Thursday 18 September 2014

How Long? (Can this go on)

It's the time of year when salmon fishers rant about the weather.  Seasoned followers of this blog will recall last year's posts,  D - 14 The Countdown and D -7 Divine Madness, as examples of my ranting capacity.  However, a quick scan of the Salmon Fishing Forum, FishPal and Trout & Salmon tells you that the salmon fisher's rant has reached epidemic proportions this year.  Unlike Ebola there's no early prospect of a cure or even a vaccine. But you have to feel genuine sympathy for those fishing in north east Scotland, the ghillies and the owners.  First they sustained a dry spring that ran on into summer; then the awful floods generated by Hurricane Bertha's downpours; and now a sustained dry spell with little rain in early prospect. One of my regular readers is on the bone-dry diminished Deveron this week, having driven the 560 miles from Somerset in the full knowledge of the 7 day forecast.  While that may be a minor jaunt for American and Canadian readers, I would point out that they don't have to contend with the torture of the M5 roadworks (what is this Intelligent Motorway the Department for Transport is building?  How does inanimate concrete gain intellect?) or the lower reaches of the M6.  You have to feel sorry for the poor chap.  I can only hope that the Scottish Police don't make it even worse for him on the way back on Sunday with their beastly 'catch an English angler' speed-trap van on the bridge over the southbound motorway just north of the border at Canonbie.  It's an annual feature on Sundays in September, and a £250 fine is just what you don't need after a blank week, so go carefully on the way home.

While I am pining for our annual trip to Tomatin, which sadly is no more, the fishing conditions are no better in Yorkshire.  The MCX rain gauge is empty, and has been so since early August.  The Ure is on its bones, but thank goodness the autumnal temperatures have spared us the ravages of over-heating and oxygen depletion.  Apart from the Dark Shrimp swimming trial day, I haven't fished seriously for salmon since 30th May.  Thus far in September I've cancelled 3 days and now I'm getting worried about the 3 days I've booked for young HMCX at the beginning of October.

Screenshot of BBC Forecast

Unlike the Vanishing Rain of Inverness, in Wensleydale it's just non-existent.  Like everyone else we need a week-long 3 foot spate to freshen everything up and drag fish away from the delights of Hull, Scunthorpe and Goole.  There's nothing in sight that looks likely to deliver that dream. The shift to a south westerly trend next week may be more about hunch than science.

As a result of all this, there's a pall of gloom over the salmon fishing community.  Hysterical Jeremiahs proclaim the end of the Atlantic Salmon and demand urgent government action for its salvation.  Panic stalks the river banks, fishery boards and opinion. The spectre of 100% catch and release looms large.  Science goes out the window, and what remains is used selectively, narrowly, blindly and partially.  Ulterior motives and agendas crowd the wings of the theatre of debate. These are worrying times, not for the salmon, which survived 2 great and 2 small Ice Ages, 4 corresponding periods of rapid global warming and a host of other things we don't know about in the past million years and more, but rather for the potential unforeseen consequences of the 'something must be done' syndrome.  I fear the effects of good intentions far more than I do the variables of our globe.  Of course I like catching salmon and get upset when I don't or can't.  But if, for a time, I can't catch salmon, it's not the end of the whole world.

One of the few advantages of growing old is the perspective of time.  I'm at that nice, if brief, balance where I can still remember things whilst having accumulated lots to remember.  I'm not 100, but in this year it's fashionable to remember 1914 and the outbreak of the First World War. Of course that year's salmon season was submerged under the mass of big history being made, but the meteorology suggests that it was probably at least as bad as 2014 and possibly worse. Certainly it was far hotter and drier for longer.  More recently 1961, 1976, 1995 (when I watched fish panting to their death in hot pools), 2002, 2003 and 2009 come to mind.

With the perspective of time comes scale.  In pondering longer you tend to think bigger and look more widely, whilst contemplating the complexity of the earth's systems.  In particular, the infinitely variable interactions between its gravity, rotation and temperature (via distance from and aspect to the sun). We know our weather is usually variable, but the causes and effects of that variability have wide ranging consequences elsewhere.  Because the salmon ranges widely across the northern hemisphere in its travels, it encounters both ends of the process - our local variability and the distant consequences.  For example, the far end of the processes that gave us a freezing winters in 2009 and 2010 may conversely have seriously impacted the food chain in the Greenland-Labrador Basin on which maturing Newfoundland salmon rely.

North Atlantic Oscillation
Pressure differential between the Azores and Iceland
& 5 year moving average (black line)
1870 - 2010

And this variability is not new. The weather that comes to us in the autumn and winter is largely determined by the balance between the Azores High and Iceland Low atmospheric pressure systems, known as the North Atlantic Oscillation.  This graphic shows the annual balance over the past 140 years, which is clearly highly variable.  When it's positive (i.e. the 2 systems are in the 'right' place) the cyclones generated by heat at the equator can reach us, and we get 'British' weather.  When it's negative, they can't and don't.

At the moment we're in negative territory. The pressure is higher in Reykjavik than Gibraltar.  In a 'normal' year that lovely low south of Greenland would spend 3 days dumping rain onto Scotland to deliver salvation to the Findhorn.  This year it doesn't look like it's going to happen.  Just like last year, the North Atlantic weather map is a disorderly, but wholly natural mess.  Once a high gets settled, it's hard to shift, sits tight over Scotland and deflects all the nice rain to Spitzbergen.

Now, just when you thought you'd had enough science for one day, we encounter the associated phenomenon, the Arctic Oscillation (or more properly, the Northern Annular Mode).  If I understood the interaction between NAO, NAM and Jet Stream I wouldn't be here.  However, the key point is that our weather and the salmon's life is affected by unpredictable global scale influences, most of which remain unseen and unknown to us.  A couple of seasons of adverse NAO and NAM outcomes may cause a massive change in surface plankton availability in the Labrador-Greenland Basin, leading to copepod losses; consequent capelin, shad and sprat prey species decline; and salmon degradation.  Of course, there's also, and always, a reverse case: think of 2004 or 2011, and hope for 2015.  Please don't panic and don't succumb to 'something must be done' unless it's a genuinely big thing on the Vigfusson scale.  I'd hate to have a blank year, but growing up deep in the countryside I learned that I must accept the inherent variability of the natural world, for without that variability there is no wonder.  My young life was determined by sunrise and sunset; the rise and fall of the tide; the passage of the seasons; and at all times by the weather, over which I had no control.  There are cycles in all natural things, and nothing is constant.  The fact that those cycles trump our desires does not bode the end of the world.

I'm not saying everything is perfect, or denying that the fishing in some rivers is presently in decline.  North Sea oil in the east and salmon farms in the west have undoubtedly had significant consequences.  But I note that others are improving: the Tyne is well documented; the Ure up-count has more than trebled in 3 years; the Wear is coming on nicely; and there are high hopes for the Tees.  The salmon is a uniquely successful and adaptable species (have you seen the latest research on its temperature tolerance range? It's 5 times greater than the cod's), but there are limits.  I suspect it finds the noise pollution of the North Sea oilfields and Aberdeen harbour unbearable.  

On that note, I'll go back to my apple crop, which is cyclically good this year.  Best of all my wife can't see my frantic Yorkshire Rain Dance when I'm in the orchard.