Permanent
Address
Department of Fisheries and Marine Biology
University of Bergen
P.O. Box 7800
N-5020 Bergen
NORWAY
Research Interests
Main topics: Salmon biology with particular focus on smoltification (parr-smolt
transformation), fish physiology and endocrinology, fish reproduction
and growth.
In studies of salmon smoltification my main objective has been to better
understand the environmental and endocrine control of the development
of hypo-osmoregulatory ability. Further, much of my work in recent years
has been focusing on genetic x environment interactions controlling growth
and puberty (age at first sexual maturity) in fish species like salmon,
turbot, halibut and cod.
In my studies I have tried to combine a basic approach to general biological
questions with species and processes of major interest in nature and culture.
Publications
Handeland, S. O. and S. O. Stefansson, 2001. Photoperiod
control and influence of body size on off-season parr-smolt transformation
and post-smolt growth. Aquaculture 192, 291-307.
Handeland, S. O. and S. O. Stefansson, 2002. Effects of salinity acclimation
on pre-smolt growth, smolting and post-smolt performance in off-season
Atlantic salmon smolts (Salmo salar L.). Aquaculture 209, 125-137.
Imsland, A. K., T. M. Jonassen, R. Hoare, A. Langston, H. Wergeland, R.
FitzGerald, M. Mulcahy and S. O. Stefansson, 2002. The interrelation of
growth and disease resistance of different populations of juvenile Atlantic
halibut (Hippoglossus hippoglossus L.). Aquaculture 204, 167-177.
Imsland, A. K., A. Foss, S. Gunnarsson, M. H. G. Berntssen, R. FitzGerald,
S. E. Wendelar-Bonga, E. van Ham, G. Nævdal and S. O. Stefansson,
2001. The interaction of temperature and salinity on growth and food conversion
in juvenile turbot (Scophthalmus maximus). Aquaculture 198, 353-367.
Imsland, A.K., A. Foss, B. Sveinsbø, T. M. Jonassen and S. O. Stefansson,
2001. Comparisons of RNA/DNA ratios, growth and metabolism of different
populations of juvenile turbot Scophthalmus maximus reared at four temperatures.
J. World Aqua. Soc. 32, 1-10.
Imsland, A. K., A. Foss, G. Nævdal and S. O. Stefansson, 2001. Selection
or adaptation: differences in growth performance of juvenile turbot (Scophthalmus
maximus Rafinesque) from two close-by localities off Norway. Sarsia 86,
43-51.
Porter, M. J. R., N. Duncan, S. O. Handeland, S. O. Stefansson and N.
R. Bromage, 2001. Temperature, light intensity and plasma melatonin levels
in juvenile Atlantic salmon. J. Fish. Biol. 58, 431-438.
Andersson, E., Fjelldal, P. G., Klenke, U., Vikingstad, E, Taranger, G.
L., Zohar, Y. and Stefansson, S. O., 2001. Three forms of GnRH in the
brain and pituitary of the turbot, Scophthalmus maximus: immunological
characterization and seasonal variation. Comp. Biochem. Physiol. 129,
551-558.
Hoare, R., H. Hovland, A. L. Langston, A. K. Imsland, S. O. Stefansson,
M. Mulcahy and H. I. Wergeland, 2002. Susceptibility of three different
strains of juvenile Atlantic halibut (Hippoglossus hippoglossus L.) cultured
at two different temperatures to Vibrio anguillarum and temperature effect
on antibody response. Fish Shellfish Immunol. 13, 111-123.
Andreassen, P. M.R., M. B. Martinussen, N. A. Hvidsten and S. O. Stefansson,
2001. Feeding and prey-selection of wild Atlantic salmon post-smolts.
J. Fish Biol. 58, 1667-1679.
Imsland, A. K., A. Foss and S. O. Stefansson, 2001. Variation in food
intake, food conversion efficiency and growth of juvenile turbot from
different geographic strains. J. Fish Biol. 59, 449-454.
Ebbesson, L. O. E., P. Ekström, S. O. E. Ebbesson, S. O. Stefansson
and B. Holmqvist, 2003. Neural circuits and their structural and chemical
reorganization in the light-brain-pituitary axis during parr-smolt transformation
in salmon. Aquaculture 222, 59-70.
Arnesen, A. M., H. Toften, T. Agustsson, S. O. Stefansson, S. O. Handeland
and B. Th. Björnsson, 2003. Osmoregulation, feed intake, growth and
growth hormone levels in 0+ Atlantic salmon (Salmo salar L.) transferred
to seawater at different stages of development. Aquaculture 222, 167-187.
Nilsen, T. O., L. O. E. Ebbesson and S. O. Stefansson, 2003. Smolting
in anadromous and landlocked strains of Atlantic salmon (Salmo salar).
Aquaculture 222, 71-82.
Imsland, A. K., A. Foss, S. W. Bonga, E. van Ham and S. O. Stefansson,
2002. Comparison of growth and RNA:DNA ratios in three populations of
juvenile turbot reared at two salinities. J. Fish Biol. 60, 288-300.
Fivelstad, S., A. B. Olsen, T. Åsgård, G. Bæverfjord,
T. Rasmussen, T. Vindheim and S. O. Stefansson, 2002a. Long-term sublethal
effects of carbon dioxide on Atlantic salmon smolts (Salmo salar L.):
ion regulation, haematology, element composition, nephrocalcinosis and
growth parameters. Aquaculture 215, 301-319.
Fivelstad, S., R. Waagbø, S. F. Zeitz, A. C. D. Hosfeld, A. B.
Olsen and S. O. Stefansson, 2002b. A major water quality problems in smolt
farms: combined effects of carbon dioxide, reduced ph and aluminium on
Atlantic salmon (Salmo salar L.) smolts: physiology and growth. Aquaculture
215, 339-357.
Handeland, S. O., B. Th. Björnsson and S. O. Stefansson, 2003. Seawater
adaptation and growth of post-smolt Atlantic salmon (Salmo salar L.) of
wild and farmed strains. Aquaculture 220, 367-384.
van Ham, E. H., M. H. G. Berntssen, A. K. Imsland, A. C. Parpoura, S.
E. Wendelaar Bonga and S. O. Stefansson, 2003. The influence of temperature
and ration on growth, feed conversion, body composition and nutrient retention
of juvenile turbot (Scophthalmus maximus). Aquaculture 217, 547-558.
Stefansson, S. O., P. McGinnity, B. Th. Björnsson, C. Schreck, S.
D. McCormick, 2003. The importance of smolt development to salmon conservation,
culture, and management: perspectives from the 6th International Workshop
on Salmonid Smoltification. Aquaculture 222, 1-14.
Handeland, S. O., M. Porter, B. Th. Björnsson and S. O. Stefansson,
2003. Osmoregulation and growth in a wild and selected strain of Atlantic
salmon smolts on two photoperiod regimes. Aquaculture 222, 29-43.
Imsland, A. K., S. Gunnarsson, A. Foss and S. O. Stefansson, 2003. Gill
Na+,K+-ATPase, plasma chloride and osmolality in juvenile turbot (Scophthalmus
maximus) reared at different temperatures and salinities. Aquaculture
218, 671-683.
Imsland, A. K., M. Dragsnes and S. O. Stefansson, 2003. Exposure to continuous
light inhibits maturation in turbot (Scophthalmus maximus). Aquaculture
219, 911-919.
Handeland, S. O., E. Wilkinson, B. Sveinsbø, S. D. McCormick and
S. O. Stefansson, 2003. Temperature influence on the development and loss
of seawater tolerance in two fast-growing strains of Atlantic salmon.
Aquaculture 00, 000-000.
Stefansson, S. O., B. Th. Björnsson, K. Sundell, G. Nyhammer and
S. D. McCormick, 2003. Physiological characteristics of wild Atlantic
salmon post-smolts during estuarine and coastal migration. J. Fish Biol.
63, 942-955
.
Ebbesson, L. O. E., C. K. Tipsmark, B. Holmqvist, T. O. Nilsen, E. Andersson,
S. O. Stefansson and S. S. Madsen, 2003. Nitric oxide synthase in the
gill of Atlantic salmon: co-localization with and inhibition of the Na+,K+-ATPase.
J. Exp. Biol. (in revision).
Taranger, G. L., E. Vikingstad, U. Klenke, I. Mayer, S. O. Stefansson,
B. Norberg, T. Hansen, Y. Zohar and E. Andersson, 2003. Effects of photoperiod,
temperature and GnRHa treatment on the reproductive physiology of Atlantic
salmon (Salmo salar) broodstock. Fish Physiol. Biochem. (in revision).
van Ham, E. H., R. D. Van Anholt, G. Kruitwagen, A. K. Imsland, A. Foss,
B. O. Sveinsbø, R. FitzGerald, A. C. Parpoura, S. O. Stefansson
and S. E. Wendelaar Bonga, 2003. Environment affects stress in exercised
turbot. Comp. Biochem. Physiol., 000, 000-000.
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