MEPS 449:263-276 (2012)  -  doi:10.3354/meps09557

Searching for common threads in threadfins: phylogeography of Australian polynemids in space and time

John B. Horne1,*, Paolo Momigliano1,2, David J. Welch3,5, Stephen J. Newman4, Lynne van Herwerden1

1School of Tropical and Marine Biology, Molecular Ecology and Evolution Laboratory, and 3Fishing and Fisheries Research Centre, School of Earth and Environmental Sciences, James Cook University, Townsville, Queensland 4811, Australia
2Australian Institute of Marine Science, PMB No. 3, Townsville, Queensland 4810, Australia
4Western Australian Fisheries and Marine Research Laboratories, Department of Fisheries, Government of Western Australia, PO Box 20, North Beach, Western Australia 6920, Australia
5Queensland Primary Industries and Fisheries, Department of Employment, Economic Development and Innovation, PO Box 1085, Oonoonba, Queensland 4811, Australia

ABSTRACT: Proper management of marine fisheries requires an understanding of the spatial and temporal dynamics of marine populations, which can be obtained from genetic data. While numerous fisheries species have been surveyed for spatial genetic patterns, temporally sampled genetic data is not available for many species. We present a phylogeographic survey of the king threadfin Polydactylus macrochir across its species range in northern Australia and at a temporal scale of 1 and 10 yr. Spatially, the overall AMOVA fixation index was Φst = 0.306 (Fst = 0.838), p < 0.0001 and isolation by distance was strong and significant (r2 = 0.45, p < 0.001). Temporally, genetic patterns were stable at a time scale of 10 yr. However, this did not hold true for samples from the eastern Gulf of Carpentaria, where populations showed a greater degree of temporal instability and lacked spatial genetic structure. Temporal but not spatial genetic structure in the Gulf indicates demographic interdependence but also indicates that fishing pressure may be high in this area. Generally, genetic patterns were similar to another co-distributed threadfin species Eleutheronema tetradactylum, which is ecologically similar. However, the historical demography of both species, evaluated herein, differed, with populations of P. macrochir being much younger. The data are consistent with an acute population bottleneck at the last glacio-eustatic low in sea level and indicate that the king threadfin may be sensitive to habitat disturbances.


KEY WORDS:Australia · Pelagic larvae · Self-recruitment · Metapopulation · Genetic drift · Polydactylus macrochir


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Cite this article as: Horne JB, Momigliano P, Welch DJ, Newman SJ, van Herwerden L (2012) Searching for common threads in threadfins: phylogeography of Australian polynemids in space and time. Mar Ecol Prog Ser 449:263-276

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