Loch Leven Catch Survey Update (to end July)

You may recall that, just over a month ago, we produced our first attempt at analysing data from the Angler Catch Return cards that many anglers had been good enough to complete when they go out and fish on the loch in April & May. This was published on the blog on 9th July and you can refresh your memories regarding the background if you wish by clicking HERE.

APRIL MAY JUNE JULY YTD
Total Boat Turns 88 313 304 248 953
Anglers Cards Completed 20 74 92 104 290
23% 24% 30% 42% 30%

As you can see, we had a total of 196 completed Catch Survey cards handed in for June & July which brings the total for the season to date to 290. representing just under 1 in 3 of the total boat turns (boats x sessions fished).

However cards are only currently completed by trout anglers whereas quite a number of boat turns were by pike anglers particularly during April & May – we will probably look to introduce pike return cards next season because we estimate that over 1000 pike have been caught this year. In reality, cards were probably completed by about 40% of boats fishing for trout – whilst that is a guesstimate, it is still a very impressive percentage and illustrates tremendous cooperation from anglers!

APRIL MAY JUNE JULY YTD
Total No of Rods / Anglers 39 147 144 218 548
Total Hours Angling Effort 304 1127 1056 1437 3924
Total Boat Hours 156 584 558 724 2022

The Catch Survey cards record the number of anglers per boat (rods) as well as the number of hours fished. From the completed cards, we can see that boat hours  total 2,022 hours in total for the season so far and that the total hours of angling effort represented by the cards  (a boat with 2 anglers fishing 8 hours each = 16 hours angling effort) comes to 3,924 hours!

APRIL MAY JUNE JULY YTD
Total Fish Caught 28 197 164 178 567
Released 18 144 110 115 387
% 64% 73% 67% 65% 68%

From the 290 completed cards, we were able to see that 567 brown trout had been recorded as caught during the first 4 months of the season, out of which 387 (68%) were released and 180 (32%) kept.

APRIL MAY JUNE JULY YTD
Average catch per boat per session 1.4 2.7 2.0 1.6 2.0
Average catch per boat hour 0.18 0.34 0.29 0.25 0.28
Average catch per angler per session 0.72 1.34 1.14 0.82 1.03
Average catch per angler per hour 0.09 0.17 0.16 0.12 0.14

This is where it starts to get a bit more interesting.  The data suggests that the average catch per boat per session up until the end of July was 2.0 trout and the average angler caught a fraction over 1 fish per session (1.03 to be exact) on average.

Bearing in mind that we are looking at a wild brown trout fishery, the fishing results for May and to a slightly lesser extent June look pretty good. July’s figures though confirm what we have been reporting in the blog that fishing on the loch was pretty difficult in terms of the number of fish being caught with the usual culprits such as conditions being too bright or windy, lack of fly hatches etc being cited at different times.  It reminds me sometimes of race horse trainers who always have a list of excuses as to why their horse has come in 6th!

Although we have not yet started analysing the cards for August, it is clear already that far more fish are currently being caught and could even be on course to improve on even May’s figures – famous last words! Perhaps that is not so surprising because at this stage of the season, the small trout tend to emerge from the weed beds and this starts to stir everything up.

We are now sure how meaningful the catch per hour figures are but it would suggest that an angler should catch a brownie on average once every 7 hours 8 minutes  (0.14 fish per hour) which is an hour longer than the figures suggested in May.  Again, it looks as though August will lead to a sharp improvement and hopefully that will continue through to the end of the season.

APRIL MAY JUNE JULY YTD
No of boats catching 0 trout 9 23 34 35 101
No of boats catching 1-2 trout 7 28 39 44 118
No of boats catching 3-5 trout 3 10 13 19 45
No of boats catching over 5 trout 1 13 6 6 26
Anglers Cards Completed 20 74 92 104 290

The first thing that jumps out at you is that 101 of the 290 total cards submitted up to the end of July have recorded no fish being caught which is equivalent to 35%.  Gut feel suggests that is probably pretty representative of the actual position and nobody who knows Loch Leven will be too surprised.  The loch has always been one of the more demanding waters to fish and makes you fight for each one.  Getting the tactics right for the conditions (where to fish, what depth in the water column, fly patterns etc) is of paramount importance which is why Loch Leven regulars have a huge advantage over those who fish here relatively infrequently – fishery staff are only too willing to pass on advice to anyone who wishes it!

APRIL MAY JUNE JULY YTD
No of Trout measured for length 27 124 133 134 418
Average Length (millemetres) 415 407 389 378 393
No of Trout weighed 11 89 53 75 228
Average weight (lbs) 2.08 2.42 2.39 2.48 2.42

Although we are obviously interested in the numbers of fish being caught, we are also gathering information on the sizes and therefore age groups of the trout.  The above table shows that a total of 418 trout were measured for length and 228 in total were weighed.  Before anyone queries why 418 + 228 = 646 which is more than the 567 total recorded fish caught, 79 fish were both measured & weighed!

The average length of fish measured had been 409 mm at the end of May but that has now dropped to 393 mm at the end of July and will probably drop a bit further in August now that young fish are more in evidence. Data taken to date suggests that a fish measuring 390 mm in length would weigh about 1 lb 5 ozs, give or take a couple of ounces either way.  And yet the average weight of those fish weighed appears to come in much higher at 2.42 lbs (2 lbs 7 ozs) – why the big differential?  We can only surmise that it tends to be the larger fish that are weighed whereas the smaller ones are more likely to be measured. The true average therefore is somewhere between the 2 figures with a definite bias towards the bottom end of the range. So let’s perhaps say for sake of argument that the average size of fish caught so far this season has been about 1 lb 10 ozs or thereabouts.  We have said it before and will say it again that the average size of the million+ trout caught on Loch Leven in more than a century up to the 1990s was 15 ounces whereas nowadays the average is approaching double that.

What is interesting too is the number of big fish being caught.  Although there are no real whoppers as yet that have been caught (although there have been various anecdotal reports of them being seen), barely a week has gone by without someone recording one of 6 lbs or more and the various photos that have been sent to us show them to be fabulous specimens.

APRIL MAY JUNE JULY YTD
Total Trout measured / weighed 28 197 164 178 567
Trout measuring > 480mm / 3 lbs 9 46 25 23 103
Trout measuring > 590mm / 5 lbs 0 10 10 11 31

As  you can see from the table above, so far this season, 31 trout have been recorded as having weighed more than 5 lbs or measured more than 590 mm (which we estimate from data collected represents a fish of about 5 lbs) which represents 5.5% (or 1 in 18 or so) of the total fish recorded to date this season.  I doubt Loch Leven has ever had a higher frequency (actual or relative) of fish of this size being caught.

If we broaden the scope to include all those fish weighing over 3 lbs, (and / or measured 480 mm), then the ratio falls to under 1 fish in 6 (103 out of 567).  I suppose you could say that Loch Leven emphasises quality more than quantity most of the time.  It is always lovely to hear anglers coming back to the pier saying that they have caught a ‘fish of a lifetime’ – which hopefully makes up for those times that you come back empty-handed!

Finally, once again, our sincerest thanks go out to all anglers who make the effort to fill in the Catch Survey cards and return them to us and we hope that giving this feedback on the results makes it feel worthwhile.

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