Journal of the Marine Biological Association of the United Kingdom

Research Article

In situ observations of trophic behaviour and locomotion of Princaxelia amphipods (Crustacea: Pardaliscidae) at hadal depths in four West Pacific Trenches

Alan J. Jamiesona1 c1, Anne-Nina Lörza2, Toyonobu Fujiia1 and Imants G. Priedea1

a1 Oceanlab, Institute of Biological and Environmental Science, University of Aberdeen, Main Street, Newburgh, Aberdeenshire, UK, AB41 6AA

a2 National Institute of Water & Atmospheric Research (NIWA), 301 Evans Bay Parade, Wellington 6021, New Zealand


The genus Princaxelia, Pardaliscidae, is a rarely recorded, infrequently collected and hitherto observed benthic amphipod, typically found at hadal depths (>6000 m) in the Pacific Ocean trenches. Little is known about the behaviour or physiology of this genus. Using a baited camera lander, observations of Princaxelia jamiesoni were made in the Japan Trench (7703 m) and Izu–Ogasawara Trench (9316 m) and of Princaxelia aff. abyssalis in the Kermadec Trench (7966 m) and Tonga Trench (8798 m). These amphipods rapidly intercepted the bait and preyed upon smaller lysianassoid amphipods. Mean absolute swimming speeds for P. jamiesoni and P. aff. abyssalis were 4.16 cm.s−1 ± 1.8 SD and 4.02 cm.s−1 ± 0.87 SD respectively. These amphipods have the capacity for long range swimming, high manoeuvrability in close range, and efficient predatory behaviour. Burst swimming speeds for P. aff. abyssalis were 9 and 10 cm.s−1 with accelerations up to 22–25 cm.s−2.

(Received November 22 2010)

(Accepted February 28 2011)

(Online publication April 19 2011)