Ectopleura Crocea Class: Hydrozoa, Hydroidolina Order: Anthoathecata, Aplanulata Family: Tubulariidae Tubular Hydroid

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Phylum: Cnidaria Ectopleura crocea Class: Hydrozoa, Hydroidolina Order: Anthoathecata, Aplanulata Family: Tubulariidae Tubular hydroid

Taxonomy: Ectopleura crocea was originally "hairs" (diatoms). The stiff perisarc extends to described by Agassiz, 1862 as Parypha the base of the hydranth (Mills et al. 2007). crocea, though it was soon after classified as Hydranth: The hydranth lacks Tubularia crocea (Allman 1871). The primary a theca. The manubrium is surrounded by a synonyms are T. crocea and Pinauay crocea whorl of tentacles, is simple, and circular (Fig. (Mills et al. 2007). There has been much 3). debate about the appropriate genus for this Gonophore: The gonophores each species, but Ectopleura crocea is now contain an abortive medusae, or generally accepted (van der Land et al. 2001; gonomedusae. They are in clusters on stalks Schuchert 2015). Additional synonyms (racemes) between the two whorls of include Tubularia ralphi, T. gracilis, T. tentacles (Fig. 3). Within the gonophores australis, and T. warreni (Schuchert 2010). develop the planulae larvae, which leave the gonophore but remain in close association Description with the polyp (Kozloff 1983). Female General Morphology: The only form of E. gonophores have short distal crests (Mills et crocea is the large, colonial polyp. Each polyp al. 2007), with 4-8 flattened bladelike has a stem (hydrocaulus) covered in a rigid tentacles at the apical end (Kozloff 1987). perisarc and an athecate hydranth with a Male gonophores lack tentacles (Mills and mouth (manubrium), stomach, tentacles, and Strathmann 1987). gonophores (Figs. 1, 2). Cnidae: Medusa: The medusa is not free-swimming Tentacles: Tentacles are filiform (Ricketts et al. 1985); though it is biologically (thread-like), simple, and in two whorls (oral similar to other free-swimming hydromedusa, and aboral, Mills et al. 2007). The proximal, or it is entirely retained in the tissue of the aboral, whorl consists of long, extended gonophore (Kozloff 1983). feeding tentacles at the base of the hydranth, Polyp: while the distal, or oral, whorl has short Size: The colony grows in large tentacles usually contracted around mouth bushy clusters up to 15 cm (Ricketts et al. (Figs. 2, 3). There are similar numbers of 1985). Stems grow to 2 cm long, and distal and proximal tentacles (Kozloff 1987). "flowers" (the hydranth) are up to 1 cm when Older specimens have more tentacles than extended. The genus Ectopleura contains young ones; juveniles will have only 10 species that are considered the largest proximal tentacles. athecate hydroids (Kozloff 1974). Color: The hydrocaulus is white to Possible Misidentifications light tan, the feeding tentacles (proximal and The family Tubulariidae is composed distal) are transparent white, the gonophores of hydroids with a thick perisarc and stolons are light pink and dark coral, and the (ground-level shoots connecting branches). manubrium is a pale yellow-orange. The Species in this family have at least two organism’s dominant color comes from the tentacle whorls and gonophores between the pink to red hydranths (Ricketts et al. 1985). oral and aboral whorls. The medusae in this Body: family can be either free-swimming or Pedicel: The hydrocaulus is retained, have four radial canals, a simple unbranched, crooked, and covered with fine

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12644 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] mouth, and few tentacles. Divisions of the The genus Ectopleura is composed of family into its genera are based on presence hydroids with only two tentacle whorls, one of stolons, texture of the stem, origin of the oral and one aboral. The perisarc originates perisarc, and morphology of the medusa below the connection between the hydranth stage (Schuchert 2012). and stem, and ends at the base of the al. 2007). It thrives in cold water with good hydranth. The stem is a hollow tube with 0-5 movement. In the lab, it is not bothered by ridges. Stolons are present. The medusae strong light (Mackie 1966). It is one of the can be free-swimming or retained (Schuchert invertebrate organisms most resistant to 2012). poisons, such as copper (Barnes in Pyefinch The other common local species of and Downing 1949). It lives in the low Ectopleura, E. marina, is a small, solitary intertidal and down to 40 m (Mills et al. 2007), athecate (without a cup-like theca) hydroid of and is always attached to solid substratum the outer coast. Its stalk is usually about 2.5 rather than mud or sand (Kozloff 1987). cm long, it has fewer distal tentacles than Salinity: Collected at 30. proximal ones, and it is less showy than E. Temperature: Specimens respond badly to crocea, as it does not occur in clumps as the warm water in the lab and will lose hydranths. latter does. While E. crocea branches Regression occurs with summer temperatures extensively from its base, E. marina does not (Mackie 1966). Ectopleura crocea is usually (Kozloff 1983). found at temperatures above 18°C, but can Other athecate hydroids often have be kept in laboratories at 14° C (Mills and some capitate (knobbed) tentacles as adults, Strathmann 1987). i.e. Cladonema, Hydrocoryne. Of those with Tidal Level: Low intertidal; subtidal to 40m only threadlike tentacles, some like (Haderlie et al. 1980) Hydractinia and Eudendrium have only a Associates: On floating docks, the colonial single whorl of tentacles, not two whorls as in Ectopleura crocea and its substrate constitute Ectopleura crocea. Others, such as a rich microecosystem. Some of the most Turritopsis and Clava have tentacles in common epibionts are suctorian protozoans, scattered patterns rather than in whorls (Rees diatoms (especially in fall, darkening stems) and Hand 1975). (Pyefinch and Downing 1949), caprellid and The species Ectopleura larynx looks similar to tube-building amphipods, isopods, copepods, E. crocea, but is not found in Oregon. and mussels. Ectopleura crocea has, however, become a nuisance to mussel- Ecological Information growing aquaculturists. The hydroid will foul Range: The type locality is Boston Harbor on juvenile mussels, restricting their growth by (Agassiz 1862). This species is native to the impeding their ability to filter water and by northern Atlantic Ocean, and was introduced competing for food. Additionally, E. crocea will to the Pacific via ship bottoms (Mills et al. eat incoming mussel larvae, which decrease 2007). It has been found on both sides of the settlement rates in commercial mussel Atlantic and from the Gulf of Alaska to facilities (Fitridge and Keough 2013, Fitridge southern California, and thrives in northern 2011). A pycnogonid, Anoplodactylus erectus, temperate oceans (Ricketts et al. 1985). is parasitic in the digestive tract of Ectopleura Local Distribution: This species is common crocea in southern California, distending the in Oregon and California estuaries, and polyps abnormally (Ricketts et al. 1985, Rees seems to be a more northern species. In the and Russell 1937). Some amphipods Coos Estuary, it has been found in South (Stenothoe) are immune to E. crocea’s Slough, Charleston, and Fossil Point. nematocysts (Mackie 1966). The colonies Habitat: One of the most prominent fouling also provide a habitat for the egg masses of organisms, E. crocea is often found on some benthic opisthobranchs (Mills et al. undersides of floating docks, boat bottoms, 2007). and wharf pilings (Ricketts et al. 1985, Mills et

Piazzola, C.D. 2015. Ectopleura crocea. 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. Abundance: Colonies can be quite dense Larva: Actinula larvae are the larval stage; under the right conditions of water and these larvae attach to substrate and become currents. In ideal conditions, actinulae are a new polyp. They can have up to 10 capitate released August-October and February-March (knobbed) tentacles containing nematocysts; (Elkhorn Slough, CA), and, in less favorable visible inside are the manubrium and distal environments, August-November (Mills and tentacle buds (Fig. 5). In E. larnyx, tentacles Strathmann 1987). In warmer waters the can vary from 6 to 13, though most have 10 species shows a seasonal pattern of high (Pyefinch and Downing 1949). abundance during cool months and low Juvenile: Juveniles develop from settled abundance during warm; it has also been actinulae, often near the “parent” polyp. They decreasing in abundance since about 1980, have fewer tentacles and will develop more likely due to increasing ocean temperatures as they age. (Mediterranean Sea) (Di Camillo et al. 2013). Longevity: Unknown Growth Rate: It takes two weeks for Life-History Information juveniles to reach maturity, and takes 6-8 Reproduction: The polyps can reproduce days to go from ripe female gonads to the both sexually and asexually. In asexual liberation of viable actinulae (Mackie 1966). reproduction, new hydranths can grow from Time from settlement of actinulae to first the stolons (horizontal shoots at the base of generation of new larvae takes 24 days each hydrocaulus). Ectopleura crocea is (Pyefinch and Downing 1949). The stolon dioecious, so each colony is entirely male or growth rate is a steady 1 mm/day (Mackie entirely female during sexual reproduction. 1966). Settlement of actinulae begins after The gonophores correspond to the medusae about 24 hours (Pyefinch and Downing 1949). stage in other hydroids, and so are called This species is easily grown in the lab. gonomedusae. In the summer, male Food: The polyps eat copepods, gonomedusae release their sperm, which are chaetognaths, portunid zooae, small mysids, attracted to the female gonomedusae and siphonophores, eudoxids, and salps; they their eggs (Ricketts et al. 1985). Within the reject pteropods and pycnogonids. gonomedusae develop the planulae, which Predators: The polyps are eaten by leave the gonomedusae but remain in close pycnogonids and nudibranchs (Mills et al. association with the polyp (Kozloff 1983) and 2007; Pyefinch and Downing 1949; metamorphose into the actinulae (Fig. 5). Strathmann 1987). Actinulae are mobile, crawling larvae shaped Behavior: While each polyp is technically an like little polyps with the characteristic whorls individual organism, behavior tends to be on a of tentacles (Kozloff 1983). To develop into colonial scale (Pyefinch and Downing 1949). the adult polyp form, the actinulae moves Hydranths will fall off (autotomize) in away from its “parent” polyp and settles on unfavorable conditions (Ricketts et al. 1985). the nearby substratum (Kozloff 1983). There The behavior of the actinula stage differs the is no swimming stage. One polyp can most from other hydroids (see behavior in produce over 100 gonomedusae (not Reproduction above). simultaneously) (Miller 1976). Gonomedusae most distal on the racemes (stalks) mature Bibliography soonest (Mackie 1966). Mature male gonomedusae are white, while immature have 1. AGASSIZ, L. 1862. Contributions to the a red stripe. The mechanism for spawning natural history of the United States of and larvae release is not known (Miller 1976), America. IV Discophorae. Hydroidae. but possibly could be due to a change in light Homologies of the Radiata. Little intensity and water speed (Pyefinch and Brown, Boston. Downing 1949). In one area, only one species 2. ALLMAN, G. J. 1871. A Monograph of of Ectopleura will be sexually active at a time the gymnoblastic or tubularian (Miller 1976). hydroids. Ray Society, London.

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12644 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] 3. DI CAMILLO, C. G., G. GIORDANO, M. papers]. G. O. Mackie (ed.). Plenum BO, F. BETTI, M. MORI, S. PUCE, and Press, New York. G. BAVESTRELLO. 2013. Seasonal 12. MILLS, C. E., A. C. MARQUES, A. E. patterns in the abundance of MIGOTTO, D. R. CALDER, C. HAND, Ectopleura crocea (Cnidaria: Hydrozoa) J. T. REES, S. H. D. HADDOCK, C. W. on a shipwreck in the Northern Adriatic. DUNN, and P. R. PUGH. 2007. Marine Ecology. 34:25-32. Hydrozoa: Polyps, Hydromedusae, and 4. FITRIDGE, I. 2011. The ecology of Siphonophora, p. 118-167. In: The hydroids (Hydrozoa: Cnidaria) in Port Light and Smith Manuel. J. T. Carlton Phillip Bay, Australia, and their impacts (ed.). University of California Press, as fouling species in longline mussel Berkeley. culture. PhD. University of Melbourne. 13. MILLS, C. E., and M. F. STRATHMAN. 5. FITRIDGE, I., and M. J. KEOUGH. 1987. Phylum Cnidaria, Class 2013. Ruinous resident: the hydroid Hydrozoa, p. 44-71. In: Reproduction Ectopleura crocea negatively affects and development of marine suspended culture of the mussel invertebrates of the northern Pacific Mytilus galloprovincialis. Biofouling. coast: data and methods for the study 29:119-131. of eggs, embryos, and larvae. M. F. 6. HADERLIE, E.C., C. HAND, and W.B. Strathman (ed.). University of GLADFELTER. 1980. Cnidaria Washington Press, Seattle, WA. (Coelenterate): the sea anemones and 14. PYEFINCH, K. A., and F. S. allies, p.40-75. In: Intertidal DOWNING. 1949. Notes on the general invertebrates of California. R. H. Morris, biology of Tubularia larynx Ellis and D. P. Abbot, and E.C. Haderlie (eds.). Solander. Journal of the Marine Stanford University Press, Stanford, Biological Association of the United California. Kingdom. 28:21-43. 7. KOZLOFF, E. N. 1974. Keys to the 15. REES, J. T., and C. H. HAND. 1975. marine invertebrates of Puget Sound, Class Hydrozoa, p. 65-84. In: Light's the San Juan Archipelago, and manual: intertidal invertebrates of the adjacent regions. University of central California coast. S. F. Light, R. Washington Press, Seattle. I. Smith, and J. T. Carlton (eds.). 8. —. 1983. Seashore life of the northern University of California Press, Berkeley. Pacific coast. University of Washington 16. REES, W. J., and F. S. RUSSELL. Press, Seattle. 1937. On rearing the hydroids of 9. —. 1987. Marine invertebrates of the certain medusae, with an account of Pacific Northwest. University of the methods used. Journal of the Washington Press, Seattle and Marine Biological Association of the London. United Kingdom. 22:61-82. 10. MACKIE, G. O. 1966. Growth of the 17. RICKETTS, E. F., J. CALVIN, AND hydroid Tubularia in culture, p. 397- J.W. HEDGEPETH. 1985. Between 412. In: The Cnidaria and their Pacific tides. Stanford University Press, evolution: the proceedings of a Stanford. symposium held at the Zoological 18. SCHUCHERT, P. 2010. The European Society of London on 3 and 4 March athecate hydroids and their medusae 1965. W. J. Rees (ed.). Academic (Hydrozoa, Cnidaria): Capitata Part 2. Press, London. Revue Suisse De Zoologie. 117:337- 11. MILLER, R. L. 1976. Some 555. observations on sexual reproduction in 19. —. 2012. North-west European Tubularia, p. 299-308. In: Coelenterate athecate hydroids and their medusae. ecology and behavior: [selected Field Studies Council Publications, Telford, UK.