Trawl Exposure and Protection of Seabed Fauna at Large Spatial Scales

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  • Tessa Mazor
    CSIRO Oceans and Atmosphere, Brisbane
  • C. Roland Pitcher
    CSIRO Oceans and Atmosphere, Brisbane
  • Nick Ellis
    CSIRO Oceans and Atmosphere, Brisbane
  • Wayne Rochester
    CSIRO Oceans and Atmosphere, Brisbane
  • Simon Jennings
    4Centre for the Environment, Fisheries and Aquaculture Science, LowestoftUniversity of East Anglia
  • Jan Hiddink
  • Robert McConnaughey
    NOAA, Alaska Fisheries Science Center, Seattle
  • Michel Kaiser
  • Ana Parma
    Centro Nacional Patagónico, Puerto Madryn Chubut
  • Petri Suuronen
    FAO Fisheries and Aquaculture Department, Rome, Italy
  • Mervi Kangas
    Department of Fisheries, Perth
  • R. Hilborn
    University of Washington
Aim: Trawling leads to widespread direct human disturbance on the seabed. Knowledge of the extent and consequences of this disturbance is limited because large-scale distributions of seabed fauna are not well-known. We map faunal distributions in the Australian Exclusive Economic Zone (EEZ) and quantify the proportion of their abundance that occurs in areas 1) that are directly trawled, and 2) where legislation permanently prohibits trawling — defined as percentage exposure or protection respectively. Our approach includes developing a method that integrates data from disparate seabed surveys to spatially expand predicted benthos distributions. Location: Australia Methods: We collate data from 18 seabed surveys to map the distribution of seabed invertebrates (benthos) in nine regions. Our approach combines data from multiple surveys, groups taxa within taxonomic classes, and uses Random Forests to predict spatial abundance distributions of benthos groups from environmental variables. Exposure and protection of benthos groups were quantified by mapping their predicted abundance distributions against the footprint of trawling and legislated boundaries of marine reserves and fishery closures. Results: Trawling is currently prohibited from more area of Australia’s EEZ (58%) than is trawled (<5%). Across 134 benthos-groups, 96% had greater protection of abundance than exposure. The mean trawl exposure of benthos-group abundance was 7%, compared to mean protection of 38%; whereas the mean abundance neither trawled nor protected was 55%. Fishery closures covered 19% less study area than marine reserves, but overlapped with a higher proportion (5% more) of benthos-group abundance. Main Conclusions: This study provides the most extensive quantitative assessment of the current exposure of Australia’s benthos to trawling. Further, it highlights the contribution of fishery closures to marine conservation. These results help identify regions and taxa that are at greatest potential risk from trawling, and supports managers to achieve balance between conservation and sustainable industries in marine ecosystems.
Original languageEnglish
Pages (from-to)1280-1291
JournalDiversity and Distributions
Volume23
Issue number11
Early online date6 Sep 2017
DOIs
Publication statusPublished - Nov 2017

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