Develop a general framework for estimating cetacean density from data collected by slow moving autonomous ocean vehicles, investigating key aspects of survey design, data collection and data analysis
Abstract
In this project, we focus on cetacean density estimation using autonomous underwater vehicles such as ocean gliders. These instruments are of particular interest to the Navy and have the potential to play a key role in future marine mammal monitoring efforts. The major advantage of gliders and other autonomous vehicles over prior methods is their ability to provide both spatial and temporal coverage of an area during a survey. However the methods for estimating cetacean density from autonomous vehicles do not currently exist. We propose to develop a general framework for estimating cetacean density from data collected by autonomous ocean vehicles. We will investigate key aspects of survey design, data collection and data analysis, leveraging already-funded projects that are collecting data from profiling gliders to form case studies. Data from three different Navy-relevant locations (Gulf of Alaska, Mariana Island Range Complex, Hawaii Range Complex) will be utilized. We will select three species for analysis: a baleen whale, a deep diving odontocete (sperm or beaked whale) and a delphinid – final species selection depends on which are found to be most suitable after initial acoustic processing, with our preference being to select species whose acoustic behavior has been most extensively studied. For each species and site, we will demonstrate how the general framework can be applied to produce estimates of animal density (or call density if call rates are needed for the method but not available). One key component of the framework is to estimate the probability of detecting vocalizations on the autonomous vehicles as a function of range. To do this, we will utilize the tracking abilities of the hydrophones at the Southern California Offshore Range (SCORE) Navy range during an additional glider deployment. Although not our primary focus, we also propose to investigate the detection probability of drifting profiling sensors (or floats), which will also be deployed at SCORE. However, relying on the instrumented ranges necessarily restricts the inferences about density that can be made in other locations; we therefore propose, as a fully costed option, to undertake an additional experiment to estimate glider detection probability in a non-instrumented area, using an ad-hoc array of non-profiling drifting sensors.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2016
- Source ID
- N000141512142
Entities
People
- Len Thomas
Organizations
- Office of Naval Research
- United States Navy
- University of St Andrews