Please see below for material on the WTT website. The links to slide presentations have been added to the WTT site and these slides fill in some of the unavoidable gaps in presentations due to changes of video cassette. They also allow you to read the text/see diagrams that cannot always be picked up on the condensed video.

Despite the titles of the talks, BOTH TALKS are equally relevant to Trout and to Salmon management, conservation and restoration. You will probably need to watch each talk at least a couple of times to absorb all the info.

As Eric says at the beginning of his talk, the issues affecting salmon genetics and management follow the same principles in trout management.

There is huge food for thought here with respect to wild brood stock and domestic brood stock hatchery programmes for the attempted restoration and support of either Salmon runs or self-sustaining wild trout populations (including Soft mouth trout Madjoni!!

These presentations were part of last year's (2009) Wild Trout Trust annual get together (hosted in Youlgreave Derbyshire). Talks from this year's (2010) annual get together will be online soon as well (hosted in Hungerford, Berkshire).

Wild Trout Trust.


Parts 3 and 4 of Andrew's talk clearly and objectively outline the dangers of diploid hatchery strain fish to self-sustaining stream-breeding trout populations. This is based on the results of controlled experiments, not on unproven theories or beliefs. Overall, both talks emphasise the need to understand what is ACTUALLY THE PROBLEM in the system before you can solve it. If greater angling amenity must be supported by supplemental stocking - at least make that a reversible situation that does not dilute away the natural abilities of stream-bred fish to survive and reproduce themselves.

Hi Paul
I look it.Genetic diversity of trout have to be preserved.That is main goal.
I found interesting also part about marble trout in Adriatic.Our marble is pure and that fish dont mix with brownies.
I sad somewhere before,Skadar basen was only part of fresh water during Ice Age.And that ancestor of our trouts developed in 3 species:brown,marble and softmouth trout.This species spawn in different time and that is probably why they dont mix.

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Save the Softmouth
The ancient noble trout of Montenegro

These are indeed very interesting talks and do mitigate against the success of introducing diploid stock fish that originate from brood fish that are non-native to the river in question. However the inference is that these reservations may not be so clear cut if the stocked fish were obtained from native brood stock, especially if harvested every year and the progeny returned to that river.

This would suggest that the salmon stocking schemes that rely on catching brood fish and then stocking their progeny back into the rivers from where they were taken may not actually be that detrimental to the gene pool.

Also, if stocked fish survival rates are poor as a result of the stocked fish being so poorly adapted for life in any particular river that mortality was very high then concerns about inter-breeding where few stocked fish are going to make it to the redds might not be so justified.

In rivers like the Monnow and Test where trout have been stocked for over many decades, you have to wonder what the genetic make up of the trout actually is and I suspect that, either stocked fish had minimal impact because they had a very low interbreeding rate or, if the interbreeding was successful, the result gene pool is so mixed that it is pointless trying to purify it at such a late stage as there are no "native" fish to protect.

The other interesting point was that a number of stockings, principally of trout, into waters where the fish were not native and therefore could not have possibly been the result of generations of adaptation to the particular environment, have been spectacularly successful and that must give some food for thought.

The other argument is that concerns for the integrity of the native stock are perhaps overblown if the level of native stock is so low that extinction is approaching. This means that the choice might be no salmon or stocked salmon. This must still infer that stocking the Wye with the progeny of carefully selected brood fish from that river may not be the disaster that some suggest.

We are now in April and the Wye catch has barely broken 20 which following last year's disaster gives no cause for optimism in a natural recovery.

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“There is no more lovely country than Monmouthshire in early spring. Nowhere do the larks sing quite so passionately, as if somehow inspired by the Welsh themselves. There is a blackbird on every thorn and a cock chaffinch, a twink as they call him there, on every bush...... It moved me profoundly. I had been spared to see another spring, and I thank God for it.”

Oliver Kite
“A Spring Day on the Usk”
A Fisherman’s Diary

Sewin, many thanks for absorbing the talks and devoting attention to the subject.

A couple of additional bits of food for thought - Eric's talk flags up the dangers of cross breeding brood stock from the same river system; but which form parts of different breeding populations. This is very likely because the brood fish are not caught on the spawning beds - but in resting pools in the river. These resting pools often contain fish from lots of different populations...

Secondly, domestication effects - even when using wild broodstock - are nigh on impossible to avoid. The only time supportive breeding (i.e. wild broodstock and egg box schemes) have been observed to make a positive contribution is when the habitat is completely degraded.

The first generation offspring from wild broodstock have been observed to be significantly different from stream-spawned juvenile fish in terms of foraging ability and other vital "life-skills". You also have to factor in the loss of offspring (and their subsequent better survival and reproduction) that WOULD have resulted if wild brood stock were able to select their own mates and spawn in-stream rather than being artificially mated in hatchery conditions.

That's really interesting - I had assumed previously that the marble trout relied on physical separation (e.g. by impassable barriers) in order to avoid hybridisation.

I hope it is OK if I broaden out the debate a bit by musing on the above selected points too??

1.) The interbreeding rate could be quite high in terms of "attempted breedings" where low fertility hatchery fish cross with wild fish. However, the lower survival and fertility of the hybrid offspring would mean the rate at which hatchery genes "penetrate" into the population is quite slow (on average there has been about a 25% loss of genetic variation across the UK trout genome). BUT you will be losing overall numbers of fish through time because of all the "wasted" breeding efforts of wild fish crossed with hatchery fish. You then have to stock more fish to support the same angling return...and thus speed up the loss of genetic variability. In that sense, it is not about "purification" of wild strains - it is about not irreversibly losing the mongrel-like variation in the wild genome that confers such good survival and reproduction.

2.) Two points here - one is that the natural environment in places like New Zealand is fantastic habitat, I WISH WE COULD FIX UP ALL OUR RIVERS TO THE SAME PRISTINE STATE!! It would make the lives of salmon and trout a lot easier in the UK!!! Secondly, it was also a completely "naive" ecosystem - which are famously easy to invade by exotic species which has no pre-existing similar species. In other words, an exotic species being placed into a vacant ecological niche has a massive advantage - like the kid who found the key to the tuck shop with no grown-ups around!

3.) As Eric says, there is no point trying to fix a habitat (perhaps other than a spawning habitat issue - but why not fix the spawning habitat???) or pollution bottleneck with supportive breeding. Furthermore, if your hatchery breeding programme has a poorer success rate than your wild fish - you actually push the population to extinction sooner. Far better to actually fix the real problem and let the fish sort themselves out - they are much better at surviving and breeding than when we try to do it for them (they've had more practice over the last few million years )

There is no physical separation on our rivers like big waterfalls or something.
All salmonides lives together and still there is no hybridisation in Zeta river.
Only bigger river in adriatic drenage that have major problem with hybridization (marble and brown trout) is Slovenian river Soča.

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Save the Softmouth
The ancient noble trout of Montenegro

Very cool - inherited spawning timings either causing or maintaining separate speciation.

yap..mother nature take care
That ancestor of this three salmonids(marble,brown and softmouth trout) developed in way that all three species have their place....in river,in food chain,behaviour....

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Save the Softmouth
The ancient noble trout of Montenegro

PG and SB, if I may butt in here and add a little of my received wisdom on no.2 the trout eggs that were shipped out to NZ and other colonies were probably from crosses of wild or much less domesticated stock than is available now. I would also muse upon how many (failed) attempts at stocking there were until sustainable populations came about?

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"The sun was so delightfully warm, and the stone, which had been sitting in it for a long time, was so warm, too, that Pooh had almost decided to go on being Pooh in the middle of the stream for the rest of the morning."

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