Taxonomy
Clytia hemisphaerica
Distribution
Status
Conservation status
Ireland: Not considered threatened.
Europe: Not considered threatened.
Global: Not considered threatened.
Legal status
Clytia hemisphaerica is not afforded legal protection in Ireland.
Native status
Resident
Invasiveness
Not assessed
Species Biology
Identification
Key identification features include:
- Hemispherical shaped medusa up to 20 mm in diameter
- 4 straight radial canals with oval or elongated gonads attached
- 16-32 marginal tentacles
- Colour of the base of tentacles and stomach varies; yellowish, brown, red, and purple
- Can have 2-3 marginal vesicles between each pair tentacles
Habitat
Clytia hemisphaerica is found in shallow neritic waters. The small hydroid (ca. 10 mm) can settle on a variety of surfaces.
Source: Russell, 1953
Life cycle
Clytia hemisphaerica alternates between an asexual hydroid and a sexual medusa stage, with hydroids budding off male and female medusa during spring and summer. Medusa mature in 2-3 weeks and spawn over a 4-8 week period, spawning throughout the summer, leading to a prolonged presence in the water column compared with other similar species. Abundance peaks twice annually in UK waters (so probably the same in Irish waters) and large medusa can survive through the winter. In the warmer Mediterranean waters, spawning is throughout the year.
Source: Russell, 1953; Lucas et al., 1995; Bouillon et al., 2004; Houliston et al., 2010
Threats faced
This species has not been assessed.
Distribution
World distribution(GBIF)
Clytia hemisphaerica has a cosmopolitan distribution. Found in all major oceans, it is one of the most common and numerous hydromedusae in Irish and UK waters, and if found throughout Europe from the Mediterranean to Norway.
Source: Russell, 1953; Lucas et al., 1995; www.marinespecies.org
Irish distribution
Very common on all Irish coasts in the near shore area.
Source: Russell, 1953; Lucas et al., 1995
Temporal change
Records submitted to Data Centre in 2024
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Further information
Due to its widespread distribution and suitability for culturing in the lab, C. hemisphaerica has become a model organism for many genetic and developmental experiments. The genetic homogeneity from asexually produced hydroids and medusa makes this an ideal species for evolutionary development studies.
References
Publications
Bouillon, J., Medel, M. D., Pagès, F., Gili, J. M., Boero, F., and Gravili, C. 2004. Fauna of the Mediterranean Hydrozoa. Scientia Marina, 68: 5-438.
Houliston, E., Momose, T., and Manuel, M. 2010. Clytia hemisphaerica: a jellyfish cousin joins the laboratory. Trends in Genetics, 26: 159-167.
Lucas, C., Williams, D., Wiliams, J., and Sheader, M. 1995. Seasonal dynamics and production of the hydromedusan Clytia hemisphaerica (Hydromedusa: Leptomedusa) in Southampton water. Estuaries and Coasts, 18: 362-372.
Russell, F. S. 1953. The medusae of the British Isles: anthomedusae, leptomedusae, limnomedusae, trachymedusae and narcomedusae, University Press.