Archive for September, 2012

Some South Esk salmon numbers

Tuesday, September 25th, 2012

These bulletin blogs represent news about Finavon and the South Esk, and my views as a riparian owner. They are not the views of any other organisation, nor are they designed to promote the interests of any individual or organisation other than Finavon Castle Water and factors affecting the fishery. Tony Andrews

In the light of the publication of 2011 catch statistics for all Scottish salmon districts, it may be useful to revisit my blog of last summer when, based on calculations of smolt production and ICES/NASCO returning adult fish percentages, I concluded that the annual run of salmon and grilse into the South Esk is about 10,000.

What did the nets catch in the September 2012 extension period? The item of news that should interest anyone who knows the South Esk is the number of salmon and grilse caught by Usan Fisheries Ltd during the two week extension of the netting season into September. This “two weeks” was actually eighteen tides, and the total catch was 272, of which the main part was grilse. I have good reason to believe that my source is reliable. TA

In 2011 I wrote;

“While there’s no room for complacency, it is very encouraging that in 2011 there are good numbers of spring fish in the river. Of course one swallow doesn’t make a summer, but it is also true that the 2010 run of spring salmon indicated a reasonable return of adult salmon, despite the poor rod catches resulting from low water yet again. The evidence therefore suggests that there appears to be a surplus of spring salmon year-on-year. By “surplus” I mean an escapement of fish to spawn that allows the regeneration of numbers of adult fish well above the minimum number required for sustaining stocks to return to the river between the start of the season and the end of May each year. That for me is the meaning of the term ‘sustainable’.

Ken Whelan fishing Pheasantry (Castle Beat)

Ken Whelan fishing Pheasantry in May 2010 (above)

We don’t know how many salmon and grilse run the South Esk. It is a pity that the Esk Board has not devoted some of its considerable resources to a proper assessment of South Esk stocks, and continues to make management decisions on the current guesswork basis. We only have rod catch statistics to tell us what the trends are. But I will hazard a guess that the five-year average of returning adults, based on 60% of Usan net catches and the declared rod catch, plus our own observations, is somewhere around 10,000 fish. That figure has not yet been challenged and reflects more the general ignorance of the numbers and structure of South Esk stocks than it does on the actual numbers of fish”.

I based that speculative figure on 1,500 MSW fish up to 31 May, 3,000 MSW salmon and grilse in June, July and August and 5,500 MSW salmon and grilse from 1 September until spawning time (ie including salmon that enter the river after the close season on 31/10).

Since these figures were not challenged, and in fact a number of scientists commented that the method of reaching them was logical and consistent with experience from other rivers, I think it is fair to quote them again here. Based on those figures I wrote the following:

Average number of South Esk salmon and grilse killed by mixed stocks nets = c. 2,500*

Total number of salmon and grilse returning to the River = c. 10,000*

Total number of spawning females, allowing for 20% in-river losses = c.4,000

Average weight of spawning hen salmon = c. 8 lbs

Average number of eggs deposited by each hen fish = 4,500

Total number of eggs deposited in South Esk catchment (4,500 X 4,000) = c.18 million

Number of smolts produced annually by S.Esk (say 1% of total deposited eggs) = c.180,000*

Assume smolts returning as grilse is about 8% and of MSW fish about 5% (average 6.5%)

6.5% of 180,000 = c. 11,700 salmon and grilse arriving off the Angus coast (PFA) prior to nets exploitation.

Looking at those figures now, I really don’t see much need to change them. Perhaps I would reduce the return average from 6.5% to 6% to reflect the downturn in grilse numbers, and the proportion of fish caught at Usan and attributed to the South Esk more like 40% than 60%, but I think that those are the only adjustments neccessary.

In the context of those (admittedly speculative) figures I was interested to see the 2011 catch statistics published by Marine Scotland last week for salmon and grilse caught in the South Esk District. These returns include net and rod fisheries of fish killed and fished caught and released by rods. Nets of course kill everything they catch.

Here are the 2011 salmon and grilse catch returns for the South Esk District

Salmon killed                                                               = 5,646

Grilse killed                                                                  = 1,203

salmon caught & released                                           =   518

Grilse caught & released                                             =     85

Total South Esk District catch                                    = 7,452 salmon & grilse

If we take the figures for the South Esk District nets (the only legal nets being those belonging to Usan Fisheries Ltd) we see that:

In May 2,307 salmon were killed: average weight 4.13 Kgs

In June 1337 were killed: average weight 4.26 Kgs

In July 1053 were killed: average weight 4.2 Kgs

In August 746 were killed:  average weight 4.36 Kgs

The consistent average weight of fish throughout the season (about 9lbs) suggests that there was a predominance of MSW fish throughout the season, expressed either as some very large MSW salmon offset by the lower average weights of grilse, or (more likely) a reflection of very low numbers of grilse, which would typically average 2 Kgs.

The figure that stands out in the 2011 season is the large number of 2,307 salmon killed in May. There are a number of aspects relative to this figure that are worth comment:

1. The value of 2.307 of prime spring salmon is very high. One may assume a per fish value of £150 to £200, giving a gross income to Usan Fisheries Ltd for May month of £300,000 plus. No wonder the Usan business doesn’t want May removed from the netting season, as has already happened in February, March and April.

2. If the 2012 radio tracking data are used to indicate how many of these May fish were bound for the South Esk, we might assume, from the proportion of recorded tagged salmon in the South Esk, that 40% of those 2,307 salmon killed in May 2011 were South Esk fish.

3. Upper proprietors observed that there was a prolific run of spring salmon in 2011. Usan’s May return confirms that the spring run continued to be strong into May. Based on Usan’s May catch return we might assume that about 900 of those fish were of South Esk origin. That figure tallies with my guess that an average of 1,500 salmon enter the South Esk before the end of May.

4. Catch returns from Cortachy & Downie Park, Inshewan and Finavon indicate that there were good numbers of MSW salmon in the South Esk from March onwards, and of course with no netting taking place in March and April, these salmon had free access to the river. Moreover, none of the rod-caught salmon in those two months was killed. Spawning escapement in 2011, even with the 900 fish killed in May by Usan nets, was clearly significant.

It is important that the Marine Scotland radio tracking project fulfills its purpose, which is to find out where early running South Esk salmon spawn. The project has nothing to do with stock assessment beyond that single purpose, although people (such as I!) will inevitably extrapolate from the data to support their arguments. We need to have a health warning on such methodology because the data coming from the MS project are not fit for any purpose other than demonstrating where some spring fish go in the South Esk catchment.




Return to the Lemno Burn in low water

Sunday, September 23rd, 2012

These bulletin blogs represent news about Finavon and the South Esk, and my views as a riparian owner. They are not the views of any other organisation, nor are they designed to promote the interests of any individual or organisation other than Finavon Castle Water and factors affecting the fishery. Tony Andrews

Today was one of those September mornings that confirm childhood memories of golden autumn days. In the 1950s there were no high-roll bales of straw after the barley harvest. At that time the mechanised baler produced a rectangular bale that could easily be lifted by one person. But I rather like the haphazard jigsaw of the 6’0” high-roll bales in the harvested fields, even if it is impossible to lift them manually – or is it? Is there some giant of a farmer’s son somewhere in Aberdeenshire or Angus who routinely lifts and carries the huge bales from the fields to the steading?

Lemno Woods & high-roll bales

This is the view looking south across the big field towards the Lemno Burn and the policy woodlands that line its banks. This is the section of the Lemno discussed in this bulletin blog.

So, today was a sunlit autumn Sunday, and I decided to extend the dogs’ constitutional with a wander up the Lemno Burn, which was very low after our long summer of spates. I wanted to see how the channel downstream of the A90 had developed since the volunteer day on 1st April, and what I saw surprised and delighted me.

Lemno Burn low water stream

Low water stickle in the Lemno Burn just upstream from the Red Brae

On first inspection you might think that the differences between now and a year ago are marginal: there is still far too much silt in the long flat section 300 metres upstream of the Red Brae, but below that there is now plenty of gravel exposed by healthy streams, riffles and stickles. While the gravel is still covered with algae and it is obvious that agricultural enrichment is dominant, there are places where fish might spawn. The reduced tree canopy is letting far more light in than a year ago, with the result that grasses and wildflowers are starting to re-colonise the banks.

Lemno Burn pool in the margin of the wood

One of the main pools (above) in the Lemno Burn in the section where the high tree canopy was reduced by thinning in the winter of 2011/12. It was in this part of the lower Lemno that I observed large numbers of salmon and sea trout parr on Sunday 23rd September.

As I walked up the left bank of the burn in the margins of the woods that define the burn’s course, peering into the water I saw small fish in every single pool. At first it was just the odd fish darting for cover as I appeared above them. But when I reached the long flat pool about half way between Red Brae and the main road (A90) I saw literally hundreds of parr, ranging in size from about 5cms to 10 or 11cms in length. In some places there were shoals of these little fish numbering 40 or 50, quite closely packed together. When disturbed they darted around the pool individually, afterwards to return to a deeper section where the shoal reformed. I was able to get quite close to a small group of fish and study them in detail with the use of my Polaroid glasses. They were certainly parr, but I have no idea whether they were salmon or trout.

 Lemno pools full of parr

Woodland pools in the lower Lemno Burn are holding large numbers of salmon and sea trout parr. The abundance of juveniles is encouraging, but as yet we do not know the ratio of salmon to sea trout. Those data would be useful in understanding the role that the Lemno Burn plays in the makeup of South Esk stocks of both species.

The same pattern repeated itself all the way up to the village. There is absolutely no point in exaggerating, and every reason to try and report as accurately as possible what I actually observed. I estimate that in the lowest 800 metres of the Lemno Burn there are at least 500 salmon and sea trout parr, and there may be more than this because my estimate is pretty conservative. These juvenile fish look to be in good condition and, judging from the quality of the riparian habitat, there is probably plenty of food available. What I cannot say, and will avoid speculating, is whether the removal of about 40% of the tree canopy and obstructions from the bed of the burn have influenced the numbers of fish using this section. In other words I have no baseline for comparison.

September Lemno silt

Above: not a very good photo of the silty bed of the pool in which I observed a large shoal of salmon or sea trout parr (probably the latter I guess).

Thinking through the implications of the various bits of information on the Lemno Burn I have recently received:

  1. A government scientist told me that the middle Lemno supports small numbers of very large parr (or did when it was electro fished a couple of years ago)
  2. The farmer at the Meadows on the King’s Burn, the only major tributary of the Lemno, described his father finding dead salmon kelts on the banks of that burn in late winter in recent years.
  3. My own observation on 23 September 2012 of large numbers of salmon and/or sea trout parr in the 800 metres of the Lemno Burn upstream of its confluence with the South Esk.

One could not possibly argue that all is well in the Lemno Burn, especially after the dredging vandalism carried out by the farmer to the section that runs parallel to the A90 just north of the Kirriemuir junction. There is no doubt that a lot of work needs to be done to increase the Lemno’s output of smolts. However, I am surprised and delighted to allay my concerns to some extent after what I saw today. These little fish are almost certainly in the second year of their lives and should smolt next year (April/May 2013). If, as may well be possible, the Lemno Burn is releasing two or three thousand  pre-smolting parr into the South Esk each year, it is making a much better contribution to the overall stocks of salmon and sea trout of the South Esk than I had feared.

 A newly hatched Red Admiral (Vanessa Atlanta)

Autumn and a newly hatched Red Admiral butterfly Vanessa atlanta. The Rajah Brooke birdwing butterfly Trogonoptera brookiana is bigger, the Purple Emperor Apatura iris more regal and the Camberwell Beauty Nymphalis antiopa more exotic, but is there a more beautiful insect on earth than our very own Vanessa atlanta ? (even the Latin name is gorgeous!)

Wouldn’t it be interesting to learn what proportion of the fish I saw today were salmon or sea trout? I shall ask the Esk Trust to help us answer that question.

TA 23/9/2012

Low water, the first since March!

Thursday, September 20th, 2012

These bulletin blogs represent news about Finavon and the South Esk, and my views as a riparian owner. They are not the views of any other organisation, nor are they designed to promote the interests of any individual or organisation other than Finavon Castle Water and factors affecting the fishery. Tony Andrews

Despite the low water level, where on our webcam there is only a paltry stream around the north side of the Armchair Rock, Sally Bateman caught a grilse in House Pool (see the photo below) bringing the FCW salmon catch to 99 in 2012. Congratulations to Sally, and to her ghillie, Moray Macfarlane, for advising her to fish House Pool at the right moment in the day.

Sally Bateman's grilse from House Pool

Sally Bateman with her grilse from House Pool. She caught this fish in very low water in bright sunlight. 

Listening to the jungle drums from upstream and downstream of Finavon it appears that, even in these low water conditions, fresh MSW fish are running. Earlier in the week Moray reported fresh fish in Finavon’s pools and from Inshewan and Cortachy I understand 5 or 6 salmon have been caught, some of them fresh. We need water!

The netting extension ended last weekend but there has been no news of Usan Fisheries’ catches during the extension period. The important thing is that the river is now open to our late running salmon, and any sea trout yet to migrate into the river.

TA on 20/9/2012

Update on 21st September with a report from Milton Beat. Again, another day’s fishing in sunny and low water conditions, but not too difficult for Julian Staples, who caught a very nice grilse of 6lbs from Tyndals Pool. Julian is an expert at eliciting responses from salmon and sea trout in Tyndals. There are many people who fish Finavon regularly who beliueve Tyndals is our best pool. It is certainly a very nice pool to fish. TA

Update on 26 September Yesterday and the night before saw the worst September storm we have seen for many years. I am just glad I wasn’t at sea! A quick glance at the FCW webcam today shows a nice autumn spate that peaked during the night and is now starting to drop back. There should be fresh fish in all four beats later in the day and I expect catches to stasrt to pick up today and for the rest of the week. TA