Video monitoring of the River Lákšjohka salmon migrations in 2009-2011

An underwater video monitoring study for counting adult salmon and smolt numbers was conducted in 2009-2011 in the River Lákšjohka, a tributary of the River Tana. On the video monitoring site the natural river channel was narrowed from both riverbanks to allow full monitoring efficiency with four underwater video cameras. The an-nual numbers of ascending salmon (336-587 ind.) and descending smolts (901-2105 ind.) observed were rather low bearing in mind that the River Lákšjohka and its tributaries represent a relatively large watershed suitable for salmon production. The exploitation rate of the Lákšjohka salmon fisheries was rather high (c. 30 %, only rod and line fishing) when compared to the fishing effort.

It is evident that the Lákšjohka salmon population did not meet the defined spawning targets (> 1100 female salmon/year) in 2009-2011 and management measures should thus be applied.

Overall, the River Lákšjohka is an ideal index river of the lower Tana area and easily monitored by us-ing underwater video cameras. Continuation of the Lákšjohka video counts would add a highly valuable part in assessing the status of the River Tana salmon stocks and to ensure biologically sound management decisions in long term.