Scavenging abyssal amphipods from the North-East Atlantic ocean

A baited trap set on the bottom (4855 m) in the eastern North Atlantic Ocean caught over 600 specimens belonging to 7 species of lysianassid amphipods. Photographic evidence showed a slow build up of numbers and demonstrated fluctuations apparently related to current and pressure changes and to the presence of fish. Length-frequency distributions for the more abundant species reveal size classes related to growth stages. Paralicella caperesca produces a single brood of about 90 eggs. Maturity in this species may be attained in 7 to 11 moults, the precise number possibly being determined by food availability. Orchomene gerulicorbis requires about 11 moults to reach maturity, and females are double-brooded. Mortality within the trap is discussed. A comparison of species of Paralicella and Orchomene based on morphological, developmental, reproductive and ecological characters indicates that the former genus are specialized necrophages whereas the latter are opportunist generalists. The abundance and mobility of necrophagous amphipods indicate that they play a very significant role in the trophic web.