Quantification of bottom trawl fishing damage to ancient shipwreck sites

Bottom trawl fishing presents a severe yet largely unquantified threat to shipwreck sites. Here we present a quantification of damage to sites from the Aegean and Black seas through high resolution imaging of 45 shipwrecks discovered by the E/V Nautilus expeditions, 2009-2012. These shipwrecks are part of a modern submarine landscape that is heavily damaged by trawls, which also remove sediment and smooth out natural features of the seabed. We quantify the severity of this threat to archaeological sites through repeat visits to one ancient shipwreck and quantify the change to the seabed over a period of eleven months. The results illustrate the benefits of enforced areas of restricted bottom trawling (Marine Protected Areas) to the in situ preservation of shipwreck sites and to natural seabed features and benthic habitats. Careful marine spatial planning and coordinated management of fishing activity can mitigate this destructive activity. In addition, we counter the claim made by some commercial salvors who use trawl damage as an excuse to salvage artifacts from wrecks, further destroying historically significant sites for profit.