The otolith or ear bone of a fish can be measured to determine its age. The bone is cut into cross-sections and the growth rings, like those of a tree, are counted. Here, scientist David Banks removes an otolith from an orange roughy. The students in the background are being trained how to do this, as they are to work as scientific observers on fishing vessels.
Te whakamahi i tēnei tūemi
Permission of the Alexander Turnbull Library, National Library of New Zealand, Te Puna Mātauranga o Aotearoa, must be obtained before any re-use of this image.