Calyptospadix cerulea

Invasion History

First Non-native North American Tidal Record: 1901
First Non-native West Coast Tidal Record: 1901
First Non-native East/Gulf Coast Tidal Record:

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General Invasion History:

Calyptspadix cerulea (Rope Grass Hydroid) was first described from Fort Wool, off Norfolk, Virginia (Clarke 1882). A very similar hydroid, was described from San Francisco as Bimeria franciscana,( Torrey 1902.). The chief difference between the two species was the apparent number of eggs in the gonophores, single in, G. franciscana, versus multiple eggs in C. cerulea. Calder (2019) found that the varying number of cells represented developing planulae, rather than a species difference in numbers of eggs, and that the 'G. franciscana' and 'G. cerulea', at least on the East Coast, are conspecific. Genetic comparisons need to be made among Eastern Pacific, European, and other disjunct populations of 'G. franciscana, but we will provisionally treat them as introduced populations of the Western Atlantic Calyptospadix cerulea (Calder 2019).

North American Invasion History:

Invasion History on the West Coast:

Calyptospadix cerulea was collected and described from Oakland, California, in San Francisco Bay, in 1901, as Bimeria franciscana by Torrey (Torrey 1902; USNM 43484, U.S. National Museum of Natural History 2007). It was subsequently found in "various scattered locations' in each of the three sections of San Francisco Bay (Fraser 1937). It has been collected from Suisun Bay and the Carquinez Straits, the Napa River, San Pablo Bay, and the Central and South Bays (Cohen and Chapman 2004; Cohen et al. 2005; U.S. National Museum of Natural History 2007), from brackish (mesohaline, 5-19 PSU) to marine (polyhaline-euhaline conditions, 18-35 PSU). The occurrence of C. cerulea outside San Francisco Bay is uncertain. Two specimens in the California Academy of Science collections are reported from Monterey Bay (1921, CAS 1132 and CAS 1194, California Academy of Science 2008), but no further reports of this hydroid have been made from here. In 1941, Fraser collected 'G. franciscana from the San Diego and San Nicolas Island (Fraser 1948). Ruiz et al. (unpublished data) found this species in San Diego Bay in 2000, but another survey in the same area and season (Cohen et al. 2002), sampling some of the same locations, did not find this species. Records are also known from Newport Bay (2011, Ruiz et al., unpublished date) and Morro Bay (2006, Needles and Wendt 2012). A record from Homer, Alaska (Hines et al. 2000) needs to be verified.

Invasion History on the East Coast:

Calyptospadix cerulea was described from Chesaeake Bay,(Clarke 1882), but rarely reported.  On the East Coast, 'Garveia. franciscana' was first reported in Chesapeake Bay, in the Potomac estuary by Frey (1946) as 'Bimeria tunicata', and was reported as abundant by 1967 (Cory 1967). In Delaware Bay, G. franciscana was reported by 1968 and had an apparent range expansion (or fluctuation) between 1968 and 1971 (Maurer and Watling 1972). Calder (1971) considered 'Garveia cerulea' tp be native to Chesapeake Bay, and associated with higher salinities, while 'Garveia franiciscana' was considered to be a probable invader, of unknown origin  based on its occurrences on the West Coast and Europe (Vervoort 1964; Dale Calder, personal communications).  .It was treated as a biological invader with significant impacts on fisheries and power plants (Cory 1967; Calder 1971; Andrew 1973; Thompson 1993).).  Garveia franciscana' was found in South Carolina in 1974 and was reported to be abundant in 'numerous areas across the coastal region' (Calder 1976, Calder and Hester 1978). This hydroid was abundant and widespread in the St. Johns River estuary, around Jacksonville, Florida in 2003 (Ruiz et al., unpublished data)  .Calyptospadix cerulea  has been reported from Providence River, Rhode Island, at the head of Narragansett Bay (in 2000, e( MIT Sea Grant 2003), Great Bay, New Hampshire, and Port de Grave, Newfoundland (Ruiz et al., unpublished data).  Calder (2019; Dale Calder, personal communications 1996-2005) had long suspected and finally  concluded that Garvea francisana and 'G. cerulea' were conspecific, and that Clarke's original name (Calyptospadix cerulea) had priority., this converting the hydroid from a exotic invasive species tp a probematic native.

Invasion History on the Gulf Coast:

In the Gulf of Mexico, Calyptospadix .cerulea was first reportedc as 'Bimeria tunicata was from 1943 on the 'Louisiana coast' (Fraser 1944), including Bayou Chene Fleuri and Sabine Pass (Deevey 1950,  as B. franciscana), and it was abundant by 1950 in Lake Pontchartrain (Deevey 1950; Crowell and Darnell 1955). It now occurs from Tampa Bay, Florida (Ruiz et al. unpublished data) to Galveston and Corpus Christi, Texas (Defenbaugh 1973; Ruiz et al., unpublished data). A notable occurrence was in the Crystal Springs cave system, north of Tampa Bay on the Gulf Coast of Florida (Garman et al. 1999). Deevey had noted its cosmopolitan distribution, together with that of other hydroids, suggesting the possibility of introduction.  However, C. cerulea is now regarded as native to the Northwest Atlantic (Calder 2019).

Invasion History Elsewhere in the World:

In Europe, Calyptospadix cerulea was first found in 1920 in the Netherlands, in the Zuiderzee, before it was converted to a freshwater lake. (Vervoort 1964). Subsequently, it was found in the Netherlands at Edam, Amsterdam, Heelvoetsluis, in Belgium in the lower Scheldt (1962, Vervoort 1964) and in Germany in the Elbe River estuary (1946) Initially, it was confused with Cordylophora caspia, but was later recognized as a new species, Perigonimus megas (Kinne 1955, cited by Vervoort 1964) and the Kiel Canal (1950, Vervoort 1964). In the Mediterranean Sea, this hydroid was discovered in the Lagoon of Venice, Italy on the Adriatic Sea in 1978 (Morri 1982), where it is abundant (Mizzan 1999), and in Alexandira, Egypt in. In the Black Sea, C. cerulea was collected in Lake Varna, Bulgaria, in 1933, and is now widespread and abundant (Gomiou et al. 2002). By 1960, it was appearing in powerplants aling the Sea of Azov (Simkina 1963; Simkina 1975), and in 1962 it was collected in the Caspian Sea, which it reached by canal shipping (Aladin et al. 2002; Grigorovich et al. 2003).

There are several outlying records of Calyptospadix cerulea which may include some introductions by shipping, but some probably require re-examination of specimens, Occurrences in Brazil could either represent extensions of the native range. It was found in Paranagua Bay 2010, 25 31S; 48 30W), in 1985 and Neves et al. 2007; and 2007, Cangassu et al. 2010;) and closer to the Equator, in the small Rio Formosa estuary in Pernambuco State, Brazil (8 43 S, 35 6W 1993, Calder and Mayal 1998; Calder 2019; Teixeira and Creed 2020). Specimens of "Garviea franciscana' have been identified from Port Harcourt,, Nigeria 1957, Schuchert 2007) and Cameroon (1027, Vervoort 1964), from the east and west coasts of India, and Brisbane, Australia (Vervoort 1964), Genetic and morphological studies of these remote specimens are desirable.

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Description

Calyptospadix cerulea, known as the Rope-Grass hydroid, lacks a planktonic medusa stage, undergoing sexual reproduction by means of attached gonophores. It has erect colonies, usually monosiphonic (single-stemmed), bushy, and densely branched. The colonies reach 100-300 mm in height. The branching is more or less regular and alternate, occurring at a 60 degree angle. The branches are helically arranged. The hydrocaulus (stem) arises from a mat of root-like fibers (hydrorhizae). Multiple hydrocauli may rise from the same mat. The perisarc is thick, wrinkled (especially near the base of the hydrocaulus), horn-colored, and often annulated around the base of the branches. The hydranths are partially covered by a pseudohydrotheca and end in a dome-shaped hypostome, which is surrounded by about 8-16 filiform tentacles in a single whorl. The sexes are separate, with gonophores born on the pedicels of the hydranths. The male gonophores are elongate-oval in shape and are covered with perisarc. The spermatozoa develop around a distinct spadix. The female gonophores are round or oval, also covered by perisarc, and have a large spadix. Clarke's (1882) description reported multiple eggs in each gonophore. A similar hydroid, originally described as Bimeria franciscana (Torrey 1902) from San Francisco Bay was reported to have only a single egg in each gonophore. Specimens of C. cerulea from Florida had both single and multiple clusters of cells in the gonophores, resulting from cell division (Calder 2019). Calder now considers Garveia fransciana to be conspecific with C. cerulea, subject to molecular studies of populations around the world.. ,

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Taxonomy

Ecology

General:

Calyptospadix cerulea is a sessile hydrozoan which lacks a planktonic medusa stage. Colonies grow on a solid substrate, with polyps arising from a creeping stolon. The polyps form bushy structures, with many hydranths, whose tentacles capture zooplankton. The polyps produce gonophores, which produce either eggs or sperm. Colonies are diecious (single-sexed). Female gonophores usually produce a single egg. After fertilization the egg develops into a ciliated non-feeding planula larva which is released into the water column (Crowell and Darnell 1955; Bouillon et al. 2004; Schuchert 2007).

Planulae of C. cerulea settle and grow on a wide range of substrates, including shells, rock, wood, and vegetation. They can also be found on man-made substrates including pilings, buoys, fouling plates, and inside industrial water systems (Woods Hole Oceanographic Institution 1952; Calder 1971; de Rincon and Morris 2003). Calyptospadix cerulea grows in a wide range of estuarine environments, varying in salinity, temperature, currents, and oxygen. Colonies grow slowly, but survive at 1 PSUt, and grow well at 3.5 - 35 PSU (Crowell and Dayrnell 1955). However, during heavy freshwater flows in the Caloosahatchie River estuary, C. cerulea died out, and was replaced by Cordylophora caspia (Calder 2019). This hydroid survives in estuarine areas such as the Chesapeake and Delaware Bays, and estuaries in northern Europe, wher s occasionally approach 0C (Vervoort ydr1964; Watling and Maurer 1972). It does this by remaining dormant in the winter (Crowell and Darnell 1955; Calder 1992). It can tolerate temperatures as high as 37.5?C in thermal effluents (Nauman and Cory 1969). In the Sea of Azov, sexual reproduction occurred at 19.5 - 23 C and 7.5-9 ppt (Simkina 1965).

Food:

Zooplankton and small epibenthos

Consumers:

Nudibranchs

Trophic Status:

Carnivore

Carn

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Habitats

General Habitat	Coarse Woody Debris	None
General Habitat	Oyster Reef	None
General Habitat	Marinas & Docks	None
General Habitat	Vessel Hull	None
General Habitat	Mangroves	None
General Habitat	Rocky	None
General Habitat	Grass Bed	None
General Habitat	Unstructured Bottom	None
General Habitat	Canals	None
Salinity Range	Oligohaline	0.5-5 PSU
Salinity Range	Mesohaline	5-18 PSU
Salinity Range	Polyhaline	18-30 PSU
Salinity Range	Euhaline	30-40 PSU
Tidal Range	Subtidal	None
Tidal Range	Low Intertidal	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)	37.5	Field- collected in thermal effluent (Nauman and Cory 1969)
Minimum Salinity (‰)	1	In Lake Pontchartrain, sexual reproductive structures were seen only in the higher salinity parts of the estuary, (to 12 ppt) "It is quite likely that gonophore production is seasonal and depends on narrower ranges of environmental factors than those permissible for hydroid growth." In the Sea of Azov, asexual reproduction decreased below 8 ppt and was nearly absent at 2 ppt (Simkina 1963). Sexual reproduction occurred at 5-25 ppt in experiments, but survival of planulae at 9-15 ppt (Simkina 1965).
Maximum Salinity (‰)	35	Maximum Salinity, Survival - No survival occurred at 40 ppt, for animals from Sea of Azov (Simkina 1965). Colonies from the Surry Nuclear Power Plant, James River, VA, 0-15 ppt, deteriorated quickly at 30-40 ppt (Thompson 1993). Hydroids from Lake Pontchartrain LA showed "good growth" at 35 ppt (Crowell and Darnell 1955).
Minimum Reproductive Temperature	19.5	Development of gonophores (Simkina 1965, Sea of Azov)
Maximum Reproductive Temperature	34	Field data, Lake Pontchartrain LA (Crowell and Darnell 1955).
Minimum Reproductive Salinity	5	For sexual reproduction, Sea of Azov, Russia (Simkina 1965)
Maximum Height (mm)	300	(Calder 1971; Andrews 1973)
Broad Temperature Range	None	Cold temperate-Tropical
Broad Salinity Range	None	Oligohaline-Polyhaline

General Impacts

Garveia franciscana is a widespread fouling organism, which can be very abundant on man-made structures and can compete with native fouling organisms under suitable conditions. However, it can also have positive impacts and its bushy colonies may provide habitat for small fishes and invertebrates.

Economic impacts

Garveia franciscana can have negative impacts by fouling power plants and other industrial water systems. These effects are best documented in Chesapeake Bay, but they have also been reported from Venezuela (de Rincon and Morris 2003) and the Ukraine (Simkina 1963).

Industry- Fouling of power plants and other industrial water systems by G. franciscana has been reported from Chesapeake Bay (Cory 1967; Virginia Power 1992); Lake Maracaibo, Venezuela (de Rincon and Morris 2003); and the Sea of Azov, Ukraine (Simkina 1963; Simkina 1965). Fouling can block flow through water systems, cause breakdowns of traveling screens which remove debris, and speed up corrosion of metal structures (Virginia Power 1992; de Rincon and Morris 2003). Costs include shutdowns for cleaning and the cost of biocides to reduce fouling. At the Surry Nuclear power plant in Virginia, fouling by G. franciscana prompted an expensive redesign of the cooling system (Virginia Power 1992). The use of biocides to prevent fouling, such as chlorine and other chemicals, raises environmental concerns about their toxicity to other organisms (McLean 1972; Virginia Power 1992).

Fisheries- Fouling by G. franciscana has been a major problem on fishing gear in Chesapeake Bay, including crab pots and oyster trays (Andrews 1973). On the other hand, G. franciscana probably benefits commercial and sport fisheries by providing habitat for juvenile and bait fishes, shrimps, crabs, and other motile organisms in the Chesapeake Bay (Thompson 1993) and Lake Pontchartrain, Louisiana (Crowell and Darnell 1955).

Ecological Impacts

Although G. franciscana (Rope Grass Hydroid) is an abundant and sometimes dominant part of the fouling community in many estuaries, its ecological impacts are largely unknown.

Competition - Garveia franciscana and Victorella pavida (cryptogenic on the East and Gulf Coasts) overgrew most other organisms on fouling panels at Calvert Cliffs, Maryland, in summer (Abbe 1987). Garveia franciscana overlaps spatially with Cordylophora caspia, although C. caspia ranges into lower salinities (Calder 1971; Cory 1967; Thompson 1993). It also co-occurs with V. pavida (cryptogenic). Victorella pavida and G. franciscana settle at the same time at Calvert Cliffs, but G. franciscana persists longer in summer (Abbe 1987).

Habitat Change - Growths of G. franciscana provide cover for numerous amphipods, mud crabs, and other organisms in Patuxent River, Maryland (Cory 1967); James River, Virginia (Thompson 1993); and Lake Ponchartrain, Louisiana (Crowell and Darnell 1955).

Food - Garveia franciscana is fed on by nudibranchs, particularly Tenellia spp. (Abbe 1987; Cory 1967; Thompson 1993).

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Regional Impacts

NA-ET3	Cape Cod to Cape Hatteras		Economic Impact	Industry
Calyptospadix cerulea is a major fouling organism in the Chesapeake Bay region. The organism with the highest quantified cost to power plants in the Chesapeake Bay is C. cerulea, which is a major fouler of power plants along mesohaline waters of Chesapeake Bay (Cory 1967; Virginia Power 1992) and elsewhere in the world (Simkina 1963). At two power plants in Chesapeake Bay, Chalk Point (Patuxent River) and Morgantown (Potomac River), the cost of biocides to control fouling dominated by C. cerulea was 95,000 to $180,000 per year in 1995-97 (Krueger 1997, personal communication). At the Surry Nuclear Power Plant on the lower James River, the weight of the hydroids caused breakdowns of the traveling screens which remove debris. Aggregates of hydroids blocked water flow in the main condensers, in the circulating water systems used for cooling during routine operation, and in the service water systems, which would be used in shutdown after an accident. 'Almost daily' cleaning was required during warm weather to keep water flowing through the service system. In 1992, the projected cost of 'doing nothing' about the biofouling problem, except routine cleaning and repairs was $37.5 million projected over the plant's remaining license period (to the year 2013), or $3.4 million per year. The operators of the plant instead undertook an extensive reconstruction of the cooling and screen system, which was intended to reduce fouling problems, with a projected cost of $23.6, or $2.1 million per year (Virginia Power 1992). One major consequence of the invasion of exotic fouling organisms is the increased use of biocides and antifouling coatings in power plants and industrial water systems. These chemicals are toxic substances used to kill microbial and invertebrate organisms on surfaces exposed to natural waters. Among coatings used in power plants are copper oxide paints, organotin compounds, as well as nontoxic coatings that inhibit attachment of organisms (Virginia Power 1992). At the Surry Nuclear Power Plant, several biocides in addition to chlorine were tested against G. franciscana, including ammonium hydroxide, hydrogen peroxide, sodium bromide-hypochlorite mixture, a surfactant mixture ('ClamTrol'), and chemically induced anoxia. However, at doses allowed by their U.S. EPA permit, these were ineffective (Virginia Power 1992).
NA-ET3	Cape Cod to Cape Hatteras		Economic Impact	Fisheries
Fisheries- Costs: Fouling by Calyptospadix cerulea has been a major problem on fishing gear, including crab pots and oyster tayCalyptospadix ceruleaCalyptospadix cerulea probably benefits commercial and sport fisheries by providing habitat for juvenile and bait fishes, shrimps, crabs, and other motile organisms (Thompson 1993).
NA-ET3	Cape Cod to Cape Hatteras		Ecological Impact	Competition
Competition- Although Calyptospadix cerulea (Rope Grass Hydroid) is an abundant and sometimes dominant part of the fouling community in parts of Chesapeake Bay, its ecological impacts are largely unknown. Calyptospadix cerulea and Victorella pavida overgrew most other organisms on fouling panels at Calvert Cliffs, Maryland, in summer (Abbe 1987).
NA-ET3	Cape Cod to Cape Hatteras		Ecological Impact	Habitat Change
Growths of Calyptospadix cerulea provide cover for numerous amphipods, mud crabs, and other organisms in the Patuxent River (Cory 1967) and James River (Thompson 1993).
NA-ET3	Cape Cod to Cape Hatteras		Ecological Impact	Food/Prey
Food/Prey- Calyptospadix cerulea is fed on by nudibranchs, particularly Tenellia sp. (Cory 1967; Abbe 1987; Thompson 1993).
CAR-I	Northern Yucatan, Gulf of Mexico, Florida Straits, to Middle Eastern Florida		Ecological Impact	Habitat Change
May provide shelter for invertebrates and small fishes (Crowell and Darnell 1955).
MED-X	None		Economic Impact	Industry
Power plant fouling (Simkina 1963)
CAR-III	None		Economic Impact	Industry
Fouling of industrial plants using Lake Maracaibo water and submerged structures (de Rincon and Morris 2003).
M130	Chesapeake Bay		Economic Impact	Industry
Calytpspadix cerulea is a major fouling organism in the Chesapeake Bay region. Industry- The organism with the highest quantified cost to power plants in the Chesapeake Bay is C. cerulea, which is a major fouler of power plants along mesohaline waters of Chesapeake Bay (Cory 1967; Virginia Power 1992) and elsewhere in the world (Simkina 1963). At two power plants in Chesapeake Bay, Chalk Point (Patuxent River) and Morgantown (Potomac River), the cost of biocides to control fouling dominated by C. cerulea was $95,000 to $180,000 per year in 1995-97 (Krueger 1997, personal communication). At the Surry Nuclear Power Plant on the lower James River, the weight of the hydroids caused breakdowns of the traveling screens which remove debris. Aggregates of hydroids blocked water flow in the main condensers, in the circulating water systems used for cooling during routine operation, and in the service water systems, which would be used in shutdown after an accident. 'Almost daily' cleaning was required during warm weather to keep water flowing through the service system. In 1992, the projected cost of 'doing nothing' about the biofouling problem, except routine cleaning and repairs was $37.5 million projected over the plant's remaining license period (to the year 2013), or $3.4 million per year. The operators of the plant instead undertook an extensive reconstruction of the cooling and screen, which was intended to reduce fouling problems, with a projected cost of $23.6, or $2.1 million per year (Virginia Power 1992). One major consequence of the invasion of exotic fouling organisms is the increased use of biocides and antifouling coatings in power plants and industrial water systems. These chemicals are toxic substances used to kill microbial and invertebrate organisms on surfaces exposed to natural waters. Among coatings used in power plants are copper oxide paints, organotin compounds, as well as nontoxic coatings that inhibit attachment of organisms (Virginia Power 1992). At the Surry Nuclear Power Plant, several biocides in addition to chlorine were tested against G. franciscana, including ammonium hydroxide, hydrogen peroxide, sodium bromide-hypochlorite mixture, a surfactant mixture ('ClamTrol'), and chemically induced anoxia. However, at doses allowed by their U.S. EPA permit, these were ineffective (Virginia Power 1992).
M130	Chesapeake Bay		Economic Impact	Fisheries
Fisheries- Costs: Fouling by Calyptospadix cerulea has been a major problem on fishing gear, including crab pots and oyster trays (Andrews 1973). Benefits: Calyptspadix cerulea probably benefits commercial and sport fisheries by providing habitat for juvenile and bait fishes, shrimps, crabs, and other motile organisms (Thompson 1993).
M130	Chesapeake Bay		Ecological Impact	Competition
Competition- Although Calyptspadix cerulea (Rope Grass Hydroid) is an abundant and sometimes dominant part of the fouling community in parts of Chesapeake Bay, its ecological impacts are largely unknown.n. Calyptspadix cerulea and Victorella pavida overgrew most other organisms on fouling panels at Calvert Cliffs, Maryland, in summer (Abbe 1987).
M130	Chesapeake Bay		Ecological Impact	Habitat Change
Growths of Calyptospadix cerulea provide cover for numerous amphipods, mud crabs, and other organisms in the Patuxent River (Cory 1967) and James River (Thompson 1993).
M130	Chesapeake Bay		Ecological Impact	Food/Prey
Food/Prey- Calyptospadix cerulea is fed on by nudibranchs, particularly Tenellia sp. (Abbe 1987;Cory 1967; Thompson 1993).

References

Abbe, George R. (1987) Epifauna, In: Heck, Kenneth L.(Eds.) Ecological studies in the middle reach of Chesapeake Bay- Calvert Cliffs. , Berlin. Pp. 82-91

Aladin, Nikolai V.; Plotnikov, Igor S.; Filipov, Andrei A. (2002) Invasive aquatic species of Europe: Distribution, impacts, and management., Kluwer Academic Publishers, Dordrecht. Pp. 351-359

Andrews, Jay D. (1973) Effect of tropical storm Agnes on epifaunal invertebrates in Virginia estuaries, Chesapeake Science 14(4): 223-234

Bancila. Raluca I.; Skolka, Marius; Ivanova, Petya; Surugiu, Victor; Stefanova, Kremena; Todorova. Valentina; Zenetos, Argyro (2022) Alien species of the Romanian and Bulgarian Black Sea coast: state of knowledge, uncertainties, and needs for future research, Aquatic Invasions 17: Published online

Barnes, Robert D. (1983) Invertebrate Zoology, Saunders, Philadelphia. Pp. 883

Boero, Ferdinando (2002) Ship-driven biological invasions in the Mediterranean Sea., CIESM Workshop Monographs 20: 87-91

Bouillon, Jean; Medel, Maria Dolores; Pagès, Francesc; Gili, Josep-Maria; Boero, Ferdinando ; Gravili, Cinzia (2004) Fauna of the Mediterranean Hydrozoa., Scientia Marina 68(suppl. 2): 5-438

Bumbeer, Janaína de Araújo; da Rocha, Rosana Moreira (2012) Detection of introduced sessile species on the near shore continental shelf in southern Brazil, Zoologia 29(2): 126-134

Calder, D.R.; Mayal, E.M. (1998) Dry season distribution of hydroids in a small tropical estuary, Pernambuco, Brazil., Zoologische Verhandelingen 323: 69-78

Calder, Dale R. (1971) Hydroids and hydromedusae of southern Chesapeake Bay., Virginia Institute of Marine Science, Special Papers in Marine Science 1: 1-125

Calder, Dale R. (1972) Phylum Cnidaria, Special Scientific Report, Virginia Institute of Marine Science 65: 97-102

Calder, Dale R. (1976) The zonation of hydroids along salinity gradients in South Carolina estuaries, In: (Eds.) Coelenterate Ecology and Behavior. , New York. Pp. 165-174

Calder, Dale R. (1992) Seasonal cycles of activity and inactivity in some hydroids from Virginia and South Carolina, U.S.A., Canadian Journal of Zoology 68: 442-450

Calder, Dale R. (1997) Introduced hydroids in Chesapeake Bay, email, Zoologische Verhandlingen Leiden <missing volume>: <missing location>

Calder, Dale R. (2019) On a collection of hydroids (Cnidaria, Hydrozoa) from the southwest coast of Florida, USA, Zootaxa 4689(1): 1-141

Calder, Dale R.; Brehmer, Morris L. (1967) Seasonal occurrence of epifauna on test panels in Hampton Roads, Virginia., International Journal of Oceanology and Limnology 1(3): 149-164

Calder, Dale R.; Hester, Betty S. (1978) Phylum Cnidaria., In: Zingmark, Richard G.(Eds.) An Annotated Checklist of the Biota of the Coastal Zone of South Carolina. , Columbia. Pp. 87-93

Calder, Dale R.; Stephens, Lester D. (1997) The hydroid research of American naturalist Samuel F. Clarke, 1851-1928, Archives of Natural History 24(1): 19-36

Calder, Dale Ralph (1966) <missing title>, M.S. Thesis, College of William and Mary, Williamsburg, VA. Pp. <missing location>

California Academy of Sciences 2005-2015 Invertebrate Zoology Collection Database. <missing URL>



California Department of Fish and Wildlife (2014) Introduced Aquatic Species in California Bays and Harbors, 2011 Survey, California Department of Fish and Wildlife, Sacramento CA. Pp. 1-36

Cangussu, Leonardo C. and 5 authors (2010) Substrate type as a selective tool against colonization by non-native sessile invertebrates, Brazilian Journal of Oceanography 58(3): 219-231

Carlton, James T. (1979) History, biogeography, and ecology of the introduced marine and estuarine invertebrates of the Pacific Coast of North America., Ph.D. dissertation, University of California, Davis. Pp. 1-904

Carlton, James T. (Ed.) (2007) The Light and Smith Manual: Intertidal Invertebrates from Central California to Oregon Fourth Edition, Completely Revised and Expanded, University of California Press, Berkeley. Pp. <missing location>

Clarke, Samuel F. (1882) New and interesting hydroids from Chesapeake Bay, Memoirs of the Boston Society of Natural History 3(4): 135-141

Cohen, Andrew N. and 10 authors (2005) <missing title>, San Francisco Estuary Institute, Oakland CA. Pp. <missing location>

Cohen, Andrew N. and 12 authors (2002) Project report for the Southern California exotics expedition 2000: a rapid assessment survey of exotic species in sheltered coastal waters., In: (Eds.) . , Sacramento CA. Pp. 1-23

Cohen, Andrew N.; Carlton, James T. (1995) Nonindigenous aquatic species in a United States estuary: a case study of the biological invasions of the San Francisco Bay and Delta, U.S. Fish and Wildlife Service and National Sea Grant College Program (Connecticut Sea Grant), Washington DC, Silver Spring MD.. Pp. <missing location>

Cohen, Andrew N.; Chapman, John T. (2005) <missing title>, San Francisco Estuary Institute, San Francisco. Pp. <missing location>

Cory, R. L.; Nauman, J. W. (1969) Epifauna and thermal additions in the upper Patuxent River estuary., Chesapeake Science 10(3-4): 210-217

Cory, Robert L. (1967) Epifauna of the Patuxent River Estuary, Chesapeake Science 8(2): 71-89

Crowell, Sears; Darnell, Rezneat M. (1955) Occurrence and ecology of the hydroid Bimeria franciscana in Lake Ponchartrain, Louisiana., Ecology 36(3): 516-518

da Rocha, Rosana Moreira; de Faria, Suzana Barros (2005) Ascidians at Currais islands, Paraná, Brazil: Taxonomy and distribution., Biota Neotropica 5(2): 1-20

da Silva, Eder Carvalho; Barros, Francisco (2011) [Benthic macrofauna introduced in Brazil: List of marine and freshwater species and actual distribution], Oecologia Australis 15(2): 326-344

de Rincon, Oladis; Morris, Eleanor (2003) Studies on selectivity and establishment of "pelo de oso" (Garveia franciscana) on metallic and non-metallic materials submerged in Lake Maracaibo, Venezuela, Anti-Corrosion Methods and Materials 50(1): 17-24

Dean, Thomas A.; Bellis, Vincent J. (1975) Seasonal and spatial distribution of epifauna in the Pamlico River Estuary, North Carolina, Journal of the Elisha Mitchell Scientific Society 91(1): 1-12

Deevey, Edward S. (1950) Hydroids from Louisiana and Texas, with remarks on the Pleistocene biogeography of the western Gulf of Mexico, Ecology 31: 334-367

Defenbaugh, Richard E. (1973) <missing title>, Dept. for Marine Resources Information, Center for Marine Resources, Texas A & M University, College Station, Tex.. Pp. <missing location>

Farrapeira, Cristiane Maria Rocha; Tenório, Deusinete de Oliveira ; do Amaral, Fernanda Duar (2011) Vessel biofouling as an inadvertent vector of benthic invertebrates occurring in Brazil, Marine Pollution Bulletin 62: 832-839

Fraser, C. McLean (1937) <missing title>, The University of Toronto Press, Toronto,. Pp. <missing location>

Fraser, C. McLean (1944) Hydroids of the Atlantic Coast of North America, In: (Eds.) . , Toronto. Pp. 1-441

Fraser, C. McLean (1948) Hydroids of the Alan Hancock Pacific expeditions since 1938, Allan Hancock Pacific Expeditions 4-5: 179-343

Frey, David G. (1946) Oyster bars of the Potomac., United States Fish and Wildlife Service Special Scientific Report 32: 1-93

Garman, Michael (1999) Karst Ecosystem Spotlight: Crystal Beach Springs, Florida., North American Biospeleology Newsletter 47: 8-10

Gognetti, Gusseppi; Maltagliati, Ferruccio (2000) Biodiversity and adaptive mechanisms in brackish water fauna., Marine Pollution Bulletin 40(1): 7-14

Gomiou, Marian-Traian; Alexandrov, Boris; Shadrin, Nikolai; Zaitsev, Yuvenaly (2002) The Black Sea- a recipient, donor, and transit area for alien species., In: Leppakoski, E.; Gollasch, S.; Olenin, S.(Eds.) Invasive aquatic species of Europe: Distribution, impacts, and management.. , Dordrecht. Pp. 341-350

Gravili, Cinzia; Di Camillo, Cristina Gioia; Piraino, Stefano; Boero, Ferdinando (2013) Hydrozoan species richness in the Mediterranean Sea: past and present, Marine Ecology 34(Suppl. 1): 41-62

Grigorovich, Igor A.; Therriault, Thomas W.; MacIsaac, Hugh J. (2003) History of aquatic invertebrate invasions in the Caspian Sea., Biological Invasions 5: 103-115

Hildebrand, Samuel F. (1939) The Panama Canal as a passageway for fishes, with lists and remarks on the fishes and invertebrates observed, Zoologica (New york Zoological Society) 24: 15-45

Hines, Anson H.; Ruiz, Gregory M.; Chapman, John; Hansen, Gayl; Carlton, James T.; Foster, Nora; Feder, Howard M. (1998) <missing title>, Regional Citizens Advisory Council of Prince William Sound, Valdez, Alaska.. Pp. <missing location>

Kerckhof, Francis; Haelters, Jan; Gollasch, Stephan G. (2007) Alien species in the marine and brackish ecosystem: the situation in Belgian waters., Aquatic Invasions 2(3): 243-257

Larsen, Peter F. (1985) The benthic fauna associated with the oyster reefs of the James River estuary, Virginia, U. S. A., Internationale Revue der Gesamten Hydrobiologie 70(9): 707-814

Lippson, Alice J.; Haire, Michael S.; Holland, A. Frederick; Jacobs, Fred; Jensen, Jorgen; Moran-Johnson, R. Lynn; Polgar, Tibor T.; Richkus, William (1979) Environmental atlas of the Potomac Estuary, Martin Marietta Corp., Baltimore, MD. Pp. <missing location>

Liu, X. X.; Li, C. Y. (1987) Six new species of bryozoans from the waters of Hong Kong and Zhu Jiang Estuary., Journal of Oceanography in Taiwan Strait 6: 59-67

Llansó, Roberto J.; Sillett, Kristine (2009) <missing title>, Versar, Inc., Columbia MD. Pp. 1-34

Llansó, Roberto J.; Sillett, Kristine; Scott, Lisa (2011) <missing title>, Versar, Inc., Columbia MD. Pp. <missing location>

Maurer, Don, Watling, Les (1973) <missing title>, College of Marine Studies, University of Delaware, Newark, DE. Pp. <missing location>

McLean, Richard I. (1972) Chlorine tolerance of the colonial hydroid Bimeria franciscana., Chesapeake Science 13: 229-230

Mendoza-Becerril, María de los Angeles; Marques, Antonio C. (2013) Synopsis on the knowledge and distribution of the family Bougainvilliidae (Hydrozoa, Hydroidolina), Latin American Journal of Aquatic Research 41(5): 908-924

Migotto, Alvaro E.; Marques, Antonio C.; Morandini, André C.; da Silveira, Fábio L. (2002) Checklist of the Cnidaria Medusozoa of Brazil, Biota Neotropica 2(1): 1-31

Mimura, Haruo; Katakura, Hiroshi Ishida (2005) Changes of microbial populations in a ship's ballast water and sediment on voyage from Japan to Qatar., Marine Pollution Bulletin 50: 751-757

MIT Sea Grant 2003-2008 Introduced and cryptogenic species of the North Atlantic. <missing URL>



Mizzan, Luca (1999) Le specie alloctone del macrozoobenthos della laguna di venezia: il punto della situazione., Bolletin del Museo Civico di Storia Naturale di Venezia 49: 145-177

Morri, Carla (1982) Sur la presence en Mediterannee de Garveia franciscana (Torrey 1902) (Cnidaria, Hydrozoa), Cahiers de Biologie Marine 23: 381-391

Nauman, J. W.; Cory, R. L. (1969) Thermal additions and epifaunal organisms at Chalk Point, Maryland., Chesapeake Science 10(3-4): 218-226

Naumov, D. V. (1969) <missing title>, Israel Program for Scientific Translations, Jerusalem. Pp. <missing location>

Needles, Lisa A.; Wendt, Dean E. (2013) Big changes to a small bay: Introduced species and long-term compositional shifts to the fouling community of Morro Bay (CA), Biological Invasions 15(6): 1231-1251

Neves, Carolina Somaio; da Rocha, Rosana Moreira (2008) Introduced and cryptogenic species and their management in Paranaguá Bay, Brazil, Brazilian Archives of Biology and Technology 51(3): 623-633

Neves, Carolina Somao; Rocha, Rosana Moreira; Pitombo, Fabio Bettini; Roper, James J. (2007) Use of artificial substrata by introduced and cryptogenic marine species in Paranagua Bay, southern Brazil, Biofouling 23(5): 319-330

Norris, James N. (2010) Marine Algae of the northern Gulf of California: Chlorophyta and Phaeophyceae, Smithsonian Contributions to Botany 94: 1276

Partaly, E. M. (1979) Ecology of bryozoan foulings in the Sea of Azov, Soviet Journal of Marine Biology 5(3): 213-216

Partaly, Ye. M. (2003) Peculiarities of successions in biocenoses of fouling in the Sea of Azov, Hydrobiological Bulletin 39(1): 103-112

Patrick, Ruth (1994) Rivers of the United States, In: (Eds.) . , New York. Pp. <missing location>

Pfitzenmeyer, Hayes T. (1976) Some effects of salinity on the macroinvertebrates of the lower Potomac., In: Mason, William T.; Flynn, Kevin C.(Eds.) The Potomac Estuary: Biological resources - Trends and Options. , Bethesda MD. Pp. 75-80

Poirrier, Michael A.; Mulino, Maureen M. (1977) Impact of the 1975 Bonnet Carré spillway opening on epifaunal invertebrates in southern Lake Pontchartrain, Journal of the Elisha Mitchell Scientific Society 93(1): 11-18

Rao, K. Satyanarayana; Baljaji, M. (1988) Marine biodeterioration- advanced techniques applicable to the Indian Ocean, Oxford & IBH Pub. Co., New Delhi. Pp. 551-574

Rocha, Rosana M.; Cangussu, Leonardo C.; Braga, Mariana P. (2010) Stationary substrates facilitate bioinvasion in Paranaguá bay in southern Brazil, Brazilian Journal of Oceanography 58(Special Issue 4): 23-28

Schuchert, Peter (2007) The European athecate hydroids and their medusae (Hydrozoa, Cnidaria): Filifera Part 2, Revue Suisse de Zoolgie 114(2): 195-396

Shadrin, Nikolai 2000 List of exotic introduced species in the Black Sea. <missing URL>



Simkina, R. G. (1965) [Settlement, growth, and feeding of the hydroid polyp Perigonimus megas Kinne], Trudy Instituta Okeanologii 85: 98-110

Simkina. R. G. (1963) {On the ecology of the hydroid polyp Perigonimus megas Kinne- a new species in the fauna of the USSR.], Akademiya Nauk SSSR - Trudy Instituta Okeanologii 70: 216-224

Sumner, Francis B.; Osburn, Raymond C.; Cole, Leon J.; Davis, Bradley M. (1913b) A biological survey of the waters of Woods Hole and vicinity Part II. Section III. A catalogue of the marine fauna Part II. Section IV. A catalogue of the marine flora, Bulletin of the Bureau of Fisheries 31: 539-860

Thompson, Michelle Lynne (1993) <missing title>, M.S. Thesis, College of William and Mary, Williamsburg VA. Pp. <missing location>

Torrey, Harry Beal (1902) The Hydroida of the Pacific Coast of North America, University of California Publications, Zoology 1(1): 1-104

U.S. National Museum of Natural History 2002-2021 Invertebrate Zoology Collections Database. http://collections.nmnh.si.edu/search/iz/



Vervoort, W. (1964) Note on the distribution of Garveia franciscana (Torrey 1902) and Cordylophora caspia (Pallas, 1771) in the Netherlands., Zoologische Mededelingen 39: 125-146

Virginia Power, Stone and Webster Engineering Corp. (1992) <missing title>, <missing publisher>, <missing place>. Pp. <missing location>

Watling, Les; Maurer, Don (1972) Shallow water hydroids of the Delaware Bay region, Journal of Natural History 6: 643-649

Wolff, W. J. (2005) Non-indigenous marine and estuarine species in the Netherlands., Zoologische Verhandelingen 79(1): 1-116

Woods Hole Oceanographic Institution, United States Navy Dept. Bureau of Ships (1952) Marine fouling and its prevention., United States Naval Institute., Washington, D.C.. Pp. 165-206

Young, Craig S; Gobler, Christopher J. (None) Coastal ocean acidification and nitrogen loading facilitate invasions of the non-indigenous red macroalga, Dasysiphonia japonica, Biological Invasions <missing volume>: 1367-1391(

Zaitsev, Yuvenali; Ozturk, Bayram (2001) <missing title>, Turkish Marine Research Foundation Publication, <missing place>. Pp. 1-265

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