title: A large population of king crabs in Palmer Deep on the west Antarctic Peninsula shelf and potential invasive impacts.
abstract: Lithodid crabs (and other skeleton-crushing predators) may have been excluded from cold Antarctic continental shelf waters for more than 14 Myr. The west Antarctic Peninsula shelf is warming rapidly and has been hypothesized to be soon invaded by lithodids. A remotely operated vehicle survey in Palmer Deep, a basin 120 km onto the Antarctic shelf, revealed a large, reproductive population of lithodids, providing the first evidence that king crabs have crossed the Antarctic shelf. DNA sequencing and morphology indicate the lithodid is Neolithodes yaldwyni Ahyong & Dawson, previously reported only from Ross Sea waters. We estimate a N. yaldwyni population density of 10 600 km(-2) and a population size of 1.55 × 10(6) in Palmer Deep, a density similar to lithodid populations of commercial interest around Alaska and South Georgia. The lithodid occurred at depths of more than 850 m and temperatures of more than 1.4°C in Palmer Deep, and was not found in extensive surveys of the colder shelf at depths of 430-725 m. Where N. yaldwyni occurred, crab traces were abundant, megafaunal diversity reduced and echinoderms absent, suggesting that the crabs have major ecological impacts. Antarctic Peninsula shelf waters are warming at approximately 0.01°C yr(-1); if N. yaldwyni is currently limited by cold temperatures, it could spread up onto the shelf (400-600 m depths) within 1-2 decades. The Palmer Deep N. yaldwyni population provides an important model for the potential invasive impacts of crushing predators on vulnerable Antarctic shelf ecosystems.
authors: Department of Oceanography, University of Hawaii at Manoa, 1000 Pope Road, Honolulu, HI 96822, USA. craigsmi@hawaii.edu
authors: Craig R
authors: CR
authors: Smith
authors: Laura J
authors: LJ
authors: Grange
authors: David L
authors: DL
authors: Honig
authors: Lieven
authors: L
authors: Naudts
authors: Bruce
authors: B
authors: Huber
authors: Lionel
authors: L
authors: Guidi
authors: Eugene
authors: E
authors: Domack
mesh_terms: D000818:Animals; D033381:Anomura / Q000502:physiology*; D000864:Antarctic Regions; D044822:Biodiversity; D057231:Climate Change; D058865:Introduced Species; D011156:Population Density; D011157:Population Dynamics