Aquatic high-throughput tracking: comparison among technologies, post-processing methods and species´behaviour

Abstract

[eng] Acoustic telemetry provides an important tool to study the spatial ecology and behaviour of organisms in marine and freshwater systems. Due to the large amount of data provided by the different available telemetry systems (based on PPM or BPSK coding systems), applying post-processing methods is required when working with certain behavioural characteristics of the species (speed, turning angles, and use of space). This study presents the usefulness of different post-processing methods when analysing trajectories and their different components. We collected data from 122 individuals belonging to 18 different fish species provided by 5 European research institutions, reaching a total of 41.873.445 positions. Two different post-processing techniques were applied to the data; a polynomial smoothing filter and the Continuous Time Correlated Random Walk (CTCRW) movement model, to determine the feasibility of their use and whether or not may be used in future comparative studies. Our results showed that the high-resolution BPSK coding systems provides way more information on a specific temporal range compared with PPM coding systems, so each system should be used according to the purpose of the study. In addition, when working with speeds and turning angles, the use of post-processing methods, specifically the CTCRW model, provided us with more realistic and homogeneous data. By contrast, data post-processing had a less evident effect when analysing the space use estimations. By applying a data post-processing method, we were able to reduce the effect of the different telemetry systems to allow a comparative study on the movement patterns of the studied species. Therefore, our work highlights the importance of stablishing a data post-processing workflow to generate and analyse large collaborative acoustic telemetry datasets.