[Mike Barrio]

Interesting stuff from the Deveron, Bogie & Isla Rivers Charitable Trust on Facebook today

Facebook page: https://www.facebook.com/DeveronBogieIsla/
Website: http://deveron.org/



BEHIND THE SCENES
Brown Trout Tracking Pilot

You may or may not have heard of this project that we took part in back in 2012/13 – it is well worth a read and the results are fascinating and influence our catchment wide approach to protecting our rivers and fish.

A pilot tracking project on the River Deveron has revealed that some of the large brown trout, that this river is renowned for, are making significant annual migrations throughout the catchment. This collaborative project, between Marine Scotland Science (MSS) and the Deveron, Bogie and Isla Rivers Trust (DBIRT), was coordinated by the Moray Firth Trout Initiative (MFTI) to improve understanding of how resident brown trout are using the catchment. The trout used in the study were from the Blackwater tributary of the River Deveron which has a strong run of large fast‐growing trout. These fish have historically been thought of as sea trout however scales reading analysis suggest that they are more likely fast growing brown trout.

Ten large trout (>44cm long) were caught in the small spawning tributary of the Deveron called the Blackwater at 380m above sea level. This upland catchment is dominated by wet heath and blanket bog and managed primarily for grouse and red deer. The trout were subsequently tagged with transmitters (9mm diameter, 29mm long). These each emit unique acoustic high frequency pulses, which identify the specific fish when picked up by suitable receivers, and were programmed to transmit the signal for 1 year.

The tagged trout were released at the capture site on the Blackwater on 31st October 2012. Thirteen acoustic receivers were deployed along the length of the Deveron in large pools at key locations (see map). When a tagged fish passed a receiver, its tag code was logged together with time and date. These data were later downloaded to build up a picture of the trout’s migration route.

Of the trout tagged, five were logged as far downstream as Avochie, having migrated 42 km from the release site right into the middle of the Deveron Catchment. Of these, one particular trout, a 55cm female (ID22239), recorded a remarkable track; migrating 84km from the Blackwater to Montcoffer nearly at the mouth of the Deveron within a month of release. This fish then stayed in the vicinity of the gorge at Montcoffer and was regularly logged on the receiver positioned right underneath the fishing hut until July. During this time it was never logged on either of the receivers positioned further downstream. The last log at this location was the 8th of July when she began to move upstream and was logged subsequently at Muiresk and Avochie before eventually being logged back at the release site a year later on 16th October 2013.

This pilot study has revealed how this one brown trout has used the entire Deveron catchment throughout the year and not resided in one area, as might have previously been expected. Although the study provides a fascinating insight into the behaviour of these trout further work is required to truly understand the overall variation in movement strategies within the population and to determine whether similar migrations are routinely made by large trout in other catchments too. Furthermore, when considering protection for such fish it stresses the importance of considering habitats throughout the entire catchment and not just those in distinct locations.

[Rob Brownfield]

Very interesting reading indeed!

I have noticed that certain areas hold certain fish at certain times of the year....year in , year out.

The areas become occupied or vacated almost to the day each year by the same fish.

[Hamish Young]

This pilot study has revealed how this one brown trout has used the entire Deveron catchment throughout the year and not resided in one area, as might have previously been expected.

The study is interesting and doesn't really expand too much on what most regular fishers of more northern Scottish rivers either know or suspect... that 'resident' trout are really itinerant in nature and you're often fishing for a different resident in the same location.
Let me put this a different way, a long, long time ago in a (then) well known fishing hotel somewhere on the upper Don I explained 'my theory'  on the movement of trout within the upper catchment and described the 'lies' as being something like hotel rooms in nature....
Depending on season they're sometimes vacant, at other times they're occupied and at some times of the year there's a queue waiting to get in.

I haven't met many hardened river fishers who hadn't also come to the conclusion that trout migrate throughout miles of water rather than stay in the same stretch all the time and, I have to say, I'm slightly surprised that the study suggests folk might expect anything other than that.

Maybe I'm just grumpy. Nevertheless, an interesting piece of work 

H

[James Laraway]

So what about Stillwater trout? What’s people’s views on whether they move about a lot? Most books says they are very territorial...

[Hamish Young]

So what about Stillwater trout? What’s people’s views on whether they move about a lot? Most books says they are very territorial...

In my experience, bigger fish tend to follow habitual patterns (in lochs) and ferox especially so. I recall seeing a bucket load of big (some really ferkin big) trout all massing - like a wolf pack of U-boats - waiting for the smolt run in the shallows where Loch Shiel becomes the River Shiel. Other than some minor jostling for position, they were quite well behaved and almost seemed to be working co-operatively.
I don't think that defines them as territorial - far from it , in fact - but most books should say that trout are opportunistic feeders.
I take the view that all trout try to be territorial, some are better than others and invariably when they're bigger they're better at it.
That's why I like fishing for the ones that are better at it 
H

[Allan Liddle]

There was a nice article on this very subject a little while back in FFFT by someone 
Anyway the above only tells part of the story and i was lucky enough to be involved a little throughout this project, which threw up interesting points and a little bit more than trout move around theory.

Essentially one point that looked fairly conclusive was the fact that big trout breed big trout with he Deveron fish all congregating together (as far as we could see) and it appears also spawning early ( early September) some of which are actually back way down the system feeding again before season end (certainly salmon season end).  So the old adage of remove a big fish and another will simply take its place appears not to be true, more likely other smaller fish of a slightly different gene base will replace said trophy.
In other words you could very likely destroy a system of it's ability to produce large trout (in number) if you chapped all the big ones (salmon the same re River Awe)

In truth there was more questions than answers following the survey and it is clear we need more study into a species of fish many thought (think) they knew (know).
Brilliant study, would love for it to be followed up and expanded if the funding could be found.

Allan

[Derek Roxborough]

The trout in some of our lochs must stay around the same area ,these are the Marks where we go to fish  for them , one loch locally that gets a run of sea trout, there is one particular place where you will always get a hit when the ST are in the loch,  It would seem that Trout have their preferences, especially in the lochs.
Derek Roxborough