds can absorb as fertilizers. The sand that sea cucumbers process along with the debris they consume is eliminated as strings of flaxen beads.This march helps “ change by reversal over ” sediments .
