ART Blog

 

Thanks to funding from SEPA and the Doon Fishery Board we have been able to make a start on controlling invasive weeds on the Doon. Himalayan balsam is was well established on the Chapleton Burn (the one that flows in at Cassillis) but with the enthusiastic help of BTCV volunteers, ART staff, spouses etc we have removed most of it.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Being an annual plant it is very shallow rooted and can be pulled quite easily, the main hazards being nettles/insects/soft muddy bottoms and bit of grass in the eye. However with a bit of determination this sort of scene:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

can soon be turned into this:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

We hope we have caught the balsam in time on the Doon as so far there is very little on the main river downstream. Having said that we were electrofishing at Monkwood Mill last week and we found a single plant growing by the famous Lemon Pots pool.

 

This plant was removed but there will be others. We would urge all lower Doon to be vigilant and to remove any flowering balsam plants before the pods start to explode.

 

Himalayan balsam is regarded as a pretty and harmless plant by many but the rate at which it spreads and its dominance once established is amazing. If we don’t get on top of the balsam now the Doon will soon be the same as the lower Stinchar: wall to wall balsam. Take a drive round the roads upstream of Ballantrae and you will soon see the extent of the problem. There the balsam is forming hedges round fields, becoming established along roadsides, taking over any rough ground,gardens, etc.

 

Thanks for your help: your river needs you.

 

It was good to get out electrofishing today, our first proper day surveying, although the Salmon in the Classroom project had involved a few mini surveys.

 

Gillian and myself, with the assistance of Galston Angling Club members surveyed a few tributary sites in the upper Irvine Valley before the rain put us off  (looks like the announcement of a hosepipe ban in Dumfries & Galloway has worked a treat!)

 

The first site was in Galston in the Burn Anne, or Burnawn as it’s known locally. The findings here were very good with an abundance of salmon fry and parr, with even better densities than the excellent results recorded at the same site last year. In 2008 a fish pass was installed in the lower reaches of the burn and a massive number of salmon were seen spawning in the burn for the first time. This year the fry density was even higher, despite no one reporting seeing any salmon spawning last winter. The salmon parr density was 6x higher than last year, presumably a result of the high fry densities last year.

We also had some nice trout parr, although the largest was only 168mm, whereas we had 10 bigger ones last year. The condition of all the fish was superb, as can be seen in this photo of a 168mm trout.

 

 

 

 

 

 

 

 

Another site, the Huggin Craig Burn at Newmilns gave us our highest ever density of trout parr (156/100m2).  54 parr came from a site that was only 19m long and under 2m wide. Nearly all the parr came from a single deep pool with overhanging bushes. The remarkable concentration of parr in that pool was probably a result of the extended period of low water, with the larger fish congregating in the deeper holes. This highlights the importance of habitat variety. If that burn had been dredged or straightening in the past, would it have held any parr? The condition factor, and growth rate of the trout parr was relatively poor, probably due to the over crowding and competition. At least two herons flew away from the vicinity of the site as we approached so they were obviously aware of the potential food source.

The trout parr were very pretty, although this photo doesn’t do this one justice (we were under a tree and I had to use the flash).

 

 

 

 

 

 

 

 

The deep pool where we found all the parr.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Keep tuning in for more titbits of info on the work of the Trust.

Brian Shaw

 

June and July are the months when the rare sea lampreys can be seen spawning in Ayrshire. We saw a lamprey spawning nest today (known as a redd) in the lower River Irvine. The redds can be easily spotted and identified by the trained eye, especially at this time of year when the river gravels have a good coating of algae. A clean area of river bed with a mound of gravel on the downstream side could be a potential lamprey redd.

 

The redds can be sizeable affairs, in fact it is not unknown for wading fishermen to fall over when they step into a hole in an otherwise flat river bed. The lampreys use their sucker-like mouths to lift cobbles and pebbles to create the spawning depression and to cover the eggs.

 

This photo shows three sea lampreys spotted in the Doon in July 2008.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Adult sea lampreys are 2-3′ in length and they die after spawning. If anyone sees a sea lamprey in Ayrshire the Trust would be delighted to hear about it.

 

Brian Shaw

 

We are working our way slowly through the massive pile of scale samples taken during the smolt trap project on the River Ayr. The majority of the salmon (and sea trout) smolts have been two year olds but some of the scales have highlighted the different growth strategies followed by fish of the same species.

The photo below shows scales taken from a salmon smolt of 116mm  (a small one) caught in mid May. It was a one year old plus (meaning new growth this spring, a salmon’s birthday is generally considered to be on the 1st April) smolt, nothing unusual about that nowadays but the growth burst put on this spring was huge. It is possible to backcalculate the length of the fish when any particular feature on the scale occurred. By doing this we can see that the smolt was small at the end of the first winter, around 60mm, meaning that it almost doubled in length this spring.

 

 

 

 

 

When we are electrofishing in late summer a fry of that length would be considered quite small or perhaps from an upland part of the catchment where temperatures and growth rates are slower.

 

 

 

 

In contrast the photo below shows a scale from a salmon smolt of 193mm, the biggest one captured in the smolt trap. It was a two year old plus at the time of capture in mid May but it was also very small at the end of its first summer, again about 60mm. This fish put on a huge growth spurt in its second year in the river.

 

So here we have two fish, both relatively small at the end of their first winter in the river, one of which puts on a growth spurt and becomes a one year old smolt, whilst the other piles on the weight during its second summer in the river before migrating to sea as a giant two year old smolt.

 

This highlights one of main differences between Atlantic salmon and pacific salmon where the lifecycle of some pacific species is very rigid with one year in the river and one in the sea. This can result in predictable runs e.g. even years producing more that odd years. Atlantic salmon are much more flexible and the fish returning to the river in any particular year could be from eggs laid in the river from several different spawning years. This provides insurance against a catastrophic loss of fish in any year, but on the other hand pacific salmon don’t seem to be doing too badly!

 

Brian Shaw

 

I had a wee walk along the banks of the River Ayr last evening to see how effective the Giant hogweed spraying had been. The spraying had made a huge difference although it was annoying to see the odd plant that had been missed. A follow up visit will be required to mop up the survivors.

 

We took great care to try and target the spraying on the hogweed only although where it is dense it is impossible to avoid collatoral damage to the more desireable native plants. The photo below is a good example of well controlled spraying.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

There were quite a lot of Yellow May Duns hatching. In the past I have witnessed similar hatches being decimated by sand martins, swifts etc but there doesn’t seem to be the same number of these birds about so far this spring. This Yellow May landed beside me.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

However, the young mallards were taking advantage of the hatching flies. This brood was particularly well advanced.

 

 

 

 

 

 

 

 

 

 

 

A nice evening for a walk by the riverbank.

 

BS