EFFECTS OF TEMPERATURE AND VATERITE REPLACEMENT ON THE CHEMISTRY OF METAL-IONS IN THE OTOLITHS OF ONCORHYNCHUS-TSHAWYTSCHA

Chinook salmon (Oncorhynchus tshawytscha) were reared from the egg to 297 days under the same experimental conditions and then separated for a further 43 days into five temperature treatment groups each of 100 fish at 8, 10, 12, 14, and 16 degrees C plus a control group for a tot al of 634 fish. Many otoliths recovered from the experiment had aragon ite partially replaced by vaterite. Whole otolith chemistry was measur ed using inductively coupled argon plasma optical emission spectrometr y. The concentrations of the metal ions strontium, magnesium, manganes e, sodium, iron, and zinc as well as phosphorus were recorded. The che mistry of the otolith was weakly related to somatic weight, somatic le ngth, temperature treatment, and otolith weight. Vaterite replacement accounted for a large part of the variation observed in metal ion conc entrations in the otolith.