Archive for March, 2012

Cleaning the Lemno. Volunteers please!

Monday, March 12th, 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

I am flattered and pleased that so many people read these bulletin blogs, and I have been wondering whether there is any way I can use your interest and enthusiasm for the South Esk to improve the habitat.

The owner of the lower section of the Lemno Burn is Craigeassie Estate, who have allowed woodland thinning and habitat improvement on the lowest section of the Lemno from the A90 down to the confluence with the South Esk at the Red Brae.

The bank work done during the winter months has left a lot of fallen timber and flood debris in the bed and close to the banks of the Burn. If we had a team of 6 to 10 people clearing and burning this rubbish the result would be a much lower risk of the burn getting clogged up in the next spate.

What we are looking for is a free flowing Lemno Burn in the stretch above the confluence. If the flows were able to dislodge the silt and reintroduce the natural sequence of riffle-pool-riffle, thereby cleaning the gravels and restoring spawning areas and juvenile habitat, we would probably attract up to 100 spawners in that section of the Burn. Let’s say that is 60 hen fish depositing an average of 4,000 fertilised ova, and that 1% of those eggs make it to the sea as smolts. On the basis that 5% of those smolts return to the river that could lead to an extra 120 salmon returning to the South Esk. OK, this is a pretty crude way of predicting improvements, but at least it is something!

If any of my readers are interested in cleaning out the Lemno starting at 1000 on Sunday 1st April, with a BBQ lunch provided and finishing by 1500, please e-mail me at Colonsay@hotmail.com or phone Moray (07835 717 150) or me (07748 634 658) to confirm. You will need wellies or waders and your own choice of tools, although some will be provided. I hope to see some of you on April Fools’ Day, but this is no April Fool!! TA on 12/3/2012

The salmon tracking project starts

Friday, March 9th, 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

I met Gordon and Julian, the scientists from the Marine Scotland office in Montrose, at the gate to FCW’s Milton Beat today, where they had been enjoying a day out of the office checking their receivers, replacing batteries etc. Their report to me on progress with the South Esk salmon tracking project was the first bit of output from the project.

Julian Maclean at the Haughs of Finavon with mobile radio tracking receiver for following returning salmon to their preferred spawning locations.

Usan nets now operating: The weather at sea over the last couple of weeks has been variable and some days the sea has been too rough to work the nets. However, catches have been steady, and MSS targets for tagging met. Yesterday (Thursday 8th of March) the Usan nets caught 16 salmon, a mixture of 3SW and 2SW fish. That is a good number to catch in the nets in early March and, although at present we have no idea of where these fish were going, or which river they ‘belong to’, a catch of this size at this time of year may start to give succour to the Pullars, who have long claimed that early spring socks are better than some have recently claimed.

Building the picture, piece by piece:Of course, one day’s catch does not get close to telling the full story, especially about the fragility or otherwise of populations from the different rivers exploited by the net fishery. What it does do however is to tell us that these unattributed multi sea winter (MSW) fish were present in quite respectable numbers very early in the year. One should speculate no further. That is the fact!

First South Esk salmon tracked:But we can go a little further than this because the tracking receiver at Bridge of Dun picked up a signal in the very early hours of Sunday morning showing that a salmon tagged at Usan had entered the South Esk. It was subsequently tracked at the Middle Kinnaird Hut, some two and a half miles upstream, but has not yet been picked up by a receiver upsttream of Kinnaird dyke.

What does this tell us? First, that the tracking methodology and technology works! Secondly, that at least one fish caught in the Usan nets was bound for the South Esk. Thirdly, there are no reports of fish being tracked in the Tay, and none so far on the North Esk.

Whilst we shouldn’t get too excited, I think it is fair to claim that this is a good starter, and that we can anticipate more news on the migration of returning adult salmon to the South Esk (and perhaps elsewhere) over the next few months.

TA 0n 9/3/2012

Postscripts:

9/3/2012 I wanted to add a note on another aspect of the way this project is being approached by the MSS team. Julian and Gordon told me about a big fish, almost certainly a 3SW hen salmon, which, after being caught and selected, responded “too quickly” to the anaesthetic they give to every fish before fitting a transmitter. They decided not to radio-tag this salmon because, although it would have been a most interesting fish to track to its spawning location, they felt that the risk of it not surviving was too high. The salmon was therefore returned safely to the sea after recvovering from its anaesthetic.

I very much like this sensitive approach to the tagging task. Both Julian and Gordon are keen to minimise the amount of handling each fish gets as it is anaethetised and then fitted with a radio transmitter (about the size of a gerkin). Rather than risk a fish, however interesting the data it might produce, they are adopting a cautious approach in order to maximise the data set from the project. This I feel is good solid science targeting core data, and deserves our support. TA

12/3/2012 I spoke with Gordon Smith this morning, one of the scientists in the MSS Montrose office. He confirmed that up to now 23 salmon have been tagged, of which about 50% are 3SW and 50% 2SW. Deciding whether thay have been at sea for two or three sea winters is done by reading scales from fish anaesthetised and tagged. Apart fom that analytical tool, the only other sampling is a small, almost untraceable, clip of the trailing edge of the adipose fin taken for DNA analysis. I say “untraceable” because I was curious to know how the MSS scientists would identify salmon already tagged and caught again in the Usan nets. In fact the sharp eyes of a scientist would be able to find any fish that had already been tagged, and thus avoid loading them up with another transmitter!

I asked Gordon how he thought the project is going, to which he said that if they had known in advance that by the 12th of March they would have successfully tagged 23 salmon they would have been well satisfied.

To summarise: one fish tracked into the South Esk as far as Kinnaird. No other fish reported from receivers elsewhere. Gordon and I agreed that until there is some fresh water in the rivers we are unlikely to see much movement upriver. TA on 12/3

Tributaries: The Lemno Burn

Monday, March 5th, 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

After reading Bill Menzie’s report of 1957 I came away with the conviction that the South Esk’s tributaries are of more importance than I had thought to the capability of the river to regenerate its distinct populations of salmon and sea trout. This function applies as much to the catchment’s low ground burns as it does to those in the upper catchment. This is not to suggest that the main stem of the South Esk, especially downstream of its confluence with the Prosen, does not play a vital role in providing spawning habitat for summer and backend fish, and juvenile habitat for parr that have moved out of their native tributaries, as well as well as parr born in the main stem of the river. It is worth remembering that Menzies wrote his report at a time of strong runs of spring salmon and summer sea trout.

Lemno BurnThis is the section of the Lemno Burn immediately upstream of the Red Brae confluence. The banks have recently been cleared of unthinned woodland that prevented light getting to the bed of the burn. Woody obstructions have also been removed from the bed of the stream, along with overhanging bankside vegetation. For the first time in at least 20 years the burn is now flowing freely which should start to clean its gravels and encourage increased spawning.

The Lemno Burn is an important middle-river tributary of the South Esk which enters the River about 1000 yards downstream of the A90 bridge at Finavon. The Lemno flows through an intensively farmed section of the Vale of Strathmore where repeated unauthorised dredging over the years has been normal land management practice. The most recent of these dredging incidents took place in 2010/11 after considerable pressure was exerted by a farmer on SEPA officials who, apparently disregarding the SAC status of the S Esk and its tributaries, and in contravention of the letter and the spirit of the Controlled Activity Regulations, allowed a dredging operation on nearly a kilometre of the burn upstream of Bogindollo. The straightening of this already damaged water course smacks of the abuse of the Rottal Burn in Glen Clova. If you add the diffuse pollution from fertilisers and pesticides to the point pollution from roads run-off and slurry pits to the catalogue of abuse that the Lemno represents, it is not surprising that it is a poor performer spawning and juvenile-wise.

Lemno Burn

The Lemno a bit further upstream from the picture above. This section of the Lemno Burn used to include the lade from Tannadice Dam, which was demolished in 1946. The artificially wide channel has never had a chance to close up because of the lack of bank growth and consequent protection from erosion. This picture was taken immediately after the remedial forestry work was completed. A good spate should clear out the bed of the stream and start the long process of moving the silt and cleaning the gravels.

But how bad a performer is the Lemno? At present I don’t have the details (but I am working on that). Suffice to say that electro fishing of the Lemno up to Bogindollo reveals some salmon fry but very few parr, and those that were caught were (I quote an MSS scientist) “gigantic”. We can assume they have feasted well on fry. One of the problems of the burn in terms of juvenile salmon habitat is that there is very little riffle because of the woody dams holding back the water in a series of deep and slow moving pools, ideal for predators, including large parr. That problem may now be solved in the bottom section (downstream of the A90) after the remedial work completed in March 2012.

It is worthwhile comparing the shapes of the catchments of the North and South Esks. In the case of the former, the line drawn around the river’s watershed produces a shape not unlike a chestnut tree, with a short trunk and tributaries spreading widely as the full foliage of a mature chesnut tree does. The South Esk’s watershed shape by contrast looks more like a poplar tree with its long trunk and relatively few small branches. The confluence with the Prosen (or to continue the tree analogy, the fork in the poplar), the South Esk’s main tributary, is located in the upper third of the river catchment, some 28 miles from the sea. The shape of the North Esk’s catchment is similar to that of Tweed, where good-sized tributaries flow through fertile and relatively low ground glens to form a chestnut tree shaped catchment. In terms of the ‘wetted area’ available as nursery habitat, Tweed and North Esk provide better facilities for young salmon than the South Esk, and that is reflected in their relative abundance of salmon.

Until about ten years ago sea trout were the South Esk’s dominant species. It may well be the case that the trend of fewer spring salmon and the increase in autumn salmon has displaced sea trout from their spawning and juvenile areas. Certainly, the ratio of salmon to sea trout has changed noticeably in the last few years. In the longer term, species identification and genetics should help us understand whether this thesis is defensible.

As Menzies points out, the tributaries of the South Esk and Prosen are crucial in regenerating salmon and sea trout. The fact that the South Esk depends so heavily on its tributaries, and that there are so few of them, means that we need to value every yard of every tributary, from Pow Burn to Noran, Melgund, Lemno, White Burn, Carity, Moy and all the other tributaries above the Meetings. We should pay attention to the detail of managing these precious streams and of monitoring their outputs of parr/pre-smolts. That means more measuring – boring, but essential groundwork of accurate and effective fishery management.

TA 5/3/2012