Dwarfs and cannibals in the Arctic: production of Arctic char ( Salvelinus alpinus (L.)) at two trophic levels

摘要: Due to extensive cannibalism, Arctic char (Salvelinus alpinus (L.)) often represent the two highest trophic levels in freshwater ecosystem where is only fish present. There a general lack of stock size and production estimates from lakes although high catchability late maturation large piscivorous individuals raise considerable management challenges because growing forms are valued resource. Here, we use mark-recapture estimate biomass both invertebrate feeding dwarfs (60–150 mm) their cannibalistic conspecifics (>150 mm) small lake at Bear Island (74.5°N, 19.0°E; 11.3 ha; mean depth 1.8 m). Biomass was 10.1 2.0 kg ha−1 2.1 0.5 kg ha−1 yr−1 for cannibals, respectively. All removed by cannibals. The low ecosystems combined with indicates that these stocks may be particularly vulnerable exploitation. We finally point out similarity between sub-arctic alpine populations life-history parameters.