Continental-scale animal tracking reveals functional movement classes across marine taxa

Abstract

Acoustic telemetry is a principle tool for observing aquatic animals, but coverage over large spatial scales remains a challenge. To resolve this, Australia has implemented the Integrated Marine Observing System’s Animal Tracking Facility which comprises a continental-scale hydrophone array and coordinated data repository. This national acoustic network connects localized projects, enabling simultaneous monitoring of multiple species over scales ranging from 100 s of meters to 1000 s of kilometers. There is a need to evaluate the utility of this national network in monitoring animal movement ecology, and to identify the spatial scales that the network effectively operates over. Cluster analyses assessed movements and residency of 2181 individuals from 92 species, and identified four functional movement classes apparent only through aggregating data across the entire national network. These functional movement classes described movement metrics of individuals rather than species, and highlighted the plasticity of movement patterns across and within populations and species. Network analyses assessed the utility and redundancy of each component of the national network, revealing multiple spatial scales of connectivity influenced by the geographic positioning of acoustic receivers. We demonstrate the significance of this nationally coordinated network of receivers to better reveal intra-specific differences in movement profiles and discuss implications for effective management.

The importance of sample size in marine megafauna tagging studies

“…Another subset of 1,648 tracks representing 14 species was also used to show annual patterns of movements through the high seas and across geopolitical boundaries in the Pacific Ocean (Harrison et al 2018). Most recently, the coastal movements of 2,181 individuals from 92 species including fish, sharks, turtles, and marine mammals were used to identify four distinct functional movement classes in the coastal waters of Australia, with these classes emerging only through aggregating data across the entire data set (Brodie et al 2018). Finally, the Marine Megafauna Movement Analytical Program (MMMAP) used >2,500 individual tracks across 50 species of marine vertebrates including whales, sharks, seals, seabirds, polar bears, sirenians, and turtles, to show that, unlike terrestrial animals, movement patterns in marine animals are strongly conserved across species regardless of evolutionary history, with movements being more complex in the coastal than in the open ocean (Sequeira et al 2018).…”

“…Recent advances made in the field of telemetry and bio-logging have led to an exponential increase in satellite telemetry studies (Thums et al 2018a), with very large sample size (≫1,000 tracks) recently starting to appear in the literature (Block et al 2011, Brodie et al 2018, Sequeira et al 2018. In spite of that, a sample size of one with sufficient track length can still lead to scientific insights.…”

Australia’s Long-Term Plankton Observations: The Integrated Marine Observing System National Reference Station Network

“…IMOS is a broad program covering physical, chemical and biological observing systems, with sufficient flexibility that as government priorities change, there are many parts of the observing system that can deliver relevant responses (Lara-Lopez et al, 2016). Diverse data streams produced by IMOS have been integral in responding to many pressing government and industry priorities, including: better managing eutrophication on the Great Barrier Reef to help maintain its World Heritage status (Brodie et al, 2017); mitigating risks associated with carbon sequestration under the seafloor 11 ; providing integrated baselines and assessments to support the oil and gas industry (Kloser and van Ruth, 2017); identifying the best search locations to find the Malaysian Airlines flight MH370 (Maclaughlin, 2017); providing advice for locating ocean turbines to generate the most renewable energy and describing the movements of recreational and commercial fish species to inform fisheries management (Brodie et al, 2018). The plankton observing system is only a small part of the whole system and would be unlikely to attract sustained funding in isolation.…”

Sharks, rays and marine protected areas: A critical evaluation of current perspectives

“…This information can be incorporated into MPA design to ensure that the placement and scale of spatial protections are relevant to the species targeted for protection. While an increasing number of studies use electronic tagging for monitoring shark movement (e.g., Brodie et al., ; Speed et al., ), the study of movement remains challenging. As mentioned by participants in our study, the lack of available data and the relatively poor understanding of many species remain major challenges to the effective design of MPAs for sharks and rays.…”