Towards an acoustic‐based coupled observation and modelling system for monitoring and predicting ecosystem dynamics of the open ocean

Abstract

http://onlinelibrary.wiley.com/doi/10.1111/j.1467-2979.2012.00480.x/abstractInternational audienceAssessment of open-ocean ecosystems relies on understanding ecosystem dynamics, and development of end-to-end ecosystem models represents an approach that addresses these challenges. These models incorporate the population structure and dynamics of marine organisms at all trophic levels. Satellite remote sensing of ocean colour and direct at-sea measurements provide information on the lower trophic levels of the models, and fisheries studies provide information on top predator species. However, these models suffer from a lack of observations for the so-called mid-trophic levels, which are poorly sampled by conventional methods. This restricts further development, and we argue that acoustic observations from a range of platforms (e.g. buoys, moorings) can be linked to the ecosystem models to provide much-needed information on these trophic levels. To achieve this, the models need to be tailored to incorporate the available acoustic data, and the link from acoustic backscatter to biologically relevant variables (biomass, carbon, etc.) needs attention. Methods to progress this issue are proposed, including the development of observation models and focal areas for ground truthing. To ensure full use of the potential of acoustic techniques, we argue that a systematic and long-term strategy incorporating the following elements is required: development of metadata standards and automated data analysis, inclusion of acoustic sensors in large-scale observatory programmes, improvement of observation-model links, and efficient sampling strategies. Finally, these elements should be tied together in an observation-modelling framework, coordinated by international organizations, to improve our understanding and quantification of open-ocean ecosystem dynamics

High Latitude Epipelagic and Mesopelagic Scattering Layers—A Reference for Future Arctic Ecosystem Change

“…Such initiatives are strongly recommended (Rogers, 2015). The magnitude of DSL acoustic backscattering and the determination of its biological components both to the west of the Spitsbergen archipelago and northwards into the Arctic Ocean should be evaluated on a regular basis as an important additional method to properly assess ecosystem change, although methodological caveats and challenges still exist (Handegard et al, 2013;Davison et al, 2015).…”

Derived Ocean Features for Dynamic Ocean Management

“…Basin-scale prey field data sets are now generated from some models (e.g., Lehodey et al, 2010), but they can differ from field-based observations by orders of magnitude (Kloser et al, 2009). Until improved prey observations are available to refine models (Handegard et al, 2013), it is unlikely that prey field data will be as commonplace as physical descriptions of ocean conditions. It is partly due to availability that the primary products we describe are so widely used, but the derived products based on them should be equally useful until products such as prey fields, which better describe the linkages between physics and high trophic level pelagic species, are available.…”

An assessment of the use of ocean gliders to undertake acoustic measurements of zooplankton: the distribution and density of Antarctic krill (Euphausia superba) in the Weddell Sea.

“…Whereas, with two replicates in this study, it is not reasonable to infer the optimal coverage requirements as a general rule, it is clear that to get appropriate spatial resolution within a short period multiple platforms are required to provide a holistic picture. A combination of platforms with overlapping sampling strategies is most desirable (Handegard et al 2012). Notwithstanding the necessity of target identification and TS model parameterization, it is envisaged that a coordinated fleet of acoustic gliders might one day support biomass surveys undertaken by research vessels, extending temporal and spatial coverage by being able to exploit challenging environments such as during winter or during rough weather.…”