Seabed photography, environmental assessment and evidence for deep-water trawling on the continental margin west of the hebrides

• Published in: Hydrobiologia Vol. 441; no. 1; pp. 173 - 183
• Main Authors: ROBERTS, J. M, HARVEY, S. M, LAMONT, P. A, GAGE, J. D, HUMPHERY, J. D
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer 01.12.2000; Springer Nature B.V
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Applied ecology; Atlantic Ocean; Biological and medical sciences; Commercial fishing; Continental margins; Continental slope; Deep sea; Deep water; Environmental assessment; Environmental impact; Environmental surveys; Exploitation and management of natural biological resources (hunting, fishing and exploited populations survey, etc.); Fundamental and applied biological sciences. Psychology; Marine; Marine ecology; Ocean bottom; Ocean floor; Photography; Physical oceanography; Sea water ecosystems; Synecology; Trawling; Xenophyophoria; Scotland; United Kingdom; Great Britain; Hebrides; Europe; Atlantic, Rockall Trough, Hebrides Slope; ANE, Atlantic, Rockall Trough, Hebrides Slope; Community structure; Protozoa; Hydrocarbon; Interspecific comparison; Environmental factor; Zoobenthos; Deep water; Sediments; Spatial variation; Trawl; Ocean floors; Depth; Fishing gear; Marine environment; Rhizopoda; Photographic observation; Environment impact; Continental margin; Population density; Anthropogenic factor
• ISSN: 0018-8158; 1573-5117
• DOI: 10.1023/A:1017550612340

A photographic survey in 1998 of the seabed along depth transects from 700 to 1300 m across the N.E. Atlantic continental slope off north-west Scotland shows clear depth-related change in sediment type and megabenthic community in an environment where biological communities and species distributions are poorly known. Small-scale features, such as trawl marks and dense fields of xenophyophores, were resolved that may have remained unknown using conventional sampling or lower resolution imaging techniques. Because xenophyophores accumulate barite, a constituent of some drilling muds, their local-scale occurrences will be important to baseline environmental survey prior to hydrocarbon prospecting in deep water. Our results indicate that deep-sea trawling is physically impacting the seabed to depths of more than 1000 m. The persistence and biological consequence of this impact is unknown, but may depend on sediment type and natural physical disturbance. Comparison with similar seabed photographs taken from a neighbouring area in 1988, which show a high incidence of trawl marks, indicates that such impacts have been taking place over at least 10 years.[PUBLICATION ABSTRACT]