Reply to: Caution over the use of ecological big data for conservation

Our global analysis (*1) estimated the overlap and fishing exposure risk (FEI) using the space use of satellite-tracked sharks and longline fishing effort monitored by the automatic identification system (AIS). In the accompanying Comment, Harry and Braccini (*2) draw attention to two localized shark–longline vessel overlap hotspots in Australian waters, stating that 47 fishing vessels were misclassified as longline and purse seine vessels in the Global Fishing Watch (GFW)(*3) 2012–2016 AIS fishing effort data product that we used. This, they propose (*2), results in misidentifications that highlight fishing exposure hotspots that are subject to an unexpected level of sensitivity in the analysis and they suggest that misidentifications could broadly affect the calculations of fishing exposure and the central conclusions of our study (*1). We acknowledged in our previously published paper (*1) that gear reclassifications were likely to occur for a small percentage of the more than 70,000 vessels studied, however, here we demonstrate that even using much larger numbers of vessel reclassifications than those proposed by Harry and Braccini (*2), the central results and conclusions of our paper1 do not change.

1. Queiroz, N. et al. Global spatial risk assessment of sharks under the footprint of fisheries. Nature 572, 461–466 (2019).
2. Harry, A., Braccini, M. Caution over the use of ecological big data for conservation. Nature
https://doi.org/10.1038/s41586-021-03463-w (2021).
3. Kroodsma, D. A. et al. Tracking the global footprint of fisheries. Science 359, 904–908
(2018).