Test of unmanned surface vehicles to conduct remote focal follow studies of a marine predator

Abstract

We tested the feasibility of using Saildrone unmanned wind- and solar-powered surface vehicles to conduct remote focal follow studies of northern fur seals Callorhinus ursinus. Using Argos satellite and transmitted GPS locations, the Saildrones followed a fur seal while recording oceanographic conditions and mapping prey abundance and depth distribution using a scientific echosounder. The Saildrones successfully followed 6 fur seals over 2.4 ± 0.2 d (mean ± SE) and 149.7 ± 16.3 km of the foraging path. Median separation distance between the Saildrone and fur seal path was 0.65 ± 0.1 km and average time separation was 9.9 ± 1.4 h, with minimum time separations ranging from 1.9-4.9 h. Time and distance separation were a function of both animal behavior and study design. Our results show that Saildrones can approach satellite tracked marine predators from long distances and follow them over extended periods while collecting oceanographic and prey data. These successful focal follows demonstrate that unmanned surface vehicles are a valuable tool for collecting data on fine-scale relationships between marine predators, their prey, and the environment.

Key questions in marine mammal bioenergetics

“…They also provide information on the physical and biological environment that can characterise the prey landscape ( Arranz et al, 2011 ; Goulet et al, 2019 ; McMahon et al, 2019 , 2021 ). Unmanned systems are currently being applied to marine mammal bioenergetics, particularly the use of aerial systems to estimate body condition and growth ( Fearnbach et al, 2018 ; Lemos et al, 2020 ; Aoki et al, 2021 ; Currie et al, 2021 ; Shero et al, 2021 ; Stewart et al, 2021a ; Christiansen et al, 2022 ), and surface and underwater systems to survey prey communities ( Kuhn et al, 2019 ; Benoit-Bird et al, 2020 ). Environmental DNA (eDNA) is a promising emerging tool for addressing questions related to prey landscapes, as it appears able to characterise the distribution and diversity of prey communities ( Visser et al, 2021 ) as well as prey biomass ( Rourke et al, 2022 ).…”

Saildrones and Snotbots in the Blue Anthropocene: Sensing technologies, multispecies intimacies, and scientific storying

“…“Fish are presumably more likely to react to large ships than small, quiet USVs,” or unpersonned surface vehicles, writes members of the NOAA team (De Robertis et al., 2019: 2). The Saildrone is also substantially less expensive to sail than the Oscar Dyson , more responsive in terms of movement and rapid mission modifications, and can be deployed for longer expeditions (Kuhn et al., 2020: 5). As a sensor platform, sailing athwart the elements of ocean, sunlight, and gusts, the Saildrone’s contribution is intimate yet incremental; it augments rather than revolutionizes possible proximities.…”

A Road Map to Success of International Field Campaigns in Atmospheric and Oceanic Sciences

“…In addition to manufacturing instruments and other equipment, private companies have recently established partnerships with government and academic institutes to support and operate field campaigns (Meinig et al 2019). Such private-public partnership has already led to scientific achievement (Mordy et al, 2017;Zhang et al 2019;Kuhn et al 2020;Sutton et al 2021;Zhang et al 2022) that otherwise would be impossible or very difficult to make based on the conventional model of field campaigns sponsored by the government alone.…”