A variously-shaped sponge with webbed branches, generally brownish in colour, that lives mainly on deep bedrock in areas swept by tidal currents.

In brief

• Known from four main locations in Northern Ireland
• Habitat is bedrock and caves swept by tidal currents; occasionally occurs in shallower water
• Can be found throughout the year
• Listed as a Species of Conservation Concern on account of its rarity
• Main threats / cause of decline are not known.

Species description: This is a brown, or greenish-brown to green, sponge occurring on bedrock in areas with strong tidal current. It normally has an upright growth form, but more cushion-shaped examples have been reported. It has a concealed short stalk base, and branches, but the shape of these is obscured by 'webs' of fleshy tissue joining them together. The inhalant and exhalant pores or oscules are up to 1.5mm in diameter, and regularly spaced over the body of the sponge, each set in a small depression on the surface. There are no spicules or skeletal structures - the shape of the sponge is maintained by internal fibres.

Life cycle: Sponges have either separate sexes or are hermaphrodite. In the case of the latter, self-fertilisation is avoided by eggs and sperms maturing at different rates within the same individual, so when spawning takes place and sperms are released through exhalent openings, it is unlikely that the eggs will be fertilised. Alternatively, the eggs are retained within the sponge, and sperms drawn in from surrounding water. Fertilised eggs are released and develop into planktonic larvae. Asexual reproduction may also be achieved by budding, whereby a small unit of the sponge separates and develops as an independent entity.

Similar species: Axinella dissimilis and Haliclona oculata can be similar, but usually S. pulchella is sufficiently distinctive to avoid confusion, and microscopic examination will reveal the absence of spicules.

How to see this species: This sponge does occur in shallow waters but is normally found in deep water areas on bedrock and in caves that are subject to strong tidal currents. In Northern Ireland it may be found on the north coast of Rathlin Island, off Ballycastle and Torr Head, and the Maidens. Elsewhere in Ireland it has a predominantly westerly distribution, being found on Tory Island, Rathlin O'Birne, Achill, the Aran Islands and off most counties along the western coast. Further afield, it occurs in Greenland, Shetland, Azores through to the Mediterranean.

Current status: The species is known from only four locations in Northern Ireland, and is regarded as rare throughout Britain and Ireland. It has no legal protection.

Why is this species a priority in Northern Ireland?

• Listed as a Species of Conservation Concern on account of its rarity and restricted range.
• Northern Ireland is a Stronghold for this species.

Threats: This erect sponge is vulnerable to bottom fishing and potting activities. It is especially vulnerable due to its dependence on a very small number of sites in Northern Ireland.

Action:

• Maintain the number of viable populations
• Maintain the range
• Monitor the populations (or a sample of them) from key sites.

Objectives: Records of new sites for this species, with details of habitat and population are always valuable. Send these to CEDaR, National Museums Northern Ireland, 153 Bangor Road, Cultra, Holywood, County Down, BT18 0EU. Tel 028 9039 5257 or e-mail cedar.records@nationalmuseumsni.org, or via the online portal. You can also record observations including a photograph using iNaturalist, find the MBDP-NI iNaturalist project here.

Conservation: Rathlin Island and its waters have been designated as a Marine Conservation Zone (MCZ) with a ban on bottom fishing.

Distribution Map from NBN: Spongionella pulchella at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Spongionella pulchella at iNaturalist World Species Observations database.

WoRMS: Spongionella pulchella at World Register of Marine Species. Accepted name: Spongionella pulchella (Sowerby, 1804). AphiaID: 132335.

Classification: Biota; Animalia; Porifera; Demospongiae; Keratosa; Dendroceratida; Dictyodendrillidae; Spongionella

Next species

(2026). Spongionella pulchella. (Sowerby, 1804). [In] Priority species, Marine Biodiversity Portal NI. https://www2.habitas.org.uk/marbiop-ni/priorityaccounts.php?item=C8960. Accessed on 2026-07-28