Amphipods as food sources for higher trophic levels in the Southern Ocean: a synthesis

With more than 820 different species, among which about 75% endemics, the amphipod crustaceans form one of the richest animal group of the Southern Ocean. They have colonized most habitats and exhibit very diverse life styles and trophic types. They moreover show a broad size spectrum, with numerous giant species. Despite their importance in terms of biodiversity, very few is known about the role of amphipods in Antarctic trophodynamics. Based on an exhaustive literature survey (more than 300 references), we tried to delineate their importance as potential food for higher trophic levels. About 200 different predators were recorded: 33 invertebrates (from 12 orders), 101 fishes (19 families), 48 birds (11 families) and 10 mammals. Using this vast dataset (total amount of citations close to 1500) and published values about predators' standing stocks and feeding rates, an attempt was made to build up a small model, distinguishing between benthic and pelagic species of both amphipods and predators. The total amount of consumedamphipods was estimated to 60 millions of tons per year for the whole Southern Ocean, i.e. the second animal group in importance after euphausiids.