Juvenile salmon stocks in the Dee 2019

December 11, 2020

The national assessment of salmon stock health (conservation status) in Scottish rivers is based on the number of adult fish caught by anglers and those passing through fish counters. Stocks can be assigned to 3 categories based on the number of fish recorded over a 5-year period. The Dee is currently a Category 1 river, which is the highest, and indicates that enough adult fish are successfully spawning to meet the egg requirement of the river

This is not the whole story, however, because it does not include information on juvenile fish. Consequently, in 2018 the National Electrofishing Programme for Scotland (NEPS) was created to assess the number of juvenile fish in relation to a benchmark value (the number of fish that would be expected if the site was in a good state or “healthy”).

Trust Biologist, Dr Al Reeve has completed his analysis of the 2019 data and explains what it means for the Dee and our juvenile salmon.

You can read the report in full here.

What Does NEPS mean for the Dee?

'NEPS helps Boards and Trusts to build on adult estimates which were once the sole basis for categorisation of Scotland's salmon rivers. By carrying out NEPS surveys, we remove any unconscious bias we may have in selecting sites to survey. These are chosen by a computer programme and provide us with a broad and unbiased view of juvenile salmon throughout the catchment. Over the long term it will give us a better idea of stocks going forward.'

How are our Fry and Parr Doing?

'The 2019 results are mixed, if not unexpected. Overall, fry numbers were poor, perhaps a reflection of the exceptionally dry year we had in 2018, followed by high water during spawning. Our parr did better and the data was largely in line with what we expected.

With returns of adult salmon in decline, NEPS reinforces our understanding that salmon are in a precarious position. Our primary aim is to get as many smolts to sea as possible; NEPS allows us to see where there are any issues affecting fry and parr and helps us to plan our habitat restoration work accordingly.'