Aquatic & Fisheries Depth Movements of Homing Atlantic Salmon In Coastal Waters Star-Oddi.com

Sturlaugsson, J. and K. Thorisson. 1996. Depth movements of homing Atlantic salmon (Salmo salar L.) in coastal waters W- Iceland, in relation to environmental factors. In Book of abstracts. Fifth European Conference on Wildlife Telemetry. Strasbuorg, France, 25 - 30 August 1996. 1 pp.

 

NOT TO BE CITED WITHOUT PRIOR REFERENCE TO THE AUTHOR

 

DEPTH MOVEMENTS OF HOMING ATLANTIC SALMON (Salmo salar L.) IN COASTAL WATERS W - ICELAND, IN RELATION TO ENVIRONMENTAL FACTORS

by

Johannes Sturlaugsson*

and Konrad Thorisson

*Institute of Fisheries and Aquaculture Research, Vagnhofdi 7, 110, Reykjavík, Iceland

Tel:(+354) 567 64 00 Fax:(+354) 567 64 20 E-mail: johannes@laxfiskar.is

Abstract

In 1995 a migration study on the homing of Atlantic salmon (Salmo salar L.) in coastal waters was carried out in Iceland using data storage tags (DST). The tags measured pressure (depth) and temperatures at 1.5-30 minutes intervals during periods of 1-21 days.

Schools of homing salmon were captured in an estuary in July, when entering their home water at Hraunsfjord ocean ranching station. A total of 70 salmon were tagged and transferred 45-420 km away to 2 releasing sites, one inshore at NW-Iceland and one offshore at W-Iceland where the salmon were released over a depth of 180 m. Salmon from both release sites were recaptured in Hraunsfjord (34% mean recapture rate).

The majority of the recaptured salmon had spent most of their time in the uppermost 3 meters. A common behaviour among the salmon however, were occasional deep dives, the deepest dive recorded being 153 m. The highest vertical swimming speed recorded was 0.73 m/sec (66 m dive/1.5 min).

The records of sea temperatures showed that the salmon were occasionally swimming down through the thermocline. During the homing migration the salmon experienced sea temperatures ranging from 4.2-12.6°C.

The patterns of vertical movements of the salmon are further discussed in relation to environmental factors and the possible cues/clues used by the salmon while navigating to their home water.

Key words: Atlantic salmon, behaviour, homing migration, navigation, coastal waters, electronic data storage tags.