Mainstem sampling days 6 & 7

I had a meeting yesterday but Steve, Michael (Hi Mum) and Polly continued the mainstem surveys in the Kinrara to Newtonmore area. Today we continued upstream with surveys from the Truim confluence to above Spey Dam.

Excluding the 3 sites above Spey Dam the mean salmon fry numbers from the last 2 days surveys were 64.1 (47.4 in 2012) whilst for salmon parr the mean was 11 (6.7 in 2012). The lowest fry count was at the Truim confluence site were we found 13 compared to 66 the previous year, however almost all the other sites fry counts were up (note that all the figures I mention refer only to salmon, trout are rarely encountered in the mainstem surveys).

From the Truim confluence upstream the gradient of the river is low and there are few areas with suitable run/riffle habitat for fry surveys.

The upper Spey valley looking west towards Laggan; a very heaviliy modified river which has been extensively dredged and controlled via floodbanks

The upper Spey valley looking west towards Laggan; a very heavily modified river which has been extensively dredged and controlled via floodbanks

The site at the Allt na Cubhaige confluence provided just enough habitat for surveying.

Survey site at the mouth of the Allt na Cubhaige. There was just enough habitat for a 3 minute survey.

Survey site at the mouth of the Allt na Cubhaige. There was just enough habitat for a 3 minute survey. Extensive weed cover provided good cover for the fry; we found 53  here, similar to the 59 last year and 12 parr, again close to 2012.

 

Closer to Spey Dam the more stable the flow regime in the upper Spey becomes as much is derived from the compensation flow. The site at the mouth of the Gergask Burn at Laggan provided almost twice as many fry as last year and more than twice as many parr. The next site at Blargie is the last survey site before Spey Dam, here the flow is very stable, rarely changing unless the dam spills which only happens a few times a year. The results from this site would help inform the debate about whether the good survey results from the river this year were due solely to the current low water conditions!

Blairgie site which is lcated about 1km downstream from Spey Dam. The flow here is largely compensation water and hardly varies.

Blargie site which is located about 1km downstream from Spey Dam. The flow here is largely compensation water and river levels hardly varies.

The results from the Blargie site were good with 75 fry and 33 parr compared to 54 fry and 18 parr in 2012. The habitat at this site is perfect mixed habitat for fry and parr. The improvements in both fry and parr counts recorded reflected pretty closely what we had found across the river.

A very silver parr of 126mm, it looked like a smolt as it was swept into the banner net.

A very silver parr of 126mm, it looked like a smolt as it was swept into the banner net. There were some scales missing from the tail area, I noted the same on some other parr, there must have been a predator active in the area recently.

So the results in the upper Spey below Spey Dam were generally good, with significant increases for both fry and parr, what would we find upstream of Spey Dam?

We had time to do 3 sites above Spey Dam today, all in the same locations as last year. The mean results for fry were 5.0 (4.7 in 2012) and for parr 13.3 (5.0 in 2012). Fry numbers were almost identical. We still have one more day surveying to do in the upper river but the results from today confirm the pattern we found last year – a step change downwards in fry above Spey Dam. Let there be no doubt about it; the habitat in the Spey upstream of Spey Dam is far superior for salmon than anywhere between Loch Insh and Laggan, it should be supporting an abundant juvenile salmon population – sadly reservoirs and everything associated with them rarely improve the lot of the salmon. The parr counts were good but the habitat here is absolutely top drawer, it would support more if there were more fish spawning.

 

Site at Sherramore Lodge

Site at Sherramore Lodge. As in 2012 no salmon fry at this site despite highly suitable habitat.

The other two sites were close to Garva Bridge. Similar fry counts to last year were observed but once again the parr counts had doubled.

Excellent mixed juvenile habitat downstream of Garva Bridge

Excellent mixed juvenile habitat downstream of Garva Bridge (sorry about the finger appearing in every photo but it is only a wee camera!)

There endeth another very interesting and encouraging day. One more day will complete the Spey mainstem surveys. This level of surveying represents very intensive monitoring but as 60% of the available habitat in the catchment is found there understanding what is happening in the mainstem is of fundamental importance.

 

 

 

There are 2 comments for this article
  1. John at 9:32 pm

    Hi Brian
    Have you any thoughts on the collapse of the sea trout run this year. Catches appear to be the lowest for many years despite conservation measures being in place for the last few.
    Regards
    John

    • Brian Shaw Author at 10:47 pm

      Hi John,

      The sea trout catches are worrying, there has been a downward trend in recent years and from the reports I have received this year will be particularly poor. I suspect that marine survival is the main issue, the last good year, 2010, was good almost across many rivers. The same widespread geographical effect is apparent this year with catches on the Dee also poor. The reports from the main sea trout beats suggest far fewer but bigger fish; never a good population dynamic. On the positive side I saw decent numbers of sea trout spawning past year and trout fry and parr densities in the burns are generally good. We intend to do some research this autumn on current catches along with historical catches to put things in context, once complete the report will be published on the website.

      We continue to work on improving habitat in the burns along with fish pass improvements where required, these works will be of benefit to the sea trout. Hopefully the runs will improve again once sea survival conditions improve. I am sure the current conservation measures will remain in place although rod exploitation rates for sea trout are probably lower than for salmon. Conserving the big hen sea trout is especially important as they produce a lot of eggs, are repeat spawners and have the migratory tendency.

      I’d like to make sea trout research a higher priority but resources are limited.

      Best regards

      Brian

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