Spey mainstem surveys update

After eight days of surveying we finished the Spey mainstem salmon fry index surveys today (below Spey dam at least). We usually leave the sites above Spey Dam for a couple more weeks so the results from there will follow in due course.

53 sites were surveyed although only 51 are reported below. The two other sites are an additional site introduced at Kinchurdy in 2015 and an alternative Aviemore site surveyed for the first time today. The results from the Aviemore site will be discussed below these sites are not presently part of our routine reporting network.

The Spey 2012 – 2016 salmon fry index survey classification scheme and the 2017 salmon fry counts are shown in the tables below.

Spey salmon fry index fry and parr classification scheme (based on 442 Spey surveys completed 2012 to 2016).

 

Of the 51 surveys only four were not in the good or excellent categories. The two sites in the low category were the perennial low fry count site at Phones and the site closest to Spey Dam.

The mean salmon fry count for sites downstream of Spey Dam in 2017 was 32.5/min, the highest mean count recorded during the six year monitoring period. This situation was not unexpected; there were good numbers of spawning fish in the mainstem last year and flows during the critical incubation period were benign. We have yet to do a mainstem survey, downstream of Spey Dam, where no salmon fry were found, but to find such consistently high numbers is unprecedented. The relatively high abundance of fry at present is readily observed by anyone who takes a few steps along the shallow margins. Fry are only the building blocks but our monitoring shows that high fry counts are usually followed by high parr counts in subsequent years; barring population limiting or regulating, events.

These surveys are primarily to assess the salmon fry population but we also catch parr. In 2016 the parr counts were published in the same format for the first time with similar colour coding based on 20% bands.

We start these surveys in the lower river, working upstream, and during the first day or two parr were notable by their relative absence. As we progressed upriver the parr counts improved with some sites producing their highest parr counts (Ballindalloch through Tulchan in particular). The mean parr count  (downstream of Spey Dam) is just below average for the sequence, with the lower river counts probably reflecting the lower fry counts in that part of the river in 2016. The Phones sites may be a low fry count site but it is often above average for parr, as was the case in 2017.  We noticed in 2015, another year with low parr counts in the lower river, the fry grew well, well enough that a proportion would reach the size threshold to become a one year old smolt. This is likely to happen again this year, although the future viability of young, and small, smolts is probably not as good as the normal older and larger type.

Most of the sites surveyed are considered to provide good or excellent habitat for fry, but not all. One example of a site where the habitat is categorised as parr in the Aviemore site S195L1. However, despite the poor habitat we still caught 53 salmon fry in three minutes today; even the poor areas of the Spey support decent numbers this year.

S195L1 survey site at Aviemore. The substrate is mainly sand/pebbles with the sampling done in little runs between weedy mounds. (Photo credit Sean Robertson)

There are few suitable run/riffle habitat sites in this part of the river but we did survey a new site today 1,500m further upstream. The habitat here was excellent resulting in a catch of 224 salmon fry, the highest count from any site this year. It is good to see that suitable habitat is being well used as fry produced in these small patches of good habitat will help populate the entire stretch with parr.

The new Aviemore site surveyed today. The substrate and fast, shallow, flows are ideal for salmon fry. The results from this site have been filed but are not presently used as part of the routine monitoring. (Photo credit Sean Robertson)

It was good to complete the mainstem surveys within a relatively short period during a period with consistent low water conditions. Our attentions will now turn to the Avon, and Livet, where we will repeat some of the surveys from last year to see if fry counts have recovered from the low values recorded in the wake of Storm Frank.

Incidentally volunteers are always welcome on these surveys. If you fancy a hard working day out in a beautiful part of the Spey catchment just get in touch.

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Spey salmon fry index mainstem surveys 2017

Conditions have been perfect this week for the mainstem salmon fry index surveys, low water being one of the most desirable factors.  Therefore we started the 2017 surveys on Monday making good progress reaching as far upstream as Tulchan by the end of play today. The salmon fry index surveys consist of 3 minute timed surveys, primarily in shallow run riffle habitat although for continuity and historical reasons some of the sites are equally suited to parr. We try to do these surveys at the same time of year keeping as many variables as consistent as possible e.g. same sites, staff and equipment.

The draft results to date for salmon fry are shown in the table below (for those not familiar with the colour coding black is absent, red the bottom 20%, followed by amber, yellow, light green, with dark green for the top 20% of Spey results 2012 to 2016)

Spey mainstem salmon fry index results to date.  The results from the lower half of the river have been good with all sites in the moderate to excellent categories. The mean salmon fry count from the sites surveyed so far is the highest in the sequence. Tulchan D remains the only site with 100%  dark green classification, although the counts were actually below average for that site today, perhaps a consequence of the unusually good parr counts (see below). (Note that the Phones & Lower Pitchroy sites have still to be surveyed)

These initial results are encouraging although not unexpected following an excellent spawning and relatively benign flows overwinter. The 8ft spate in early June does not seem have had too much of an impact; thankfully. A feature this year is the consistency of the results, perhaps this is a consequence of the spate which may have evened out the distribution of the fry from their initial clumped distribution arising from proximity to the redds.

The situation for parr is a bit different with low parr counts in the lower reaches, improving greatly as we progressed upstream.

Spey salmon fry index parr counts. Although these surveys are primarily intended to assess salmon fry parr are also captured. Parr were notable by their relative absence in the lower sites but from Aberlour upstream the results are much better. The salmon parr counts from two of the four Tulchan sites were the best recorded with results from the other two being the second highest. The low parr counts in the lower sites are likely to be a consequence of the low fry counts in the river downstream of the Avon confluence in 2016 – remember Storm Frank?

 

A sample of the typical mixed catch of fry and parr from the Tulchan, Ballindalloch and Knockando sites today.

The June 2017 spate may not have affected fry counts too severely but large scale riverbed movements were apparent almost everywhere downstream of the Avon. The locations of one or two of the survey sites has to be moved slightly due to the riverbed movements. This is not critical with this type of survey where we follow the habitat rather than fixed landmarks. At other sites the surveys may have been completed in the same location but the habitat had changed due to sediment deposition.

Recent deposits of cobbles in a survey site at Knockando. These fresh looking cobbles are recent arrivals, formerly this site was dominated by boulder habitat, some of which protrude above the new cobbles. It was much easier wading than usual today but these cobbles are likely to move during the next few spates.

 

It doesn’t take long for nature to colonise empty habitat as can be seen by the number of simuliidae larvae on this recently deposited rock.

Few trout have been recorded so far during these surveys, no surprise as they generally spawn in the tributaries, but there does seem to be more eels than in recent years. In the first two sites elvers were present in abundance with the size distribution increasing quickly as we progressed upstream. The concern regarding low eel numbers in recent years seems to have abated a little, which in my view is a good thing. I like to see everything in the river doing well, well nearly everything! Eels, like salmon, are ocean migrants, and whilst their life cycles are quite different both species depend on the health and suitability of a range of different habitat types.

Ultimately today turned out to be a good day; we made good progress with our surveys, spent some quality time with the new Tulchan factor and ghillies and there were lots of juveniles to be counted. Not bad at all considering I was on the point of going back to bed when I got up this morning. A summer cold is a bind but once I was up and about it was forgotten about. I even did some maintenance on the pick-up tailgate – it shuts now, the old 3 in 1 is great stuff.

 

 

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Spey mainstem salmon fry surveys 2015

It may have been a summer of excellent conditions for angling but the up and down water levels have played havoc with the electrofishing programme, especially in the mainstem. However, with only three sites remaining to do the results are almost complete. It should be noted that the surveys were completed over an extended period this year compared to normal with the median survey date 16 days later than in 2014.

The mainstem salmon fry index surveys comprise 3 minute electrofishing sites, generally in shallow run/riffle with cobble substrate. However, due to habitat distribution and a mix of historic and new locations, the sites cover a range of habitat types. We do this type of survey to try and understand the distribution, and success or otherwise, of salmon spawning along the full length of the Spey mainstem.

Spey mainstem salmon fry index survey 2015

Spey mainstem salmon fry index survey 2015. The table is ordered from the bottom of the river to the top with the site code based on 500m sections from the sea. For example Site S264R1, Truim is 132km from the sea.

Th mean number of salmon fry/minute in 2015 was 18.8, exactly the same as recorded in 2014 (it is unlikley that the three remaining sites will alter the average significantly). Considering the low catch of salmon, and the apparent low number of adult fish in the river last year this is a satisfactory result for fry.

After four years of consistent surveying some patterns are emerging;

  • From Craigellachie downstream the results are generally above average with all sites in the moderate to excellent categories this year.
  • From Craigellachie to Phones the results are generally lower, no doubt a result of the higher gradient here and the restricted availability of spawning gravel.
  • The Ballindalloch to Castle Grant area generally supports above average counts although Tulchan D is the only site to be in the excellent category every year.
  • The two sites in the Grantown Angling Association water were good this year – better than normal
  • Above Grantown the gradient flattens out and suitable survey sites are less frequent.  In suitable sites fry counts are often good e.g. Abernethy AA and Dalraddy. The production of juvenile salmon in this area should not be underestimated, on warm, still, days in the summer many parr can be seen rising in the wide, shallow glides prevelent in this area, and it is not as bereft of spawning gravels as it may appear at first glance.
  • We introduced a new site this year in the upper river to replace the Truim site which was difficult to access and contained barely enough suitable habitat for 3 minutes surveying. The new site was 2km further downstream with good habitat and is likely to support higher fry counts on average than the site it replaced. Note the lower Badenoch AA site will not be surveyd this year due to access restrictions associated with bridge repairs.
  • The two sites closest to Spey Dam produced lower counts than usual this year.
  • Above Spey Dam we found fry at 70% of the sites, a big improvement on the last two years. The fry counts here were all in the very low or low categories so whilst some fish must have made it up to spawn last year the counts suggest the spawning stock above the dam was small.

Water levels were on average higher this year than in the two previous years but the relatively stable results support our previous conclusion that this survey technique is not as sensitive to water levels as it may appear (H&S being an equally important consideration for mainstem surveys).

Whilst some of the survey dates were later than normal we have surveyed some sites later in the past but never have we found mainstem sites where the average size of the fry was over 7omm in August. At the Boat o’Brig site the largest salmon fry were 86mm; a size and date combination with the potential to produce one year old smolts next year.

Why such large fry you may ask as it has certainly not been a year with high water temperatures which would promote growth? The relatively low numbers of parr recorded this year is likely to be a contributing factor, as could the medium water levels with high wetted areas of habitat available. The presence of high densities of larger parr is likely to depress the feeding activity, and therefore growth of, the smaller fry but in years when the parr counts are lower the absence of “despotic behaviour” by the parr could allow more of the new season fry to survive and thrive.

Again we can say that salmon fry were present at every site below Spey Dam. Above Spey Dam the juvenile salmon population continues to be too low and we can only conclude the adult spawning stock in that part of the river is not in a healthy state.

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Spey mainstem semi-quantitative surveys

For our last day electrofishing we headed for the mainstem to collect some semi-quantitative (no stop nets and only one run through with the electrofisher) data on fish densities. Mostly we do timed salmon fry index electrofishing surveys on the mainstem but that techique doesn’t produce data on fish densities. It is impossible to fish the entire width of the Spey mainstem (even in these very low water conditions) so we restricted ourselves to surveying defined areas along the margins, a technique that had been used before and should be repeatable in the future.

The mainstem density site at Aberlour. The site was 5m X 22m long giving an area of 112m2. We found over 150 salmon fry anf 70 parr in the area outlined by the red lines. Habitat quality is excellent with mosy boulders and the remnants of ranunculus plants.

The mainstem density site at Aberlour. The site was 5m X 22m long giving an area of 112m2. We found over 150 salmon fry and 70 parr in the area outlined by the red lines. Habitat quality was excellent with mossy boulders and the remnants of ranunculus plants.

This area of the river at Aberlour has in the last couple years produced high salmon and parr counts so it was no surprise to find that densities of both were excellent. The density of salmon fry was 134/100m2 and for parr 62/100m2. Over 60% of the parr were larger than 90mm, a size threshold considered to indicate it would be ready for smoltification the following spring.

The next site had been surveyed before in 2002 and 2003, although the river had changed a little making exact replication difficult.

Mainstem site upstream of Blacksboat. Not an easy site to fish now, its was deep on the outer edge with sandy deposits along the bank. Habitat quality was rated as moderate. However we still caught 85 salmon fry and 20 parr along wiht a few trout, eels and a minnow.

Mainstem site upstream of Blacksboat. Not an easy site to fish now; it was deep on the outer edge with sandy deposits along the bank. Habitat quality was rated as moderate. However we still caught 85 salmon fry and 29 parr along with a few trout, eels and a minnow. 80% of the parr were large enough to be expected to smolt next year.

The density this year was 98 fry and 33 parr per 100m2 respectively. The salmon fry density was similar compared to 2002 (114/100m2) and 2003 (79/100m2) whilst the parr density was higher than found in 2002 (20.2/100m2) but less than the 50/100m2 recorded in 2003. Still there appears to have been little overall change in fish densities now compared to that snapshot from over a decade ago.

The next site was upstream of Advie Bridge where the habitat looked good but fish densities were lower than anticipated. I don’t have a good photo showing the entire site but the picture below shows the type of habitat present.

Lower half of the mainstem site at Advie Bridge. We caught 15 salmon fry and 7 parr in a site 73m2. Lower than expected but still moderate in the SFCC classificaton for a stream over 9m wide

Lower half of the mainstem site at Advie Bridge. We caught 15 salmon fry and 7 parr from an incomplete site of 73m2. Lower than expected but still moderate in the SFCC classificaton for a stream over 9m wide. 70% of the parr at this site were big enough to smolt in 2015 (if they survive).

Unfortunately two thirds of the way through the site Steve slipped on the slimy rocks, landing on the anode which ceased to function. Thankfully he was okay and it was the the last electrofishing day rather than in the middle of our survey programme. We missed out on the last planned site at Grantown but we had at least gathered some interesting semi-quantitative data from the mainstem, the most important part of the Spey catchment in terms of smolt production.

Spey biologist with obligatory clipboard!

Spey biologist with obligatory clipboard!

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Auchnahannet Burn surveys 2014

Almost finished our electrofishing for 2014, just a few odds and ends to tidy up including two monitoring sites in the Auchnahannet Burn today. This burn was the subject of a habitat restoration project by the Spey Catchment Initiative over 2012/13 with fencing to exclude stock access and tree planting. We have monitored these sites over the last three years – there has been quite a transformation in the quality of the instream and bankside habitat.

The Auchnahannet Burn upper site in 2012. This site is located immediatly upstream of the Dulnain / Carrbridge road

The Auchnahannet Burn upper site in 2012. This site is located immediatly upstream of the Dulnain / Carrbridge road

Roughly the same view today, the burn is a lot narrower and deeper,. Trout habitat you may say but you'd be wrong, there was a great population of salmon.

Roughly the same view today, the burn is a lot narrower and deeper. Trout habitat some may say but they’d be wrong in this case – there was a great population of salmon. There is a lot less sand in the stream bed now. The water was deceptive in its depth, it was almost to the top of our waders in the foreground.

The view downstream from below the road bridge. This shot was taken in winter but the bare banks and erosion have gone.

The pre-fencing view downstream from the road bridge. This shot was taken in winter but the bare banks and erosion have gone.

The downsteam view today, what a transformation.

The downsteam view today, what a transformation.

The results from the surveys in the upper site are shown in the table below.

An impressive increase in the salmon population in particular at this site

An impressive increase in the salmon population in particular at this site, same for the trout parr. Note that the figures are expressed as fish per 100m2 wetted stream bed area.

Some of the mixed salmon and trout catch during processing (note: they some are still under the effects of the anaesthetic).

Some of the mixed salmon and trout catch during processing (note: some are still under the effects of the anaesthetic).

I didn't think the lower fish looked quite right, it is potentially a trout/salmon hybrid. Upper one is a cracking fat salmon parr.

I didn’t think the lower fish looked quite right, too many parr marks for a trout, potentially a trout/salmon hybrid. Upper one is a cracking fat salmon parr.

One problem at the site were the long streamers of fibrous algae which made catching the fish difficult. We only fished each site once but I reckon our efficiency was lower than usual.

The long strands of algae made fish capture and net movement difficult, consequently we left a lot more fish behind than normal.

The long strands of algae made fish capture and net movement difficult, consequently we left a lot more fish behind than normal.

The lower site produced less good results than we recorded last year when a tremendous density of parr were found. Not sure why the parr numbers were lower today but we caught a lot of salmon fry.

The results from the lower site. Less parr thanlast year for some reason but no shortage of salmon fry.

The results from the lower site. Less parr than last year for some reason but no shortage of salmon fry.

Must remember to survey these sites immediately after a spate next year, there might be less algae about then.

Kirsteen and Polly processing the catch on a fresh autumn day.

Kirsteen and Polly processing the catch on a fresh autumn day.

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