26 April 2020 News/Editorial
Some informative, even learned, fishy reading for you this week, mercifully none of it the drivel normally associated with these pages.
Before getting to that, an update on the river itself. Our cauld is out of the water and the herons are standing there sentry-style ready to pounce on any errant smolts. In short, it is summer level, however you define that, and, scant comfort for those who should have been fishing last week, they would have caught little. East winds, summer level, gin clear water and piercingly bright cloudless skies are guaranteed to make life very hard for salmon anglers.
Smolts arrived here last week, joyously leaping about and gleaming bright silver in the evening sun. The forecast is for the current prolonged dry spell to crack up increasingly as we move into next month, with more changeable conditions throughout May. Until then, with low and clear water, keen littoral observers will easily see the sheer numbers of smolts passing downstream.
Speaking of which, one of the papers referred to below comes from the Dee’s smolt tracking study. Spoiler alert, it provides little or nothing by way of proof, for those determined to blame birds for everything, that goosanders and cormorants are the (wholly) responsible killers.
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And so to that reading matter. First, try the April edition of “The River” from the RTC here https://www.rivertweed.org.uk/news/wp-content/uploads/2020/04/The-River-April-2020.pdf
Included are excellent explanations as to why none of us can now fish, even if we live here on the river bank, as well as Ronald Campbell’s historical perspective; further spoiler alert, that never (ever) before has the Tweed been unfished (both by rod and net) for the majority of the spring, despite, plague, famine, wars and every other sort of disaster that this country has suffered over the centuries.
These are indeed unprecedented times.
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And then there is Fisheries Management Scotland's annual review of the Scottish 2019 salmon season here http://fms.scot/wp-content/uploads/2020/04/200402-Final-Review-FMS-2020
Most compelling are the 2019 catch figures per river at the back. Despite favourable fishing conditions, in stark contrast to drought ridden 2018, the estimation is that the total Scottish rod catch will exceed 2018 but only because of those contrasting conditions, nothing to do with there being more fish. Indeed, because there was no North East drift and T&J net fishery in 2019, you could well argue that there were even fewer fish.
If there is one thing that looks odd, it is the continuing success, masked briefly by the drought in 2018 when they could hardly operate, of those far northern rivers, Messrs Halladale, Wick,Thurso and Naver, all of which did very well in 2019, some even beating their long term averages.
Unlikely as it seems, it would not take Hercule Poirot to deduce that the only difference between a Tweed/Tay/Dee/Spey/Findhorn/Beauly/Conon etc smolt and one from the Naver is the extra miles of the journey up the east coast of Scotland, which the Naver smolt never has to make on its way north. Seldom are explanations that simple, but it is undeniably odd. No such oddities for west coast smolts travelling north, because we all know that fish farms and their sea lice make their chances of survival miniscule.
Whenever the Missing Salmon Alliance can conclude its smolt tracking work on the east coast, maybe, just maybe there will be the glimmer of an answer.
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Speaking of which, we now come to the Dee’s smolt tracking paper covering the last four years, 2016 to 2019 inclusive, available for all to study here http://www.riverdee.org.uk/f/articles/Smolt-migration-through-the-River-Dee-and-2019
Tags (ie smolts) lost were 2016 26%, 2017 48%, 2019 49% and 2019 32%, if my maths is correct meaning that slightly over 60% on average survived past Aberdeen harbour and into the North Sea over that four year period. Those who blame goosanders, mergansers and cormorants will be disappointed to hear that losses were no different in the control zone in 2019, where there were no piscivorous birds, to other zones where there were. Again if I read the conclusions correctly, but for two significant dredging events in Aberdeen harbour in 2017 and 2018, which significantly impacted the 48% and 49% losses in those years, the average survival over the four years would have been 70%.
With a very much larger tracking study being done on the Tweed this year, and now in progress, it will be of particular interest to compare our 2020 results with those of the Dee and other rivers. Without the hazard of any harbour as busy, and as occasionally lethal to smolts, as Aberdeen, the Tweed smolt’s chance of making it to the sea should be up there in the 70% range. That it was not 70% in the (comparatively small) 2019 pilot study was a concern, with losses occurring disproportionately in the middle river, with almost none below Kelso. That too is at odds with the Dee study where losses in the river were spread approximately evenly as the smolts progressed downstream.
But if losses within rivers are not as large as feared, even if 30% is still a very large number (eg 30% of 1 million smolts?), and if the birds are not solely to blame for overall smolt mortality, then it would be no surprise to me, and many others, if the far bigger problem of smolt, and post-smolt, survival is not in our rivers, but in the sea.
Where it may be very difficult to do anything about it. Especially if it is, directly or indirectly, related to our ever warming climate.
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With apologies for the quantity of referred reading this week, but fear not, if anything is certain in this troubled world, it is that the normal lowbrow fare will resume in these pages next week. Until then, keep very safe.
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