Ectopleura crocea

Invasion History

First Non-native North American Tidal Record: 1859
First Non-native West Coast Tidal Record: 1859
First Non-native East/Gulf Coast Tidal Record:

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General Invasion History:

Ectopleura crocea (also known as Pinauay crocea or Tubularia crocea) was first described from 'Boston Bay', Massachusetts by Louis Agassiz in 1862 (as Parypha crocea). On the Atlantic coast of North America, its presumed native region, E. crocea has been collected from the Miramichi Estuary, New Brunswick, south to Lake Worth, Florida and Port Aransas, Texas (Fraser 1944; Deevey 1950; Defenbaugh 1973; Ruiz et al. unpublished data). It has also been collected on the Caribbean shore of South America at Santa Marta, Colombia (Wedler 1975), where we consider it cryptogenic. Ectopleura crocea has a wide global distribution and was apparently introduced to non-native locations starting in or before the 19th century (Deevey 1950; Carlton 1979; Watson 1999).

North American Invasion History:

Invasion History on the West Coast:

Even before its description in Massachusetts, this hydroid was collected from San Francisco Bay, California (as Parypha microcephala, Agassiz 1859, cited by Carlton 1979). In San Francisco Bay, it occurs in the Central Bay, the South Bay, and San Pablo Bay (Carlton 1979; Cohen and Carlton 1995; Cohen et al. 2005; Ruiz et al. unpublished data).To the south, E. crocea was collected from the major ports of San Diego (in 1876, Clark 1876, cited by Carlton 1979) and Los Angeles (in 1902, Torrey 1902, cited by Carlton 1979), before it was recorded from the smaller coastal bays: Mission Bay (in 1896, USNM 43547, U.S. Museum of Natural History 2007), Newport Bay (in 1938, Carlton 1979, USNM 43543, U.S. Museum of Natural History 2007), Kings Harbor, Santa Monica Bay (Fraser 1948, cited by Carlton 1979), and Elkhorn Slough (MacGinitie 1935, cited by Carlton 1979, Wasson et al. 2001).

To the north, E. crocea was reported from Port Simpson, British Columbia (54.6 N) in 1911. Early collections were also made from the San Juan Islands (Washington), north to the Queen Charlotte Islands, and an unspecified record from 'the Gulf of Alaska' (Fraser 1937; Carlton 1979). Mills (in Cohen et al. 1998) considered the reports from San Juan Islands to be unverified, and perhaps the result of taxonomic confusion. However, this hydroid was found on fouling plates in Ketchikan, Alaska, in 2003 (Ruiz et al. 2006). We do not know if this hydroid is established in Alaska or British Columbia. Ectopleura crocea was collected in Coos Bay, Oregon starting in 1948 (Fraser 1948, cited by Carlton 1979; Carlton 1989; Ruiz et al., unpublished data), and on fouling plates in Humboldt Bay, California in 2003 (Ruiz et al., unpublished data).

Invasion History Elsewhere in the World:

Ectopleura crocea has been reported from the tropical Pacific at Jicaron Island, Panama (Fraser 1938), from fouling plates in Salinas, Ecuador (2018, Calder et al. 2021), and the southeastern Pacific at Valparaiso, Chile (1905, Deevey 1950). In the southwestern Pacific, it was first collected in Victoria, Australia, in Port Phillip Bay (as Tubularia ralphii, Bale 1884, cited by Watson 1999). It has also been collected in Sydney Harbor and Port Kembla, in New South Wales, at Fremantle, in Western Australia (Watson 1999), at Auckland, New Zealand (Cranfield et al. 1998). In the northeast Atlantic, E. crocea appears to be an introduction. It was first collected in the Azores in 1989 (Cardigos et al. 2006) and is also known from Madeira (Wirtz 2007). It was noted as a rare occurrence on ship hulls at Plymouth, England in 1895 and 1907 (Plymouth Marine Fauna, http://www.mba.ac.uk/pmf/) and at Ipswich, England in 1959 (Rees 1963). It is not listed as a Mediterranean invader by Galil (2009), but available references suggest that it is mostly known from harbors (e.g., Villefranche-sur-mer, France, 1895, Schuchert 2010; Bay of Naples, Italy, 1892, Bouillon et al. 2004; Israel 1946, Vervoort 1993). In the southwest Atlantic, it occurs from Uruguay to Bahia Blanca, Argentina (Genzano et al. 2005). It was first reported from this region in 1971 and is considered cryptogenic there (Orensanz et al. 2003). In South Africa, it was found in Durban and Cape Town in 1947 (Ewer 1953, cited by Millard 1975, as Tubularia warreni; Schuchert 2010; (1947, Millard 1952, cited by Mead et al. 2011). In the Northwest Pacific, Tubularia sagaminea and T. mesembryanthemum, reported from Japan (Stechow 1907; Yamada 1959; Hirohito 1988) and China (Hargitt 1927, Yamada 1959. all cited by Imazu et al. 2014), are all considered synonyms of E. crocea.

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Description

Ectopleura crocea, also commonly known as Pinauay or Tubularia crocea, is a hydrozoan which lacks a medusa stage. Its colonies grow from branching stolons, in tangled masses up to 100–120 mm in height, and consist of up to several hundred unbranched stems, with one hydranth per stalk. The perisarc is wrinkled with a few annulations, but there are no joints in the stalk. The hydranth is vase-shaped with a long hypostome. The tentacles are threadlike, in two whorls of 20–24 each. The proximal-whorl tentacles are larger and longer than those in the distal whorl. The female gonophores are carried on 12–16 blastostyles, hanging below the tentacles. The female gonophores produce eggs, which develop into planktonic actinula larvae resembling miniature hydranths, usually with four tentacles. Production of these larvae may vary regionally; being rare (West Coast, Fraser 1937) or frequent (Chesapeake Bay, Calder 1971). The male gonophores are oval or spherical, without apical processes. The body of the hydranth is pink (description from: Fraser 1937; Calder 1971; Watson 1999; Schuchert 2010).

The correct genus name for this hydroid is disputed. Marques and Migotto (2000) published a cladistic analysis of the genus Ectopleura which supported the monophyly of the genus, but found that genus consisted of two subclades, and put several widespread species including E. larynx, E. crocea, and E. marina into a new genus, Pinauay. Schuchert (2010) considers the split to be unjustified. Imazu et al. (2014) review the taxonomy and distribution of this hydroid, using the name E. crocea. They tentatively support the synonymy of Western Atlantic E. crocea with E. ralphi, as described from Australia and based on Brazilian specimens, but suggest that worldwide morphological and genetic comparisons are needed.

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Taxonomy

Ecology

General:

The hydroid Ectopleura crocea lacks a free-living medusa. It does have a short-lived (~24 hours) planktonic lecithotrophic larval form, known as an actinula, resembling a small sea-anemone. It grows on a solid substrate, with polyps arising from branching, creeping stolons. The polyps grow as single stalks, each bearing a hydranth, whose tentacles capture zooplankton. The polyps produce bunches of gonophores, which produce either eggs or sperm. Colonies are diecious (single-sexed). Female gonophores produce multiple eggs, typically 2–4, which are brooded and fertilized by sperm in the water column. The egg develops in the gonophore through the planula stage into an actinula (Barnes 1983; Bouillon et al. 2004; Schuchert 2010). Larvae spend about 24 hours in the water column (as Ectopleura mesembryanthemum; Yamashita et al. 2003).

This hydroid occurs on a variety of substrates, including rocks, shells, concrete, pilings, buoys, jetties, pipes, and ships’ hulls (Fraser 1944; Woods Hole Oceanographic Institution 1952; Calder 1971; Gosner 1978). It is characteristic of harbors and polluted waters (Bouillon et al. 2004; Schuchert 2010). In South Carolina, it was found at a salinity range of 23–34 PSU (Calder 1976). The occurrences of Ectopleura crocea in Salinas, Ecuador, with mean water temperature of 24 °C, increases the known temperature tolerance of this hydroid (Calder et al. 2021).

Food:

Zooplankton, small epibenthos

Consumers:

Nudibranchs

Competitors:

Trophic Status:

Carnivore

Carn

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Habitats

General Habitat	Oyster Reef	None
General Habitat	Coarse Woody Debris	None
General Habitat	Marinas & Docks	None
General Habitat	Rocky	None
General Habitat	Vessel Hull	None
Salinity Range	Polyhaline	18-30 PSU
Salinity Range	Euhaline	30-40 PSU
Tidal Range	Subtidal	None
Vertical Habitat	Epibenthic	None

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Life History

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Tolerances and Life History Parameters

Minimum Temperature (ºC)	0	Based on geographical range
Maximum Temperature (ºC)	30	Charleston Harbor SC (Calder 1992)
Minimum Salinity (‰)	23	Field distribution, SC (Calder1976)
Maximum Salinity (‰)	34	Field distribution, SC (Calder1976)
Maximum Duration	1	Yamashita et al. 2003, for Ectopleura mesembryanthemum
Broad Temperature Range	None	Cold temperate-Tropical
Broad Salinity Range	None	Polyhaline-Euhaline

General Impacts

Ectopleura crocea is frequently an abundant fouling organism in its native and introduced ranges. It seems to prefer man-made structures and is tolerant of polluted waters (Schuchert 2010). It is also occurs on mussel shells and around mussel beds, and is a potential competitor with mussels and a possible predator on their larvae (Okamura 1986; Fitridge 2011).

Economic impacts

Ectopleura crocea has been reported from pilings, buoys, jetties, pipes, and ship hulls (Fraser 1944; Woods Hole Oceanographic Institution 1952; Calder 1971; Gosner 1978). It is probably an important contributor to fouling communities because of its size and frequent abundance. However, specific impacts on shipping have not been reported.

Fisheries- Ectopleura crocea fouls cultured mussels (Mytilus galloprovincialis) in Port Phillip Bay, Australia, with adverse effects on their growth and condition, possibly due to competition for food, and on the recruitment of larvae due to predation (Fitridge 2011).

Ecological Impacts

Competition-Ectopleura crocea was a dominant form on fouling plates in San Francisco Bay (Okamura 1986).

Habitat Change- The degenerating stalks of Ectopleura crocea provided a filamentous surface for metamorphosing larvae of Mytilus spp. on fouling plates in San Francisco Bay (Okamura 1986), and in Port Phillip Bay, Australia (Fitridge 2011).

Impacts in the Galapagos Islands

Impacts are unknown in the Galapagos Islands.

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Regional Impacts

NEP-V	Northern California to Mid Channel Islands		Ecological Impact	Competition
Ectopleura crocea was a dominant form on fouling plates in San Francisco Bay in late summer and fall, occupying up to 60% of the plates' surface, reaching a peak in October (Okamura 1986).
NEP-V	Northern California to Mid Channel Islands		Ecological Impact	Habitat Change
The degenerating stalks of Ectopleura crocea provided a filamentous surface for metamorphosing larvae of Mytilus spp. on fouling plates in San Francisco Bay in winter, facilitating the establishment of dense populations in spring (Okamura 1986).
P090	San Francisco Bay		Ecological Impact	Competition
Ectopleura crocea was a dominant form on fouling plates in San Francisco Bay in late summer and fall, occupying up to 60% of the plates' surface, reaching a peak in October (Okamura 1986).
P090	San Francisco Bay		Ecological Impact	Habitat Change
The degenerating stalks of Ectopleura crocea provided a filamentous surface for metamorphosing larvae of Mytilus spp. on fouling plates in San Francisco Bay in winter, facilitating the establishment of dense populations in spring (Okamura 1986).
AUS-VIII	None		Economic Impact	Fisheries
Fisheries- Ectopleura crocea was fouling cultured mussels (Mytilus galloprovincialis) in Port Phillip Bay, Australia, reducing their condition index, particularly for younger mussels. Competition for food may be affecting mussel growth. The hydroid's predation on larval mussels, especially settling larvae, may be reducing recruitment. However, the stalks of the hydroids, especially when degenerating, provide a surface for the settlement of mussel larvae (Fitridge 2011; Fitridge and Keough 2013).
CA	California		Ecological Impact	Competition
Ectopleura crocea was a dominant form on fouling plates in San Francisco Bay in late summer and fall, occupying up to 60% of the plates' surface, reaching a peak in October (Okamura 1986)., Ectopleura crocea was a dominant form on fouling plates in San Francisco Bay in late summer and fall, occupying up to 60% of the plates' surface, reaching a peak in October (Okamura 1986).
CA	California		Ecological Impact	Habitat Change
The degenerating stalks of Ectopleura crocea provided a filamentous surface for metamorphosing larvae of Mytilus spp. on fouling plates in San Francisco Bay in winter, facilitating the establishment of dense populations in spring (Okamura 1986)., The degenerating stalks of Ectopleura crocea provided a filamentous surface for metamorphosing larvae of Mytilus spp. on fouling plates in San Francisco Bay in winter, facilitating the establishment of dense populations in spring (Okamura 1986).

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