Diversity and abundance of fish grunts recorded off coastal Guam

To assess fish diversity and abundance around Guam Island, a set of two stereo hydrophones were deployed in ca. 5 m of water depth and recorded continuously over a 48-h time period. The soundscape of this nearshore environment was dominated by fish grunts, which are produced by drumming muscles attached to their swim bladder. Here, we provide an analysis of these grunt signals received on the double-channel hydrophone by matched filter time-series analysis. Each 10-min sequence of acoustic data was first analyzed to extract the most significant grunt via amplitude thresholding. Next, each significant grunt signature was used as a matched filter template against significant grunts and a matrix of cross matched filter outputs were used to extract unique grunt signatures present in the dataset. The set of unique grunt signatures indicates the level of biodiversity in measured acoustic signals. These were then used as templates to extract similar grunts in the dataset via second stage matched filtering that quantifies the abundance of signals in each grunt category. Results from the acoustic analysis will be combined with concurrent eDNA sampling analysis in the future.