Sammendrag
One of the major challenges for understanding
the ecological impact of escaped farmed Atlantic
salmon (Salmo salar L.) is predicting their dispersal
patterns after an escape event. Here, we quantify the
behaviour of escaped farmed salmon using a
simulated-escape experiment within a Norwegian
fjord system. Thirty-seven individuals were tagged
with acoustic transmitters and their spatial distribution,
horizontal movements and diving behaviour
was monitored throughout the fjord and accompanying
rivers using 29 acoustic receivers. A rapid
movement away from the release site occurred.
There was no movement into the rivers feeding the
fjord and there was no preference for residence at the
fish farms: nearly a third of the individuals had a final
detection in the outer part of the fjord and no detections
occurred from approximately 2 months after
release. As it is unlikely that all fish died or remained
undetected within the study area it is reasonable to
assume that a substantial proportion of the fish moved
out of the fjord system. If a recapture program is not
implemented immediately after an escape event, we
recommend spreading potential recapture efforts over
a relatively large area.
Fish farms . Atlantic salmon . Escape
patterns . Acoustic telemetry
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