in

a r t i c l e i n f o detrimental to fisheries because they feed on zooplankton and ich-thyoplankton, and so are both predators and potential competitors of fish (Purcell and Arai, 2001), and because they interfere with fishing directly (reviewed in Purcell et al., 2007). The effects of jel-lyfish population outbursts on ecosystems and the economies that depend on them can be profound (Purcell and Arai, 2001; Brodeur et al., 2002; Daskalov, 2002; Lynam et al., 2005b, 2006). Factors including climate change, overfishing, eutrophication, and species et al., 2002). In the relatively unpolluted Bering Sea, only climate variability and fishing are probable causes for changes in the jelly-fish population. The southeast Bering Sea shelf was relatively warm between 1999 and 2005, with winter depth-averaged tem-peratures over the southeastern shelf 3 C warmer than in the 1990s. Winters since 2000–2001 have had sea ice coverage typi-cally 30–80 % less than the climatological average (1972–2000); the retreat of this ice in spring since 2001 was not only earlier, but also more rapid than average (Overland and Stabeno, 2004; Grebmeier et al., 2006). This anomalous warmth has been associated with below-normal sea level pressure (SLP) an