Genetic Approaches to Measuring Connectivity

Abstract

Understanding the connectivity of marine populations is vital for conservation and fisheries management, particularly for the strategic design of reserve systems.A recent proliferation of molecular and statistical tools allows increasingly sophisticated integration of genetic and geographic data (e.g., Manel et al., 2003). Such advances have fueled considerable hope that the challenging problem of tracking movement of individuals within the vast ocean will soon be solved. Here, we focus on some of the inherent limitations of genetic approaches to inferring connectivity, particularly in marine environments. More optimistically, we also point to a number of situations where genetic approaches have been particularly successful in the past, as well as newer integrative approaches that deserve further attention. structure of Marine PopulationsEstimating connectivity depends on the extent of spatial genetic variation.

Temporal genetic homogeneity among shore crab (Carcinus maenas) larval events supplied to an estuarine system on the Portuguese northwest coast

“…This suggests that the phenomenon might not be as widespread among marine species as previously acknowledged (Hedgecock et al, 2007a). High temporal genetic homogeneity and stability of both larvae and adults suggest great connectivity among populations, which may explain the invasive success of the species around the globe.…”

High population connectivity across the Indo-Pacific: Congruent lack of phylogeographic structure in three reef fish congeners

“…However, it can be difficult to capture the molecular signal of populations and assess their connectivity, particularly when the effective population size is large and genetic diversity is high, as is the case with many benthic marine organisms (Palumbi 2003;Hellberg, 2007;Hedgecock et al 2007). When much of a population's diversity remains unsampled, the molecular method is less effective.…”

Phylogeography of the sea star Marthasterias glacialis (Asteroidea, Echinodermata): deep genetic divergence between mitochondrial lineages in the north-western mediterranean

“…It is currently well known that barriers to gene flow exist in the ocean realm generating different levels of population differentiation in marine species (Hellberg 1996;Lessios et al 2001;Hedgecock et al 2007). Gene flow between populations, promoted by migration and dispersion of both larvae and adults, does not only preclude local adaptation (Barton and Hewitt 1985) but also introduces new polymorphisms in the populations on which selection can potentially act.…”