SS1.02 Geochemical Tracers in Calcified Structures: Implications for Fisheries Research
Date: Tuesday, June 11, 2002
Time: 4:45:00 PM
Location: Carson A
 
BrownJA, University of California, Santa Cruz, Santa Cruz, USA, brown@biology.ucsc.edu
 
USING THE CHEMICAL COMPOSITION OF OTOLITHS TO EVALUATE THE "NURSERY" ROLE OF ESTUARIES FOR JUVENILE FISHES ALONG THE CENTRAL CALIFORNIA COAST
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Estuaries are often considered to be "nursery grounds" - habitats that contribute more individuals to adult populations than other juvenile habitats. To evaluate this nursery hypothesis one must be able to differentiate between adults that resided in estuarine and non-estuarine habitats. The purpose of this research was to (1) determine if juvenile habitats leave a chemical "tag" in otoliths that can be used to discriminate fish that reside in different habitats; and (2) evaluate if this tag is reliable over space and time. I collected otoliths from juvenile English sole (Pleuronectes vetulus) and speckled sanddab (Citharichthys stigmaeus) from 7 estuarine and 11 coastal (subtidal sandflat) sites in central California over three years. The abundance of certain elements (e.g., Sr, Ba, Mn) was determined using solution-based inductively coupled plasma mass spectrometry. The chemical composition of otoliths differed significantly among habitat types (estuary and coast) as well as among different estuaries. The chemical composition of the juvenile core of adult otoliths was then compared to that of the estuarine and coastal juveniles to retrospectively identify in which juvenile habitat the fish resided.