Arctic Biodiversity Trends 2010: Indicator #16, Changing Distribution of Marine Fish

Different species of fish, both marine and freshwater, are important resources for human populations in the Arctic. Fish are also prey for many species of birds and mammals, and form an essential link in Arctic food chains. Changes in the distribution and abundance of fish populations will, therefore, have consequences for the different species of prey which the fish feed on, for the predators of the fish, and for humans who depend on these fish or their predators. As an example, in times when the Barents Sea capelin, Mallotus villosus, stock is very low, concentrations of its zooplankton prey are higher, while the seabirds and harp seals that prey on the capelin show increased mortality and recruitment failure. During these periods, the Barents Sea cod, which also feeds on capelin and which supports an important commercial fishery, shows reduced growth and delayed maturation, and cannibalism within the stock increases.