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Pink Spiny Lobster (Palinurus mauritanicus) in Irish waters

Declan Quigley reports: During late November 2020, the MFV Audacious (DA14) [Skipper: Declan Clinton, Clogherhead] captured a specimen of the Pink Spiny Lobster or Mauritanian Crawfish (Palinurus mauritanicus) while trawling at a depth of c.420m on the southern Porcupine Bank, off the west coast of Ireland (Fig. 1).

The Pink Spiny Lobster occurs in the NE Atlantic from western Ireland (53.250N) southwards to southern Senegal (160N) and in the western Mediterranean Sea (160E). The species lives in relatively deep water (180-748m), with greatest densities at 200-400m along the edge of the continental shelf, especially in canyons, preferring muddy and coralligenous substrates near rocky outcrops. In the Bay of Biscay they have been observed in deep water sheltering at the entrance of circular holes dug at the base of compact mud cliffs. Males measuring up to 230mm carapace length (CL) and weighing up to 7kg have been reported from the Bay of Biscay where sporadic targeted netting for Pink Spiny Lobsters occurs on coral grounds at depths of 280-375m off Brittany (between La Chapelle and La Petite Sole). However, good spots are very restricted and rapid decreases in catch rates prevent this activity from remaining economical for long.

The species was first reported from Irish waters during May 1911 when a single male specimen measuring 154mm total length (TL), was captured by the research vessel HYM Helga II (Fig. 2) at a depth of c.400m, c.93km west of Blackball Head, Co Cork.

Five years later, the Helga was infamously tasked with shelling several Irish rebel bases during the 1916 Easter Rising in Dublin, including Boland’s Mills, Liberty Hall and Irish Distilleries, and was used during the War of Independence to transport equally notorious British auxiliary troops (‘Black & Tans’) around the Irish coast. Ironically the Helga was subsequently purchased by the newly formed Irish Free State's Coastal and Marine Service (CMS) in 1923, and renamed the SS Muirchú. She was decommissioned during May 1945 but sank off the Saltee Islands, Co Wexford while under tow from the Free State Naval Base (Haulbowline, Cork) to Hammond Lane Scrap Merchants in Dublin. Her crew were rescued by a Welsh trawler. The wheel was recovered from the wreck by local divers and is on display in Kehoes Pub in Kilmore Quay.

Over the next 60 years there was a complete absence of records until four specimens were recorded during 1971-72. Two were captured by the MFV Star of Mace (Skipper: D. Clocherty) and MFV Caoran (G76) [Skipper: P. Burke] in relatively shallow (25-30m) inshore waters off the Skird Rocks, Co Galway. The first specimen (September 1971) was a berried female measuring 380mm TL, 138mm CL, and weighing 1.63kg. The second specimen (May 1972) was a male measuring 410mm TL, 165mm CL, and weighing 2.267kg. The third specimen (November 1972), measuring c.300mm TL, was captured by the French research vessel RV Thalassa at a depth of 300m on the Porcupine Bank. The fourth specimen (October 1971), a berried female measuring 421mm TL and 145mm CL, was found in an on-shore lobster and crawfish holding pond formerly operated by Shellfish Industries of Ireland Ltd. at Ballvaughan, Co Clare.

During August 1983, the MFV Aine Ide (G180) [Skipper: J. Murphy, Dunmore East], captured a small specimen measuring 47mm CL while trawling at a depth of 400m on the Porcupine Bank. During June 1984, the MFV Roving Swan (D64) captured a female specimen 133mm CL and weighing 1.531kg, while trawling in relatively shallow water (50m) on the Near Ground, Dingle Bay, Co Kerry (Fig. 3).

During July 1986 and March 1987, exceptionally large numbers (1430) were captured by two Castletownbere trawlers, the MFV Orion (SO643) and MFV Menhaden (S135) [Skipper: Larry Murphy] in deep water (300-360m) off Blackball Head, Co Cork, the same location where the first Irish specimen was recorded during 1911. The CL and weight of the latter specimens ranged from 54-157mm and 0.1-2.4kg respectively. It appears that groups, primarily composed of females, undergo migrations during late autumn, which probably increases their vulnerability to capture in demersal trawls. Indeed, off NW Africa, individual hauls of 200-400 specimens have been reported.

There were no subsequent reports from Irish waters until May 2010, when at least 30 specimens measuring 129-145mm CL and weighing 1.3-1.6kg, were taken by the MFV Ocean Venture (S121) [Skipper: Ross Minihane, Castletownbere] while trawling at a depth of 200m on the south Porcupine Bank. Although some of these specimens were transferred alive to Dingle Oceanworld, they did not survive (Fig. 4).

Figure 4. Pink Spiny Lobster (4.2kg) captured by the MFV Brittania 320km SW of Newlyn, Cornwall (2007) [Photo Paul Gainey]

Pink Spiny Lobsters have occasionally been recorded off SW England. During July 1987, a specimen was captured c.37 km NW of St Ives, N Cornwall and survived in the former Penzance Aquarium for a number of years. During July 2005, a specimen was observed by a SCUBA diver in shallow water off Church Rock, Broadhaven, S Wales. During September 2007, an exceptionally large male specimen, measuring 595mm TL and weighing 4.2kg, was captured by the MFV Brittania (Skipper: 'Masher') while gill netting on a wreck c.320km SW of Newlyn, Cornwall (Fig. 5). The specimen was transferred alive to the Blue Reef Aquarium (Newquay), but did not survive for long.

Although some Pink Spiny Lobsters occasionally stray into inshore waters, it is possible that they are not distinguished from the closely related Common Spiny Lobster or Crawfish (Palinurus elephas) [Fig. 6]. According to FAO statistics, a total of 2757 tonnes of Spiny Lobsters (Palinurus sp.) were landed globally during 2018, but almost 60% were not identified to species level, including 9 tonnes (as Palinurus spp.) from Irish waters. Indeed, only 3 tonnes (0.1%) were specifically logged of P. mauritanicus. by French vessels.

In summary, it appears that there may be a resident self-sustaining population of Pink Spiny Lobsters occupying inaccessible deep water habitats off the SW Irish coast as far north as the Porcupine Bank, but they are now rarely captured (or recorded), possibly due to the closure of large tracks of deep-water cold-water coral areas to demersal trawling.

Declan is always interested in receiving reports about unusual specimens (087-6458485; Email: declanquigley@eircom.net)