Red sea stars detect their environments with using chemoreceptors, which they rely on to recognize potential prey. These chemoreceptors also have the ability to elicit an alarm response which tells the sea star to move away from the stimulus quickly. There is both interspecific and intraspecific communication using chemoreceptors.
Communication Channels: chemical
Perception Channels: chemical
Despite the harsh conditions within the Antarctic, red sea star populations appear to be thriving and the species has no special conservation status.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
Fertilized eggs develop into planktotrophic larvae, allowing members of the species to disperse. Red sea stars have a rather slow rate of growth, typically gaining 1-2 grams per year.
There are no known negative economic impacts of this species.
The Antarctic conditions required by red sea stars mean that they are usually not kept in captivity and so they have little economic importance for humans.
Red sea stars eat the larvae of several sympatric sea stars that prey on various sponge communities, sometimes so heavily as to negatively impact the sponges' populations. Therefore, these sea stars may help maintain sponge populations.
Ecosystem Impact: keystone species
Red sea stars are omnivorous, feeding on a variety of species such as bivalves (e.g. Limatula hodgsoni and Laternula elliptica), sponges (e.g. Rossella racovitzae, Rossella nuda, Scolymastra joubini, Craniella leptoderma, and Homaxinella balfourensis), hydroids (e.g. Halecium arboreum), other echinoderms (e.g. Acodontaster conspicuus and Sterechinus neumayeri), and isopods (Glyptonotus antarcticus), as well as red algae, diatoms and seal feces. Due to the harsh environment of the Antarctic, red sea stars must be capable of surviving for long periods (potentially an entire winter) with no food. This sea star does not exhibit cannibalism; however, it is quite common for it to prey on other sea stars, particularly Acodontaster conspicuus. It is not yet known if red sea stars are more likely to search for food in groups or individually.
Animal Foods: carrion ; mollusks; aquatic crustaceans; echinoderms; cnidarians
Plant Foods: algae; phytoplankton
Other Foods: detritus ; dung
Primary Diet: carnivore (Eats non-insect arthropods, Molluscivore , Eats other marine invertebrates, Scavenger ); herbivore (Algivore); omnivore
Red sea stars are found in the Antarctic region, most prevalently in the waters surrounding the Antarctic continent and islands.
Biogeographic Regions: antarctica (Native )
Red sea stars are unique amongst sea stars in their ability to withstand the cold environment of the Antarctic region (averaging -1.8 degrees Celsius). They live at depths of 0-914 meters and are found most often in shallower waters (14 m).
Range depth: 0 to 914 m.
Habitat Regions: polar ; saltwater or marine
Aquatic Biomes: benthic ; coastal
Other Habitat Features: intertidal or littoral
The lifespan of this sea star is not currently known, although there is evidence that they can live up to 100 years.
Range lifespan
Status: wild: 100 (high) hours.
Like most other sea stars, red sea stars have a central disk with five arms radiating outward. These sea stars are typically a dark shade of red dorsally and a light shade of pink ventrally. Red sea stars have a rather large lightly-colored, pink madreporite dorsal plate which is an opening to its water vascular system. Red sea stars grow 1-2 grams per year and range from 2-11 centimeters in diameter (average 6-8 centimeters). There are no externally visible physical features distinguishing males and females of this species.
Range length: 2 to 11 cm.
Average length: 7 cm.
Other Physical Features: ectothermic ; radial symmetry
Sexual Dimorphism: sexes alike
Red sea starts tend to form larger clusters when a potential predator is sensed, as if to ward off any predators by seeming to be one large entity. This is unique because echinoderms are otherwise only known to form groups or clusters in order to better capture food or to increase the likelihood of fertilization. Known predators of red sea stars include sea anemones, sea stars, and jellyfish.
Known Predators:
As with most echinoderms, red sea stars reproduce via broadcast spawning and external fertilization.
Mating System: polygynandrous (promiscuous)
This species reaches sexual maturity at 3-6 years. Reproduction occurs once a year during the winter season, between the months of April and June, with peak spawning occurring during June. Scientists are able to determine when the sea stars are spawning by a decrease in the size of their gonads (sexual organs). Fertilization occurs from June to September. This sea star is known for releasing a large number of oocytes that, once fertilized, then mature into larva. The ova of this sea star typically take 18 months to mature.
Breeding interval: Red sea stars breed once yearly.
Breeding season: April to June
Range age at sexual or reproductive maturity (female): 3 to 6 years.
Range age at sexual or reproductive maturity (male): 3 to 6 years.
Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); broadcast (group) spawning
There is currently no evidence that red sea stars exhibit any parental investment.
Parental Investment: no parental involvement
