Identifying high risk seafloor areas to bottom trawling in Aotearoa New Zealand to support marine spatial management

Abstract

Seafloor species play important ecological roles within marine ecosystems, yet many are vulnerable to the impacts of bottom fishing. Despite the known vulnerability of many seafloor taxa, destructive bottom fishing remains prevalent in many parts of the world given demand for wild-caught seafood. Species Distribution Models (SDMs) are increasingly used to estimate the distribution of vulnerable taxa and estimate possible risk of interactions with fishing gears, but most approaches have used a limited number of taxa. In this study, spatial predictions of species distributions for 207 seafloor invertebrate taxa in New Zealand waters were combined with a comprehensive database of functional traits related to bottom trawling to predict areas of high vulnerability. In addition, this study combined functional redundancy and vulnerability scores to identify ‘high combined risk’ areas that covered 182,087 km 2 (9.5%) of the study area. The interactions of these areas with current Marine Management Areas (MMAs) and highly fished zones revealed that current MMAs protect 50% of the ‘high combined risk’ areas (91,000 km 2 ), and less than 1% is within fished areas. This leaves a predicted 90,937 km 2 (49%) outside current protection, some are close to current MMAs and are potentially of high priority for future marine spatial management. Identifying areas most vulnerable to bottom trawling showcases interactions within previously fished areas (areas that have been fished in the past and could potentially be fished again), as well as highlighting areas for management action. Using different sets of functional traits as a combined approach could also be used to assess other anthropogenic impacts, improving ecosystem-based spatial management by ensuring protection of functions at globally significant scales.

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