Otolith formation and endolymph chemistry: a strong correlation between the aragonite saturation state and pH in the endolymph of the trout otolith organ

摘要

This is the first report on the aragonite saturation state of the endolymph in a single fish species, the ranbow trout Oncorhynchus mykiss, based on the direct quantification of electrolyte concentrations in the saccular endolymph. The Ca~2+ level, CO_2 partial pressure and pH of the saccu- lar endolymph in 1+ and 2+ yr old trout were simultaneously determined using an automatic pH/blood gas/electrolyte analyzer. From the values of CO_2 partial pressure and pH, HCO_3~- and CO_3~2- levels were obtained using the Henderson-Hasselbalch equation.