Sea cucumbers are soft-bodied Echinoderms, an ancient group of animals which are entirely found in the sea. This species has recently changed its name, being originally described as Cucumaria hyndmani and more recently known as Paracucumaria hyndmani. Panningia hyndmani is of interest in a Northern Ireland context in being described originally from Strangford Lough. This cucumber is found in horse mussel beds in Strangford Lough but appears to have declined rapidly in recent years.

In brief

• In Northern Ireland this species is most abundant in horse mussel beds in Strangford Lough which have decreased significantly in the last 30 years
• Lives in the sea at depths of 20-1150m with populations most common in deep water.
• Individuals probably live for several years
• Scarce in Northern Ireland but also found in Scottish Sea Loughs and from Norway to the Mediterranean
• Threatened primarily by bottom fishing with trawls or dredges which disrupt the biogenic reef habitat.

Species description: A gherkin-shaped body with glistening white skin and five broad double rows of tube-feet are characteristic of this species. The tentacles are pale brown or pale pink in colour and small and sparsely branched. The body is usually covered with particles of shell and is buried in mud. The spicules are flat and irregular with numerous holes. Length up to 10cm by 2cm diameter.

Life cycle: Unknown.

Similar species: The smooth white skin between rows of tube feet is quite distinctive and only Pawsonia saxicola could be confused with this species. The latter is usually a rock crevice dweller, sometimes found beneath rocks on the lower shore.

How to see this species: This species can be found amongst living horse mussels in Strangford Lough, where it was formerly a common member of this community.

Current status: The current status of this species is not clear and it may be undergoing a natural fluctuation in its populations. It has smaller tentacles than the other cucumbers present in the habitat and may be easily overlooked. Investigations in 2003 confirmed that the horse mussel beds have declined considerably in the past 30 years and this species in particular seems to have become rare, it was found only once during the 2003 SLECI fieldwork. Sea cucumbers are known to disappear beneath the surface for extended periods and it is possible that more specimens are present than have been observed.

Why is this species a priority in Northern Ireland?

• Rapid decline
• Rare with Northern Ireland being both a UK and Irish stronghold.

Threats: In rapid decline possibly due to physical impact of bottom fishing gear in its habitat though initial observations on areas which had been dredged recently (Brown and Picton, 1987) suggested that sea cucumbers were less affected than other species due to their burial in the bottom (personal observation). The target for the fishery is the queen scallop, Aequipecten opercularis, which lives in more open muddy patches between the horse mussel clumps, but requires stable biogenic reefs for successful recruitment.

Action:

• Establish appropriate management on suitable historical sites
• Monitor numbers present in horse mussel beds in Strangford Lough
• Investigate recruitment and predation of this species.

Objectives: As with most underwater species these animals are only normally seen by divers, but any new populations of this species should be notified to CEDaR, National Museums Northern Ireland, 153 Bangor Road, Cultra, Co. Down, BT18 0EU. Tel: 028 9039 5257, cedar.info [at] nmni.com. Divers are encouraged to record species and habitats through involvement with the SeaSearch programme (www.seasearch.org.uk) which has a Northern Ireland co-ordinator.

Conservation:

• Strangford Lough is designated as a Special Area of Conservation and a Marine Nature Reserve
• Implementation of the Northern Ireland habitat action plan for Modiolus modiolus beds.

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

iNaturalist: Panningia hyndmani at iNaturalist World Species Observations database.

WoRMS: Panningia hyndmani at World Register of Marine Species. Accepted name: Panningia hyndmani (Thompson, 1840). AphiaID: 848014.

Classification: Biota; Animalia; Echinodermata; Echinozoa; Holothuroidea; Actinopoda; Dendrochirotida; Cucumariidae; Panningia

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Bernard Picton, Curator of Marine Invertebrates, Ulster Museum (2026). Panningia hyndmani. (Thompson, 1840). [In] Priority species, Marine Biodiversity Portal NI. https://www2.habitas.org.uk/marbiop-ni/priorityaccounts.php?item=ZB4690. Accessed on 2026-07-28