IN THE latest instalment of Not Exactly Fishing, Gordon Mack ponders the values of catch returns and makes his own analysis of a week’s fishing this summer in South Uist.

I MUCH admire angling friends who studiously keep a fishing diary. It is unquestionably a valuable resource, especially if you are a regular on certain waters, to be able accurately to recall the huge variation of dates, times, tackle, locations and weather which combined to bring success.

I have tried, from time to time, to keep facts and figures up to date.  But somehow tiredness at the end of a hard day or week fishing, coupled with a memory which nowadays seems about as elusive as double-figure sea trout, conspires to ensure that my diaries contain more blank pages than completed ones. And as anyone who has ever consulted a diary knows, you only reap the information you sow.

Followers of the on-going heated war of words between the wild salmon lobby and the aquaculture industry over the reasons for the decline in Scottish west coast catches, will be no strangers to statistics.  Selective interpretation of figures ensures that the polarised views of both sides can always be stoutly argued and disputed.  As for facts?  It always seems a bit odd to me, that my mathematically-inclined chums when faced with a strong debate always rush to the safety of numbers, holding them up to be the mirror of indisputable certainty.

If even the IMF apparently struggles to provide a consistent interpretation of financial performances, what chance has the humble angler got?

Anglers may be no more honest, or dishonest, than any other recreational group, but it is commonly accepted that catch returns are a notoriously tricky science.  The “one that got away” is now apocryphal; unverified weights are frequently unreliable, with catch-and-return adding an even larger element of uncertainty to many statistics.

The bald figures of total fish caught, weight and single largest specimen or basket, may offer satisfactory measures for, say, a competition, but sadly deliver only vague clues about relative performances for any day, week or season on any water anywhere.

So what figures can you rely on?  A single number cannot on its own provide a trend.  And without supporting totals for numbers of anglers, or the myriad other factors which bear on angling such as time of day, weather and water conditions, give no genuinely accurate picture about the performance of any fishery.  And that assumes actual rod returns are 100% complete and accurate in the first place – or that your favourite stillwater fishery is bold enough to publish full details of its stocking dates, volumes and weights.

It was with some hesitation, therefore, that I sat down the other day to compile a set of catch returns for this summer’s outing to South Uist.  The machair lochs and those controlled by the local angling club, comprise what Stan Headley neatly understates in The Loch Fisher’s Bible as “some of the finest wild trout fishing to be found anywhere.”

I was fortunate enough to be sent at the beginning of this season, a copy of SUAC’s catch returns for 2010.  They made entertaining reading, and offered a month-by-month set of totals for more than 45 lochs. Among the statistics were details of the heaviest fish of the season, numbers returned and those under-sized.  Valuable information especially if tracked against previous years, and a huge and commendable effort by SUAC.

But for the visiting angler, of course, they give only the most rudimentary guidelines, as a word in the ear of any of the regular local ghillies soon reveals.  So I thought I would carry out my own statistical analysis of my week in the Uists.

I fished for seven days from June 10 and the conditions were generally accepted to be “challenging” with strong cold winds, mainly from the north or east and air temperatures averaging 12 or 13 deg.  On the big machair lochs like Bornish, Upper Bornish, West Ollay, Stilligary and Altabrug there was almost no fly life to be seen and surface feeding fish were very scarce.  Many boats were recording blanks.

These lochs are not deep but we fished at all depths, trawling the weedy bottoms without any greater success: daytimes mainly, with a ghillie, although I did have a few evening hours bankside on Dun na Cille.  There was no single fly any more successful than another. But one of the larger fish on the final day – and I’m not telling you from which loch – was so full of 1cm snails that they were spilling out of both ends when landed.

It was not a great week for traditional loch style, free drifting boat anglers. My catch returns to Storas Uibhist and SUAC will show a somewhat-less-than-grand total of 15 fish, of which I kept just five.  The best was 1.5 lb. What the figures can’t reveal is this little analysis, carried out solely for my own amusement:

• Days fished = 7
• Hours fished = 42
• Est. no of casts (@ 3/min less time for tangles and fly changes) = 7200
• Fish caught = 15
• Average casts per fish = 480

Whit?  Who’d take up fly fishing.  It’s just as well there’s so much more to it than simple counting.