Influence of seismic shooting on the lesser sand eel (Ammodytes marinus)

TitleInfluence of seismic shooting on the lesser sand eel (Ammodytes marinus)
Publication TypeJournal Article
Year of Publication2004
AuthorsHassel, Arne, Knutsen Tor, Dalen John, Skaar Kristian, Løkkeborg Svein, Misund Ole Arve, østensen øivind, Fonn Merete, and Haugland Eli Kyrkjebø
JournalICES Journal of Marine Science: Journal du Conseil
Volume61
Pagination1165-1173
EndNote Rec Number8561
Abstract

A field experiment on the effect of seismic shooting on the lesser sand eel (Ammodytes marinus) was conducted on the fishing grounds in the southeastern part of the North Sea in May 2002. Sand eel buried in the sand at night were trapped in steel frame cages (2.0 × 1.8 × 2.0m) deployed in positions with high abundance of fish located by a van Veen grab. In an experimental area, three sand eel cages were exposed to full-scale seismic shooting for about 2.5 d. Cameras in the cage and on a remotely operated vehicle (ROV) were used to monitor the activity of the enclosed fish. A control area about 35km southeast of the seismic shooting area was established with two sand eel cages. The distribution and abundance of the lesser sand eel during daytime in the experimental region were regularly monitored by acoustic surveying, but the present methodology could not demonstrate that seismic shooting caused any change in sand eel abundance. Repeated grab surveys were conducted using a van Veen grab for a predetermined set of localities almost every night during the experimental period, both prior to and after seismic shooting. The results indicate that the seismic shooting had a moderate effect on the behaviour of the lesser sand eel. We did not observe any immediate lethal effect, neither from the cage experiments nor from the grab samples. The total mortality in the cages of about 35% on average, both in the experimental group and the control group, was probably a result of injuries during deployment, due to handling and confinement. Analyses of landing data from the Norwegian sand eel trawlers show a temporary drop in the sand eel landings for a short period after the seismic experiment.