The Diet Composition of Pilot Whales, Dwarf Sperm Whales and Pygmy Sperm Whales in the North Pacific
Abstract
Knowledge of a species diet is crucial for understanding it s behavior and ecology and is also relevant in assessing the impact of potential changes in behavior or spatial use that may be associated with anthropogenic activities. Assessing diet for many species" of cetaceans is difficult, given that most foraging occurs far below the surface and that stomach contents of stranded animals are"" rarely available. Pilot whales, dwarf sperm whales, and pygmy sperm whales may be susceptible to the impacts of underwater noise, y""et nothing is known of the diet of either pilot whales or dwarf sperm whales in the central Pacific. Prior to 2009, similarly no inf"ormation was availalbe on the diet or foraging behavior of pygmy sperm whales (Kogia breviceps) from any location in the central Pacific. Our research group published the first report on the diet of K. breviceps from this region of hte world by examining 7 stranded specimens in Hawaii. From the identification of 728 prey items in the stomachs of these whales we described a diverse diet of ceph"alopods, fish, and deep water shrimp that suggested K. breviceps forage at depths of at least 600-1200m in Hawaii (West et al 2009)." Stomach contents are also available for stranded or by-caught Kogia sima and Globicephala macrorhyncus specimens from the central P"acific, but have yet to be examined to describe the food habits of either species." This project proposes to describe the diet composition of both pilot whales and K. sima form the prey remains of 20 speciments (9 pilot whales and 11 dwarf sperm whales) that are available to date. This will allow for the first investigation of pilot whale diet composition form the central Pacif"ic. Additionally, dwarf sperm whale diet composition will be evaluated for the first time from this area and potential niche partiti"oning between K. breviceps and K. sima will be investigated by building on our knowledge of K. breviceps diet through the examination of prey remains from 8 additional K. breviceps specimens that have been obtained since 2009. The identification of each prey item to the species level and size and mass estimates of prey will allow for a detailed description and comparison of diet compostion as well as provide insight into the foraging behavior and ecology of these whales in the North Pacific.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 01, 2017
- Source ID
- N000141712789
Entities
People
- Kristi West
Organizations
- Office of Naval Research
- United States Navy
- University of Hawaiʻi System