Blar i ICES CM documents authored by IMR scientists (1949-2011) på forfatter "Iversen, Svein A."
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A preliminary study of microstructure in otoliths of seacaught mackerel (Scomber scombrus L.) larvae
Iversen, Svein A.; Moksness, Erlend (ICES CM Documents;1990/H:4, Working paper, 1990)Mackerel larvae have been sampled during two cruises south of lrland, in May and June 1989 and preserved in ethanol. The microstructure of the otoliths (sagittae) from the mackerel larvae have been examined. There is a ... -
Changes on horse mackerel (Trachurus trachurus) catch distribution in the Northeast Atlantic
Borges, Maria Fatima; Silva, Alexandra; Abaunza, Pablo; Eltink, A.; Lucio, Paulino; Walsh, Martin; Poulard, Jean-Charles; Casey, John; Iversen, Svein A.; Skagen, Dankert W.; Sanchez, Francisco (ICES CM Documents;1996/S:26, Working paper, 1996)The distributions of international commercial catch data were mapped by ICES rectangle and quarter from 1983-1994. These indicate a northward expansion of horse mackerel distribution in the Northeast Atlantic since 1987. ... -
Comparison of Northeast Atlantic mackerel (Scomber scombrus) distribution patterns in the Norwegian Sea using lidar, sonar, and trawl
Tenningen, Eirik; Godø, Olav Rune; Iversen, Svein A.; Slotte, Aril; Hjellvik, Vidar; Torkelsen, Terje (ICES CM documents, Working paper, 2003)In July 2002 the Institute of Marine Research (IMR), Bergen mapped the distribution and density of mackerel in the Norwegian Sea using lidar, sonar and trawl. A major objective was to test the efficiency of the lidar as ... -
The development and mortality of mackerel eggs (Scomber scombrus L.) in different temperatures
Danielssen, Didrik S.; Iversen, Svein A. (CES CM Documents;1977/L:19, Working paper, 1977) -
Distribution and abundance of sprat in the North Sea in winter 1979-1980 determined by acoustic methods.
Aglen, Asgeir; Iversen, Svein A. (ICES CM Documents;1980/H:41, Working paper, 1980)To estimate the size of the North Sea sprat stock acoustically two cruises were carried out in November 1979-January 1980. The method is described and the size of the sprat stock was estimated to about 1 million tons. ... -
Distribution of Norwegian spring-spawning herring and mackerel in the Norwegian Sea in late summer, 1991
Holst, Jens Christian; Iversen, Svein A. (ICES CM Documents;1992/H:13, Working paper, 1992)A pairtrawl survey was carried out in the Norwegian Sea during July - August 1991 to map the distribution of pelagic fish. Herring were caught throughout most of the surveyed area, with the largest concentrations observed ... -
FiSHU@LiS, a Computer Game on a General Pelagic Fish
Hauge, Kjellrun Hiis; Iversen, Svein A. (ICES CM documents, Working paper, 2003)Experience has shown that making political decisions that ensure sustainable use of natural resources is difficult. This has raised the question on how to include stakeholders and citizens in decision processes. ViRTU@LiS ... -
Influence of climate on recruitment and migration of fish stocks in the North Sea
Svendsen, Einar; Aglen, Asgeir; Iversen, Svein A.; Skagen, Dankert W.; Smedstad, Odd M. (ICES CM Documents;1991/H:12, Working paper, 1991)For several decades one of the prime targets within fishery science has been to be able to understand and explain the great variability in the success of survival from egg to mature fish. One of the reasons why such effort ... -
Influx of Atlantic water and feeding migration of horse mackerel
Iversen, Svein A.; Skogen, Morten D.; Svendsen, Einar (ICES CM documents, Working paper, 1998) -
Interaction and integration of observation and models – the EcoFish approach
Godø, Olav Rune; Hauge, Kjellrun Hiis; Hjøllo, Solfrid Sætre; Iversen, Svein A.; Kjesbu, Olav Sigurd; Nash, Richard D.M.; Svendsen, Einar (ICES CM documents;2007/R:14, Working paper, 2007)Ecosystem approach to fisheries management demand new scientific approaches and tools. The EcoFish project is a recently established project that pursues the challenges set by the new approach. It aims at supporting ... -
Mackerel egg investigations in the North Sea
Iversen, Svein A.; Westgård, Trond (ICES CM Documents;1984/H:38, Working paper, 1984)This paper deals with the mackerel egg investigations in the North Sea in 1982 and 1983. The egg production is estimated by a computerized method. The confidence limits of the egg samples were estimated at 20-30%. The ... -
Migration of western mackerel to the North Sea 1973 - 1988
Iversen, Svein A.; Skagen, Dankert W. (ICES CM Documents;1989/H:20, Working paper, 1989)The latest years, it is evident that most of the mackerel present in the North Sea belongs to the Western stock, since the yearly catches by far exceed the presumed size of the North Sea stock. The Norwegian tagging ... -
Norwegian sprat investigation in the North Sea in later years
Iversen, Svein A.; Ljøen, Rikard (ICES CM Documents;1984/H:37, Working paper, 1984)The variation in abundance and distribution of sprat during November 1979, January 1980, 1981 and 1982 is studied in relation to environmental factors. The main abundance of sprat was observed in waters with salinity ... -
On fecundity of North Sea mackerel (Scomber scombrus)
Borges, Maria Fatima; Iversen, Svein A.; Dahl, Oddvar (ICES CM Documents;1980/H:47, Working paper, 1980)This paper presents a preliminary analysis of the fecundity-length relationship of the North Sea mackerel. The relationship was compared to that of the Western mackerel stock (LOCKWOOD,1978) by an analysis of covariance ... -
Report on an acoustic survey for mackerel in the North Sea, Skagerrak and Kattegat in July - August 1987
Degnbol, P.; Iversen, Svein A.; Kirkegaard, E.; Lewy, P. (ICES CM Documents;1988/H:40, Working paper, 1988)An acoustic survey in the North Sea, Skagerrak and Kattegat was carried out in July-August 1987 by vessels from Denmark and Norway. This paper gives the distribution and the abundance estimates for mackerel. -
Report on echo-integrator surveys for sprat undertaken in the North Sea during the 1981 -82 winter season.
Johnson, P.O.; Iversen, Svein A.; Edwards, J.I.; Bailey, R.S. (ICES CM Documents;1982/H:13, Working paper, 1982) -
Report on the 1985 ICES-coordinated herring acoustic survey in the northern North Sea
Simmonds, E. John; Bailey, R.S.; McKay, D.W.; Aglen, Asgeir; Iversen, Svein A. (ICES CM Documents;1986/H:16, Working paper, 1986) -
Size and condition of mackerel in research vessel trawl hauls versus commercial purse seine catches: implications for acoustic biomass estimation
Slotte, Aril; Skagen, Dankert W.; Iversen, Svein A. (ICES CM documents, Working paper, 2006)In September, after the summer feeding has ceased, the Northeast Atlantic mackerel (Scomber scombrus) stock tends to aggregate in ICES Area IVa before they start to migrate southwards in December-February towards the ... -
Spatial pattern of migration and recruitment of north east Atlantic mackerel
Uriarte, A.; Alvarez, Paula; Iversen, Svein A.; Molloy, John; Villamor, Begoña; Martins, Maria Manuel; Myklevoll, Sigmund (ICES CM Documents;2001/O:17, Working paper, 2001)An International tagging program on both adult and young mackerel was implemented in 1997 (and partly in 1998) from Portugal to the Shetland isles within the frame of European Study Project 96-035 with the objectives of ... -
Spawning and stock size of North Sea mackerel in 1981
Iversen, Svein A. (ICES CM Documents;1982/H:7, Working paper, 1982)