Otolith Research

Otoliths, or fish ear bones, are calcium carbonate structures (aragonite and/or calcite) that form in the ears of most fishes and aid in balance and hearing. Otoliths grow throughout the life of the fish forming cooncentric layers that are commonly used to age the fish. These layers also record information about the environment in which the fish is living. By measuring the osygen and carbon isotopic composition of otoliths we are often able to identify seasonal layers that may not be visible even using a high power microscope, making aging of the fish feasible. Isotopic data may also allow researchers to better understand the life history of fishes (e.g., changes in habitat that occur seasonallly and/or during the life cycle of the fish).