Data from: Searching for common threads in threadfins: phylogeography of Australian Polynemids in space and time

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. Here we present a phylogeographic survey of the king
threadfin, Polydactylus macrochir, across its species range in northern
Australia and at a temporal scale of one and ten years. Spatially the
overall AMOVA fixation index was Φst = 0.306 (F’st = 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 ten years. 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.