Trawling damage to Northeast Atlantic ancient coral reefs

Jason Hall–Spencer, Valerie Allain, Jan Helge Fosså

Abstract

This contribution documents widespread trawling damage to cold–water coral reefs at 840–1300 m depth along the West Ireland continental shelf break and at 200 m off West Norway. These reefs are spectacular but poorly known. By–catches from commercial trawls for deep–water fish off West Ireland included large pieces (up to 1 m2) of coral that had been broken from reefs and a diverse array of coral-associated benthos. Five azooxanthellate scleractinarian corals were identified in these by-catches, viz. Desmophyllum cristagalli, Enallopsammia rostrata, Lophelia pertusa, Madrepora oculata and Solenosmilia variabilis. Dating of carbonate skeletons using 14C accelerator mass spectrometry showed that the trawled coral matrix was at least 4550 years old. Surveys by remotely operated vehicles in Norway showed extensive fishing damage to L. pertusa reefs. The urgent need for deep–water coral conservation measures is discussed in a Northeast Atlantic context.