A Pilot Study To Determine The Effect Of An Anti-Sea Lice Agent On The Marine Survival Of Atlantic Salmon On The West Coast Of Scotland : Scottish Marine and Freshwater Science Vol 10 No 6

There are concerns that sea lice in the coastal environment are impacting on the return rates of wild Atlantic salmon on the West coast of Scotland. Studies in Norway and Ireland involving examining survival of groups of migrating salmon smolts treated with anti-sea lice medicines have shown that se...

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Bibliographic Details
Main Author: Marine Scotland
Format: Article in Journal/Newspaper
Language:English
Published: Marine Scotland Science 2019
Subjects:
Online Access:https://dx.doi.org/10.7489/12212-1
https://data.marine.gov.scot/dataset/pilot-study-determine-effect-anti-sea-lice-agent-marine-survival-atlantic-salmon-west-coast
Description
Summary:There are concerns that sea lice in the coastal environment are impacting on the return rates of wild Atlantic salmon on the West coast of Scotland. Studies in Norway and Ireland involving examining survival of groups of migrating salmon smolts treated with anti-sea lice medicines have shown that sea lice can adversely affect certain salmon populations. A pilot project conducted by Marine Scotland Science using portable traps determined that developing a network of experimental sites across Scotland was not likely to be feasible. The pilot study here was to make an assessment whether the Awe catchment could be used as a West coast site that could provide an indication of impact of coastal sea lice on wild Atlantic salmon survival. This catchment was of interest as it has an automatic PIT detector located within the fish lift associated with a permanent barrage : In total 1003 salmon smolts were captured and PIT tagged on the Orchy and Strae tributaries of the Awe during spring 2017. Half of these fish (n= 454)were treated with the anti-lice compound FLUX (100 mg/ml) and the other half (n=460) treated as control fish before release to continue their migration. In 2018 the automatic PIT detector at the Awe barrage recorded 16 returning salmon grilse from the experiment. Eleven of these were from the treated group, while the remaining 5 were from the control group. Differences between the groups was not statistically significant at the p=0.05. The total return rate was 1.6%. The numbers of returning fish detected suggests that the Awe catchment could be used for future treatment- release studies on the West coast of Scotland to assess impact of sea lice in the coastal zone.