Smolt traps update 26th April

admin Latest 26th April 201526th, April, Smolt, traps, update

It has been ten days since the last update so apologies for that. The numbers of smolts caught in the Avon traps increased greatly last week with the water temperatures increasing in the lovely sunny weather. This weekend it has turned a lot colder with snow falling down to below 500′.

The total catch in the Avon traps to date is 2647 salmon and 166 trout. The trout numbers this year are similar to 2014 but on this day last year we had caught 4543 salmon. We are expecting a lower smolt run this year due to the impact of the big August spate but with the exception of last week the winter of 2014/2015 and the spring of 2015 have been more normal compared to the exceptionally mild conditions pertaining last year. So the catch is lower so far but the peak of the run is likely to be later this year.

The catches in the Tommore Burn trap have been steady at a low level over the last two weeks although the 13 salmon smolts caught today was the best daily catch since the 9th April. The burn has been low so we may well see another burst of fish if the level rises again. In total we have caught 296 salmon and 32 trout in the Tommore traps. The vast majority of the salmon have been fin clipped but there is a proportion which have intact fins and may be wild smolts produced in the accessible part of the burn above the trap.

Salmon smolt catch at the Avon traps related to 9am river height in cm! Smolt number are the black bars, river height the blue line. (ingore the fact it says trout on the y-axis, that is an error)

Tommore salmon catch related to burn height (cm)

Avon salmon smolt catch related to river temperature. Temperature is a realy important factor for smolt migration. This week the numbers of salmon smolts captured increased on the back of a rise in temperature despite the river height falling.

Tommore Burn trap salmon catch related to burn temperature. In the Tommore Burn the water level appears to be a more important migration cue. Not surprising considering the small size of the burn. This may also explain why the migration appears to have been a lot earlier in the burn than in the river; the fish may take advantage of the higher early spring water levels.

We have undertaken a number of recapture trials in the Avon. I don’t have the results at hand but the recapture rate appears to be similar to those obtained in 2014. We also monitor the Avon traps for fin clipped fish and yesterday there were 6. Again I don’t have all the figures available but that was the highest daily catch of fin clipped fish. The recent catches in the Tommore Burn have been low so these fin clipped fish may have been earlier migrants that were waiting in the Avon until ready to move further downstream. Alternatively they may have been fish that left the Tommore Burn as autumn parr. Without applying a further mark to the Tommore fish we won’t be able to establish that.

On this date last year we had caught 146 salmon parr in the Avon traps. These are generally smaller fish in the 60-85mm range which will not smolt this year. Steve and I mentioned that we had caught comparatively few so far this spring; probably in the order of 30-40. Not sure what the implications are of that, if anything.

The forecast is for the colder weather to remain this week so we are expecting steady catches in the Avon traps.

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Smolt traps again

admin Latest 27th March 2015again, Smolt, traps

Soon be that time of the year again when the smolts start to move. Today we were over in the upper Deveron area and the upper River Fiddich installing three of the smaller, 4 foot diameter traps. There was the usual confusion over which bit went where at first but by number three it was a well oiled team effort between the Deveron and Spey. All three traps were deployed as part of the fisheries monitoring plan associated with the Dorenell Wind Farm.

The trap in the Allt Deveron. It might not look it but the Allt Deveron was by far the biggest of the three rivers visited today. There is very good habitat in the upper Deveron and there was a good catch of salmon smolts last spring.

A short distance downstream of the Deveron trap location is the confluence of the Blackwater, a good sized spawning tributary well known for its spawning run of big river trout. Salmon spawn in it also but if I recall correctly the Deveron Trust caught more trout parr/smolts than salmon last year in this trap.

The Blackwater trap in position

The last trap was in the upper Fiddich. The Fiddich is quite small at this point but there are still 5 or 6km of first class habitat used by salmon upstream. We had a good mixed catch last year with the salmon smolts considerably larger on average than found in the upper Spey tributaries.

River Fiddich trap in location. Lovely clear water in the Fiddich. The conductivity and pH in the Fiddich are amongst the highest found in the Spey catchment.

The Fiddich is little more than a burn at this point and barely wide enough for the trap but it was turning good today.

The Fiddich is little more than a burn at this point and barely wide enough for the trap but it was turning great today. The Deveron team will be looking after all three traps initially.

On Friday the Avon traps and the Tommore Burn trap will be installed although not operational until Monday; our last weekend of freedom for a while!

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