Scoping report: Comparative assessment of pelagic sampling platforms

Despite being the most voluminous of the planet’s biomes, the pelagic ocean is chronically underexplored and drastically data-deficient . Australia, for instance, boasts the third biggest ocean territory in the world (by surface area), yet knowledge of both benthic and pelagic biodiversity values and processes throughout this vast estate remains largely incomplete. Monitoring activities are fundamental to bridging these knowledge gaps by generating the data necessary to assess, understand and document trends in natural communities throughout the country’s Marine Commonwealth Area (MCA), in response to both environmental pressures and spatial management measures.

In an era of unprecedented concern about global marine defaunation, increasingly modest conservation budgets are placing a strong emphasis on strategic resource allocation. Faced with mounting pressures to build accountability, managers and policy advisors must now more than ever make investment decisions that are not only wise but also cost-effective. This can be challenging given the smorgasbord of modern survey tools currently available, most of which differ widely in costs, capabilities, mobilisation constraints, resolution or sensitivity, and are evolving very rapidly without always being critically evaluated or compared. In recent years, novel technologies for sampling pelagic organisms and/or habitats such as drifting videography, environmental DNA, unmanned (airborne or waterborne) vehicles, or wireless sensor networks (among many others) have emerged and have been gaining traction. They can supplement (or sometimes replace) more traditional and longer-established pelagic sampling approaches like midwater trawling, aerial and vessel-based visual transects, passive and active acoustics, electronic telemetry, or remote sensing, yet protocols for choosing optimal combinations of methods for a given region, taxonomic/indicator group, or environment remain generally unavailable. Additionally, the few published studies that weigh up the merits and caveats of multiple sampling gears typically do not report explicit cost estimates, thereby undermining their potential to match research and management needs.

This scoping report provides the basic framework for a subsequent comparative synthesis report aimed at critically appraising a range of pelagic sampling platforms, particularly with respect to their suitability for supporting the long-term monitoring of the national Commonwealth Marine Reserve (CMR) network within the Australian marine estate. It is an output from the National Environmental Science Programme (NESP) expanded Project D2 (‘Standard Operating Procedures for survey design, condition assessment and trend detection’), and is complemented by a similar report focused on benthic sampling techniques.