Developing UAV Monitoring of South Georgia and the South Sandwich Islands’ Iconic Land-Based Marine Predators

John Dickens,Philip N Trathan,Gemma V Clucas,Philip R Hollyman,Eugene J Murphy,Martin A Collins,Tom Hart,Sally Poncet

doi:10.3389/fmars.2021.654215

Abstract

Many remote islands present barriers to effective wildlife monitoring in terms of challenging terrain and frequency of visits. The sub-Antarctic islands of South Georgia and the South Sandwich Islands are home to globally significant populations of seabirds and marine mammals. South Georgia hosts the largest breeding populations of Antarctic fur seals, southern elephant seals and king penguins as well as significant populations of wandering, black-browed and grey-headed albatross. The island also holds important populations of macaroni and gentoo penguins. The South Sandwich Islands host the world’s largest colony of chinstrap penguins in addition to major populations of Adélie and macaroni penguins. A marine protected area was created around these islands in 2012 but monitoring populations of marine predators remains a challenge, particularly as these species breed over large areas in remote and often inaccessible locations. During the 2019/20 austral summer, we trialled the use of an unoccupied aerial vehicle (UAV; drone) to monitor populations of seals, penguins and albatross and here we report our initial findings, including considerations about the advantages and limitations of the methodology. Three extensive southern elephant seal breeding sites were surveyed with complete counts made around the peak pupping date, two of these sites were last surveyed 24 years ago. A total of nine islands, historically recorded as breeding sites for wandering albatross, were surveyed with 144 fledglings and 48 adults identified from the aerial imagery. The UAV was effective at surveying populations of penguins that nest on flat, open terrain, such as Adélie and chinstrap penguin colonies at the South Sandwich Islands, and an extensive king penguin colony on South Georgia, but proved ineffective for monitoring macaroni penguins nesting in tussock habitat on South Georgia as individuals were obscured or hidden by vegetation. Overall, we show that UAV surveys can allow regular and accurate monitoring of these important wildlife populations.

Highlights

South Georgia and the South Sandwich Islands (SGSSI) lie in the Atlantic sector of the Southern Ocean between the latitudes of 53S and 60S, and longitudes of 26W and 36W (Figure 1)
Images captured from heights of between 40 and 75 m above ground level (AGL) provided adequate spatial resolution to clearly identify individual animals with only a single case of disturbance recorded to wildlife within the study areas
The case of disturbance involved a group of approximately 10 kelp gulls (Larus dominicanus) briefly mobbing the unoccupied aerial vehicle (UAV), the birds did not come into contact with the UAV and no injuries were recorded

Summary

Introduction

South Georgia and the South Sandwich Islands (SGSSI) lie in the Atlantic sector of the Southern Ocean between the latitudes of 53S and 60S, and longitudes of 26W and 36W (Figure 1) This remote archipelago is home to globally important populations of land-based marine predators, some of which are recovering from historic exploitation, whilst others are in decline attributed to human activities. The South Sandwich Islands have the largest population of chinstrap penguins in the world hosting almost 40% of the global population, alongside large populations of Adélie and macaroni penguins (Hart and Convey, 2018; Strycker et al, 2020) Monitoring these populations is important in the context of climate change, fisheries management and in an ecosystem that is recovering from historic overexploitation. The MPA includes both spatial and temporal restrictions on fishing activity designed to minimise impacts on the ecosystem, marine mammals and seabirds

Methods

Results

Conclusion