A new giant species of spiny lobster found off of Madagascar raises questions regarding the origins of the stock, its replenishment, and how it will react to the inevitable fishing pressure that will follow its discovery.

When a catch of spiny lobster weighing up to 4kg each caught the attention of Marine and Coastal Management officials in Durban, South Africa, they feared that it was illegal because the species didn't match the accompanying export permit. However, after lobster specialists took a closer look, they realized that the reason the catch did not match the fishing vessel's permit was because the lobsters themselves had never been encountered before. These giant spiny lobsters, which had been caught on the high seas in Walters Shoals on the Madagascar Ridge in the Southwest Indian Ocean, appeared to be a unique species that had never been landed before.

Identified as a new species and described by Johan Groeneveld, a lobster specialist with the Marine and Coastal Management section of the South African Ministry of Environment and Tourism, along with colleagues Professor Charles Griffith, of the University of Cape Town, and Anthony Van Dalsen, also of Marine and Coastal Management, these lobsters represent the sixth extant species in the well known spiny lobster genus, Palinurus. This discovery, which has been verified by both morphological and DNA analysis, is unique in that this is the only species of Palinurus that is known only to exist on a submerged seamount. With the nearest landfall some 720 km north in Madagascar or 1,100 km west in South Africa, the population of these giants has likely never been fished. The remote location of the stock and the age of the animals are thought to account for their extraordinary size.

The relative isolation of the seamount chain where these specimens were collected raises questions about the evolutionary history of the species, and calls into question the accepted taxonomy of the Palinurus genus for species in the region. It is unclear how these animals first arrived on the Madagascar Ridge and how (and from where) their stock is replenished. It is possible that research into these questions could change current views on gene flow and larval dispersal in the Southwest Indian Ocean.

Although lobster markets usually demand smaller individuals, this population may soon be exploited. How it will react to fishing pressure is currently unknown. However, researchers are concerned that the isolation that created this species may also be its demise. It is possible that fishing pressure could render this and similar isolated species commercially extinct before science can learn enough about them for sound management measures to be enacted.

Species Location: Walters Shoals are in the South West Indian Ocean (shaded area in map on left) and visible in the close-up box on the right

• What: Discovery of a new species of crustacean from the new family Kiwaidae on a hydrothermal site.
• Who: ChESS Scientists --> E. MacPherson, W. Jones, M. Segozac
• Where: March-April 2005 (PAR 5 Cruise --> MBARI)
• When: Pacific-Antarctic Ridge in the South Pacific Ocean (37°46.50'S, 110°54.70'W)
• How: Collected by slurp gun from the Alvin submersible at 2228 M water depth
• References: Macpherson E., Jones J. & M. Segonzac, 2005. A new Squat lobster family of Galatheoidea (Crustacea, Decapoda, Anomura) from the hydrothermal vents of the Pacific-Antarctic Ridge. Zoosystema 27(4): 709-723.