Spatial and temporal distribution of Hyperoodon ampullatus of Pico Island, Azores.

Abstract

The Azorean archipelago is characterized by deep coastal waters, hence it is possible to observe deep diving cetaceans close to shore, such as sperm whales, northern bottlenose whales, Sowerby's and other beaked whales. The aim of the present study was to determine the temporal and spatial distribution of Hyperoodon ampullatus of Pico Island, Azores. The analyses were based on data gathered from 2003 to 2009, using both land and boat-based surveys. A total of 87 groups were recorded, distributed over 33 days, ranging from 1 to 11 days a year. Most of the observations were made in the summer, from mid July to the beginning of August, with 2 additional sightings at the end of August and September. They were observed mainly in the morning (63% of all observations), between 7:30 and 12:00 am. Their spatial distribution ranges from 38º18 to 38º23 N and from 28º02 to 28º27 W, which correlates with an area of 400 to 1200 m deep. Using photo-ID, we encountered resightings of different individuals both within the day and within the year. We conclude that H. ampullatus is a regular migratory species of the Azorean archipelago and probably spends more time in the sea surrounding the islands, thus we believe it is necessary to obtain more data, by collaboration with researchers from other islands in order to achieve a better understanding on species' habitat use in the Azores.