3D ocean assessments reveal that fisheries reach deep but marine protection remains shallow

Abstract

The wave of new global conservation targets, the conclusion of the High Seas Treaty negotiations, and the expansion of extractive use into the deep sea call for a paradigm shift in ocean conservation. The current reductionist 2D representation of the ocean to set targets and measure impacts will fail at achieving effective biodiversity conservation. Here, we develop a framework that overlays depth realms onto marine ecoregions to conduct the first three-dimensional spatial analysis of global marine conservation achievements and fisheries footprint. Our novel approach reveals conservation gaps of mesophotic, rariphotic, and abyssal depths and an underrepresentation of high protection levels across all depths. In contrast, the 3D footprint of fisheries covers all depths, with benthic fishing occurring down to the lower bathyal and mesopelagic fishing peaking in areas overlying abyssal depths. Additionally, conservation efforts are biased towards areas where the lowest fishing pressures occur, compromising the effectiveness of the marine conservation network. These spatial mismatches emphasize the need to shift towards 3D thinking to achieve ocean sustainability.

Understanding organism-habitat relationships and critically evaluating reference areas is key to marine protected area assessment

“…Mesophotic (30-100m) reefs represent one habitat that has been historically difficult to monitor and a growing body of research acknowledges our relatively incomplete understanding of these communities globally (Kahng et al 2017; James et al 2017; Cerrano et al 2019). Mesophotic reefs support a diverse suite of commercially valuable species and it is estimated that a significant portion of commercial groundfish harvest falls within this depth zone (Miller et al 2017; Jacquemont et al 2024). As a result, these fishes are left under-surveyed and relatively data poor, while simultaneously being highly targeted.…”