Avon surveying complete

I received some feedback following the Aberlour meeting last week which I intend to take on board a) keep it short and b) present the summary first then the evidence. As this is a blog post the first point is not applicable, readers can take it or leave it and they are not stuck on  hard chair for over two hours! The second point I will adopt here. I will also touch on some of the others points raised during the Aberlour public meeting.

Today we completed the last five surveys in the Avon catchment, three mainstem density based surveys, one on the Water of Ailnack and the last site on the Conglass Water.

The conclusion from all our intensive surveying on the Avon: – juvenile stocks in the Avon are on average as good as they were when monitoring began in 1991.

The evidence – comparison of results from sites with a long history of surveying.

The timed mainstem Avon surveys I reported on a couple weeks ago were a new approach for that river so I was keen to repeat some more of the density (area) based surveys that were held on file as they would provide a more direct comparison with historical figures. The upper site today was above the Linn of Avon upstream of Inverloin Bridge.

Avon mainstem upstream of Inverloin Bridge

Avon mainstem upstream of Inverloin Bridge. The site here consisted of a quadrant extending halfway across the channel between rock markers – not ideal but it was fished this way in the past. Today we captured 35 fry and 24 parr from the site which was only 92m2. I don’t have the previous survey results home with me but this this years figures were good, especially for a site at 1500′.

The next site was 6m downstream above Dalhestie. Even in the current low water the Avon here was about 20m wide. We surveyed a transect across the river about 12m long.

Avon survey site above Dalhestie. 103 fry and 29 parr were found here.

Avon survey site above Dalhestie. 103 fry and 29 parr were found here, again good results.

The third Avon site was at an island below Dalhestie.

Island monitoring site below Dalhestie. This site has a long history of surveying providing a good comparison with todays findings.

Island monitoring site below Dalhestie. This site has a long history of surveying providing a good comparison with todays findings.

Electrofishing results from Dalhestie island site.

Electrofishing results from Dalhestie island site. The salmon fry densities this year were the best found at the site and the salmon parr the second best. As always in a wide mainstem site trout are only present at low densities, usually a few trout fry turn up in the still margins of the site. There are older paper records for this site showing that fish densities were little different pre-computerisation.

On the way up we passed the Water of Ailnack which for some reason had never been surveyed by the Foundation.  After tracking down the keepers house permission was received to carry out a survey. The Ailnack is inaccessible to salmon about half a mile up from the confluence with the Avon although considering that the average width at the site was 13m the short accessible area provided room for significant smolt production.

The Ailnack looked pretty good and it was with a good mixed population of salmon and trout.

The Ailnack looked pretty good and so it turned out with a good mixed population of salmon and trout. Much larger fry and parr in the Ailnack than in the Avon, it is obviously a richer water.

The last site today was the usual monitoring site in the lower Conglass at Ruthven Farm.

The site in the Conglass consisted of a 10m long section of the river opposite from where Michael is standing.

The site in the Conglass consisted of a 10m long section of the river opposite where Michael is standing. The Conglass is a very productive burn which always supports a high density of fish. In the 10m long section we found about 240 salmon fry and 49 parr as well as many trout fry.

Long term monitoring results form the Conglass at Ruthven Farm. Tisnis absolute core salmon habitat in the spey catchment. any reduction in salmon densities at this site will be worrying.

Long term monitoring results from the Conglass at Ruthven Farm. This is absolute core salmon habitat within the Spey catchment; any reduction in salmon densities at this site would be cause for concern. If the Spey salmon juvenile population is declining it will tend to show in the more peripheral habitat first with core areas such as the Conglass retaining healthy salmon populations for longer. Fortunately there is no sign of any long term decline in the excellent salmon population at this site.

 

A full report on all the Avon monitoring sites will appear in the Spey electrofishing report 2013 in due course, the above is just a synopsis of todays results.

Whilst juvenile stocks in the Avon appear to be good this year, only a fool would suggest that the numbers of adult salmon and grilse are returning in anything like the numbers seen in the past. Jimmy Gray, the retired river superintendent, and many others have described to me how the bottom of the pools in the Avon used to be red in colour close to spawning with the accumulation of coloured cock fish. That is just not happening at the moment with the poor marine survival but last year and the previous year there were still adequate numbers of spawning fish to populate the river with fry. It is clear now that despite the relative low abundance of spawning salmon last autumn incubation conditions were good for fry over the winter, with summer survival of fry and parr also good. Perhaps we are fortunate to have such good recruitment from a limited stock of spawning adults last year but the evidence shows that juvenile densities in the Avon are at least as good as those recorded over the last 20 years.

Three yar classes of juvenile salmon from the Avon at Inverloin

Three year classes of juvenile salmon from the Avon at Inverloin.

Whilst we have new electrofishing equipment the bits in the water are still the same as they have always been: a stainless steel ring anode and a copper braid cathode; the gubbins in between just provide the power and better control of the settings. The survey technique used today has not changed since the SFCC established its protocols in 1997 (I think!) so direct comparison with previous surveys is justifiable.

We have gathered a lot of data from the Avon this year but we won’t do much surveying in this part of the river again until 2016. Hopefully juvenile densities are at least as good then, and hopefully adult stocks will have returned to something like the abundance seen only a few years ago.

 

There are 2 comments for this article
  1. GRAHAM SALISBURY (SRG) at 11:23 am

    Hello Brian, there simply was not enough time at the Aberlour meeting to ask all the questions without excluding others, so first and foremost, your results of the juvenile stocks, I do not doubt or question your professionalism in carrying this work. The question is how this is comparable to past results and conditions with your predecessor and his team, I know you attempt to justify a comparison in above but could it be you and your team are simply better at catching fish? Also what where the parr and fry numbers actually like in the halogen days? No one truly knows? Yes we now have a scale with a green and red index but this is merely a guide produced by scientists of what they consider to be good guidance generally, you may find our ghillie members have their own scales for accessing adequate juvenile densities!
    So long as our habitat is good, accessible with plenty of clean water, the only results that really matter from the fishery’s view point are the number of returning adults judged by the catch records. If we factor in today’s 80%-90% catch and release figures and the distortion due to a percentage of recaptures whichever way we dress up the stats we are in serious decline! On the subject of abstraction I suggest the Board speak with Fish Legal sooner rather than later re the abstraction threats covered at the meeting.
    Mr McGinnity’s talk was interesting but would have been better balanced with the alternative professional view from a speaker like Dr Summers of the Tay, John Gibb of the Lochy, E. McCarthy of the Thurso or P Gray. I like many of our members attending the meeting feel that the risk of diluting our native stock by using an intelligently run hatchery taking brood stock from the same stream and planting back the progeny in the same area is worth the risk in our current situation. In fact our members spoke with Mr McGunnity after the meeting and the discussions revealed a slightly different outcome to that delivered in the presentation.
    The Spey is a salmon fishery with an annual turnover in excess of 12 million pounds and directly supporting 400 plus FTE jobs for the valley, probably funding all of the posts at your head office including your own. There are many businesses and livelihoods other than the individual fisheries which are dependent on its continued success. Most businesses of this scale have a business plan looking forward, we know this is not so straight forward with a fish that migrates out to distant feeding grounds and back but we can apply variables to account for this. At the moment we seem to be running our plan by the red and green indicators of your juvenile surveys. If I might suggest we change this to the number of returning adults evaluated by a true catch return, we may decide we need to open our minds to using the full complement of fishery management tools available. I suggest we consider a policy allowing stocking above impassable obstructions, then in areas of suitable habitat where there are no juveniles present and finally in areas of low juvenile density that can support additional stock. Eddie McCarthy on the Thurso has managed with the use of his hatchery to bring back a self-sustaining stock of salmon to his river which has allowed him to moth-ball his hatchery over the past two seasons, that should be our end goal on the Spey.
    GRAHAM SALISBURY (SRG)

    • Brian Shaw Author at 8:39 pm

      Wow Graham, your reply is almost as long as my presentation the other evening!
      1) I have justified my comparisons of todays monitoring results with past surveys. In addition I should also point out that most of the data over the years has been collected by Steve and Jim with the assistance of summer students. I have been present during some of the surveys over the last two years but probably only 50% – the actual electrofishing teams are more consistent than you think.
      2) We can continue to debate fish densities back in the good old halcyon! days for ever more, a good topic for the pub.
      3) I never suggested adult returns were good, quite the opposite in fact.
      4) I am sure Fish Legal have already been involved in abstraction discussions
      5) I have already heard all of your suggested speakers except one although to bring other views into the Spey forum would be a good thing. I would personally love to hear Eddie McCarthy report on how he managed to restore the salmon stock on the Thurso with the hatchery (was it unfed fry they stocked?) although I wasn’t aware they were ever under threat?
      6) Your proposed stocking policy sounds very much like the one developed and used by the Spey Fishery Board from 2003 to 2009, in fact it is almost a carbon copy.

      I must admit Graham you are persistent but I’m not sure these constant exchanges on the blog are benefitting anyone? We seem to go round in circles. I can do little more than present the evidence we find in as honest and transparent a manner as I can. It is clear that in the opinion of some to be a biologist on the Spey is akin to being a banker in 2008. “Scrounging” & “losers” were terms I saw used recently in a blog related to the Spey! What can I say?
      Best regards

      Brian

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