This paper presents results on the distribution, abundance, and size of Lophelia pertusa coral reefs in mid-Norway (62830 H^6 5830 H N) as compiled from own investigations, earlier scienti¢c reports, reports from ¢shery surveys and ¢shermen. Detailed bathymetrical mapping covering an area of $ 600 km 2 along the Halten gas-pipeline, and two nearby areas across the shelf revealed 70 Lophelia reefs. In general, the reefs occurred close to breaks and escarpments. High densities of up to nine reefs per km 2 were found in areas with a rugged seabed topography and with a slope 40.68. These seabed features have probably positive in£uence on the transport and concentration of food particles and thus control the local distribution of Lophelia. The area covered by individual reefs varied between 1230 m 2 and 37,310 m 2 with a mean of 5628 m 2 . The height of the reefs was positively correlated with the area. Reefs 510,000 m 2 had a circular outline, while larger reefs were elongate, aligned parallel to the depth contours. Along the pipeline the average density of Lophelia reefs was 0.09 km 72 which indicates that the total number of reefs is $ 6300, covering $ 35 km 2 within the whole study area.

No abstract

No abstract

. Infectious salmon anaemia (ISA) is a viral disease of farmed Atlantic salmon, Salmo salar L., in Norway. The enveloped virus particles (100nm) believed to be the causative agent of the disease have been observed budding from endothelial cells in heart blood vessels. However, it is not known if the virus propagates in endothelial cells in all tissues/organs, if other target cells exist or if material collected from different salmon farms with natural outbreaks of ISA contain the same virus particles. Salmon smolts from three hatcheries with no history of disease were taken into the laboratory and experimentally challenged with ISA collected from Atlantic salmon during natural outbreaks of the disease in three different fish farms outside Bergen. Norway. Tissues for TEM studies were Collected from: (1) organs that showed clinical signs of ISA (i.e. used in the diagnosis of the disease); (2) tissues believed to be important in transmission of the virus (integument, kidney, urinary bladder, gut and somatic muscle); and (3) hormone‐producing tissues (pituitary gland, saccus vasculosus, thymus, thyroid, ultimobranehial gland, gonad, head kidney, heart and ventral aorta). The same virus as that believed to be the causative agent of ISA was found in all tissues examined from the challenged fish, i.e. a multiorgan infection with the same virus present in salmon from all three fish farms. The virus particles are about 100 nm in diameter, consisting of a slightly pleomorphic unit membrane envelope within which are a number of granules about 10–12nm in diameter. The granules seemed to be arranged in two concentric circles (spheres). The virus was seen budding from the surface of endothelial cells in blood vessels/sinus only. However, the virus was found intracellularly in both endothelial cells and in leucocytes.