Invasion History

First Non-native North American Tidal Record:
First Non-native West Coast Tidal Record:
First Non-native East/Gulf Coast Tidal Record:

General Invasion History:

Hydroides sanctaecrucis was described from St. Croix on the U.S. Virgin Islands. It has been found from North Carolina and Florida to Atlantic Panama, Colombia, French Guiana and Brazil (Bastida-Zavala et al. 2017; US National Museum of Natural History 2010). It has been found at the Pacific end of the Panama Canal in 1972–1974 (Bastida-Zavala et al. 2002; U.S. National Museum of Natural History 2021). This serpulid has also been found in Pacific Mexico (2000, Oaxaca, Bastida-Zavala and ten Hove 2003), the Galapagos Islands (2016, Keppel et al. 2019), Hawaii (1972, Long 1974; cited by Carlton and Eldredge 2009), Singapore (2002, Jaafar et al. 2012), Australia (1998, Lewis et al. 2010), Hong Kong (2015, Ferrario and Minchin 2017); and Taiwan (2009, Sun et al. 2012). This Caribbean polychaete has been carried through the Panama Canal, and widely distributed by fouling and ballast water. 

North American Invasion History:

Invasion History in Hawaii:

Hydroides sanctaecrucis was reported on fouling plates off Oahu in 1968–1972, (Long 1974; cited by Carlton and Eldredge 2009) but has not been reported since.

Invasion History Elsewhere in the World:

Ships leaving the Panama Canal were the probable vector for the spread of H. sanctaecrucis into the Eastern Atlantic. Hydroides sanctaecrucis has been found at many sites in Australia, including fouling in a marina in Darwin, Northern Territory in 1998, in Cairns, Queensland in 1999, and on the hulls of naval ships and recreational vessels (Lewis et al. 2006). This polychaete has not been reported from other locations in Australia (Sun et al. 2015). Hydroides sanctaecrucis has become established in several major Asian ports, including Singapore (2002, Wells et al. 2019); Hong Kong (2009, Sun et al. 2012); and Kaohsiung, Taiwan (2015, Ferrario and Minchin 2017).  


Hydroides sanctaecrucis secretes a calcareous tube as do other serpulid polychaetes. The tube is smooth and white with two longitudinal ridges or none at all and lacks a peristome (raised ring around the opening) (Bastida-Zavala et al. 2017). Serpulids have a feathery crown of modified prostomial palps called radioles (the prostomium is the first segment, projecting above the mouth). There are 16 radioles each, on the right and left sides of the mouth (Bastida-Zavala et al. 2008). The radioles can be folded and withdrawn into the tube. One of the of the radioles is modified to form an operculum, which acts as a plug when the animal contracts. The peristomium (segment behind the mouth) is folded back to form a collar, which bears uniramous parapodia, with a distinctive set of collar chaetae which have spines or serrations. The collar is the first of seven thoracic chaeta-bearing segments (chaetigers). The subsequent segments have biramous parapodia. The dorsal branch of the parapodium is called the notopodium; the ventral branch is the neuropodium. Chaetae in the two branches and along the body can vary greatly in their morphology, which can be critical in the taxonomy.  The operculum is supported by a cylindrical peduncle. The opercular funnel has 19-29 radii with pointed tips. The verticil has 11–14 yellowish winged spines, all curving ventrally, with pointed tips and external spinules. The collar chaetae are bayonet chaetae, with two blunt or pointed teeth and a smooth distal blade (Bastida et al. 2008; Bastida-Zavala et al. 2017). The thorax has six chaetigers bearing short, saw-shaped setae called uncinae, and limbate chaetae. The abdomen has about 94 segments (57-149, n=4). The overall length is about 20.8 mm (11–306.5 n=54). The worm is yellow to light brown. (Description from Bastida-Zavala and ten Hove 2002; Bastida-Zavala 2008; Bastida-Zavala et al. 2017). 


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Annelida
Class:   Polychaeta
Subclass:   Palpata
Order:   Canalipalpata
Suborder:   Sabellida
Family:   Serpulidae
SubFamily:   Serpulinae
Genus:   Hydroides
Species:   sanctaecrucis


Eupomatus sanctae crucis (Fauvel, 1919)
Hydroides dianthoides (Augener, 1922)
Hydroides sanctae-crucis (Krøyer in Mörch, 1863)
Hydroides sanctaecrusis (Duenas, 1981)

Potentially Misidentified Species


Hydroides bispinosus

Caribbean native (Bastida-Zavala et al. 2017).

Hydroides dianthus

Western Atlantic, Mediterranean (Bastida-Zavala et al. 2017).



Life History- Hydroides sanctaecrucis feeds by extending its feathery gills and trapping plankton in the water column. In most serpulid species, the sexes are separate, and larvae are planktotrophic. 
Ecology- Hydroides sanctaecrucis occupies subtropical to tropical habitats, at salinities of 18–31 PSU (Bastida-Zavala and ten Hove 2002; Bastida et al. 2017). The species is known from a wide range of substrates, including 'coral, mollusk shells, seagrass, algae, sponges, rocks and artificial substrates' (Bastida-Zava et al. 2017). 


Phytoplankton, detritus

Trophic Status:

Suspension Feeder



General HabitatCoarse Woody DebrisNone
General HabitatOyster ReefNone
General HabitatMarinas & DocksNone
General HabitatRockyNone
General HabitatMangrovesNone
General HabitatVessel HullNone
Salinity RangePolyhaline18-30 PSU
Salinity RangeEuhaline30-40 PSU
Tidal RangeLow IntertidalNone
Vertical HabitatEpibenthicNone

Life History

Tolerances and Life History Parameters

Minimum Salinity (‰)18Field, Gatun Locks, Panama Canal (Bastida-Zavala and ten Hove 2002)
Maximum Salinity (‰)37Field (Bastida-Zavala and ten Hove 2002)
Maximum Length (mm)36.5Bastida-Zavala and ten Hove 2002
Broad Temperature RangeNoneSubtropical-Tropical
Broad Salinity RangeNonePolyhaline-Euhaline

General Impacts

The Caribbean polychaete Hydroides sanctaecrucis has successfully invaded many harbors. Impacts are unknown.

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
CAR-IV None 1863 Native Estab
CAR-II None 0 Native Estab
SA-II None 0 Native Estab
CAR-III None 0 Native Estab
SEP-H None 1972 Def Estab
CAR-I Northern Yucatan, Gulf of Mexico, Florida Straits, to Middle Eastern Florida 0 Native Estab
CAR-VI None 0 Native Estab
SP-XXI None 1972 Def Unk
AUS-XII None 1999 Def Estab
AUS-I None 1998 Def Estab
AUS-IX None 1998 Def Unk
NEP-IX None 2003 Def Unk
NEP-VII None 0 Def Estab
EAS-VI None 2002 Def Estab
NWP-2 None 2009 Def Estab
NEP-VIII None 0 Def Estab
PAN_PAC Panama Pacific Coast 1972 Def Estab
PAN_CAR Panama Caribbean Coast 0 Native Estab
SEP-Z None 2016 Def Unk

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude


Bastida-Zavala, J. Rolando; McCann, Linda D.; Keppel; Erica; Ruiz, Gregory M. (2017) The fouling serpulids (Polychaeta: Serpulidae) from United States coastal waters: an overview, European Journal of Taxonomy 344: 1-76

Bastida-Zavala, J. Rolando; Ten Hove, Harry A. (2002) Revision of Hydroides Gunnerus, 1768 (Polychaeta: Serpulidae) from the Western Atlantic region., Beaufortia 52(9): 103-178

Bastida-Zavala, J. Rolando. (2008) Serpulids (Annelida: Polychaeta) from the Eastern Pacific, including a brief mention of Hawaiian serpulids., Zootaxa 1722: 1-61

Bastida-Zavala, Jose Rolando; Salazar-Vallejo, Sergio (2000) Serpulidos (Polychaeta: Serpulidae) del Caribe norocidental: Hydroides Y Serpula, Revista de Biologia Tropical 48(4): 841-858

Bastida-Zavala, Rolando J; Ten Hove, Harry A. (2003) Revision of Hydroides Gunnerus, 1758 (Polychaeta: Serpulidae) from the Eastern Pacific region and Hawaii, Beaufortia 53(4): 67-110

Bastida-Zavala, Rolando; de León-González, Jesús Ángel; Carballo Cenizo, José Luis; Moreno-Dávila, Betzabé (2014) [Aquatic Invasive Species in Mexico], Comisión Nacional para el Conocimiento y Uso de la Biodiversidad, <missing place>. Pp. 317-336

Ferrario, Jasmine; Minchin, Dan (2017) Spread of the non-indigenous serpulid Hydroides sanctaecrucis Krøyer in Mörch, 1863 in the Pacific Ocean: a new record from Taiwan, BioInvasions Records 6(1): 33-38

Jaafar, Zeehan; Yeo, Darren C. J.; Tan, Heok Hui; O’Riordan, Ruth M. (2012) Status of estuarine and marine non-indigenous species in Singapore, Raffles Bulletin of Zoology Supplement 25: 79-92

Keppel, Erica; , Keith, Inti; Ruiz, Gregory M.; Carlton, James T. (2019) New records of native and non-indigenous polychaetes (Annelida: Polychaeta) in the Galapagos Islands, Aquatic Invasions 14(1): 59-84

Lewis, John A.; Watson, Charlotte; ten Hove, Harry A. (2006) Establishment of the Caribbean serpulid tubeworm Hydroides sanctaecrucis Krøyer [in] Morch, 1863, in northern Australia., Biological Invasions 8: 665-671

Lindsay, Denise and 9 authors (2021) Genetic analysis of North American Phragmites australis guides management approaches, Aquatic Botany <missing volume>(1023589): Published online

Low-Pfeng, Antonio; Recagno, Edward M. Peters (2012) <missing title>, Geomare, A. C., INESEMARNAT, Mexico. Pp. 236

Ruiz, Gregory; Geller, Jonathan (2021) Spatial and temporal analysis of marine invasions: supplemental studies to evaluate detection through quantitative and molecular methodologies, Marine Invasive Species Program, California Department of Fish and Wildlife, Sacramento CA. Pp. 153 ppl.

Sun, Yanan; Ten Hove, Harry A.; Qiu, Jian-Wen (2012) Serpulidae (Annelida: Polychaeta) from Hong Kong, Zootaxa 3424: 1-42

Sun, Yanan; Wong, Eunice; Ten Hove, Harry A.;Hutchings, Pat A.; Williamson, Jane E.; Kupriyanova, Elena K. (2015) Revision of the genus Hydroides (Annelida: Serpulidae) from Australia, Zootaxa 4009: 1-99

U.S. National Museum of Natural History 2002-2021 Invertebrate Zoology Collections Database.

Wells, Fred E.; Tan, Koh Siang; Todd, Peter A. Jaafar, Zeehan; Yeo, Darren C. J. (2019) A low number of introduced marine species in the tropics: a case study from Singapore, Management of Biological Invasions 10(3): 23-45

Wesselingh, Frank P. and 20 authors (2019) Mollusc species from the Pontocaspian region- an expert opinion list, ZooKeys 824: 31-124