Features of the vertebral column and caudal fin skeleton for identifying Engraulis australis in food of the Australasian gannet Morus serrator, Hauraki Gulf, New Zealand.

Abstract

Identifying fish species from their bone remains is employed in identifying the prey of aquatic animals. However, diagnostic skeletal descriptions are scarce for fish species prey found in the food of piscivorous birds and other marine predators in New Zealand. The present article addresses this knowledge gap, providing a diagnostic description for the vertebral column and the skeleton of the caudal fin of the Australian anchovy Engraulis australis inhabiting coastal waters in and around the Hauraki Gulf, New Zealand. The vertebral column of E. australis is divided into four morphologically distinct regions more complicated than the classical division in abdominal and caudal parts only and the drawing of characteristic-looking vertebral profiles. Each of these four regions is associated with characteristic vertebral profiles. These morphological descriptive parameters express a morphotype that may be linked with the swimming mode of the Australian anchovy. The skeleton of the caudal fin of E. australis showed distinctive characteristics that will be useful as diagnostic criteria to identify specimens of the Australian anchovy and separate them from the skeletal elements of other fish species found in the food of gannets and other marine predators in future studies.