PNW cetacean muscle biochemistry (Muscle Myoglobin Content and Acid Buffering Capacity of Cetaceans from the Pacific Northwest to Assess Dive Capacity and the Development of Diving Capabilities)

This project assesses the development of two important skeletal muscle adaptations for diving (enhanced myoglobin content and acid buffering capacities) in a range of cetaceans from the Pacific Northwest in order to understand constraints on diving capacities (primarily dive duration) with development. Myoglobin is an important oxygen store for supporting aerobic diving, while enhanced buffering capacity could support anaerobic metabolism during apnea. Yet little is known about the post-natal development of muscle biochemistry in cetaceans.

To assess the development of these important adaptations in cetaceans, muscle myoglobin content and buffering capacity due to non-bicarbonate buffers were measured in the longissimus dorsi of harbor porpoise (Phocoena phocoena), killer whale (Orcinus orca), and Dall's porpoise (Phocoenoides dalli).

Dawn Noren is the principal investigator from NWFSC. Projects on individual species within this larger project include different collaborators. For the project on harbor porpoise (nearly complete), Shawn Noren (UCSC), Robin Dunkin, (UCSC), and Joe Gaydos (SeaDoc Society) are external collaborators. Dawn Noren is responsible for project oversight, Shawn Noren trained Northwest Fisheries Science Center (NWFSC) staff on laboratory procedures for sample analysis, and Robin Dunkin and Joe Gaydos collected samples. The specific work includes experimental design, data collection, data analysis, and writing for submission to peer-reviewed journals. These projects are ongoing until sufficient samples are collected for sound statistical analysis. This research addresses some data gaps associated with dive capacities and potential limitations in habitat use by local cetaceans. Muscle adaptation to diving