INTRODUCTION

Climate change can have direct and indirect impacts on marine fisheries (Brander, 2007). Impacts of overfishing and other human factors, such as habitat destruction and pollution, on marine ecosystems and fisheries resources, are generally well known. Overfishing causes large-scale depletion of fish biomass in the ocean and structural changes in ecosystems (Pauly et al., 1998; Jackson et al., 2001; Pauly et al., 2002; Christensen et al., 2003; Myers and Worm, 2003). Simultaneously, other human activities disturb natural habitats and disrupt the ecology and biodiversity of marine ecosystems (Lotze et al., 2006; Worm et al., 2006; Halpern et al., 2008).

In contrast, impacts of global climate change on marine ecosystems are just starting to be recognized, lagging behind such recognition in terrestrial systems (Rosenzweig et al., 2008). Theory and empirical evidence show that climate change is an important factor affecting marine organisms, ecosystems, and the services they provide (Costanza et al., 1999; Roessig et al., 2004; Pörtner and Knust, 2007; Munday et al., 2008; Rosenzweig et al., 2008). For example, distributions of exploited marine fish and invertebrates have shifted as temperature and other ocean conditions change. Observations from the North Sea (Perry et al., 2005) and the Bering Sea (Mueter and Litzow, 2008) show that the average rate of latitudinal range shift has been around 30 km per decade over the last few decades. Fish assemblages in the North Sea are also found to have moved deeper at an average rate of 3.6 m per decade (Dulvy et al., 2008).