The Laxford Sea Trout Tracking Project
During 2018 we tracked 99 sea trout within Loch Laxford in order to determine how the fish are using the sea loch, its estuaries and bays. This will help inform future coastal management of sea trout. The project was undertaken in collaboration with Atlantic Salmon Trust, Marine Scotland, and the University of Glasgow (SCENE).
Videos of the project can be viewed on the Trust Youtube page
A talk about tracking - including a bit on the Laxford tracking project - can be viewed here
The final report can be viewed here
The Project
We aim to inform the development of management strategies to better protect these incredible fish by gaining a much more detailed understanding of their behaviour within the coastal environment.
Sea trout have been a highly sought after game fishing species for centuries; their elusive nature still attracts anglers from the world over to try and tempt one of these bejewelled bars of speckled silver. Sea trout also play an important role within ecosystems and are an indicator of clean and healthy freshwater burns and rivers. But sadly sea trout are now under threat and are listed as a UK Biodiversity Action Plan (UK BAP) priority species. West Sutherland Fisheries Trust (WSFT), Atlantic Salmon Trust (AST), The Scottish Centre for Ecology and the Natural Environment (SCENE), and Marine Scotland Science (MSS) teamed up to track sea trout movements within Loch Laxford throughout the summer of 2018.
Threats to sea trout survival
Natural threats include predation from egg to adult, by fish eating birds, mammals, and predatory fish. Unnatural threats include:
- Exploitation; legal and illegal
- Habitat degradation and pollution
- Barriers to migration; impassable culverts and dams stop sea trout from accessing spawning grounds
- Natural sea lice levels can multiply within coastal salmon farms leading to dangerous infestations on wild sea trout
|
|
What we have done so far…
Since 1997, West Sutherland Fisheries Trust has been gathering information on local coastal sea trout populations in liaison with Marine Scotland Science and local aquaculture companies.
We now have a vast data set, including information on:
- Sea lice: species, lifecycle stage, number per fish
- Fish Condition Index: calculated through length/weight of specimens
- Scale samples: used to calculate fish age and spawning details
- Growth rates: calculated through recaptures
- Fish movements: noted through recaptures and genetic analysis
Therefore, fish do not appear to stray far from the sea lochs corresponding to their native river catchments
For more information about WSFT sea trout sweep netting surveys, click here
To read the latest reports, click here
|
|
|
Through visual implant tagging, recapture data has told us:
- Only 5 of 195 recaptures from Laxford estuary were caught out-with the Loch Laxford area
Genetic analysis has told us:
- Sea trout populations originating from Laxford, Polla, and Dionard are unique
Sweep netting surveys cannot tell us:
- How the fish are behaving within these sea lochs
- How many (if any) are migrating to the open sea; are our theories correct?
- Are there specific areas and habitats within the estuaries and sea lochs that are of particular importance to sea trout
- How sea trout interact with aquaculture units
- If sea trout with sea lice burdens behave differently to those without
- Detailed information on freshwater re-entry
- Information on sea trout predation
- If sea trout populations across similar sites on the west coast of Scotland are behaving in the same way
Through WSFT’s local knowledge and AST, SCENCE, MSS resources and expertise in Acoustic Tracking, we have addressed these queries in the hope of building towards better protection and conservation of our sea trout populations through improved evidence-based management.
 |
The Tracking Study :
38 acoustic receivers were strategically positioned throughout Loch Laxford, and it’s estuaries and bays in order to provide coverage of different habitat types, aquaculture facilities, and likely migration routes.
 |
99 sea trout of differing lifecycle stages were caught from WSFT’s Badnabay smolt trap and Laxford estuary sweep netting site. They were fitted with a transmitter tag which could be detected by the receivers as they swam near them. The receivers were recovered after a 6 month study period and the data logged within them is currently being analysed.
|
|
Outcomes :
The local picture :
Results will be used to..
- Highlight sensitive areas of importance to sea trout
- Highlight sensitive temporal factors such as migration timings
- Provide information on sea trout predation
- Inform the development of local management strategies in order to better protect sea trout populations in the coastal environment
The bigger picture :
Results will be cross referenced with similar Scottish west coast sea trout tracking study sites, meaning current theories on west coast sea trout behaviour may be solidified as a result. This has the potential to influence wider management policies. Other study sites include:
- Isle of Skye (SCENE)
- Loch Linnhe (MSS)
- Shieldaig/Torridon (MSS)
What can you do to help our sea trout studies?
Report sea trout captures to us:
If you are fishing in West Sutherland and catch a sea trout with a clipped adipose fin, it will have a visual implant tag behind the eye. Please make a note of the tag number, release the fish unharmed and report back to us at: This email address is being protected from spambots. You need JavaScript enabled to view it.
Volunteer with us ...
... and help us haul that net!
If you would like to come and join in with the sweep netting action, please email or call us for a chat and we will gladly get you involved if you think you are up to the challenge!
If you would simply like to come along to meet us and watch the netting, dates and times for sweep netting are updated on the home page.
We hope to see you soon!
Project Supporters
We have received a huge amount of support from local businesses, estates, private individuals, and volunteers. All have been instrumental in helping us implement this project, either through cash donations, pre-project consultations, in-kind provision of resources, or hands on graft come rain or shine.
Charles Marsham, Simon Jeffreys, Ross Barnes, Dave Deboer, Rex Onions, David Clark, Donald Mitchell, Chris Ambler, Don O’ Driscoll, Helen MacDonald, Russel Robertson, Colin Christie, Phillipa Harris, Simon Bonney, Dave Gardner, Colin Adams, Terry Jack, Jennifer Morrison, Julien Legrand, Roddy John MacDonald, Stuart Taylor, Maggie Beynon-Jones, Flora Cadzow, Vikki Christian, Ulrich Brossman, Fen Howieson, Rupert Longsdon, Christian Bruckmayr, Matt Neilsen, Cargill Nutrition
