brown trout sea lice monitoring

Sea lice monitoring

There are numerous Atlantic salmon aquaculture facilities located in sheltered sea lochs within our area. Research has demonstrated that the presence of such aquaculture facilities can lead to increased levels of sea lice (a copepod parasite) on wild fish, particularly salmonids. High levels of sea lice on salmonids can cause extensive external damage to the fish, ultimately leading to increased mortality levels. Sea trout are particularly susceptible to high lice levels given their preference for coastal habitats and the consequent overlap in habitat use with aquaculture facilities in sea lochs. In order to monitor this threat, SLRT undertakes estuarine monitoring of sea trout populations in multiple sea lochs in our area where wild sea trout are caught using netting methods and examined for lice. All lice on an individual are counted and then the fish is released back into the water to swim another day. This sea lice data is reported to Marine Scotland. See below for a time lapse video of one of our netting sessions carried out in Loch Pooltiel.

Juvenile salmonid surveys- An important part of salmonid fisheries management is monitoring population densities of the juvenile life stages in our freshwater systems. This type of monitoring is carried out using electrofishing equipment and occurs every year in select rivers and burns within our area to provide information about temporal and spatial population changes. The Trust is also involved in Marine Scotland’s National Electrofishing Programme for Scotland, which seeks to estimate the total production of fish in a river or region using standardised electrofishing protocols.

Skye and Lochalsh Rivers Trust sea lice monitoring
Skye and Lochalsh Rivers Trust
salmon sketch subject to copyright s. mckenzie

All materials Copyright © 2021 Skye and Lochalsh Rivers Trust unless otherwise stated. |Charity Reg. No. SC039771 | Co. No. SC344382