Tethys is a system for organizing and retaining information from passive acoustic monitoring efforts. We enable the retention and querying of information related to deployments of acoustic data loggers and their characteristics (e.g. sample rate, calibration functions) and information related to the detection and location of sounds within the recording. While our focus is on marine mammals, the work is applicable to a wide variety of passive acousitc monitoring problems.


While details on the system are available in the documentation as well as some of our publications, a twenty-five minute overview video of Tethys can provide potential users with knowledge about the types of things that Tethys can do.

Web Client

Starting with the Tethys 2.5 release, we have introduced a graphical interface to Tethys that runs in a web browser. It supports both novice and expert query modes. While we still recommend programmatic interfaces for large-scale analysis, the web client enables novice users to perform data exploration as well as ways to export the data into programs such as R and MATLAB for analysis.

Web Client Trailer

A quick “silent move trailer” overview of the web client capabilities. See the following video for a slower tutorial that is designed for teaching.

Web Client Basic Interface Tutorial

This 9 min tutorial shows the basics of how to work with the web client.

Web Client Advanced Interface Tutorial

Learn how to get the most out of the Tethys web client by expanding simple queries with advanced selection or return criteria (11 min).

Data Import

Data can be imported from either a web-based interface or from a Java class. Both are described in the Data Import Manual.

Some programs generate Tethys-compliant data (e.g., we are working on this for PAMGuard and expect to have it completed between Q4 2024 and Q1 2025. If you are a tool developer and are interested in generating Tethys-compliant data, the Nilus XML java library (Nilus XML Generator documentation) will let you do so.

When your data are not already in a Tethys-compliant format, you need to generate a source map that informs Tethys how to map your fields to those used by Tethys. The data source map can then be used to add other data with same structure to Tethys. Traditionally, we did this by creating a text file with the mappings. As of Tethys 3, a web-based service lets you do this graphically:

Introduction to the import map generation tool (25 min).

Programmatic interfaces

Tutorials for using the Tethys Matlab client are available in the Matlab Cookbook. In addition, a please see a set of overview slides from a tutorial on Tethys given at the Biowaves Passive Acoustics Technician Training Course (2014-02-13).