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Home , Evasterias troschelii, Orchitophrya stellarum, Orthasterias, Pisaster, Pisaster brevispinus, Pisaster giganteus

Phylum: Echinodermata ochraceus Class: Asteroidea Order: Common Pacific sea star, ochre sea star, purple sea star Family:

Taxonomy: The Pisaster includes Washington, Oregon and California but three Pacific coast sea star , including are the most common food source . One can find many in British Columbia and sites historic synonyms for P. ochraceus, including (Harley et al. 2006; see also P. confertus and P. fissispinus for this http://echinoblog.blogspot.com/search/label/Pi species, but they are not currently used. saster%20ochraceus). Furthermore, two subspecies were erected for General Morphology: Sea stars P. ochraceus in 1996 (Clark) but (Asteroidea) are conspicuous members of the morphological and genetic data does not intertidal and subtidal. Their bodies are support this designation and, instead, composed of a central disc from which arms recognizes the single species P. ochraceus or rays extend. The star-shaped body can be (Stickle et al. 1992; Lambert 2000; Frontata- divided into the oral (or ventral) side where Uribe et al. 2008). Before becoming a the mouth is located and aboral (or dorsal) member of the genus Pisaster, this species side. belonged to the, currently accepted, genus Body: Stiff body morphology that is hard to Asterias (synonyms A. ochracea, A. the touch. fissispina, A. ianthina, A. janthina, A. Rays: Five rays (unless damaged, margaritifera) or the former genus can range from four to seven rays, Asteracanthion (now Asterias). Feder 1980). Each ray is tapering, thick, large, not sharply demarcated Description from disc and broadest where they join Size: Average size (Monterey, California) is the central disc (Dyakonov 1950), but 140 mm in diameter, where each ray (arm) is not broad enough to give webbed 40 mm in length (Fisher 1930). The illustrated appearance (as in Patiria spp.). specimen is 150 mm in diameter. Puget Central Disc: Large, convex, arched, Sound specimens are regularly 250 mm in not distinct or as disc-like as in diameter (Kozloff 1993). Weight ranges (wet Ophiuroidea (brittle stars). Contains weight) from 37.8–8.34 g (28 , Feder (conspicuous) madreporite (Figs. 1, 3) 1970). and (less conspicuous) anus. Color: Aboral (dorsal) surface red, purple, Diameter of disc less than 1/3 body brown or ochre (especially on open coast) diameter. (see Plate 25, Kozloff 1993). Specimens Aboral Surface: Aboral surface rough in most commonly purple (Puget Sound, texture and red, purple, brown or ochre in Washington). Oral (ventral) surface ochre. color. Juveniles gray with brown aboral patches Spines: Low, small, serrated, (Feder 1970). Body color may vary with rounded, bead-like or papillate (Figs. geographic region. Harley et al. (2006) found 1, 3). Spines form crescentic arcs at more brown (68–90%) and orange (6–28%) arm tips. No straight mid-dorsal row of individuals in Washington (Olympic arm spines. Spines in center of disc Peninsula), Oregon and California but more form a distinct star in the illustrated (95%) purple individuals in British Columbia specimen (Fig. 1). Two types of and Puget Sound, Washington. This variation spines include: (1) small, clustered in color could be due to the predominating around dorsal spines and (2) a few food source for P. ochraceus in the two solitary, large, sessile pedicellariae regions, where mussels are more common in scattered over dorsal surface (Fig. 3).

Hiebert, T.C. and L. Hiebert. 2015. Pisaster ochraceus. In: Oregon Estuarine Invertebrates: Rudys' Illustrated Guide to Common Species, 3rd ed. T.C. Hiebert, B.A. Butler and A.L. Shanks (eds.). University of Oregon Libraries and Oregon Institute of Marine Biology, Charleston, OR.

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12925 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to [email protected] Madreporite: A sieve-like structure of groove are adambulacral spines which serves as the water intake into intermixed with stalked clustered the stone canal is conspicuous about pedicellariae (Fig. 4). 1/3 of radius from center of disc (Fig. 1, between arms numbered 1 and 2). Possible Misidentifications Pedicellariae: Among the large five-armed sea stars, Anus: Inconspicuous, near center of Pisaster species are noted for their thick aboral surface and is surrounded by arms, low papillate dorsal spines and small pedicellariae. pedicellariae. Two other Asteriidae species Oral Surface: Oral surface ochre in color share these characteristics: (1) Evasterias and consists of hard, textured extension of troschelii is a low intertidal species with a aboral surface and ambulacral grooves small disc and slender arms compared to P. running the length of each arm and ochraceus and a varied, though generally converging at the mouth. Grooves are more orange-red coloration (Mah 2007). fleshy in texture from presence of tube feet. has clusters of Spines: Spines serrated, blunt, heavy pedicellariae on its adambulacral spines, not and more spine-like than bead-like just at their bases as in P. ochraceus. (2) (Fig. 4). Adambulacral spines (lining Orthasterias koehleri has sharp dorsal ambulacral grooves) are articulated, spines, not blunt papillate ones. These long, thin (Fig. 4). Three types of spines are each surrounded by a distinct ring spines ventrally: (1) small, clustered of large pedicellariae and the dorsal spines around bases of oral spines (Fig. 4); are arranged in distinct radial rows (those of (2) small pedicellariae clustered on P. ochraceus are not). Orthasterias koehleri expandable strands between is often red with yellow mottling and it occurs adambulacral spines (Fig. 4); and (3) in the low intertidal and subtidally (Mah large pedicellariae on these same 2007). strands (Fig. 4). There are no Two other species of Pisaster can pedicellariae on the adambulacral be found locally: (1) spines (Pisaster, Fisher 1930; Hyman occurs not on rocks and pilings but on soft 1955). substrates, where it feeds on clams. Its Mouth: Large, in center of disc (Fig. aboral spines do not form reticulated 2). Pisaster species can extrude the patterns or arcs, but occur singly or in stomach through this opening, groups of two or three, and are separated engulfing food and initiating digestion by areas of soft tissue. Pisaster brevispinus externally (Feder 1980). has a straight, distinct row of mid-dorsal Pedicellariae: Stalked or sessile spines on each arm. This sea star is nearly appendages used for removing always pink and it can be mottled with gray- invaders (e.g. barnacles larvae) or green or maroon-purple color as well (Mah deterring predators (e.g. 2007). It is one of the largest asteroids, hexactis, Wobber 1975; Solaster growing to 320 mm in diameter (Hyman dawsoni, Van Veldhuizen and Oakes 1955). (2) is bluish gray 1981). Pedicellariae are bird beak-like and its dorsal spines are blunt, clubbed, and two-jawed in Pisaster species. each surrounded by a ring of blue flesh and Tube Feet: Used in locomotion and around that a ring of pedicellariae. It has part of water vascular system. tiny pedicellariae that are thickly scattered Present on ventral side in ambulacral between the dense spines and its spines grooves where they are staggered in are not arranged in radial or concentric pairs, four rows across and down each rows. Pisaster giganteus is a low intertidal ambulacral groove (Fig. 4). sea star usually found further south than Ambulacral grooves: Grooves are Oregon. Despite its name, it is usually long furrows on oral surface of arms, smaller than P. ochraceus (Ricketts and which contain tube feet (Figs. 2, 4) Calvin 1971; Mah 2007). (Boolootian 1966). Along each edge

Hiebert, T.C. and L. Hiebert. 2015. Pisaster ochraceus. In: Oregon Estuarine Invertebrates: Rudys' Illustrated Guide to Common Species, 3rd ed. T.C. Hiebert, B.A. Butler and A.L. Shanks (eds.). University of Oregon Libraries and Oregon Institute of Marine Biology, Charleston, OR. Sea stars are extremely variable Temperature: Cold to temperate. Pisaster intra-specifically. Fisher listed three forms ochraceus is more tolerant to aerial exposure (“forma”) of P. ochraceus (Fisher 1930). than other Pisaster species, e.g. P. Although these names are not used, brevispinus, (up to 50 hours exposure), but taxonomically, it should be noted that the does not tolerate warm temperatures and/or Puget Sound, Washington and Oregon low oxygen levels (Feder 1980). outer coast variety of P. ochraceus has a Tidal Level: Intertidal to 88 meters (Feder flatter, smoother surface ornamentation 1980). Large sea stars usually found at low than does our Oregon bay form (Roberts, tide mark in Puget Sound, Washington personal communication). Subspecies have (probably for warmth), but they do not move also been reported for P. ochraceus to the lower intertidal in Monterey, California including P. o. ochraceus (north of Point (Feder 1970). Conception, California) and P. o. segnis Associates: Mussels, barnacles, and (south of Point Conception) (Clark 1996), other . Other inhabitants of the mussel but morphological evidence and genetic bed include , anemones and homogeneity across populations of nematodes. On pilings in quiet waters, supposed subspecies and morphological associates include barnacles, anemones (e.g. forms (e.g. “forma” Fisher 1930; Harley et Metridium senile) and (Ricketts and al. 2006) supports the single species P. Calvin 1971). The parasitic ochraceus (Stickle et al. 1992; Lambert causes castration in 2000; Frontana-Uribe et al. 2008; see also males (Leighton et al. 1991). Several http://echinoblog.blogspot.com/search/label/ incidences of sudden sea star die off have Pisaster%20ochraceus). occurred since 1972, but the most recent to the northwest coast of North America began Ecological Information in June 2013 and is called sea star wasting Range: Type locality is near Willapa Bay, disease. Affected individuals have Washington (Ahearn 1995). Range includes ectodermal lesions and tissue decay that Sitka, Alaska south to Baja, Mexico (Ricketts eventually leads to death (within 2–3 days). and Calvin 1971). Reported subspecies with The water-vascular system loses the ability to differing distribution include P. o. ochraceus, maintain hydrostatic pressure and individuals occurring north of Point Conception, often look flaccid when infected. Increased California and P. o. segnis, which is found temperature further heightens infection south of Point Conception (Clark 1996). intensity (Bates et al. 2009). The current die However, these populations are likely a single off of sea stars is the most significant due to species based on morphological and its widespread geographic range and large molecular evidence (e.g. Frontana-Uribe et al. number of species infected (Hewson et al. 2008). 2014). Recently, researchers determined this Local Distribution: Locally in Coos Bay and disease is most likely associated with a family along the rocky shores of Cape Arago. of single stranded DNA viruses (densovirus, Typically occurs on the open sea coast as Parvoviridae) and is now called sea star- well as in bays on jetties and pilings only in associated densovirus (SSaDV). Incidentally, marine parts of large bays. this same virus was detected in museum Habitat: Jetties, rocks, pilings, bay mussel specimens and, thus, may have been present beds and hard substrates. Larger individuals on the Pacific coast and undetected since can stand prolonged exposure to air (Feder those specimens were collected in 1942. 1970). Body morphology has been shown to Although the specific pathogen is not known correlate with wave exposure, where thinner in certainty, SSaDV is currently the most likely and lighter individuals are found in areas with candidate (Hewson et al. 2014). more intense wave exposure (Hayne and Abundance: The most conspicuous sea star Palmer 2013). of rocky intertidal areas (Puget Sound, Salinity: Collected at salinities of 30 or Washington, Kozloff 1993; Mah 2007). higher and cannot tolerate long-term exposure to reduced salinities.

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12925 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to [email protected] Life-History Information Juvenile: Sexual maturity is reached at five Reproduction: Forcipulate asteroids years when individuals are 70–95 g (wet primarily have separate sexes and free- weight) (Menge 1975). swimming planktonic larvae (Fisher 1930; Longevity: Chia et al. 1987). Pisaster species do not Growth Rate: Varies with food availability brood their eggs or young as do some and microhabitat (e.g. wave exposure). With Asteriidae (e.g. Leptastarias, Mah 2007). constant food supply and proper conditions, a Many species can be induced to spawn and sea star can feed continuously and increase are routinely used in developmental research. its weight from 2–30 times in a year (Feder One pair of gonads is present in each arm 1970). It can survive at least 20 months and, when spawning, sea stars lift their body without feeding. An individual’s size is not supported by their arms and gametes are related as much to age as to food availability. released through gonopores on the aboral Calmer conditions in a bay ensure greater surface (Chia et al. 1987). Ten gonads, like opportunities for feeding than do open coast feathery tufts, two in each ray, occur next to conditions (Feder 1970). Asexual the central disc in P. ochraceus. The regeneration of arms is a characteristic of the spawning period is from March to June Asteroidea. Regeneration of entire individual (Monterey, California Feder 1956, 1980) with can occur from small portions of the arm, but peak spawning from May–June (San Juan is not possible without some portion of the Islands, Washington, Chia et al. 1987; Miller central disc (Fisher 1930). 2001). Eggs of P. ochraceus are pale orange Food: Omnivorous (Mauzey et al. 1968). and 150–160 µm in diameter and a 400 g Favorite prey seems to include Mytilus female can produce up to 40 million eggs (Mauzey et al. 1968), on which it grows (Menge 1975). The gametogenic cycle of fastest, but individuals also eat barnacles, both sexes is regulated by photoperiod (Chia clams, crabs, . Prey items (e.g. et al. 1987). At 12˚C, development proceeds mussels) are pulled open such that P. as follows: 2 cells at 5hr, 4 cells at 6hr, 8 ochraceus can insert its stomach and begin cells at 7hr, hatching at 29–32 hr, gastrula at digesting material externally. Individuals may 44–63 hr, planktotrophic bipinnaria at 5d feed year-round in central California, but less post fertilization (Chia et al. 1987). in winter months in Puget Sound, Washington Larva: Embryos develop into planktotrophic (Feder 1980). Somewhat aggressive larvae called bipinnariae (Chia et al. 1987; predators, Pisaster species are known to elicit Miller 2001). These larvae are approximately escape responses in a variety of prey items 400 µm in length and metamorphose into (e.g. mollusks, crabs, other sea stars, Feder juvenile sea stars after 76–228 days when 1980). The common predator of the lower they are 0.5 mm in length. Bipinnaria larvae Mytilus beds (Ricketts and Calvin 1971). In are easily recognizable in the (Fig. the 1969, Paine described the selective 26.1, 26.2, Chia et al. 1987), they are large, of P. ochraceus on Mytilus species fleshy and uniformly ciliated with a distinct, in shaping structure and coined continuous ciliated band that is used for the term “” for P. ochraceus. feeding and swimming. Larvae have a large Predation by P. ochraceus shapes the vertical mouth, esophagus, intestine and anus. They zonation and community structure of rocky can have many long arms, increasing in intertidal communities (e.g. Paine 1974, 1976, number with age and can become long and 1995; Mah and Blake 2012). floppy (Fig. 3, Miller 2001). The juvenile sea Predators: Seagulls (on adults), and other star develops from the left posterior portion of sea stars (e.g. , Van the larval body. Late stage bipinnaria develop Veldhuizen and Oakes 1981). three arms (called brachiolar arms) and a Behavior: Can right itself vigorously when central adhesive disc, anteriorly. Larvae at oral surface is detached from substrate and this stage are called brachiolaria (see Fig. 4, can modulate store of fluid in response to Miller 2001) and they use these arms to outside air temperature during low tide attach to the substratum at metamorphosis. (Pincebourde et al. 2009). Some invertebrates, (e.g. Lottia) can avoid P.

Hiebert, T.C. and L. Hiebert. 2015. Pisaster ochraceus. In: Oregon Estuarine Invertebrates: Rudys' Illustrated Guide to Common Species, 3rd ed. T.C. Hiebert, B.A. Butler and A.L. Shanks (eds.). University of Oregon Libraries and Oregon Institute of Marine Biology, Charleston, OR. ochraceus by a special escape mechanism 10. FRONTANA-URIBE, S., J. DE LA (see Lottia pelta in this guide). ROSA-VELEZ, L. ENRIQUEZ- PAREDES, L. B. LADAH, AND L. SANVICENTE-ANORVE. 2008. Lack Bibliography of genetic evidence for the subspeciation of Pisaster ochraceus 1. AHEARN, C. G. 1995. Catalog of the (Echinodermata: Asteroidea) in the type specimens of seastars north-eastern Pacific Ocean. Journal (Echinodermata: Asteroidea) in the of the Marine Biological Association of National Museum of Natural History, the United Kingdom. 88:395-400. Smithsonian Institution. Smithsonian 11. HARLEY, C. D. G., M. S. PANKEY, J. Contributions to . 572:1-59. P. WARES, R. K. GROSBERG, AND 2. BATES, A. E., B. J. HILTON, AND C. M. J. WONHAM. 2006. Color D. G. HARLEY. 2009. Effects of polymorphism and genetic structure in temperature, season and locality on the sea star Pisaster ochraceus. wasting disease in the keystone Biological Bulletin. 211:248-262. predatory sea star Pisaster ochraceus. 12. HAYNE, K. J. R., AND R. A. PALMER. Diseases of Aquatic Organisms. 2013. Intertidal sea stars (Pisaster 86:245-251. ochraceus) alter body shape in 3. BOOLOOTIAN, R. A. 1966. response to wave action. Journal of Physiology of Echinodermata. Wiley Experimental Biology. 216:1717-1725. Interscience, New York. 13. HEWSON, I., J. B. BUTTON, B. M. 4. CLARK, A. M. 1996. An Index of GUDENKAUF, B. MINER, A. L. names of recent Asteroidea: Part 3. NEWTON, J. K. GAYDOS, J. WYNNE, Velatida and Spinulosida, p. 183-250. C. L. GROVES, G. HENDLER, M. In: studies. Vol. 5. M. MURRAY, S. FRADKIN, M. Jangoux and J. M. Lawrence (eds.). A. BREITBART, E. FAHSBENDER, K. D. A. Balkema International Publishers, LAFFERTY, M. A. KILPATRICK, M. C. Rotterdam, Netherlands. MINER, P. RAIMONDI, L. LAHNER, 5. DYAKONOV, A. M. 1950. Sea star C. S. FRIEDMAN, S. DANIELS, M. (Asteroids) of the U.S.S.R. Seas. HAULENA, J. MARLIAVE, C. A. Israel Program for Scientific BURGE, M. E. EISENLORD, AND D. Translations, Smithsonian-NSF, C. HARVELL. 2014. Densovirus Washington, D.C. associated with sea-star wasting 6. FEDER, H. M. 1956. Natural history disease and mass mortality. studies on the Pisaster Proceedings of the National Academy ochraceus (Brandt, 1835) in the of Sciences of the United States of Monterey Bay Area. Ph.D. Stanford America. 111:17278-17283. University, Stanford, CA. 14. HYMAN, L. H. 1955. The 7. FEDER, H. M. 1970. Growth and Invertebrates: Echinodermata. predation by the ochre sea star McGraw-Hill, New York. Pisaster ochraceus in Monterey Bay, 15. KOZLOFF, E. N. 1993. Seashore life California. Ophelia. 8:161-185. of the northern Pacific coast: an 8. FEDER, H. M. 1980. Asteroidea: the illustrated guide to northern California, sea stars, p. 117-135. In: Intertidal Oregon, Washington, and British invertebrates of California. R. H. Columbia. University of Washington Morris, D. P. Abbott, and E. C. Press, Seattle, WA. Haderlie (eds.). Stanford University 16. LAMBERT, P. 2000. Sea stars of Press, Stanford, CA. British Columbia, Southeast Alaska 9. FISHER, W. K. 1930. Asteroidea of and Puget Sound. UBC Press, the north Pacific and adjacent Waters. Vancouver, B.C. Government Printing Office, 17. LEIGHTON, B. J., J. D. G. BOOM, C. Washington, DC. BOULAND, E. B. HARTWICK, AND

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Hiebert, T.C. and L. Hiebert. 2015. Pisaster ochraceus. In: Oregon Estuarine Invertebrates: Rudys' Illustrated Guide to Common Species, 3rd ed. T.C. Hiebert, B.A. Butler and A.L. Shanks (eds.). University of Oregon Libraries and Oregon Institute of Marine Biology, Charleston, OR.