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Understanding population connectivity helps inform resource and conservation managers about appropriate boundaries for management units. However, for many species facing recent increases in fishing or environmental pressure, accurate information on population structure is lacking. Reef Bugs (Thenus australiensis), commonly known as Moreton Bay Bugs, are iconic shovel-nosed lobsters in northern Australia and an increasingly important fisheries resource. Around 80% of landings occur in the Queensland East Coast Otter Trawl Fishery (ECOTF) where the first stock assessment of the species is underway. However, knowledge about population structure to inform stock assessment is lacking. We used genome complexity reduction-based sequencing to characterise high-quality Single Nucleotide Polymorphisms (SNPs) used to evaluate population structure among three management zones of the ECOTF. Post-filtering, a total of 3,031 SNPs were used to infer no genetic differences among locations indicating strong genetic population connectivity. The presence of a single panmictic population was further supported by cluster and kinship analyses. Broad-scale genetic connectivity likely results from pelagic larval dispersal due to limited adult movements. Findings of high gene flow among connected populations indicate a single biological stock of T. australiensis on Australia's east coast and will inform future fisheries management initiatives. [ABSTRACT FROM AUTHOR]

Context: In Australia, the health of our marine, estuarine and freshwater fishes are of critical importance. The aquatic and marine ecosystems, and the fishes that occupy them each have an important role in our country's ecological, economic, cultural and social wealth. Climate change, resource over-exploitation, invasive animals and diseases, and habitat degradation are just a few of the burgeoning threats that researchers and managers must address to ensure the prosperity of Australia's natural fisheries resources. In addition, differences in legislative frameworks among jurisdictions hinder our ability to coherently manage fish resources at scales that are relevant biologically, ecologically and socially. Aims: Here, we identify the key research priorities for fish and fisheries research in Australia, across seven thematic fields of study. Methods: Research priorities were evaluated using a horizon scanning approach which identified research questions related to the field of fish and fisheries research in Australia. Key results: A total of 284 unique research questions were categorised and prioritised, resulting in the formation of the top 10 highest priority research questions across each of the seven themes. Conclusions: The outcomes from this work can be used to directly complement ongoing work from research providers working in the field of fish and fisheries as well as the development of new areas of research. Implications: The priorities identified will enable researchers and policy makers to identify critical knowledge gaps, develop collaborative research programs, investigate novel approaches, and to improve transparency around decision-making processes. The health of Australia's fish and fisheries are of critical ecological, economic, cultural and social importance. The horizon scan approach identified key questions across seven themes related to fish and fisheries within Australia which allow researchers to target their skills and further investment towards addressing. [ABSTRACT FROM AUTHOR]

Fish stocking occurs in aquatic systems for conservation purposes, to create or enhance recreational fisheries and to enhance wild-catch commercial fisheries. Identifying and quantifying the contribution of stocking efforts to wild populations is crucial to informing these management objectives. Provenance determination methods trade off accuracy, replicability, and cost-effectiveness at fishery-relevant scales. We present and assess multiple methods for provenance determination using a case study of barramundi (Lates calcarifer) in the Dry Tropics region of northern Australia. A novel application of near-infrared spectroscopy (NIRS) is compared to two established methods for fish provenance, otolith microchemistry and genetic parentage analysis using microsatellites. The otolith microchemistry method was able to provide extremely high provenance resolution (>99% accuracy). The microsatellite parentage analysis method had a slightly lower overall accuracy (95%), likely as a result of genetic introgression in this region. Provenance determination using otolith NIRS had the lowest overall accuracy (76%). Once limitations regarding spectral noise, image resolution, and sample size are addressed, NIRS may have potential for cost-effectively determining provenance in fish. [ABSTRACT FROM AUTHOR]

The introduction and spread of non-native species poses a significant threat to the health of freshwater ecosystems, and has recently been identified as the single biggest danger to threatened species survival in Australia. Notwithstanding, the importation, trade and keeping of exotic and potentially invasive freshwater fishes in Australia is significant, resulting in greater propagule pressure and higher risk for deliberate or incidental release into native waterways. The jaguar cichlid (Parachromis managuensis) is an invasive cichlid that has established non-native populations in many countries throughout the world. In December 2014, the Department of Agriculture and Fisheries in Queensland was notified of an incursion of jaguar cichlids in a stormwater retention dam in the Pioneer River Catchment, Mackay, Queensland. Rotenone was applied to the dam in January 2015, and around 200 jaguar cichlid specimens at various life history stages were destroyed. Follow up surveys into mid-2015 did not detect the presence of any jaguar cichlid in the dam or in nearby creeks. In September 2017, the Department was notified of a wild capture of a mature jaguar cichlid in Fursden Creek, 1.5 km from the original incursion site. Follow up surveys in 2018/19 have also detected jaguar cichlid juveniles in surrounding tributaries, indicating successful establishment and naturalisation of the species in Australia for the first time. [ABSTRACT FROM AUTHOR]