Smolt trap update – a welcome late burst!

This time last year the smolt run was all but over in the Avon with daily catches down to single figures or just above. However no two years are the same and today’s catch of 231 salmon smolts and 29 trout was one of the higher catches this spring. Yesterday we had 156 salmon and 18 trout in the traps, all but two of which were marked and released back upstream as part of our assessment programme to quantify the total run. This morning we recaptured 10 salmon (6.5%) although we may still get more recaptures tomorrow. Even if we get a few more recaptures the smolt run down the Avon last night would have been in the order of 3,000. The river level this morning was 22cm on our gauge but the previous morning, the night when we caught 156 salmon, it was 41cm when the trap efficacy would have been lower – the challenges of trying to quantify the smolt run!

We have completed 12 mark/recapture trials covering a range of river flows from 16 to 47cm, so our strategy of pooling all the results into a single period for the run estimation calculations is probably fair. Overall the recapture rate so far this spring has been 8.96%. As the smolt run is not yet over I’ll refrain from publishing the ongoing run estimate but these nights with catches into the hundreds make a big difference. The basic figures to date are 5,134 salmon (14,035 in 2014)and 678 trout (725) with trap efficiency figures this year of 8.96 % for salmon and 3.3% for trout.

The Tommore Burn trap was removed today as the run was over with only 10 salmon smolts caught in May and 1 in the last ten days. The total number of fin clipped salmon in the Tommore Burn was 357, giving a estimated smolt production of 4.05 per 100m2 wetted area.

With the run continuing in the Avon we intend to operate those traps until the end of May at least – looks like another weekend away from the fishing then!

At the quarterly Spey Foundation meeting today we heard about low smolt trap counts from other parts of Scotland, not all of which were as badly affected by the “Bertha” spate in August last year. I will get some figures from other areas before the final blog on the smolt traps for this spring.

Some graphs below for you to ponder.

Avon salmon smolt catch related to 9am river level.

Avon salmon smolt catch related to 9am river temperature.

Avon salmon smolt catch related to river level

Avon salmon smolt catch related to river level

Avon trout catch related to river temperature

Avon trout catch related to river temperature

Avon trout catch related to river height

Avon trout catch related to river height

 

 

The post Smolt trap update – a welcome late burst! appeared first on Spey Fishery Board.

Spey Fishery Board