title: Otolith Trace Elemental Analyses of South American Austral Hake, Merluccius australis (Hutton, 1872) Indicates Complex Salinity Structuring on their Spawning/Larval Grounds.
abstract: Trace element signatures of otolith edges and cores from 335 austral hake (Merluccius autralis) were analysed using LA-ICPMS from samples collected in Chilean and Falkland Islands' waters, in order to provide potential insights into stock discrimination and migrations. Fish were caught in two locations in Chile and four locations in the south-west of the Falkland Islands Shelf. Univariate and multivariate analyses of trace element signatures in the edges of otoliths, representing adult fish, were not able to distinguish between samples collected in Chile and the Falkland Islands. Cluster analyses based on Ward's similarity/distance metric suggested that it was possible to identify two groups from core signatures. Further analyses of this perceived clustering of the core concentrations revealed that this was largely due to the wide spread of Sr/Ca ratios in the otoliths' cores. Gaussian finite mixtures using MCMC methods confirmed that Sr/Ca ratios form two separate distributions with significantly different mean values while concentrations of other elements showed no evidence of the presence of two or more distributions. The results suggest that there is only one spawning stock of austral hake with spawning situated in and around the Chilean fjords (43°30'S- 47°S) and the variation in Sr/Ca ratios likely suggests complex salinity structuring in this area.
authors.affiliation: Directorate of Natural Resources, Fisheries Department, Falkland Islands Government, Stanley, Falkland Islands.|South Atlantic Environmental Research Institute, Stanley Cottage, Stanley, Falkland Islands.|School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, AB24 2TZ, United Kingdom.
authors.forename: Paul
authors.initials: P
authors.lastname: Brickle
authors.affiliation: School of Biology, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom.
authors.forename: Pia C
authors.initials: PC
authors.lastname: Schuchert
authors.affiliation: Directorate of Natural Resources, Fisheries Department, Falkland Islands Government, Stanley, Falkland Islands.
authors.forename: Alexander I
authors.initials: AI
authors.lastname: Arkhipkin
authors.affiliation: Department of Chemistry, University of Otago, PO Box 56, Dunedin, 9054, New Zealand.
authors.forename: Malcolm R
authors.initials: MR
authors.lastname: Reid
authors.affiliation: Ecology Degree Programme, Department of Botany, University of Otago, PO Box 56, Dunedin, 9054, New Zealand.
authors.forename: Haseeb S
authors.initials: HS
authors.lastname: Randhawa
mesh_terms: D000818:Animals; D005399:Fishes / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology; D007814:Larva / Q000254:growth & development*; D012098:Reproduction; D013020:South America; D014131:Trace Elements / Q000378:metabolism*
chemical_list: D014131:Trace Elements