The River Nethy is not the biggest tributary of the Spey although it is certainly in contention as the prettiest. Over the last two days we completed the Nethy salmon fry index surveys (along with other sites). Ideally we would have completed six salmon fry index sites on the Nethy mainstem but access it not easy and after driving along ever smaller forest roads for half an hour today we gave up on reaching one of our intended sites. However the results from the five sites we did complete provide a lot of information.
As reported yesterday we found salmon fry in the uppermost expected site, the one just below the impassable waterfall at Bynack Stable. We also found salmon fry in the other four sites although in much greater numbers in the lower reaches. The graph below shows the results.
River Nethy 2015 salmon fry index results. Salmon fry were found at all sites with the lower two sites in the excellent category in the Spey classification scheme. The other sites were either in the moderate or low categories. Note that the middle site should be TSN18 not 15. This will be corrected in due course before the final results are published.
The mean number of salmon fry per minute in the Nethy sites was 31.5, higher than the Avon 2013 average in sites to the same altitude. The average parr count per minute in the Nethy was 3.7, much lower than in the Avon in 2013 but higher than in the Feshie and Tromie last year. The 90.7 fry per minute from the furthest downstream Nethy site puts it in the top five timed sites so far across the Spey catchment. Overall not bad results considering the low conductivity (25 in the upper site to 51 in the lower).
TSN03, the furthest downstream salmon fry index site in the Nethy. This site is below Nethy Bridge. Loads of fry and parr here, pity the Nethy sewage treatment works wasn’t further up the river!
Second site, which was on the upper outskirts of Nethy Bridge. We fished the margins on the right hand bank catching 107 fry in three minutes.
The middle Nethy site, fished along the right bank to midstream. Mixture of substrate sizes but not high numbers of fry.
The fourth site and the first salmon fry index survey we did on the Nethy. We were all pleasantly surprised by the decent fry and parr numbers. We fished the middle and left side of the channel, avoiding the slightly deeper and faster run down the right bank. Note that we have lost most of the broadleaf trees.
The location of survey site TSN31 (Times/Spey/Nethy/31st 500m section from the confluence with the Spey). We fished the left bank channel finding 26 salmon fry in three minutes but no parr. Did any spawn up here the year before?
One last picture – the Dorback sands. Many people have asked where all the sand in the Spey comes from? One major source are the sandy glacial and alluvial deposits found in the middle reaches of the river. The Lower Dorback Burn substrate was full of sand today, the result of erosion from sparsely vegetated, or eroding banks, in the glacial terraces in the upper reaches. This looked more like a scene from the foreshore at Findhorn than the banks of an upper tributary of the Spey.