SS1.02 Geochemical Tracers in Calcified Structures: Implications for Fisheries Research
Date: Tuesday, June 11, 2002
Time: 10:15:00 AM
Location: Carson A
PattersonWP, Syracuse University, Syracuse, NY 13244, USA,
Bergstedt, R, A, USGS, Hammond Bay Biological Station, Millersburg, MI 49759, USA,
Wurster, C, M, Syracuse University, Syracuse, NY 13244, USA,
Derivation of high-resolution life history records from fish otoliths: applications for the study of migration, thermal preference and natal origin
Computerized micromilling techniques have permitted development of life history records for a number of ecologically and economically important fish species. Temperature records from surgically implanted recording devices recovered from fish released in Lake Huron were compared to stable oxygen isotope values of their otoliths. Our data agree with previous studies that otoliths function as natural recording thermometers. Similarly, hatcheries impart a carbon isotope signature that preserves a record of hatchery food. Distinctive hatchery food mixtures are readily observed as different carbon isotope values for the portion of the otolith deposited during hatchery rearing. Carbon values of otolith cores can therefore be used to determine whether an adult fish was spawned naturally or raised in a specific hatchery. Extraction of sub-seasonal and in some cases sub-weekly aliquots of otolith carbonate for stable isotope analyses provides a means to examine behavior and diet on those scales.