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 (unpublished data) found this species in San Diego Bay in 2000, but another survey in the same area and season (Cohen et al. 2002), sampling some of the same locations, did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 Records are also known from Newport Bay (2011, Ruiz et al., unpublished date) and Morro Bay (2006, Needles and Wendt 2012).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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