Wreck Impacts & Deep-Sea Fishing
Friday, 02 April 2010 12:45 | Author: Dr Sean Kingsley | 
Wreck Impacts & Deep-Sea Fishing
Between 2005 and 2008 Odyssey Marine Exploration conducted the world's most extensive archaeological survey of the English Channel and Western Approaches. The project has revealed that much of this area’s maritime cultural heritage is in danger of being lost forever – not just from the hand of nature, but from extensive damage caused by trawlers and scallop dredges used by the international fishing industry.
Wreck Watch Int. has analysed Remotely-Operated Vehicle digital photographs of shipwrecks in depths up to 190 metres, side-scan imagery and 838,000 satellite sightings of fishing vessel movements across an area of 4,725 square nautical miles. 115 of the 267 total wrecks discovered by Odyssey (43%) display evidence of damage and impacts from scallop dredges and beam trawlers.
Fishing nets snagged on the wreck of a German U-boat in the '
Atlas' shipwreck survey zone. © Odyssey Marine Exploration.
Fishing net snagged on a 20th century steel wreck in the 'Atlas'
shipwreck survey zone. © Odyssey Marine Exploration.
These wrecks include unique snapshots of British and European maritime history:
- The wreck of the first-rate Royal Navy warship HMS Victory lost in October 1744 with Admiral Sir John Balchin, the greatest commander of his age, 1,100 sailors and 100 bronze cannon. Contemporaries considered Victory to be the greatest warship in the world, and her collection of bronze guns is the largest in existence. Her 4-ton, 42-pounders were the biggest cannon used in naval warfare during the age of sail and the only examples to survive history’s smelting pot. Her pottery and small finds will be a key study collection for appraising the cultural development of Georgian society on the verge of the Industrial Revolution.
- A 30-metre long merchant vessel lost around the middle of the 17th century with a cargo of elephant tusks, iron cannon laid across the keel and copper manilla bracelet money. The oldest carpenter’s rule ever found on a shipwreck, featuring a logarithmic scale for measuring the volume of timber, was discovered at the site.
- The wreck of the 22-gun, 460-ton Marquise de Tourny, launched as a French privateer from Bordeaux in 1744 and lost in the late 1740s or early 1750s. This is the only wreck of a privateer of this period trading with the Americas found in European waters.
- Seven World War I and II submarines.
The wrecks of HMS Victory and La Marquise de Tourny lie within a particularly heavily fished section of the survey region. Trawlers – dubbed bulldozers of the deep by marine ecologists – and scallop dredges have heavily ground down both sites. Wreck Watch concludes that HMS Victory, the only first-rate Royal Navy warship ever investigated scientifically, is at high risk, with rich archaeological artefacts, delicate hull timbers and human bones vulnerable to destruction.
The 17th-century merchant vessel has been heavily impacted by scallop dredges and remains at high risk. Its hull is almost completely destroyed, and only a very small percentage of its original cargo survives. Much of the pottery once aboard the ship has already been shattered and washed away by currents.
Future research is likely to demonstrate that the results of the English Channel and Western Approaches survey are far from unique and in deep seas is actually the rule rather than the exception. The Woods Hole Oceanographic Institution (WHOI) has detected at least two trawl nets and one gill net wrapped around the windlass of the wreck of the schooner Paul Palmer, lost off Maine in 1913.
In the Mediterranean Sea, Brendan Foley of WHOI has recalled how “we optically surveyed the sea floor off the island of Malta, for centuries a center of maritime commerce. At depths of 500+ meters, we expected to encounter marine life and hoped to discover ancient shipwrecks. Instead, we found only furrows in the sediments, indicating intensive trawling… occasionally we have seen evidence of dragging at depths approaching 1000 meters. It is unlikely that many ancient archaeologically significant sites will survive in areas subjected to trawl fishing.”
Dr Robert Ballard has also observed trawl marks in deep waters in depths of 1,000 metres off Malta, as well as off the Gulf of Naples, Egypt and in the Black Sea. Odyssey Marine Exploration has recorded a heavily trawler-impacted mid-19th century merchant vessel 370 metres beneath the Atlantic Ocean off Jacksonville, carrying a cargo of largely British blue shell-edged earthenware.
Each year, global trawling by the fishing industry crosses an area of seabed as large as Brazil, the Congo and India combined as the upper 6-20 centimetres of the seabed is ‘ploughed’ to extract scallops and drive flatfish into nets weighing up to 8 tons. Shipwrecks are an integral component of the marine environment, rich biological oases for providing shelter, feeding and nesting habitats for fish. They are therefore targeted by fishing vessels, which are largely unaware of the rich archaeological deposits below.
Although the fishing industry plays a major role in society and economy, there is a need to find a healthy balance between trawling and heritage recording and preservation. Destruction is caused when fishing vessels cut furrows into shipwrecks, causing the loosening of archaeological deposits, the dragging of artefacts off sites, the exposure of wrecks to oxygen, the breaking up of the wooden structure and the subsequent washing away of objects by currents.
The destruction identified by this survey makes it clear that the policy of in situ preservation for shipwrecks, advised by UNESCO and many national heritage organisations, is problematic in the study area and may not work as a first managerial option. Vital historic sites are being heavily damaged without any sustainable heritage management.
Wreck Watch has identified ten of Odyssey’s key sites in the English Channel that warrant further study, mapping, excavation and selective artefact recovery. This process will also benefit fishermen by identifying wrecks of non-archaeological value that can be safely fished without threatening important archaeology. The loss of expensive fishing equipment would also be minimised.
Further reading:
S. Kingsley, 'Deep-Sea Fishing Impacts on the Shipwrecks of the English Channel & Western Approaches'. In G. Stemm & S. Kingsley (eds.), Oceans Odyssey. Deep-Sea Shipwrecks in the English Channel, Straits of Gibraltar & Atlantic Oceans (Oxbow, Oxford, 2010), 191-234.
S. Kingsley, 'Into the Abyss: Deep-Sea Shipwrecks & the Rise of the Robots', Marine Scientist 32 (2010), 18-20.
Last Updated (Thursday, 10 February 2011 18:31)