Marine invertebrates

Lundy’s subtidal marine fauna is particularly rich and distinctively Mediterranean-Atlantic, with several species rarely found elsewhere in the British Isles present in abundance at some locations. These include (shown as short video clips* when you click on the name): the yellow staghorn sponge Axinella dissimilis (originally recorded as Axinella polypoides which is now considered only to occur in the Mediterranean), the sunset cup coral Leptopsammia pruvoti, red sea fingers Alcyonium glomeratum, the pink sea fan Eunicella verrucosa, the yellow cluster anemone Parazoanthus axinellae, and the trumpet anemone Aiptasia couchii (originally recorded as Aiptasia mutabilis which is now considered only to occur in the Mediterranean). The invertebrate fauna also includes many rare and scarce species, most of which are protected under marine wildlife legislation (Wildlife and Countryside Act (1981); Conservation of Habitats & Species Regulations 2010 (EU Habitats Directive); and Section 41 of the Natural Environment & Rural Communities (NERC) Act, 2006). The sponge, anthozoan and opisthobranch faunas are particularly rich (see table below).

* Video clips, all taken within the Lundy MPA, courtesy of Matt Green.

Table showing the number of species recorded for each of the main invertebrate taxa which were catalogued following dedicated surveys during the 1970s and early 1980s.

¹ All of these references have been published in the Lundy Field Society’s Annual Reports. They may be accessed via the Bibliography.

As part of the Marine Festival held during the summer of 2022, a Marine Bioblitz was organised. “What is a marine bioblitz?”, you may ask? Essentially, it’s a fun way for professionals and amateurs to record as many species as possible from a given area within a given time.

A week at the start of the Festival (14-21 July 2022), which coincided with particularly good spring tides, was chosen for the event. Shore surveyors were able to get to the lowest accessible parts of six shores at the start of the week, and diving surveyors took over for two days at the end of the week (when tidal currents had calmed somewhat) and visited four dive sites. The 31 volunteer surveyors came from various groups: Porcupine Marine Natural History Society (PMNHS), Lundy Field Society, North Devon Coastwise, Marine Biological Association and the Darwin Tree of Life project (Natural History Museum, London).

Nine intertidal sites were visited, though sadly none were on the west coast due to inaccessibility.

Table showing records for taxa recorded during the Marine Bioblitz (by taxonomic groups), 14-19 July 2022

(Key: DK = Devil’s Kitchen; RI = Rat Island; 3CB = Three Cave Bay; Lm = Lametry; QB = Quarry Bay; GB = Gannets’ Bay)

A complete list of all species recorded during the Marine Bioblitz (14-19 July 2022) can be found in the PMNHS Bulletin 19 (Spring, 2023), reproduced (with permission) in Irving (2023) The Lundy Marine Festival 2022 – An Appraisal as Appendix 7 – see Resources/Bibliography.

Paul Brazier and Anne Bunker identifying seaweeds during the Marine Bioblitz, July 2022 © Issy Irving 
Teresa Darbyshire identifying polychaete worms during the Marine Bioblitz, July 2022 © Issy Irving

Impressions

For several participants in the Marine Bioblitz, this was their first visit to Lundy. It was interesting to learn of their impressions of the island’s marine biodiversity.

• The Devonian shale shores in the south-east of the island has softer rock which provides a multitude of surfaces, fissures, crevices, overhangs and fragmentation. The southern aspect of the Devil’s Kitchen and Lametry shores provide some shelter but there is sufficient wave action to provide a wide range in exposure. The lack of fine sediments, as elsewhere on Lundy, is one of the few constraints to overall habitat richness.
• The granite shores of Quarry Beach, Brazen Ward and Gannets’ Bay are all granite shores by contrast. Habitat diversity here was relatively limited, mainly comprising the tops and sides of bedrock and boulders, plus (for the smaller boulders which could be lifted) under-boulder habitats. However, the lush lower shore algal communities were spectacular in their abundance and diversity of species (92 algal species being recorded from these three sites).
• In the sublittoral it was disappointing to learn that the numbers of sunset cup corals at the Knoll Pins have steadily declined over the past 40 years. The condition of many of the pink seafans was also sad to see, being fouled, damaged or partially dead. It was surprising how many were tightly bound by the tough, persistent tendrils of bull huss or nursehound egg cases. These egg cases had also been wrapped around certain species of erect branching sponges such as Axinella dissimilis and Raspalia ramosa.
• The sponge Stelligera stuposa was recorded as being frequent yet several individuals appeared emaciated and abnormally coloured.