First ID catalogue of Northern bottlenose whales (Hyperoodon ampullatus) off Pico Island, Azores.

Abstract

The Northern bottlenose whale (Hyperoodon ampullatus) is a deep-diving species that belongs to the family Ziphiidae. This species can reach up to 9.5 meters in length and is distributed in the North Atlantic ocean, preferring cold waters. Very little is known about this species, except for a well-studied population appearing at the Gully, an underwater canyon off Nova Scottia, Canada. This population has been monitored since 1988 and consists of about 160 identified individuals. To date, nothing has been published about bottlenose whales sighted around the Azorean archipelago. Here we present the first catalogue of the individuals off Pico Ilsand based on photo-ID techniques. We had 36 boat-based group encounters from 2003 to 2009 (except in 2004) occurring during July and August. The group size varied between 3 and 26 individuals. A total of 14460 pictures were taken, of which 5784 were chosen for analyses and only pictures with Q>3 were selected for the catalogue. Based on several identification markings on the dorsal fin and body such as notches, spots, scratches and coloration patterns, we were able to identify 135 individuals (61 both sides + 74 left side). One resighting was found between years, seen first in 2003 and later in 2008. The individuals spend between 1 and 13 days in the area. We believe the number of animals that appear in the study area could be significantly higher since there are 53 animals identified only on the right side, and many individuals were impossible to photograph during the surveys. In the future, matching with other catalogues is necessary in order to know more about their migratory behaviour.