Global collision-risk hotspots of marine traffic and the world’s largest fish, the whale shark
We combine satellite-tracked movements of the whale shark, Rhincodon typus, and vessel activity to show that 92% of sharks’ horizontal space use and nearly 50% of vertical space use overlap with persistent large vessel (>300 gross tons) traffic. Collision-risk estimates correlated with reported whale shark mortality from ship strikes, indicating higher mortality in areas with greatest overlap. Depth-recording tags provided evidence for sinking, likely dead, whale sharks, suggesting substantial “cryptic” lethal ship strikes are possible, which could explain why whale shark population declines continue despite international protection and low fishing-induced mortality.
Reply to: Shark mortality cannot be assessed by fishery overlap alone
We confirm—using regression analysis of spatially matched data—that fishing-induced pelagic shark mortality (catch per unit effort (CPUE)) is greater where Fishing Exposure Index is higher
Reply to: Caution over use of ecological big-data for conservation
Here we demonstrate that even using much larger numbers of vessel reclassifications (misclassified vessels) the central results and conclusions of our paper do not change
Shortfin mako sharks speeding to the brink
The world’s fastest shark, the shortfin mako (Isurus oxyrinchus), is globally endangered but remains overfished in the North Atlantic and in high demand commercially for its meat and fins. Even with zero retention, reducing capture and post-release mortalities will be necessary. An annual mortality of 1100 tons, already greatly exceeded in 2019, gives only an 8% chance of rebuilding by 2070.
Climate-driven deoxygenation elevates fishing vulnerability for the ocean’s widest ranging shark
Here, analysis of satellite-tracked blue sharks and environmental modelling in the eastern tropical Atlantic oxygen minimum zone (OMZ) shows shark maximum dive depths decreased due to combined effects of decreasing dissolved oxygen (DO) at depth, high sea surface temperatures, and increased surface-layer net primary production. Fisheries controls to counteract deoxygenation effects on shark catches will be needed as oceans continue warming.
Global spatial risk assessment of sharks under the footprint of fisheries
Trade in mislabeled endangered sharks
Sims, D.W. & Frost, M.T. (2019) Trade in mislabeled endangered sharks.
Shortfin mako sharks threatened by inaction
Sims, D.W., Mucientes, G., Queiroz, N. (2018)
Ocean-wide tracking of pelagic sharks reveals ...
Queiroz, N., Humphries, N.E., Mucientes, G.R., Hammerschlag, N., Lima, F., Scales, K., Miller, P.I., Sousa, L.L., Seabra, R., Sims, D.W. (2016)