Image Credit: Alli Cramer

Data Representation of Acoustic Telemetry

Understanding of animal populations relies on our ability to measure and represent animal movements in a meaningful way. To represent movement we use a variety of tools such as mark and recapture, direct observation, or tracking to quantify movements through both space and time. A complete description of animal movements would require a specific representation of the organism: at all locations, in all times, whether it was present or absent.

In the marine environment complete descriptions of organism locations are difficult to achieve. Our representation of marine animal movement is limited, restricted to technology’s ability to access the organisms themselves. Surface organisms, such as whales, can be tracked visually, but deeper organisms are known primarily from fishing surveys, which represent small moments in time with a great deal of effort. To obtain a more complete description of movement through time, many researchers rely on passive acoustic telemetry.

Scientific inference based on passive acoustic telemetry data is constrained by the reliance on an assumption that a high number of detections imply a high preference for a location. In this project we examine results from passive acoustic telemetry to determine if the “high detections – high preference” assumption is valid. We explore patterns within the literature and investigate how to distinguish real habitat use from non-preferential random movement. We also use simulations to develop a null model for passive acoustic telemetry data.