Population structure in a wide-ranging coastal teleost (Argyrosomus japonicus, Sciaenidae) reflects marine biogeography across southern Australia

Abstract

Population structure in marine teleosts is often investigated to aid conservation and fisheries management (e.g. to assess population structure to inform restocking programs). We assessed genetic population structure of the important estuary-associated marine fish, mulloway (Argyrosomus japonicus), within Australian waters and between Australia and South Africa. Genetic variation was investigated at 13 polymorphic microsatellite markers. FST values and Bayesian estimates in STRUCTURE suggested population differentiation of mulloway within Australia and confirm strong differentiation between South Africa and Australia. The 12 Australian sample sets fell into one of four spatially separated genetic clusters. Initially, a significant signal of isolation-by-distance (IBD) was evident among Australian populations. However, further investigation by decomposed-pairwise-regression (DPR) suggested five sample sets were influenced more by genetic-drift, rather than gene-flow and drift equilibrium, as expected in strong IBD cases. Cryptic oceanographic and topographical influences may isolate mulloway populations from south-western Australia. The results demonstrate that DPR is suitable to assess population structure of coastal marine species where barriers to gene flow may be less obvious than in freshwater systems. Information on the relative strengths of gene flow and genetic drift facilitates a more comprehensive understanding of the evolutionary forces that lead to population structure, which in turn informs fisheries and assists conservation management. Large-bodied predatory scale-fish may be under increasing pressure on a global scale, owing to a variety of anthropogenic reasons. In southern Australia, the iconic sciaenid A. japonicus (mulloway, jewfish or kob) is no exception. Despite the species supporting important fisheries, much of its ecology is poorly understood. It is possible that a greater understanding of their genetic population structure can help ensure a sustainable future for the only southern Australian sciaenid.

Seascape genomics of coastal bottlenose dolphins along strong gradients of temperature and salinity

“…This influence could however, be somewhat confounded by the separation of the two gulfs from open‐coast sites to the west (Figure 1b). Differences in environmental conditions either side of Eyre Peninsula appear to influence genetic differentiation in several marine organisms, such as common dolphins ( Delphinus delphis ; Bilgmann et al, 2014), Australian sea lions ( Neophoca cinerea ; Lowther & Goldsworthy, 2011), mulloway ( Argyrosomus japonicus ; Barnes et al, 2016), and perhaps clams ( Lasaea australis ; Li et al, 2013). The diversity of these examples points to the likely role of upwelling systems as a driver of population divergence of marine communities (also see Kelly & Palumbi, 2010).…”

“…Lowther & Goldsworthy, 2011), mulloway (Argyrosomus japonicus; Barnes et al, 2016), and perhaps clams (Lasaea australis; Li et al, 2013). The diversity of these examples points to the likely role of upwelling systems as a driver of population divergence of marine communities (also see Kelly & Palumbi, 2010).…”

Assessment of genetic structure among Australian east coast populations of snapper Chrysophrys auratus (Sparidae)

“…Despite having a high larval dispersal potential, C. auratus could use local coastal circulation to recruit locally, or could migrate back to its natal origins before breeding, which could create complex genetic structure. Other studies investigating the genetic structure of species with similar pelagic larval periods, namely Pristipomoides multidens (Ovenden et al 2004), Lutjanus carponotatus (Harrison et al 2012) and Argyrosomus japonicus (Barnes et al 2016) have detected genetic structure suggesting low-level mixing despite potential for wide larval dispersal.…”

Matrilineal evidence for genetic structure and Late Pleistocene demographic expansion of the Ornate goby Istigobiusornatus (Teleostei: Gobiidae) in the Persian Gulf and Oman Sea

“…Genetic differentiation can reflect isolation by distance (IBD), which implies that distance‐dependent gene flows generally limit genetic differences among natural populations (Slatkin, 1993; Wright, 1943). Marine environments are often regarded as open habitats in which IBD is the main mechanism that may promote genetic differentiation among populations (Palumbi, 1994), and patterns of IBD has been documented in numerous marine fish species (e.g., Ashe et al., 2015; Barnes et al., 2016; Drinan et al., 2018; Gold et al., 1994; Gonzalez et al., 2016; Pogson et al., 2001). Since the studied populations of I. ornatus are distributed along an east–west axis along the coasts of the Persian Gulf and Oman Sea, we expected geographic isolation to contribute to genetic affinities.…”