State-space models to infer movements and behavior of fish detected in a spatial array of acoustic receivers

Abstract

We developed state-space models for inferring movements and behaviors of fish implanted with acoustic transmitters and detected within a spatial array of stationary acoustic receivers. In these models, fish movements and behavior switching are specified using a hidden Markov model of the changes in an individual’s latent activity center. The observed number of detections at each acoustic receiver is modeled as a function of the distance between the receiver and a fish’s activity center. To illustrate these models, we analyzed the detections of individual Gulf sturgeon (Acipenser oxyrinchus desotoi) that moved within a spatial array of acoustic receivers placed in the Suwannee River, Florida. Our models of these detections provided estimates of the locations of individual sturgeon and the periods when individuals switched between spawning and resting behaviors. We anticipate that these models will be used to analyze acoustic surveys of other species and help design new surveys.