Active high frequency phased-array sonar for whale shipstrike avoidance: target strength measurements

Ship-strike is a major cause of death for large whales. For the northern right whale (Eubalaena glacialis) ship-strike is the leading cause of documented deaths. Forward-looking sonar provides one possible solution to this problem. A forward-looking sonar could provide information to the ship operator about the presence and location of large whales ahead of a vessel. This paper documents two sea tests in which target strength data was collected for humpbacks (Megaptera novaeangliae) and for northern right whales. Results are compared to previously published whale target strengths. Blubber thickness and frequency are used in a reflection coefficient model to explain the differences between the previous results and those presented in this paper.