Antho brattegardi is a yellow encrusting sponge which is a member of the Rathlin Island circalittoral sponge communities. It has been found at several sites around the Irish Sea, in Pembrokeshire and SW Scotland. Elsewhere it is only known from a Norwegian fjord and from a deep-water coral reef near Mingulay, Scotland.

In brief

• In Northern Ireland, it is found on Rathlin Island and the Maidens, off Larne.
• Lives on steep or vertical rock faces in water of 25 m, or greater depth, in moderate to strong tidal streams.
• Not seasonal, this sponge probably remains in one place for many years.
• Northern Ireland is a stronghold for this species.
• Requires rock or Lophelia reef habitats in clean water with a minimum of turbidity.

Species description: This sponge grows as encrusting patches from 2 cm to 5 cm in diameter and typically 2 mm in thickness. The surface has a porous appearance and oscules with slightly raised transparent rims. The oscules are spaced typically 2 cm apart and a surface network of transparent channels leads to each oscule. All individuals so far identified have been yellow in colour, whilst most Antho species are red or orange.

Life cycle: Reproduction is by swimming larvae which must find suitable substratum to settle on. Settlement in suitable water conditions and initial growth are probably when most mortality occurs due both to chance and to competition for space.

Similar species: There are a number of yellow encrusting sponges in our area and this species is not identifiable with certainty in situ.

How to see this species: Found on steep rockfaces in the circalittoral zone usually in places where there are many other encrusting sponges. Its bright yellow coloration makes this species conspicuous but it has no clear features which can be used to identify it in situ and requires microscopic examination of its spicules for confirmation. In Northern Ireland it is confined to a small population in one or two sites. This species has been found regularly at Rathlin Island and the Maidens, off Larne. There is a single record of a substantial patch from the wreck of the "Chirripo" at the entrance to Belfast Lough. All records are from 2005 onwards. Elsewhere it has been found in SW Scotland and Pembrokeshire, Wales. In deeper water it has been found on a Lophelia reef near Mingulay in the outer Hebrides, but not at reefs in deeper water on the edge of the continental shelf which have been surveyed using the same techniques.

Current status: Rare. Discovered on Rathlin Island by the Rathlin Island sponge project in 2005. Northern Ireland is a stronghold for this species in Britain and Ireland.

Why is this species a priority in Northern Ireland?

• Criterion 4: NI stronghold or endemic – both stronghold range/population and designation as ‘endemic’ subject to expert judgement.

Threats:

• The main threat to this species is degradation of water quality due to increased turbidity, pollution or nutrient enrichment.
• Inorganic silt clogs sponges making them unable to filter feed and such silt is artificially suspended into the water column by bottom-fishing activities.
• Some species of sponge can actively clean their surfaces to some extent and may become competitively able to displace other species if there is a shift in water quality.
• Polluted water may cause sponges to become diseased and may benefit some species at the expense of others by providing more bacteria and less plankton as food.
• Nutrient enrichment may have similar effects by changing the amounts of different types of plankton on which the sponges feed.

Action: Records of new sites for this species, with details of habitat and population are always valuable. Observations with a photograph can be recorded using iNaturalist, find the MBDP-NI iNaturalist project here.

Alternatively, records can be sent to CEDaR, National Museums Northern Ireland, 153 Bangor Road, Cultra, Holywood, County Down, BT18 0EU. Tel 028 9039 5257, e-mail cedar.records@nationalmuseumsni.org, or via the online portal.

Objectives:

• Encourage sustainable use of the seas by avoiding consumption of fish and shellfish captured by bottom dredging and bottom trawling.
• Maintain the number of viable populations of the species.
• Maintain the range of the species.
• Establish appropriate management on appropriate historic sites.

Conservation:

• Rathlin Island is a Marine Protected Area with multiple designations.
• The Maidens are a Marine Protected Area with multiple designations.
• There is Habitat Action Plan for Fragile Sponge and Anthozoan Communities on Rocky Habitats.

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

iNaturalist: Antho brattegardi at iNaturalist World Species Observations database.

WoRMS: Antho brattegardi at World Register of Marine Species. Accepted name: Antho (Jia) brattegardi van Soest & Stone, 1986. AphiaID: 827727.

Classification: Biota; Animalia; Porifera; Demospongiae; Heteroscleromorpha; Poecilosclerida; Microcionidae; Ophlitaspongiinae; Antho

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Picton, B.E., Keatley, L. & Morrow, C.C. (2026). Antho brattegardi. van Soest & Stone, 1986. [In] Priority species, Marine Biodiversity Portal NI. https://www2.habitas.org.uk/marbiop-ni/priorityaccounts.php?item=C8330. Accessed on 2026-09-13