Sea strawberry (Gersemia rubiformis)

Classification (WoRMS)

Full classification as recorded by WoRMS: Kingdom: Animalia · Phylum: Cnidaria · Class: Octocorallia · Order: Malacalcyonacea · Family: Alcyoniidae · Genus: Gersemia.

Accepted name: Gersemia rubiformis · Authority: (Ehrenberg, 1834) · Taxonomic status: accepted · AphiaID: 156103.

Synonyms and superseded combinations recorded for this taxon: Alcyonium carneum Verrill, 1864; Alcyonium rubiforme (Ehrenberg, 1834); Capnella rubiformis (Ehrenberg, 1834); Eunephthya rubiformis (Ehrenberg, 1834); Gersemia carnea (Verrill, 1864); Halcyonium carneum Agassiz, 1850; Lobularia carnea (Verrill, 1864); Lobularia rubiformis Ehrenberg, 1834; Nannodendron elegans Danielssen, 1887; Paraspongodes globosa May, 1900; Paraspongodes rubra May, 1898.

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=156103 (CC BY 4.0). Accessed 2026-09-23.

Biology and life history (SeaLifeBase)

Measured values published by SeaLifeBase for Gersemia rubiformis. Only fields the database actually holds for this species are shown; these are database values, not aquarium guidance.

Maximum length: 10 cm · Depth range: 0–1249 m · Habitat zone: sessile · Vulnerability index: 10 of 100 · Aquarium trade: never/rarely.

SeaLifeBase notes: Size refers to colony height (Ref. 865). Maximum depth range from Ref. 119577. Known from intertidal to a depth of 15 meters, on offshore pinnacles or areas of strong currents (Ref. 865).

Source: SeaLifeBase species summary (SpecCode 89324) — https://www.sealifebase.se/summary/Gersemia-rubiformis.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.

Distribution and occurrence records (GBIF)

17,457 georeferenced occurrence records for Gersemia rubiformis are published through GBIF from 11 countries or marine areas. The map above plots 151 distinct locations from a sample of 3,000 records, omitting 28 inland records that carry an institution's coordinates rather than a collection site; it shows where the species has been observed and reported, not a modelled range.

Most records by country or area: Canada (15,673); United States of America (1,265); Svalbard and Jan Mayen (221); Norway (162); Russian Federation (84).

The full country table, WoRMS marine regions and the sampling notes are on this species' Distribution page.

Source: GBIF Occurrence Search (taxonKey 2263181) — https://www.gbif.org/occurrence/search?taxon_key=2263181&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=156103 (CC BY 4.0); Natural Earth 110m basemap — https://www.naturalearthdata.com/ (public domain). Accessed 2026-09-23.

Description and natural history (Wikipedia)

Gersemia rubiformis is a colonial coral that grows in the form of knobbly clumps. The colonies are erect and branch from one main stalk. The polyps are concentrated near the ends of the narrower terminal branches and are non-retractile in their calyces. The branches are not rigid but are stiffened by the presence of sclerites, and can sway gently in the current. The sclerites are red, some being irregular and shaped like miniature capstans. Gersemia rubiformis does not contain the symbiotic alga zooxanthella.

Gersemia rubiformis is found in polar to temperate regions of the Arctic Ocean and the north west Atlantic Ocean from the coasts of Canada south to Cape Hatteras in North Carolina. A separate population is found in the Pacific Ocean off the coasts of British Columbia and south to California. It occurs on both sandy and muddy substrates, on rocks and on the hard parts of other benthic invertebrates such as shells.

Many other marine invertebrates share the habitat of Gersemia rubiformis. Juvenile basket stars (Gorgonocephalus eucnemis) are often found clinging to the coral and hiding in the interstices. The white sea anemone Metridium senile often grows nearby and the rock scallop (Crassadoma gigantea) shares the same habitat in California.

In Puget Sound, juvenile basket stars (Gorgonocephalus eucnemis) have been found to be living, growing and feeding inside the pharynges of Gersemia rubiformis polyps, only becoming free-living when they have grown large enough to catch food for themselves.

Researchers in British Columbia found that extracts of Gersemia rubiformis showed antimicrobial activity when tested in vitro. They identified three novel diterpenoids which they named gersemolide, rubifolide and epilophodione.

Source: Wikipedia: Gersemia rubiformis — https://en.wikipedia.org/wiki/Gersemia_rubiformis (CC BY-SA 4.0). Accessed 2026-09-23.

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