title: Reconstructing larval growth and habitat use in an amphidromous goby using otolith increments and microchemistry.
abstract: High-resolution analysis of growth increments, trace element chemistry and oxygen isotope ratios (δ18O) in otoliths were combined to assess larval and post-larval habitat use and growth of Awaous stamineus, an amphidromous goby native to Hawai'i. Otolith increment widths indicate that all individuals experience a brief period of rapid growth during early life as larvae and that the duration of this growth anomaly is negatively correlated with larval duration. A protracted high-growth period early in larval life is associated with a lower ratio of Sr:Ca, which may reflect low salinity conditions in nearshore habitats. A distinct shift in δ18O (range: 4-5‰) is closely associated with the metamorphic mark in otoliths, indicating that larval metamorphosis occurs promptly upon return to fresh water. Strontium and other trace elements are not as tightly coupled to the metamorphosis mark, but confirm the marine-to-freshwater transition. Integration of microstructural and microchemical approaches reveals that larvae vary substantially in growth rate, possibly in association with habitat differences. Although time and financial costs make it difficult to achieve large sample sizes, present results show that examining even a small number of individuals can lead to novel inferences about early life history in diadromous fishes and illustrates the value of integrating analyses.
authors.affiliation: Department of Life Sciences, Texas A&M University - Corpus Christi, 6300 Ocean Drive, Unit 5892, Corpus Christi, TX, 78412, U.S.A.
authors.forename: J D
authors.initials: JD
authors.lastname: Hogan
authors.affiliation: WiscSIMS, Department of Geoscience, University of Wisconsin - Madison, 1215 W. Dayton St, Madison, WI, 53706, U.S.A.
authors.forename: R
authors.initials: R
authors.lastname: Kozdon
authors.affiliation: Department of Ecology and Evolutionary Biology, Tulane University, 400 Lindy Boggs Building, New Orleans, LA, 70118, U.S.A.
authors.forename: M J
authors.initials: MJ
authors.lastname: Blum
authors.affiliation: Department of Biology, North Carolina State University, Raleigh, NC, 27695, U.S.A.
authors.forename: J F
authors.initials: JF
authors.lastname: Gilliam
authors.affiliation: WiscSIMS, Department of Geoscience, University of Wisconsin - Madison, 1215 W. Dayton St, Madison, WI, 53706, U.S.A.
authors.forename: J W
authors.initials: JW
authors.lastname: Valley
authors.affiliation: Center for Limnology, University of Wisconsin - Madison, 680 N. Park St, Madison, WI, 53706, U.S.A.
authors.forename: P B
authors.initials: PB
authors.lastname: McIntyre
mesh_terms: D000818:Animals; D017753:Ecosystem; D005399:Fishes / Q000254:growth & development* / Q000378:metabolism*; D007814:Larva / Q000737:chemistry / Q000254:growth & development; D010037:Otolithic Membrane / Q000737:chemistry* / Q000254:growth & development*; D013324:Strontium / Q000032:analysis; D014131:Trace Elements / Q000032:analysis
chemical_list: D014131:Trace Elements; D013324:Strontium
keywords: Awaous stamineus; LA-ICP-MS; SIMS; Sr:Ca; migration; otolith ageing