Assessing connectivity of a tropical estuarine teleost through otolith elemental profiles

Moore, Brad R., and Simpfendorfer, Colin A. (2014) Assessing connectivity of a tropical estuarine teleost through otolith elemental profiles. Marine Ecology Progress Series, 501. pp. 225-238.

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Abstract

Understanding connectivity between groups of a species is fundamental to effective management and conservation practices, yet is poorly understood for tropical estuarine fishes. Here, age-related trends in otolith elemental chemistry were examined to assess the degree of connectivity of Polydactylus macrochir, a large, non-diadromous, tropical estuarine teleost, across the species' Australian distribution. Elemental signatures (7Li, 43Ca, 55Mn, 88Sr and 138Ba) of transverse sections of otoliths of 3+ yr fish from the 2005 year class collected from 17 locations were sampled using laser ablation inductively coupled plasma mass spectrometry, providing elemental profiles from the otolith core through the first 3 yr of a fish's life. Univariate and cluster analyses revealed differences in elemental signatures of the otolith core among most locations, although similarities were evident among locations in the Gulf of Carpentaria and among 2 neighbouring locations in both Western Australia and the east coast of Queensland. Fewer differences were observed for post-settlement life history stages, although some differences were observed among neighbouring locations separated by as little as 50 km. SIMPROF analyses revealed that 138Ba generally provided the greatest discrimination among locations. Positive correlations were observed between otolith 138Ba concentration of individual fish and river flow indices for material laid down in all age groups, suggesting differences in flow was a significant driver of the observed patterns in 138Ba. Examined in conjunction with complementary studies into the connectivity of the study species, the spatial structuring suggests that P. macrochir populations are susceptible to localised depletion, with limited opportunity for replenishment from neighbouring populations. The results highlight the importance of using multiple, complementary methods for assessing connectivity of aquatic organisms.

Item ID: 33162
Item Type: Article (Research - C1)
ISSN: 1616-1599
Keywords: otolith chemistry, LA-ICPMS, connectivity, tropics, estuaries, fishes
Funders: Australian Fisheries Research and Development Corporation (FRDC), James Cook University (JCU)
Projects and Grants: FRDC Project No. 2007/032
Date Deposited: 14 May 2014 09:36
FoR Codes: 06 BIOLOGICAL SCIENCES > 0602 Ecology > 060205 Marine and Estuarine Ecology (incl Marine Ichthyology) @ 50%
07 AGRICULTURAL AND VETERINARY SCIENCES > 0704 Fisheries Sciences > 070402 Aquatic Ecosystem Studies and Stock Assessment @ 50%
SEO Codes: 83 ANIMAL PRODUCTION AND ANIMAL PRIMARY PRODUCTS > 8302 Fisheries - Wild Caught > 830204 Wild Caught Fin Fish (excl. Tuna) @ 100%
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