AquaNISInformation system on aquatic non-indigenous and cryptogenic species |
Species | Obelia dichotoma [WoRMS] | |
Authority | (Linnaeus, 1758) | |
Family | Campanulariidae | |
Order | Leptothecata | |
Class | Hydrozoa | |
Phylum | Cnidaria | |
Synonym (?) | Obelia australis References: Hewitt, C. L., Campbell, M. L., Thresher, R. E., Martin, R. B., Boyd, S., Cohen, B. F., ... & Lockett, M. M. (2004). Introduced and cryptogenic species in port Phillip bay, Victoria, Australia. Marine biology, 144(1), 183-202. |
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Sub-species level (?) | Not entered |
Native origin (?) | Not known References: Hewitt, C. L., Campbell, M. L., Thresher, R. E., Martin, R. B., Boyd, S., Cohen, B. F., ... & Lockett, M. M. (2004). Introduced and cryptogenic species in port Phillip bay, Victoria, Australia. Marine biology, 144(1), 183-202. Comments: "Cosmopolitan". Hewitt. et al. (2004). |
Life form / Life stage (?) |
References (not structured): Standing, J. D. 1976. Fouling community structure: effects of the hydroid, Obelia dichotoma, on larval recruitment. In Coelenterate ecology and behavior, pp. 155-164. |
Sociability / Life stage (?) |
References (not structured): Orejas, C., Rossi, S., Peralba, A., García, E., Gili, J. M., Lippert, H. 2013. Feeding ecology and trophic impact of the hydroid Obelia dichotoma in the Kongsfjorden (Spitsbergen, Arctic). Polar biology, 36, pp. 61-72. Comments: O. dichotoma is a colonial hydrozoan in the order Leptothecata that forms regular branching stems and a distinctive hydrotheca. |
Reproductive frequency (?) | Iteroparous |
Reproductive type (?) | Asexual Sexual Comments: O. dichotoma uses asexual and sexual reproduction. Obelia dichotoma house the reproductive polyps in the angles of the branches. The polyps develop and bud off to form medusae about 0.05 mm in diameter at release that grow to about 5 mm at maturity.[6] The medusae are either male or female with nematocysts on tentacles and produce either sperm or eggs. The fertilized egg develops into a planula larvae that settle out of the water column during the winter, spring, and early summer and grow colonies for 2–3 months. |
Developmental trait (?) | Planktotrophy Spawning |
Characteristic feeding method / Life stage (?) |
References (not structured): Orejas, C., Rossi, S., Peralba, A., García, E., Gili, J. M., Lippert, H. 2013. Feeding ecology and trophic impact of the hydroid Obelia dichotoma in the Kongsfjorden (Spitsbergen, Arctic). Polar biology, 36, pp. 61-72. Boero, F., Bucci, C., Colucci, A. M. R., Gravili, C., Stabili, L. 2007. Obelia (Cnidaria, Hydrozoa, Campanulariidae): a microphagous, filter‐feeding medusa. Marine Ecology, 28, pp. 178-183. Comments: This population had a diet high in fecal pellets, organic matter, and micro algae which may be due to an environmental adaptation to the high content of these substances in the waters. Obelia is a microphagous and filter-feeding medusa, at least at the onset of its medusan life. |
Mobility / Life stage (?) |
References (not structured): Orejas, C., Rossi, S., Peralba, A., García, E., Gili, J. M., Lippert, H. 2013. Feeding ecology and trophic impact of the hydroid Obelia dichotoma in the Kongsfjorden (Spitsbergen, Arctic). Polar biology, 36, pp. 61-72. Comments: O. dichotoma is widely distributed throughout protected marine and freshwaters and, like many other hydroids, colonies attach to structures such as pilings, debris, seaweeds, grasses, and barnacles. |
Salinity tolerance range (?) | Venice system: 5. α-Mesohaline [10-18psu] 6. Polymixohaline [18-30psu] 7. Euhaline [30-40psu] References: Orejas, C., Rossi, S., Peralba, A., García, E., Gili, J. M., Lippert, H. 2013. Feeding ecology and trophic impact of the hydroid Obelia dichotoma in the Kongsfjorden (Spitsbergen, Arctic). Polar biology, 36, pp. 61-72. Comments: Hydroid stage recorded in water from normal salinity down to 12‰. |
Habitat modifying ability potential (?) | Autogenic ecosystem engineers |
Toxicity / Life stage (?) | Unknown Comments: Not available. |
Bioaccumulation association (?) | Unknown Comments: Not available. |
Known human health impact? | Not known Comments: Not available. |
Known economic impact? | Not known Comments: Not available. |
Known measurable environmental impact? | Known References: Standing, J. D. 1976. Fouling community structure: effects of the hydroid, Obelia dichotoma, on larval recruitment. In Coelenterate ecology and behavior, pp. 155-164. Comments: Hydroids are common, if not always conspicuous, animals in marine epibenthic communities, frequently growing on hard substrata, plants, and other animals. Obelia dichotoma, along with many other hydroids, are responsible for a large impact on many marine fish farming industries through fouling properties. |
Included in the Target Species list? | No References: HELCOM, 2009. Alien Species and Ballast Water [PDF] Available at: https://archive.iwlearn.net/helcom.fi/stc/files/shipping/Table_2_Alienspecies_%20lists_2009.pdf [Accessed 1 July 2024]. |
Association with vessel vectors (?) | Ballast waters Biofouling References: Hewitt, C. L., Campbell, M. L., Thresher, R. E., Martin, R. B., Boyd, S., Cohen, B. F., ... & Lockett, M. M. (2004). Introduced and cryptogenic species in port Phillip bay, Victoria, Australia. Marine biology, 144(1), 183-202. |
Created by | Aleksas Narščius, 2021-01-03 |
Last update by | Sandra Gečaitė, 2024-08-10 |