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Spatial variation in life history reveals insight into connectivity and geographic population structure of a tropical estuarine teleost: king threadfin, Polydactylus macrochir

journal contribution
posted on 2023-05-19, 12:25 authored by Bradley MooreBradley Moore, Simpfendorfer, CA, Newman, SJ, Stapley, JM, Allsop, Q, Sellin, MJ, Welch, DJ
Understanding the life history of exploited fish species is not only critical in developing stock assessments and productivity models, but has a dual function in the delineation of connectivity and geographical population structure. In this study, patterns in growth and length and age at sex change of Polydactylus macrochir, an ecologically and economically important protandrous estuarine teleost, were examined to provide preliminary information on the species’ connectivity and geographic structure across northern Australia. Considerable variation in life history parameters was observed among the 18 locations sampled. Both unconstrained and constrained (t0 = 0) estimates of von Bertalanffy growth function parameters differed significantly among all neighbouring locations with the exception of two locations in Queensland's east coast and two in Queensland's Gulf of Carpentaria waters, respectively. Comparisons of back-calculated length-at-age 2 provided additional evidence for growth differences among some locations, but were not significantly different among locations in the south-eastern Gulf of Carpentaria or on Queensland's east coast. The length and age at sex change differed markedly among locations, with fish from the east coast of Australia changing sex from males to females at significantly greater lengths and ages than elsewhere. Sex change occurred earliest at locations within Queensland's Gulf of Carpentaria, where a large proportion of small, young females were recorded. The observed differences suggest that P. macrochir likely form a number of geographically and/or reproductively distinct groups in Australian waters and suggest that future studies examining connectivity and geographic population structure of estuarine fishes will likely benefit from the inclusion of comparisons of life history parameters.

History

Publication title

Fisheries Research

Volume

125-126

Pagination

214-224

ISSN

0165-7836

Department/School

Institute for Marine and Antarctic Studies

Publisher

Elsevier Science Bv

Place of publication

Po Box 211, Amsterdam, Netherlands, 1000 Ae

Rights statement

Copyright 2012 Elsevier B.V.

Repository Status

  • Restricted

Socio-economic Objectives

Wild caught fin fish (excl. tuna)

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