Geographical differences in marine feeding of Atlantic salmon post-smolts in Norwegian fjords

Stomach content analyses were conducted on Atlantic salmon Salmo salar post‐smolt (average size, 119–154 mm fork length, LF) caught in eight large Norwegian fjord systems along a north–south geographical axis during 1998–2001. In general, post‐smolts from southern Norway showed low feeding intensity...

Full description

Saved in:
Bibliographic Details
Published in:Journal of fish biology 2004-06, Vol.64 (6), p.1655-1679
Main Authors: Rikardsen, A. H., Haugland, M., Bjørn, P. A., Finstad, B., Knudsen, R., Dempson, J. B., Holst, J. C., Hvidsten, N. A., Holm, M.
Format: Article
Language:English
Subjects:
Agnatha. Pisces
Ammodytes
anadromy
Biological and medical sciences
Brackish
Clupea harengus
Copepoda
Euphausiacea
Fundamental and applied biological sciences. Psychology
Gammaridae
growth
Hyperiidae
life-history
Marine
migration
Salmo salar
smolt size
survival
Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Stomach content analyses were conducted on Atlantic salmon Salmo salar post‐smolt (average size, 119–154 mm fork length, LF) caught in eight large Norwegian fjord systems along a north–south geographical axis during 1998–2001. In general, post‐smolts from southern Norway showed low feeding intensity in the fjords, whereas extensive feeding was observed in fjords in the northern and middle parts of Norway. The marine diet mainly included different crustaceans and in particular marine pelagic fish larvae (sand‐eels Ammodytes spp., herring Clupea harengus and gadoids), but with a substantial spatial and annual variation in prey diversity and feeding intensity. Insects were most frequently taken in the estuary, although fishes often made a large contribution in mass. In contrast, fishes, and to some extent various crustaceans (particularly Hyperiidae, Gammaridae, Euphausiacea and Copepoda) dominated the diet in the middle and outer parts of the fjords, where post‐smolts also fed more extensively than in the inner part. The results indicate that extensive feeding immediately after sea entrance may be more common for post‐smolts in the northern and middle parts of Norway, than in the southern fjords. The observed differences in post‐smolt feeding may be due to spatial and temporal differences in prey availability within and between the different types of fjord systems, and this might influence post‐smolt growth and survival.
ISSN:0022-1112
1095-8649
DOI:10.1111/j.0022-1112.2004.00425.x