Introduction

The metapopulation framework stemming from Levins’s (1969, 1970) seminal concept and which evolved into a modern ecological theory (Hanski & Gilpin, 1997; Hanski, 1999a, 1999b; Hanski & Gaggiotti, 2004; Kritzer & Sale, 2006) is based on the development of ideas from, and applications to, terrestrial systems. However, key environmental differences exist between marine and terrestrial ecosystems, such as the larger scale of chemical, material and organism transport resulting in the greater “openness” of local marine environments (Carr et al., 2003; Sale et al., 2006) and higher marine population connectivity. There are relatively few barriers that might delineate dispersal and migration in the ocean compared with those in terrestrial or freshwater environments that are physically fragmented into discrete patches of habitat supporting discrete local populations (Waples, 1998). Further terrestrial-marine differences with relevance for the application of metapopulation theory in marine systems are the high per capita fecundity and dispersal potential of many marine species, leading to a more open spatial structure of the populations (via decoupling of local offspring production from recruitment to a parental population; see, e.g., Roughgarden et al., 1988; Carr et al., 2003; Kinlan & Gaines, 2003; Sale et al., 2006).