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Changes in swimming depths of Atlantic salmon Salmo salar post‐smolts relative to light intensity
Author(s) -
Davidsen J. G.,
Plantalech Manella N.,
ØKland F.,
Diserud O. H.,
Thorstad E. B.,
Finstad B.,
Sivertsgård R.,
McKinley R. S.,
Rikardsen A. H.
Publication year - 2008
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.2008.02004.x
Subject(s) - salmo , light intensity , biology , fishery , intensity (physics) , fish <actinopterygii> , oceanography , zoology , geology , optics , physics
Eight hatchery‐reared Atlantic salmon Salmo salar post‐smolts, implanted with acoustic depth sensing transmitters and manually tracked for 5–12 h in the Hardangerfjord (Norway), spent most of their time (49–99%) at 1–3 m depth during the day, whereas four of seven fish tracked were found close (<0·5 m) to the surface at night, with a strong negative cross‐correlation between general swimming depth and surface light intensity. Hence, the actual swimming depth of post‐smolts during their early marine migration may depend on the light conditions, although the individual variation in vertical movement pattern was large. No cross‐correlations were found between light intensity and swimming depth during daytime periods with rapid changes in light intensity, indicating that other factors than light intensity were important in initiating the irregular dives that were recorded down to 6·5 m depth.