Otoliths or 'ear bones' are small bone-like structures made of a hard calcium carbonate matrix found in a fish's inner ear, used by the fish for balance and hearing.

Many of the photographs show the same endemic species of fish found here along the Australian east coast and off the Illawarra, and makes for some rainy-day reading and enjoyment.

In addition to being used to age and size fish, each species has its own unique otolith shape, making fish identifiable from just these tiny bones.

Being bone, they are often the last parts remaining after the fish has been eaten, digested or decomposed.

Catalogues such as this can be used to assist researchers examining the diets of piscivores, such as seabirds, seals or dolphins.

Check the catalogue at the catalogue at https://researchlibrary.agric.wa.gov.au/fr_frr/3/