Estuaries, lagoons and enclosed embayments: habitats that enhance population subdivision of inshore fishes

Abstract

Several studies have suggested that estuaries, lagoons and enclosed embayments may offer special opportunities for local subdivision in marine species. We used data from published papers and unpublished theses to examine the effect of such water bodies on allozyme differentiation of seven species of inshore fishes in Western Australia. We included species that differ in their dispersal, and hence their intrinsic potential for gene flow. Over large distances, subdivision was generally greater among estuarine populations than among conspecific marine populations collected over similar distances. Over small distances, paired marine and estuarine samples were generally more divergent than pairs of marine samples separated by similar distances. For species with a low capability for dispersal, estuaries appear to add to the high levels of genetic subdivision that commonly result from other factors. Under special circumstances estuaries may also provide opportunities for genetic divergence in species with a high capability of dispersal that are rarely subdivided at a large geographical scale. These observations indicate that estuaries can increase the genetic subdivision of populations of inshore fishes, and that species that use both marine and estuarine habitats are likely to have greater genetic subdivision than those that are restricted to marine habitats.

Vicariance and Dispersal Effects on Phylogeographic Structure and Speciation in a Widespread Estuarine Invertebrate

“…A survey of coastal fish species showed that those presumed capable of inhabiting estuarine and marine habitats were more divergent than population pairs of the same species from marine habitats (Watts and Johnson 2004). Thus, salinity gradients may impose physiological limits to dispersal or impose strong selection pressures on dispersing individuals (Lee and Bell 1999;Bilton et al 2002).…”

Human-mediated transport determines the non-native distribution of the anemone Nematostella vectensis, a dispersal-limited estuarine invertebrate

“…Numerous genetic studies of both benthic invertebrates (Perrin et al 2004, Virgilio & Abbiati 2004, Schmidt et al 2006) and coastal fish taxa (Pampoulie et al 2004, Watts & Johnson 2004, Bradbury et al 2008 bear out this prediction, revealing significant genetic differentiation between estuarine populations, in many cases despite the presence of potentially dispersive larval forms. Empirical evidence, thus, suggests that estuarine taxa, particularly those lacking long-lived planktonic larvae, are likely to exhibit marked genetic structure as a result of limited gene flow between populations, with corresponding increases in the potential for local adaptation and limitations to the possibility of range expansion.…”

“…Ballast water is commonly cited as a favored means of anthropogenic dispersal by many coastal and estuarine invasive species , Watts & Johnson 2004, Wonham & Carlton 2005. However, this vector seems unlikely in the case of Nematostella vectensis.…”

Environmental variables, habitat discontinuity and life history shaping the genetic structure of Pomatoschistus marmoratus

“…Such environmental variation may subject the local fauna to severe adaptive challenges that could have a direct effect on the genetic composition of some species such as Aphanius fasciatus, Diplodus sargus, Elysia timida, Cerastoderma glaucum, Ostrea edulis, Ostreola stentina and Bursatella leachii (Cognetti and Maltagliati 2000;Maltagliati 2002;González-Wangüemert et al 2004, 2009Giménez-Casalduero et al 2011; or separate species into different populations (Bilton et al 2002;Trabelsi et al 2004;González-Wangüemert et al 2009;Richards et al 2010;Fluker et al 2011;Vergara-Chen et al 2013;González-Wangüemert et al 2014). The isolation and habitat fragmentation have been also supposed to contribute to the genetic structure of marine species with populations inhabiting coastal lagoons, enhancing the effects of microevolutionary processes (Watts and Johnson 2004).…”