Description
Summary:This is the report of the first behavioral response study to be carried out on beaked and pilot whales in which these animals were exposed to carefully measured doses of underwater sound while their responses were being measured. The study is seen as the first step in a series of similar experiments that are designed to safely identify the behavioral mechanisms that may be involved in the causal chain of events leading from exposure to some types of man-made underwater sound to mass strandings of beaked whales and to test whether this risk extends to other cetaceans. The objectives of work undertaken in the past year were to: 1) Establish, test and refine new protocols for studying beaked whales using established sound playback experiment paradigms. -- Demonstrate feasibility and safety of study design; -- Obtain U.S. and Bahamian permits and engage with eNGOs concerning the pros and cons of these specific kinds of playbacks; -- Collect base-line (control) data to provide a basis for comparison with playback results. 2) Define responses of beaked whales, and other species of odontocete whales, to mid-frequency active (MFA) sonar and natural sounds such as those from killer whales. Address the questions: -- Does the response help narrow the range of hypotheses for the cause of MFA sonar-related strandings? -- Does the response to MFA sonar differ from the response to killer whale sounds to test whether whales respond to sonar as if it represented a predator? -- Can responses be used as a safe predictor of risk of injury/stranding from higher level exposures? -- Do other species also respond in a way that elevates risk of injury/stranding? 3) Measure exposure parameters for sounds that evoke a behavioral response: -- Use an acoustic recording tag as the primary method to measure received level at the animal. -- Measure ship noise on the AUTEC hydrophones, and input these measures to an acoustic propagation model to predict exposure at the animals.