Trout in the Evenlode

Sat 27 May 2023, 20:52

Thanks Malcolm and Rod. 

I do not claim to be an expert - but I did marry a fisherman - a trout fisherman when we met many years ago, and a fisherman who has expanded into salmon fishing. And one thing I have learnt is that fishermen can talk, and talk and talk. So I have had to listen, listen, listen. And I have learnt a lot from conversations I have listened to. 

Yes, I have heard that  the rationale underpinning current strategy is supposedly based on a preference for indigenous fish so as not to weaken traits that have been developed. However, on the Wye the hatcheries used salmon swimming in the river - milking them for eggs which were then fertilised. So was this system producing salmon less genetically able to survive in that river?? Who knows?? Personally, I would have thought that, given the rapidly reducing numbers, any method of increasing numbers such as hatcheries would be better than doing nothing as currently is happening. 

With trout, it is the pollution that needs to be addressed. The native brown trout needs clean water. And clean is anything but what the Evenlode is.  But to increase numbers surely you also need fertile fish. 

Like so much of what is happening today, the state of our rivers and the fish in them just may ultimately be a disaster due to man's potentially "incompetent" interference. 

Sat 27 May 2023, 15:48

If I recall one of my Masters courses properly (this on Nature Conservation way back in the 80s so my fading memory competence may be tricking me) I think Rod is quite correct. If I recall correctly "hefting", i.e very environmentally specific adaptation to one area - of genetic populations becomes established in a surprisingly small number of generations. So just putting in "a trout" may -well corrupt might be too strong a word - alter the genetic adaptational fitness of a species to a, say, a particular river.

My question is hence - why isn't someone funding being given to breeding programs to restock individual river catchments? That - along with taking back the profits of shareholders and the bonuses of Water company executives - cleaning up the river properly might put things better.

Sat 27 May 2023, 11:23

I'm on uncertain ground here and am not a scientist but - Janet - I think with trout it partly has to do with not wanting to mix or weaken genetic traits that may have developed over many, possibly hundreds, of years.  The wild trout in one river can certainly have different characteristics eg colouring to the wild stock even in a river in the same system - but how different they might be genetically is an area I wouldn't dare venture into!

I agree there must surely be ways to overcome that - I claim no great knowledge on it.  As for salmon, the farming industry also does great damage to wild stocks, more of an issue in Scotland of course - you won't find one in the Evenlode!  Nor sadly eels which also used to come up Thames tributaries in large numbers.

Sat 27 May 2023, 07:20

What is the rationale for the policy, DEFRA again I guess, of only allowing neutered fish to be released? I would have thought it would have made sense to proactively work to increase the trout numbers by releasing fish that could breed. But that simply doesn’t seem to be on the agenda. Why?? All our rivers are suffering from pollution and from significantly decreasing numbers of fish. 

Our salmon rivers are in real crisis re levels of fish. Salmon face challenges on top of pollution - factory fishing ships at sea and increasing numbers of natural predators. And what does DEFRA do?? Several years ago banned virtually all hatcheries that used to raise and release additional stocks of fish. Result - you will be very lucky to see a salmon ever. 

With some successful projects in addressing species in danger such as red kites, why can’t more be done to save our river fish?? Current policies just don’t make sense. Is that a surprise? 

Fri 26 May 2023, 23:37

Liz, sorry to disappoint, that's because my neighbour and I put some in the river a couple of weeks ago (just because, not to catch) and then it rained so they went downstream!  The 'baby' was probably a chub - I doubt there are any trout breeding in the river these days, though would love to be proved wrong.  And sad to say that even with the Mayfly now hatching in reasonable numbers there aren't many native fish showing themselves....

For the record, the trout came from Bibury and were 'triploid' ie neutered as that's all you're legally allowed to put into the rivers. 

Fri 26 May 2023, 14:41

Walking back from the station we just saw four adult and one baby trout! I'm not sure I've ever seen that before.