Researcher Jason Hall-Spencer of the University of Glasgow had found pieces of coral at least 4,500 years old in the nets of trawlers operating off the coast of Ireland and Scotland. Pieces of coral up to 1 square metre (11 sq ft) were found in the nets of French trawling vessels that had been scraping the seabed 1 kilometre (0.6 mi) down. It is known that much coral was destroyed by these nets and the mounds themselves in some areas were found to be scraped and flattened.