SHEPARD ET AL.: ECOLOGY OF CERIANTHARIA 



terns, and 4) how they interact with other benthic 

 species. 



CERIANTHARIA 



Ceriantharians represent a small, incompletely 

 described order of Anthozoa. Species identification 

 is difficult, and many species probably remain 

 undescribed since twice as many larval forms as 

 adults are known (Hartog 1977; Hartog 6 ). Two 

 northwest Atlantic species have been identified; 

 Cerianthus borealis Verrill (1873) (see also Parker 

 1900; Kingsley 1904; Widersten 1976) and Cerian- 

 theopsis americanus (Agassiz 1859) (see also Ver- 

 rill 1864; McMurrich 1890; Parker 1900; Carlgren 

 1912; Field 1949; Widersten 1976). Two other un- 

 identified species have been found on the continental 

 slope (Grassle et al. 1975; Hecker et al. 1980; Valen- 

 tine et al. 1980; Sebens in press). Table 1 sum- 

 marizes the geographic and bathymetric ranges of 

 the above four species. 



Ceriantharia live in permanent semirigid tubes 

 composed of a type of cnidae peculiar to the Order 

 (called ptychocysts by Mariscal et al. 1977), mucus, 

 and adhering substrate debris (Emig et al. 1972). 

 The feltlike tube is usually deep purple in coloration 

 and distinct enough to be used alone as evidence of 

 Ceriantharia presence. New England bottom trawl 

 fishermen are familiar with nets fouled with cerian- 

 tharian tubes (Rogers 1979). In contrast to other 

 burrowing anemones which have a single whorl of 

 tentacles, Ceriantharia have two distinct whorls 

 (marginal and oral tentacles) which remain outside 



the tube during feeding and rapidly retract into the 

 tube when disturbed. 



Ceriantharia are protandric hermaphrodites; 

 gametes are produced in the mesenteries and fer- 

 tilization is external. The larvae are pelagic and 

 duration of the planktonic stage is variable (Carlgren 

 1912; Hyman 1940; Robson 1966; TRIGOM-PARC 

 1974). Adults are capable of oral disc regeneration 

 by budding (Hyman 1940; Frey 1970). Asexual 

 reproduction has been described for at least one 

 species, Aracnanthus oligopodus (Cerfontaine 1909). 



Ceriantharia are carnivorous passive suspension 

 or impingement feeders (Emig et al. 1972; Carac- 

 ciola and Steimle 1983). Digestion may begin in the 

 tentacles, and larger particles are primarily taken 

 up in the endoderm of sterile septa (Tiffon and 

 Daireaux 1974). Fish species inhabiting the region, 

 including cod, haddock, flounder, scup, and skate 

 are known predators of whole juvenile Ceriantharia 

 (Bowman and Michaels 7 ) and may graze the tenta- 

 cles of adults (TRIGOM-PARC 1974). Off the U.S. 

 west coast, a nudibranch, Dendronotus iris Cooper, 

 preys on adult Ceriantharia (Wobber 1970). 



Previous documentation of Ceriantharia in the 

 northwest Atlantic has come from grab samples 

 (Sanders 1956; Wigley 1968; Pearce 1972; Pearce 

 et al. 1976; Pearce et al. 1981; Reid et al. 1981; 

 Wigley and Theroux 1981; Caracciola and Steimle 

 1983) and submersibles (Grassle et al. 1975; Rowe 

 et al. 1975; Hecker et al. 1980; Valentine et al. 1980). 

 However, no studies in the region report exclusive- 

 ly on ceriantharian ecology. 



6 J. C. den Hartog, Curator of Coelenterata, Rijksmuseum van 

 Natuurlijke Historie, Postbus 9517, 2300 RA Leiden, Netherlands, 

 pers. commun. March 1983. 



7 Bowman, R., and W. Michaels. 1983. Unpubl. data. Food 

 Habits Program, Northeast Fisheries Center Woods Hole Labor- 

 atory, National Marine Fisheries Service, NOAA, Woods Hole, MA 

 02543. 



Table 1. — Morphologic descriptions and geographic and bathymetric ranges of previously 

 described Ceriantharia species inhabiting the study area. 



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