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

Abstract

Snapper Chrysophrys auratus is a high-value food fish in Australia targeted by both commercial and recreational fisheries. Along the east coast of Australia, fisheries are managed under four state jurisdictions (Queensland, Qld; New South Wales, NSW; Victoria, Vic.; and Tasmania, Tas.), each applying different regulations, although it is thought that the fisheries target the same biological stock. An allozyme-based study in the mid-1990s identified a weak genetic disjunction north of Sydney (NSW) questioning the single-stock hypothesis. This study, focused on east-coast C. auratus, used nine microsatellite markers to assess the validity of the allozyme break and investigated whether genetic structure exists further south. Nine locations were sampled spanning four states and over 2000km, including sites north and south of the proposed allozyme disjunction. Analyses confirmed the presence of two distinct biological stocks along the east coast, with a region of genetic overlap around Eden in southern NSW, ~400km south of the allozyme disjunction. The findings indicate that C. auratus off Vic. and Tas. are distinct from those in Qld and NSW. For the purpose of stock assessment and management, the results indicate that Qld and NSW fisheries are targeting a single biological stock.A

Continental‐scale acoustic telemetry and network analysis reveal new insights into stock structure

“…Genetic analysis, however, indicates a single population for this species, which possibly reflects occasional long‐distance movements among estuaries. Pink snapper data revealed distinct networks in NSW, South Australia and Victoria (Figure 3a), and this supports recent findings of genetically distinct stocks between Victoria and NSW (Morgan et al., 2019). Finally, mixed sand flathead ( Platycephalus bassensis , Platycephalidae & Platycephalus caeruleopunctatus , Platycephalidae) were detected on few installations but had greater route selection (density) in their network than any other fish species (Table 3).…”

Bioregional boundaries and genomically-delineated stocks in snapper (Chrysophrys auratus) from southeastern Australia

“…McGlennon, 2003) and demographic analyses (Fowler, 2016). The most detailed population genetic work done in the region are a mitochondrial DNA study with a Victoria component including Port Phillip Bay only (see Figure 1; Donnellan and McGlennon, 1996) and a microsatellite DNA study with Port Phillip Bay as its westernmost sample (Morgan et al, 2018). Additionally, all investigations of population structure and connectivity in snapper in southeastern Australia have focused on one state or sub-region, or involved sparse sampling.…”

Using integrative taxonomy to distinguish cryptic halfbeak species and interpret distribution patterns, fisheries landings, and speciation

“…Although little research has been conducted into the hybridisation of other marine fish around Eden, genetic signatures of introgression resulting from secondary contact after isolation have been discovered within the cuttlefish species Sepia apama in southern NSW (Kassahn et al 2003). Eden is also an area of overlap of two distinct stocks of the commercially important snapper Chrysophrys auratus, with the suggestion of admixture and interbreeding (Morgan et al 2018) around this area. Hybridisation at Eden was first suggested by Collette (1974) and is supported by the presence of individuals in this study with intermediate mtDNA haplotypes in Eden and adjacent areas of NSW.…”