II. HABITAT AND DISTRIBUTION
The cushioned star occurs in the eastern and western Altantic, from North Carolina to Brazil and Cape Verde Islands in western Africa. Adult Oreaster reticulatus are usually found in calm shallow waters (depths from 1 - 37 m) and more commonly occur on calcareous sandy bottoms (Anderson 1978, Guzman and Guevara 2002). Larvae and juveniles are usually found in seagrass beds (Guzman and Guevara 2002).
Oreaster reticulatus occurs in the Indian River Lagoon.
III. LIFE HISTORY AND POPULATION BIOLOGY
Age, Size, Lifespan:
The cushioned star reaches sexual maturity at approximate radius of 12 cm (Guzman and Guevara 2002). Individuals can grow up to 50 cm in diameter. The growth potential of an individual is thought to be limited by food availability, usually caused by intraspecific competition in large aggregations. During times of low food availability, O. reticulatus will reabsorb its body tissues to prevent starvation and as a result decrease in size (Scheibling 1980a).
Adults occur in dense aggregations called 'fronts' of 200 to 4000
individuals (Guzman and Guevara 2002, Metaxas et al. 2002). The size of
the fronts is dependent upon the available substratum and higher
densities of the fronts are correlated with the annual reproductive
cycle. Oreaster reticulatus can occur at densities of 14 individuals
per m2 ensuring reproductive success (Scheibling 1980a and b, Guzman and
Guevara 2002). There are mass migrations of the cushioned star to calmer
offshore habitats in the winter months to avoid turbulence (Scheibling
1980a, Scheibling 1985).
Oreaster reticulatus have separate sexes and reproduce annually in summer in subtropical regions. In more tropical areas where water temperatures are high nine months out of the year, there is asynchronous spawning year round (Guzman and Guevara 2002).
The planktonic larvae of the cushioned star are disbursed over long distances in water currents. Larvae will settle and metamorphose in seagrass beds. Recruitment to adult populations of Oreaster reticulatus from nursery grounds occurs when individuals enter the last juvenile stage, measuring 6-12 cm in length (Scheibling 1980a)
IV. PHYSICAL TOLERANCES
Sea water temperatures regulate the spawning cycles of Oreaster reticulatus (Guzman and Guevara 2002).
There are no studies specifically addressing the salinity tolerance of Oreaster reticulates.
V. COMMUNITY ECOLOGY
The cushioned star, a deposit feeder, has a complex digestive system that allows considerable variability in its feeding habits (Anderson 1978, Scheibling 1982). It is an omnivore, feeding on epiphytic microorganisms, echinoids, holothuroid juveniles and invertebrates including polychaetes, copepods, ostracods, crab larvae, and sponges (Wulff 1995, Guzman and Guevara 2002). Oreaster reticulatus uses its arms to rake piles of sediments and then everts its large cardiac stomach, enveloping the food in its folds. (Anderson 1978, Wulff 1995). O. reticulatus can turn over sediment 1.9 times within 24 hours (Scheibling 1980b).
VI. SPECIAL STATUS
Fishery: The cushioned star has been overharvested for souvenirs and the aquarium trade and are no longer common in areas of high human populations (Metaxas et al. 2002, Guzman and Guevara 2002).
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Wulff JL. 1995. Sponge-feeding by the Caribbean starfish Oreaster
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Melany P. Puglisi, Smithsonian Marine Station
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Page last updated: October 1, 2008