Structural and functional connectivity of marine fishes within a semi‐enclosed Newfoundland fjord

Abstract

The interplay between structural connectivity (i.e. habitat continuity) and functional connectivity (i.e. dispersal probability) in marine fishes was examined in a coastal fjord (Holyrood Pond, Newfoundland, Canada) that is completely isolated from the North Atlantic Ocean for most of the year. Genetic differentiation was described in three species (rainbow smelt Osmerus mordax, white hake Urophycis tenuis and Atlantic cod Gadus morhua) with contrasting life histories using seven to 10 microsatellite loci and a protein-coding locus, PanI (G. morhua). Analysis of microsatellite differentiation indicated clear genetic differences between the fjord and coastal regions; however, the magnitude of difference was no more elevated than adjacent bays and was not enhanced by the fjord's isolation. Osmerus mordax was characterized by the highest structure overall with moderate differentiation between the fjord and St Mary's Bay (F(ST)c.0.047). In contrast, U. tenuis and G. morhua displayed weak differentiation (F(ST) < 0.01). Nonetheless, these populations did demonstrate high rates (< 75%) of Bayesian self-assignment. Furthermore, elevated differentiation was observed at the PanI locus in G. morhua between the fjord and other coastal locations. Interestingly, locus-specific genetic differentiation and expected heterozygosity were negatively associated in O. mordax, in contrast to the positive associations observed in U. tenuis and G. morhua. Gene flow in these species is apparently unencumbered by limited structural connectivity, yet the observed differentiation suggests that population structuring exists over small scales despite high dispersal potential.

Genetic Structure in a Small Pelagic Fish Coincides with a Marine Protected Area: Seascape Genetics in Patagonian Fjords

“…temperature, salinity, oxygen, pH, and nutrients) have been proposed as causes of trophic and reproductive adaptation [ 27 – 29 ], and transport and retention of larvae [ 30 , 31 ]. Also, other studies have found population genetics differentiation between inner and outer fjords waters [ 25 , 32 , 33 ]. In such cases, oceanographic features can be a barrier to dispersal at different ontogenetic stages, by restricting gene flow and increasing intraspecific divergence.…”

Research progress on habitat connectivity in coastal waters: A review

“…Connectivity, a basic concept in topology, is broadly defined in ecology as the physical, chemical and biological processes and their interactions among ecosystems at all levels of the Earth, that is, ecological connectivity (Nagelkerken, 2009; Sheaves, 2009; White & Kiester, 2008). Some researchers divide ecological connectivity into landscape connectivity and patch connectivity based on the concept of landscape ecology, while most ecologists divide it into structural connectivity and functional connectivity (Bradbury et al, 2009; Du et al, 2015; Tischendorf & Fahrig, 2014). Fang reviewed the definitions of ecological connectivity by many researchers and concluded that (1) ecological connectivity is based on species composition between habitats; (2) species can perceive different habitats through lateral, vertical, large and small‐scale daily activities or seasonal migration; and (3) environmental changes in habitats will affect the flow of ecological resources among patches (Fang et al, 2018; Tischendorf & Fahrig, 2014).…”

Research Progress on Habitat Connectivity in Temperate Waters

“…Connectivity, a basic concept in topology, is broadly defined in ecology as the physical, chemical and biological processes and their interactions among ecosystems at all levels of the Earth, that is, ecological connectivity [31,32]. Some researchers divide ecological connectivity into landscape connectivity and patch connectivity, while most ecologists divide it into structural connectivity and functional connectivity [28,33,34]. Fang reviewed the definitions of ecological connectivity by many researchers and concluded that (1) ecological connectivity is based on species composition between habitats; (2) species can perceive different habitats through lateral, vertical, large and small-scale daily activities or seasonal migration; and (3) environmental changes in habitats will affect the flow of ecological resources among patches [33,35].…”