Abstract
Otoliths are small, aragonitic structures in the acoustico-lateralis in teleost fishes. Growth increments are deposited daily in juveniles, and adults can be aged with better accuracy than with scales. Beyond these timekeeping properties, otoliths take up minor and trace elements. Some of these, like strontium, are taken up in proportion to environmental concentrations. By analyzing uptake patterns simultaneously, otolith elemental concentrations ("fingerprints") can be related to lifetime habitat uses. Unlike scale or bone, otoliths are metabolically stable, containing a permanent record of the past. We will further refine methods to map out conc. of several minor and trace elements simultaneously in otoliths, via microPIXE analysis. We will map out stable isotopes of O and N, to obtain different environmental information (thermal and trophic histories). We will train a new generation of expert to work across the disciplines of physics, ecology, and fisheries biology, at the moment Anna MÖLDER a student with a future degree in both Nuclear Physics and Biology within a few months (a rare combination), is writing her master thesis doing pilot studies of stable isotopes in otoliths, with promising results. She will have a fundamental background in physics, but will intern with the co-investigators for training in fisheries science and ecology. We will apply the new methods to case studies of dire fisheries problems, i.e. cod stock identification and silver eel recruitment.
Sweden