Historic divergence with contemporary connectivity in a catadromous fish, the estuary perch (Macquaria colonorum)

Abstract

The estuary perch ( Macquaria colonorum ) represents an important model for assessing how historical changes in coastal geomorphology and current oceanographic and estuarine conditions may have impacted connectivity in a catadromous fish. A fragment of the mitochondrial control region and six microsatellite DNA markers were used to clarify connectivity in 17 populations (n = 354) of estuary perch from the southeast and southern coasts of Australia. The mtDNA data showed a latitudinal disjunction in haplotype frequencies that divided populations into two groups (ΦST = 0.419), in a pattern suggestive of isolation by geographic distance. However, no marked structure or correlation with distance was apparent within each group, a result consistent with microsatellite data that showed high contemporary population connectivity across large distances. This was contrary to expectations that the species would exhibit moderate to strong genetic structure consistent with a one-dimensional stepping stone pattern. Coalescent phylogeographic and population genetic analyses provided support for a historical divergence probably due to the emergence of the Bassian Isthmus in southern Australia. Current connectivity appears to be maintained by both large- and fine-scale oceanographic currents and processes, highlighting the important role of the marine environment for an estuarine resident species.

Patterns of genetic structuring at the northern limits of the Australian smelt (Retropinna semoni) cryptic species complex

“…382 Similar IBD relationships have been reported for other coastline restricted species (Keenan, 383 1994; Jerry & Baverstock, 1998;Shaddick et al, 2011;Schmidt et al, 2014). Lack of IBD for 384 the CEQ group may be attributed to insufficient number of population samples available for (Table 4).…”

“…In this study, a strong IBD relationship 380 was identified among the SEQ populations, but not among CEQ populations. This suggests that 381 for SEQ populations, dispersal, when it occurs, is more likely between nearby catchments.382 Similar IBD relationships have been reported for other coastline restricted species (Keenan, 383 1994; Jerry & Baverstock, 1998;Shaddick et al, 2011;Schmidt et al, 2014). Lack of IBD for 384 the CEQ group may be attributed to insufficient number of population samples available for (Table 4).…”

Microsatellite and mtDNA analysis of lake trout, Salvelinus namaycush, from Great Bear Lake, Northwest Territories: impacts of historical and contemporary evolutionary forces on Arctic ecosystems

“…; Shaddick et al. ) and can mask some of the historical influences on, or complicate inferences regarding, divergence and population structure (Turgeon and Bernatchez ; Adams et al. ).…”

A hybrid zone and bidirectional introgression between two catadromous species: Australian bassMacquaria novemaculeataand estuary perchMacquaria colonorum

“…Indeed, within NSW, the two species are thought to live in spatial and temporal isolation, thus inhibiting prolific hybridization in the rivers where they coexist. Both M. novemaculeata and M. colonorum, however, are capable of migrating considerable distances through coastal marine waters (Chenoweth & Hughes, 1997; Jerry & Baverstock, 1998; Jerry et al , 1999; Shaddick et al , 2011) facilitating the movement of hybrid individuals along the coastline. This may explain the presence of three putative hybrids outside the range of M. novemaculeata in the Tarwin, Glenelg and Barham Rivers (Fig.…”

“…This was achieved using oligonucleotide primers A and E (Lee et al , 1995) and PCR conditions and protocols outlined in Beheregaray & Sunnucks (2001). Mitochondrial DNA control region sequences were aligned by eye with existing M. novemaculeata and M. colonorum mtDNA control‐region data sets (Jerry & Baverstock, 1998; Shaddick et al , 2011).…”