Using Unmanned Aerial Vehicles (uavs) to Measure Jellyfish Aggregations

Unmanned aerial vehicles (UAVs, or drones) are becoming increasingly common as tools to perform high-resolution but broad-scale measurements of habitats and populations simultaneously. In this study, we tested the application of UAVs to aerial surveys of jellyfish and their suitability for measuring and monitoring aggregations. We paired net hauls with linear image transects taken by a UAV to measure 5 Aurelia spp. aggregations over the course of 1 d in Pruth Bay, British Columbia, Canada. Georeferenced image transects were processed to determine aggregation areal extent and estimate percent cover of jellyfish. The percent cover estimates and net haul density data were highly comparable for all aggregations. Using combined UAV-derived surface area estimates and net haul biomass estimates, we calculated that jellyfish aggregation size ranged from 65 to 117 t wet weight biomass. We discuss the potential for additional UAV-based measurements including jellyfish abundance and individual size. The study demonstrates the potential of UAVs as powerful tools for characterizing and researching jellyfish aggregations in situ.