Echopype: A Python library for interoperable and scalable processing of water column sonar data for biological information

High-frequency sonar systems deployed on a broad variety of ocean observing platforms are creating a deluge of water column sonar data at unprecedented speed from all corners of the ocean. Efficient and integrative analysis of these data, either across different sonar instruments or with other oceanographic datasets, holds the key to monitoring and understanding the response of marine organisms to the rapidly changing environments. In this paper we present echopype, an open-source Python software library designed to address this need. By standardizing water column sonar data from diverse instrument sources following a community convention and utilizing the widely embraced netCDF data model to encode sonar data as labeled, multi-dimensional arrays, echopype facilitates intuitive, user-friendly exploration and use of sonar data in an instrument-agnostic manner. Through leveraging existing open-source Python libraries optimized for distributed computing, echopype directly enables computational interoperability and scalability in both local and cloud computing environments. Echopype's modularized package structure further provides a conceptually unified implementation framework for expanding its support for additional instrument raw data formats and incorporating new data analysis and visualization functionalities. We envision the continued development of echopype as a catalyst for making information derived from water column sonar data an integrated component of regional and global ocean observation strategies.