Summary The application of the metapopulation concept to the study and management of temperate rocky reef fishes will succeed only to the extent that the concept has greater explanatory and predictive power than other approaches, such as island biogeography (MacArthur and Wilson, 1967), regional stocks, or clinal variation. As noted by Hanski and Gilpin (1997), "The metapopulation approach is based on the notion that space is not only discrete but that there is a binary distinction between suitable and unsuitable habitat types." (Levins, 1969) and (Levins, 1970) originally emphasized the importance of extinction-recolonization of local populations but Kritzer and Sale (2004) have emphasized the "degree of demographic connectivity" whereby populations that are primarily self recruiting but with some significant external replenishment are the essence of the metapopulation concept. North Pacific temperate reef fishes generally fit this notion but sometimes with the added complexity of ontogenetic migration between pelagic larval, benthic juvenile, and benthic adult habitats (Vetter and Lynn, 1997). Furthermore, the combination of extended pelagic phases coupled with unpredictable changes in ocean climate (e.g. El Niño events) allows for demographically significant but temporally rare linkages between local populations. In an era of intense overfishing and ecosystem change (Pauly, et al, 1998), (Jackson, et al, 2001) and (Dayton, et al, 2002) Myers and Worm, 2003), temperate reef communities are becoming, increasingly fragmented as inaccessible natural refugia (Yoklavich et al., 2000) and intentionally created (Airamé et al., 2003) marine protected areas (MPAs) become islands within a matrix of heavily exploited habitat. Thus the metapopulation dynamics of the past may not be the metapopulation dynamics of the future. In this chapter we consider two classes of potential metapopulation effects on temperate reef fishes: short-term demographic effects and long-term genetic effects. These can also be considered as ecological and evolutionary effects. Demographic effects are those resulting from differences in the dispersal of propagules and resultant effects on local and regional recruitment and population dynamics. Genetic effects are those that result from the collective, long-term effects of consistent patterns in metapopulation dynamics and the impact of processes such as extinction-recolonization, gene flow, genetic drift, and local selection. In a management context, both demographic and genetic effects of metapopulation dynamics on temperate reef fish communities need to be considered. Fisheries managers need to evaluate the utility of incorporating metapopulation concepts into existing ideas of fish stock dynamics, recovery plans, and regional management strategies. Conservation biologists need to consider the utility of incorporating metapopulation concepts into the provisions of the Endangered Species Act and the Act's concept of a distinct population segment (DPS), or evolutionarily significant unit (ESU). Conservation biologists may also need to incorporate metapopulation concepts such as extinction-recolonization into recovery strategies and the design of MPA networks.
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