Obelia griffini

Overview

Scientific Name: Obelia griffini

Phylum: Cnidaria

Class: Hydrozoa

Order: Leptothecata

Family: Campanulariidae

Genus: Obelia

Species:

griffini (WoRMs has this as a junior synonym of O. dichotoma, but collection report (see Calder et al. 2014) keeps it separate due to morphological differences) According to Dr. Kubota (pers. comm.), this species has never been recorded in Japanese waters. And was not included in the list of Japanese hidrozaons by Kubota (1998). [Describe here as A. iricolor]

Native Distribution

Origin Realm:

Arctic, Temperate Northern Pacific, Temperate Northern Atlantic, Tropical Atlantic, Temperate South America Stated as unclassified in: Temperate Northern Pacific, Temperate Northern Atlantic, Tropical Atlantic, Central Indo-Pacific, Western Indo-Pacific, Temperate South America

Native Region:

Origin Location:

CONFLICT: Calder et al. 2014 states that O.g. is cryptogenic in NEP, but also gives Puget Sound, Washington as the type locality; many locations overlap with introduced and cryptogenic Temperate Northern Pacific Puget Sound, Washington, USA (Calder et al. 2014) *Type locality, but also noted as possibly cryptogenic [O. dichotoma (synonymised taxon)] Alaska to the tropics in the northeast Pacific (Carlton 2007) STATUS NOT STATED [O. dichotoma (synonymised taxon)] Bodega Bay, California (Standing 1976) STATUS NOT STATED [O. dichotoma (synonymised taxon)] Friday Harbor, Washington (Caine 1980) STATUS NOT STATED [O. dichotoma (synonymised taxon)] Strait of Georgia, British Columbia (Bernard 1978) STATUS NOT STATED [O. dichotoma (synonymised taxon)] Present, but unclassified, in the northeast Pacific, eastern coast of China, southern Pacific coast of Japan, (Lee II & Reusser 2012) UNCLASSIFIED Tropical Eastern Pacific [O. dichotoma (synonymised taxon)] Alaska to the tropics in the northeast Pacific (Carlton 2007) STATUS NOT STATED Central Indo-Pacific [O. dichotoma (synonymised taxon)] Present, but unclassified, in the Philippines (Lee II & Reusser 2012) UNCLASSIFIED Western Indo-Pacific [O. dichotoma (synonymised taxon)] Present, but unclassified, in western India (Lee II & Reusser 2012) UNCLASSIFIED Temperate Northern Atlantic [O. dichotoma (synonymised taxon)] Europe, North Atlantic (Boyd et al. 2002) STATED [O. dichotoma (synonymised taxon)] SW coast of England, UK (Schuchert 2001, Calder 2012) *Type locality [Lomedea gracilis (synonymised taxon)] Sargasso Sea (34°39 ́N, 72°01 ́W) (Calder et al. 2014) STATUS NOT STATED [O. dichotoma (synonymised taxon)] West coast of Sweden (Lonnberg 1898, cited in Calder 2012; Rees & Rowe 1969, cited in Calder 2012) STATUS NOT STATED [O. dichotoma (synonymised taxon)] North Atlantic (Barents Sea to the Mediterranean Sea in Europe; Gulf of St. Lawrence to the Gulf of Mexico in North America) (Multiple authors, cited in Calder 2012) STATUS NOT STATED [O. dichotoma (synonymised taxon)] North and south coasts of Iceland (but not Greenland) (Schuchert 2001) STATUS NOT STATED [O. dichotoma (synonymised taxon)] Quebec to the Caribbean Sea in the western North Atlantic (Calder 1990) STATUS NOT STATED [O. dichotoma (synonymised taxon)] Wadden Sea of Schleswig-Holstein (Buhs & Reise 1997) STATUS NOT STATED [O. dichotoma (synonymised taxon)] Northern Gaspé waters, Upstream and downstream parts of Middle St. Lawrence Estuary, Magdalen Islands (from the eastern Bradelle valley to the west, as far as Cape North, including the Cape Breton Channel), Lower St. Lawrence Estuary, Prince Edward Island (from the northern tip of Miscou Island, N.B. to Cape Breton Island south of Cheticamp, including Northumberland Strait and St. George Bay to the Canso Strait causeway), Upper North Shore (between Sept-Iles and Pointe des Monts), Middle North Shore (from Sept-Iles to Cape Whittle, including the Mingan Islands). (Estuary and gulf of Saint Lawrence, Canada) (Brunel et al. 1998) STATUS NOT STATED [O. dichotoma (synonymised taxon)] Present, but unclassified, in the Mediterranean Sea and around Europe (Lee II & Reusser 2012) UNCLASSIFIED Tropical Atlantic [O. dichotoma (synonymised taxon)] North Atlantic (Barents Sea to the Mediterranean Sea in Europe; Gulf of St. Lawrence to the Gulf of Mexico in North America) (Multiple authors, cited in Calder 2012) STATUS NOT STATED [O. dichotoma (synonymised taxon)] Quebec to the Caribbean Sea in the western North Atlantic (Calder 1990) STATUS NOT STATED [O. dichotoma (synonymised taxon)] Belize (Calder 1991) STATUS NOT STATED [O. dichotoma (synonymised taxon)] Present, but unclassified, in Bermuda (Lee II & Reusser 2012) UNCLASSIFIED Temperate South America Santa Catarina, Brazil (Vannucci 1954) STATUS NOT STATED [O. dichotoma (synonymised taxon)] Magellan area (Cantero & Carrascosa 1999) STATUS NOT STATED [O. dichotoma (synonymised taxon)] Ilhabela, Brazil (Fernandez et al. 2014) STATUS NOT STATED [O. dichotoma (synonymised taxon)] Present, but unclassified, in southern Chile (Lee II & Reusser 2012) UNCLASSIFIED Arctic [O. dichotoma (synonymised taxon)] North and south coasts of Iceland (but not Greenland) (Schuchert 2001) STATUS NOT STATED [O. dichotoma (synonymised taxon)] Kongsfjorden, Spitsbergen, Arctic (Orejas et al. 2013) STATUS NOT STATED Uncertain realm [Obelia gracilis Calkins (not Dana) (synonymised taxon)] China (Mulitple authors, cited in Calder et al. 2014) STATUS NOT STATED

Geographic Range:

[O. dichotoma (synonymised taxon)] -174.300003051758 -46,176.200012207031 70.3000030517578 (OBIS 2015) [O. dichotoma (synonymised taxon)] Kongsfjorden, Spitsbergen (Orejas et al. 2013) to Santa Catarina, Brazil (Fernandez et al. 2014) and the Magellan region (Cantero & Carrascosa 1999) [O. dichotoma (synonymised taxon)] Alaska to the tropics in the northeast Pacific (Carlton 2007)

General Diversity:

NF

Non-native Distribution

Invasion History:

Yes (multiple authors; see inv_propens)

Non-native Region:

Northeast Pacific, Northwest Pacific, Eastern Indo-Pacific, Southern Australia and New Zealand, Southern Africa, Central Indo-Pacific, Northwest Atlantic, Southwest Atlantic

Invasion Propens:

CONFLICT: Calder et al. 2014 states that O.g. is cryptogenic in NEP, but also gives Puget Sound, Washington as the type locality; many locations overlap with introduced and cryptogenic Temperate Northern Pacific Cryptogenic in northeast Pacific (Calder et al. 2014) *Cryptogenic Puget Sound, Washingtion, USA to Vancouver Island, BC, Canada (Fraser 1946, cited in Calder et al. 2014) *Cryptogenic Kurilean region of Russia (Antsulevich 1992, cited in Calder et al. 2014) *Cryptogenic Eastern Indo-Pacific [O. dichotoma (synonymised taxon)] Introduced to Hawaii (Lee II & Reusser 2012) *Introduced Central Indo-Pacific [O. dichotoma (synonymised taxon)] Guam (Lee II & Reusser 2012) *Introduced Temperate Australasia [O. dichotoma (synonymised taxon)] Southwest Australia (Lee II & Reusser 2012) *Introduced [O. dichotoma (synonymised taxon)] Cryptogenic in southeast Australia (Lee II & Reusser 2012) *Cryptogenic Temperate Southern Africa [O. dichotoma (synonymised taxon)] Southern Africa (Lee II & Reusser 2012) *Cryptogenic Temperate Northern Atlantic [O. dichotoma (synonymised taxon)] Cryptogenic on east coast of the United States (not including Florida peninsula) (Lee II & Reusser 2012) *Cryptogenic Temperate South America [O. dichotoma (synonymised taxon)] Australia (Wyatt et al. 2005, cited in Fernandez et al. 2014) *Invasive [O. dichotoma (synonymised taxon)] Cryptogenic in southwest Brazil (Lee II & Reusser 2012) *Cryptogenic

Status Date Non-native:

Oregon, USA: June 2012, February 2013 (Calder et al. 2014) Washington, USA: December 2012 (Calder et al. 2014) [O. dichotoma (synonymised taxon)] Kaneohe Bay, Hawaii: 1972 (Lee II & Reusser 2012) [O. dichotoma (synonymised taxon)] Humboldt Bay, California: July 2000 - September 2001 (Boyd et al. 2002)

Vectors and Spread

Initial Vector:

Ballast water, Hull fouling (not specified), Aquaculture and Fisheries, Other

Second Vector:

see details

Vector Details:

Introduction vectors: ballast water, hull fouling, Atlantic oyster aquaculture (Lee II & Reusser 2012) Introduction vector: Found on tsunami debris (Calder et al. 2014) RELATED: [Obelia longissima] May be able to use fragmentation for short distance dispersal (BIOTIC 2015) Introduction vector: [Obelia longissima] Rafting on floating debris, attached to ship hulls, or as medusae in ballast water (BIOTIC 2015)

Spread Rate:

NF

Date First Observed in Japan:

NF

Date First Observed on West coast North America:

[O. dichotoma (synonymised taxon)] Kaneohe Bay, Hawaii: 1972 (Lee II & Reusser 2012) Oregon, USA: June 2012, February 2013 (Calder et al. 2014) Washington, USA: December 2012 (Calder et al. 2014)

Impacts

Impact in Japan:

NF

Global Impact:

[O. dichotoma (synonymised taxon)] May inhibit settlement of Balanus crenatus on experimental panels (Standing 1976)

Tolerences

Native Temperature Regime:

See details

Native Temperature Range:

[O. dichotoma (synonymised taxon)] [St. Lawrence estuary] Surface layer is ice-cold in the winter; surface layer summer temperatures range from 6 to greater than 20 ºC (Brunel et al. 1998)

Non-native Temperature Regime:

NF

Non-native Temperature Range:

NF

Native Salinity Regime:

Oligohaline, Mesohaline, Polyhaline, Euhaline

Native Salinity Range:

[O. dichotoma (synonymised taxon)] [St. Lawrence estuary] Surface layer in summer ranges from 0.5 to 32 ppt (Brunel et al. 1998)

Non-native Salinity Regime:

NF

Temperature Regime Survival:

See details

Temperature Range Survival:

[O. dichotoma (synonymised taxon)] 1.119 - 24.412 ºC (OBIS 2015) [O. dichotoma (synonymised taxon)] 8 - 30 ºC (NIMPIS 2015) [O. dichotoma (synonymised taxon)] [South Carolina, USA] Active year round, where temperatures range from 8 - 30 ºC; warm water species (Calder 1990)

Temperature Regime Reproduction:

NF

Temperature Range Reproduction:

NF

Salinity Regime Survival:

Mesohaline, Polyhaline, Euhaline

Salinity Range Survival:

[O. dichotoma (synonymised taxon)] Observed from 5 - 40 psu (Lee II and Reusser 2012) [O. dichotoma (synonymised taxon)] 32.793 - 36.284 pps (OBIS 2015) [O. dichotoma (synonymised taxon)] Found down to 12 ppt (Rudy et al. 1979)

Salintiy Regime Reproduction:

Polyhaline, Euhaline

Salinity Range Reproduction:

NF

Depth Regime:

Lower Intertidal, Shallow subtidal, Deep subtidal, Bathyal, Abyssal

Depth Range:

[O. dichotoma (synonymised taxon)] Observed from 0 - 216 m, but prefers 0 - 31 m. Intertidal, shallow subtidal, deep subtidal, and bathyal. Pelagic depths: surface, shallow and deep epipelagic (0 - 200 m) (Lee II and Reusser 2012) [O. dichotoma (synonymised taxon)] Lower intertidal (Boyd et al. 2002) [O. dichotoma (synonymised taxon)] Infralittoral (0 - 20m) and intertidal (mediolittoral; "Entre marées hautes de vive eau moyennes et marées basses de vive eau moyennes") (Brunel et al. 1998) [O. dichotoma (synonymised taxon)] Sampled from 0 - 5211 m (OBIS 2015) [O. dichotoma (synonymised taxon)] 1 - 120 m (NIMPIS 2015) [O. dichotoma (synonymised taxon)] Collected from 128 - 374 m (Schuchert 2001) [O. dichotoma (synonymised taxon)] 41 - 82 m (Bernard 1978)

Non-native Salinity Range:

Native Abundance:

Abundant

Reproduction

Fertilization Mode:

internal

Reproduction Mode:

Gonochoristic/ dioecious

Spawning Type:

NA

Development Mode:

Lecithotrophic planktonic larva (non-feeding)

Asexual Reproduction:

Budding/fragmentation (Splitting into unequal parts. Buds may form on the body of the “parent”)

Reproduction Details:

VARIABILITY within genus of spawning type [O. dichotoma (synonymised taxon)] Gonochoristic/dioecious; free-cast spawner; has a larval phase; asexual reproduction via budding (Lee II and Reusser 2012) RELATED: [Obelia sp.] Medusae have separate sexes. Males release sperm; eggs are fertilized while still in the gonads. Planula lavae (Kozloff 1990) *Note: entered as lecithotrophic because planula larvae are non-feeding and planktonic, and spermcast [Obelia longissima] Sessile colonial, vegetative hydroid stage, free-living sexual medusoid stage, and a planula larval stage. Medusoid stage lasts 7 - 30 days; pelagic planula larvae lasts up to 21 days. Lecithotrophic planula larva. Gonochoristic/dioecious. External fertilzation; both eggs and sperm are released into water. Asexual reproduction by budding. Larval/juvenile stage may disperse over 10 km (BIOTIC 2015)

Adult Mobility:

Sessile

Adult Mobility Details:

[O. dichotoma (synonymised taxon)] Sessile; attached to substrate (Macdonald et al. 2010)

Maturity Size:

NF

Maturity Age:

[Washington, USA] [O. dichotoma (synonymised taxon)] May begin to reduse medusae in as little as 30 days after planula settlement (Caine 1980)

Reproduction Lifespan:

NF

Longevity:

RELATED: [Obelia longissima] Less than one year (BIOTIC 2015). Potentially very long if protected from predators of physical damage (Gili & Hughes 1995, cited in BIOTIC 2015)

Broods per Year:

NF

Reproduction Cues:

NF

Reproduction Time:

[Washington, USA] Gonothecae were present some samples in December 2012 (Calder et al. 2014) [Oregon, USA] Gonothecae were present in some samples in June 2012, and present in February 2013 (Calder et al. 2014) [Northern California] [O. dichotoma (synonymised taxon)] Settling in May and June (Standing 1976). Also reported settling in winter, spring and early summer with low water temperatures (Boyd 1971, cited in Standing 1976) [Washington, USA] [O. dichotoma (synonymised taxon)] Planula settlement occurs from May to September (Caine 1980)

Fecundity:

RELATED: [Obelia longissima] An average colony might bear at least 100 gonothecae, each of which is capable of releasing ~20 medusae. Each female medusa could release about 20 eggs. If all medusae survive to release gametes, an average colony could potentially produce about 20,000 planulae larvae (however, only one of these planulae was likely to survive to form a colony which itself might survive to reproduce) (Cornelius 1990b, cited in BIOTIC 2015)

Egg Size:

RELATED: [Obelia genticulata] Up to 200 µm in diameter (Faulkner 1929, cited in BIOTIC 2015)

Egg Duration:

NF

Early Life Growth Rate:

[O. dichotoma (synonymised taxon)] Grow from 1 mm to 2.5 mm in 19 days (Russell 1953, cited in Rudy et al. 1979)

Adult Growth Rate:

[O. dichotoma (synonymised taxon)] Grew up to 12 cm from April - July (Standing 1976) RELATED: [Obelia longissima] Growth rate is dependant on food supply (Marfenin 1997, cited in BIOTIC 2015) and temperature (Berrill 1949, cited in BIOTIC 2015) [Obelia longissima] Under optimal nutritive conditions stolons grew at less than 1 mm in 24 hrs at 10-12 °C, 10 mm in 24 hrs at 16-17 °C, and as much as 15-20 mm in 24 hrs at 20 °C (Berrill 1949, cited in BIOTIC 2015)

Population Growth Rate:

NF

Population Variablity:

[Virginia, USA] [O. dichotoma (synonymised taxon)] Absent in the winter, though present for the rest of the year, and present year-round in South Carolina (where winter temperature is lower) (Calder 1990) [Northern California] [O. dichotoma (synonymised taxon)] Colonies regress after two or three months of growth (Standing 1976) [Kongsfjorden, Spitsbergen] [O. dichotoma (synonymised taxon)] Colonies grow for 2 - 3 months, then enter a senescent phase during adverse environmental conditions (Orejas et al. 2013) RELATED: [Obelia sp.] Seasonal variation in population size: colonies declined in June in North Carolina and after July in Woods Hole (Hammett & Hammett 1945, cited in BIOTIC 2015). [Obelia longissima] [St. Lawrence estuary] Colony length increased from settlement in June, reached a maximum from November to March, then decreased until June (Brault & Bourget 1985, cited in BIOTIC 2015)

Habitat

Ecosystem:

Water column, SAV, Rocky subtidal, Coral reef, Mussel reef, Kelp forest, Mangrove, Fouling, Floating plants or macroalgae, Flotsam, Other

Habitat Type:

Pelagic, Epibenthic, Epizoic, Epiphytic

Substrate:

Rock, Mixed fine sediments, Biogenic, Artificial substrate

Exposure:

Exposed, semi-exposed, protected, very protected

Habitat Expansion:

NF

Habitat Details:

Found on gooseneck barnacle, Lepas sp.; styrofoam; barnacles; tsunami debris (Calder et al. 2014) [O. dichotoma (synonymised taxon)] Occurs on many substrates, including swimming animals such as sharks and copepods (Carlton 2007) [O. dichotoma (synonymised taxon)] Observed in estuaries, but prefers coastal bays and nearshore habitat; SAV, rocky subtidal, coral reef, mussel reef, fouling (including pilings, hulls and ballast), kelp forest, and pelagic. Mixed sediments (fines: 1 - 88.86%). Epibenthic, epiphytic and epizoic (Lee II and Reusser 2012) [O. dichotoma (synonymised taxon)] Fouling, lower intertidal (Boyd et al. 2002) [O. dichotoma (synonymised taxon)] Concrete, vessels, wood; subtidal (NIMPIS 2015) [O. dichotoma (synonymised taxon)] Found on Rhizophora angle, Thalassia testudinum, floating Sargassum and Turbinaria, benthic algae, hydroids, molluscs, miscellaneous substrates including wood, peat, and rope, and wooden test panels (Calder 1991) [O. dichotoma (synonymised taxon)] Sampled from algae and Sertularella polyzonias (Calder 2012) [O. dichotoma (synonymised taxon)] Epibenthic (Macdonald et al. 2010) [O. dichotoma (synonymised taxon)] On sargassum natans and S. fluitans (Calder 1995) [O. dichotoma (synonymised taxon)] Sheltered and fairly sheltered habitat; shorter specimens possible in current-swept areas and high-water movement areas (Cornelius 1990) [O. dichotoma (synonymised taxon)] Present on Cystoseira compressa, C. barbata, and C. amentacea; exposed and sheltered habitats (Faucci & Boero 2000) [O. dichotoma (synonymised taxon)] Grows on barnacles, Ascidia sp., mussels, and other substrata (Standing 1976) RELATED: [Obelia sp.] Found on docks, pilings, boats, rocks and seaweeds (Kozloff 1990)

Trophic Level:

Suspension feeder

Trophic Details:

[O. dichotoma (synonymised taxon)] Predator and suspension-feeding (Lee II and Reusser 2012) [O. dichotoma (synonymised taxon)] Carnivorous suspension/filter feeder on zooplankton (Macdonald et al. 2010) [Kongsfjorden, Spitsbergen] [O. dichotoma (synonymised taxon)] Opportunisitic, omnivorous, suspension-feeder; high amount of macroalgae found in gastrovascular cavity of O.d.. Capture rates of food items varied from ~134000 to ~261000 prey items per square meter per day between years (Orejas et al. 2013) RELATED: [Obelia sp.] Suitable food organisms are imobilized by nematocysts after touching one or more tentacles, then the tentacles bring the food to the mouth (Kozloff 1990) [Hydroids] Suspension-feeding or carnivorous (Denny & Gaines 2007)

Forage Mode:

Generalist

Forage Details:

[Kongsfjorden, Spitsbergen] [O. dichotoma (synonymised taxon)] Opportunisitic omnivores (Orejas et al. 2013)

Natural Control:

PREDATION [O. dichotoma (synonymised taxon)] [Predation] [Humboldt Bay, California] Extensively grazed by nudibranchs (Boyd et al. 2002) [O. dichotoma (synonymised taxon)] [Predation] [Washington, USA] Preyed on by the nudibranch Eubranchus olivaceus, but not enough to overcome rate of colony growth in the summer (Caine 1980) EPIBIONT [O. dichotoma (synonymised taxon)] [Epibiont] Ulva sp. growth decreases O.d. tolerance to currents, causing some colonies to fragment and get swept away in winter storms (Caine 1980) RELATED: PREDATION [Hydroids] [Predation] Hydranths may be eaten by nudibranchs, pyconogonids, fish, and the polychaete Procerastea halleziana (Denny & Gaines 2007) PARASITES [Hydroids] [Parasites] Pycnogonid larvae may parasitize and develop in hydranths (Denny & Gaines 2007)

Associated Species:

EPIBIONT [O. dichotoma (synonymised taxon)] [Epibiont] Populations of the caprellid, Deutella californica, were most dense on O.d.. Detritus trapped in periphyton supports Ulva sp. growth. Other species associated with O.d. include: Nematoda spp., Autolytus magnus, Brania brevipharyngea, Nereis limnicola, Eubranchus olivaceus, Paradoxostoma striungulum, Pholenota spatulifera, Tegastidae spp., Munna ubiquita, Aoroides columbiae, Deutella california, Pandalus danae, Copidognathus sp., Pholis ornata (Caine 1980) [O. dichotoma (synonymised taxon)] [Epibiont] Substrate for Caprella laeviscula and Metacaprella kinnerlyi (Caine 1977) RELATED: SYMBIONTS [Hydroids] [Symbionts] Act as microhabitats for many other species, including other hydroids, gammarid amphiods, and mussel recruits (Denny & Gaines 2007) PARASITES [Hydroids] [Parasites] Pycnogonid larvae may parasitize and develop in hydranths (Denny & Gaines 2007)

References and Notes

References:

Bernard FR (1978) British Columbia Faunistic Survey: Subtidal and Deepwater Megafauna of the Strait of Georgia. Fisheries and Marine Service Manuscript Report No. 1488. www.dfo-mpo.gc.ca/Library/22187.pdf BIOTIC (2015) Biological Traits Information Catalogue of The Marine Life Information Network for Britain & Ireland. http://www.marlin.ac.uk/biotic/biotic.php. Access Date: 02-12-2015 Boyd MJ, Mulligan TJ, Shaughnessy FJ (2002) Non-indigenous marine species of Humboldt Bay, California. Department of Fish and Game, California. http://vvww.krisweb.com/biblio/hum_hsu_boydetal_2002.pdf Buhs F & Reise K (1997) Epibenthic fauna dredged from tidal channels in the Wadden Sea of Schleswig-Holstein: spatial patterns and a long-term decline. Helgoländer Meeresuntersuchungen 51(3): 343-359. link.springer.com/article/10.1007/BF02908719 Caine EA (1977) Feeding Mechanisms and Possible Resource Partitioning of the Caprellidae (Crustacea: Amphipoda) from Puget Sound, USA. Marine Biology 42(4): 331-336. link.springer.com/article/10.1007/BF00402195 Caine EA (1980) Ecology of Two Littoral Species of Caprellid Amphipods (Crustacea) from Washington, USA. Marine Biology 56: 327-335. link.springer.com/article/10.1007/BF00386871 Calder DR (1990) Seasonal cycles of activity and inactivity in some hydroids from Virginia and South Carolina, U.S.A. Canadian Journal of Zoology 68(3): 422-450. www.nrcresearchpress.com/doi/abs/10.1139/z90-065 Calder DR (1991) Associations between hydroid species assemblages and substrate types in the mangal at Twin Cays, Belize. Canadian Journal of Zoology 69(8): 2067-2074. www.nrcresearchpress.com/doi/abs/10.1139/z91-288 Calder DR (1995) Hydroid Assemblages on Holopelagic Sargassum from the Sargasso Sea at Bermuda. Bulletin of Marine Science 56(2): 537-546. www.ingentaconnect.com/content/umrsmas/bullmar/1995/00000056/00000002/art00011 Calder DR (2012) On a collection of hydroids (Cnidaria, Hydrozoa, Hydroidolina) from the west coast of Sweden, with a checklist of species from the region. Zootaxa 3171: 1-77. www.mapress.com/zootaxa/2012/f/zt03171p077.pdf Calder DR, Choong HHC, Carlton JT, Chapman JW, Miller JA, Geller J (2014) Hydroids (Cnidaria: Hydrozoa) from Japanese tsunami marine debris washing ashore in the northwestern United States. Aquatic Invasions 9(4): 425-440. http://www.researchgate.net/publication/267394881_Calder_D.R._Choong_H.H.C._Carlton_J.T._Chapman_J.W._Miller_J.A._and_Geller_J._2014._Hydroids_%28Cnidaria_Hydrozoa%29_from_Japanese_tsunami_marine_debris_washing_ashore_in_the_northwestern_United_States._Aquatic_Invasions_9_425-440 Cantero ALP & Carrascosa AMG (1999) Biogeographical distribution of the benthic thecate hydroids collected during the Spanish Antartida 8611 expedition and comparison between Antarctic and Magellan benthic hydroid faunas. Scientia Marina 63(S1): 209-218. scientiamarina.revistas.csic.es/index.php/scientiamarina/article/viewArticle/905 Carlton JT (2007) The Light and Smith manual: intertidal invertebrates from central California to Oregon. London, England: University of California Press, Ltd Cornelius PFS (1990) European Obelia (Cnidaria, Hydroida): systematics and identification. Journal of Natural History 24(3): 535-578. www-tandfonline-com/doi/abs/10.1080/00222939000770381 Denny MW & Gaines SD (2007) Encyclopedia of Tidepools and Rocky Shores. Berkeley and Los Angeles, California: University of California Press Faucci A & Boero F (2000) Structure of an epiphytic hydroid community on Cystoseira at two sites of different wave exposure Scientia Marina 64(s1): 255-264. scientiamarina.revistas.csic.es/index.php/scientiamarina/article/viewArticle/816 Fernandez MO, Navarrete SA, Marques AC (2014) Temporal variation in richness and composition of recruits in a diverse cnidarian assemblage of subtropical Brazil. Journal of Experimental Marine Biology and Ecology 460: 144-152. www.sciencedirect.com/science/article/pii/S0022098114001877 Kozloff EN (1990) Invertebrates. Philadelphia, PA: Saunders College Publishing Lee II H and Reusser DA (2012) Atlas of Nonindigenous Marine and Estuarine Species in the North Pacific. Office of Research and Development, National Health and Environmental Effects Research Laboratory, EPA/600/R/12/631. Macdonald TA, Burd BJ, Macdonald VI, van Roodselaar A (2010) Taxonomic and Feeding Guild Classification for the Marine Benthic Macroinvertebrates of the Strait of Georgia, British Columbia. Canadian Technical Report of Fisheries and Aquatic Sciences 2874. http://www.dfo-mpo.gc.ca/Library/340580.pdf NIMPIS (2015) Obelia dichotoma, National Introduced Marine Pest Information System. http://www.marinepests.gov.au/nimpis Access date: 01-12-2015 OBIS. Ocean Biogeographic Information System. http://iobis.org/mapper/ Access date: 01-12-2015 Orejas C, Rossi S, Peralba A, García E, Gili JM, Lippert H (2013) Feeding ecology and trophic impact of the hydroid Obelia dichotoma in the Kongsfjorden (Spitsbergen, Arctic). Polar Biology 36(1): 61-72. link.springer.com/article/10.1007/s00300-012-1239-7 Rudy Jr P, Rudy LH, Shanks, A, Butler B (1979) Obelia longissima. In: Oregon Estuarine Invertebrates. https://scholarsbank.uoregon.edu/xmlui/handle/1794/12641 Schuchert P (2001) Hydroids of Greenland and Iceland (Cnidaria, Hydrozoa). Meddeleelser om Gronland, Bioscience 53(1): 1-184. www.researchgate.net/publication/229439253_Hydroids_of_Greenland_and_Iceland_%28Cnidaria_Hydrozoa%29 STANDING JD (1976) Fouling community structure: effects of the hydroid Obelia dichotoma on larval recruitment. In: Coelenterate ecology and behavior. Mackie GO (ed.). New York: Plenum Press. link.springer.com/chapter/10.1007/978-1-4757-9724-4_17 Vannucci M (1951) Distribuição dos Hydrozoa até agora conhecidos nas costas do Brasil. Bolm Inst. oceanogr., S Paulo, 2(1): 105-124. www.scielo.br/pdf/bipoce/v2n1/v2n1a04.pdf

Literature:

NA

Notes:

WoRMs has this as a junior synonym of O. dichotoma, but collection report (see Calder et al. 2014) keeps it separate due to morphological differences Kubota (1998) A list of hydrozoans (8 orders) in Japan. Nanki-Seibutus 40: 13-21. (in Japanese)