Tagged smolts detected at sea

mows

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What is good about these sort of threads is that we tend to deviate, broaden out and debate other related matters.
Going back to the O/P it is interesting that the smolts were from different rivers and different parts of the country, if they found out the migration routes of a lot of the uk smolts took them near to a Salmon farm where their numbers dropped off, there could be an argument to get that farm relocated or better still shut down.
If their migration route followed a path to a commercial fishery i.e sandeels or other baitfish that is being plundered by foreign boats, we should now have the power to protect our fishery zones. It would be ironic if our smolts as a bye catch ended up as fish pellets for the Salmon farmers.

So IMO it is or could be very important to track and trace the migration routes of the smolts from our rivers.
Great in principle, but by that logic, all lochy fish farms would already be closed.
But they are all still there, and Nero is still fiddling as aquaculture pays his wages.
 

Loxie

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Great in principle, but by that logic, all lochy fish farms would already be closed.
But they are all still there, and Nero is still fiddling as aquaculture pays his wages.
Yes that's the one bit we do know. On the west coast most of the smolts have to get past open cage salmon farms and many don't.
 

SOS

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Great in principle, but by that logic, all lochy fish farms would already be closed.
But they are all still there, and Nero is still fiddling as aquaculture pays his wages.
My point was that without these tracking studies and knowing the migration routes it would be very difficult to go the authorities and say we THINK that the Salmon smolts are dying because of XYZ, where as if we had the data then it would be easier to argue the point.

I have just been looking at the smolt output and adult return rates for the Girnock burn and although there are or can be big variations year by year there is a downward trend in both smolts and returners. With adult female return rate at 1% and assuming the same rate for males that would mean that you need an extra 200 smolts to produce one pair of Salmon, if you increased the survival rate of the smolts (2000 conservative) that leave the burn by the same 2% that gives you 20 pairs of Salmon.
Although survival rates/returns will depend on the length of river migration, as CharlieH alluded to it would need a helluva lot of extra smolts to make any significant difference to the total run of Salmon on the Dee. But all improvements to habitat and food availability should also be done.
If tracking Salmon smolts in river or at sea can lead to an increase of just 1% or 2% survival rate that would make a huge difference.

file:///home/chronos/u-7465ee8fa961ef8c625d55c4861bf467a0d3c824/MyFiles/Downloads/girnock-baddock-fish-traps%20(2).pdf
 

mows

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My point was that without these tracking studies and knowing the migration routes it would be very difficult to go the authorities and say we THINK that the Salmon smolts are dying because of XYZ, where as if we had the data then it would be easier to argue the point.

I have just been looking at the smolt output and adult return rates for the Girnock burn and although there are or can be big variations year by year there is a downward trend in both smolts and returners. With adult female return rate at 1% and assuming the same rate for males that would mean that you need an extra 200 smolts to produce one pair of Salmon, if you increased the survival rate of the smolts (2000 conservative) that leave the burn by the same 2% that gives you 20 pairs of Salmon.
Although survival rates/returns will depend on the length of river migration, as CharlieH alluded to it would need a helluva lot of extra smolts to make any significant difference to the total run of Salmon on the Dee. But all improvements to habitat and food availability should also be done.
If tracking Salmon smolts in river or at sea can lead to an increase of just 1% or 2% survival rate that would make a huge difference.

file:///home/chronos/u-7465ee8fa961ef8c625d55c4861bf467a0d3c824/MyFiles/Downloads/girnock-baddock-fish-traps%20(2).pdf
But they already have sufficient evidence for the Lochy.
Fish farms appeared on linnie and the salmon disappeared.
They experimented with fallow periods and the salmon came back.
They then stopped fallow periods and salmon disappeared.

But the good news is,
The aquaculture industry, pay the lochy scientist, to turn salmon originally of norwegian and farmed mixed genes, magically into idiginous fish, to go to sea and still disappear.

As per that science, i do not believe it will be effective in removing one salmon farm.
But it will enable the placing of even more salmon farms, where there is a slightly less number of smolts going to be killed by the lice soup.

Money would be far better spent, simply policing current lice numbers on farms.
 

Jockiescott

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What is good about these sort of threads is that we tend to deviate, broaden out and debate other related matters.
Going back to the O/P it is interesting that the smolts were from different rivers and different parts of the country, if they found out the migration routes of a lot of the uk smolts took them near to a Salmon farm where their numbers dropped off, there could be an argument to get that farm relocated or better still shut down.
If their migration route followed a path to a commercial fishery i.e sandeels or other baitfish that is being plundered by foreign boats, we should now have the power to protect our fishery zones. It would be ironic if our smolts as a bye catch ended up as fish pellets for the Salmon farmers.

So IMO it is or could be very important to track and trace the migration routes of the smolts from our rivers.

That's what I took from it SOS.

Although it was not the intention of testing out this piece of equipment, it was a happy accident that these smolts were detected. The fact that they were from 4 completely different rivers and located so close in the one area of ocean, this could indicate that the vast majority of smolts follow similar routes north. This could mean that those routes could be protected in the months of smolt migration for example.
 
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Loxie

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My point was that without these tracking studies and knowing the migration routes it would be very difficult to go the authorities and say we THINK that the Salmon smolts are dying because of XYZ, where as if we had the data then it would be easier to argue the point.

I have just been looking at the smolt output and adult return rates for the Girnock burn and although there are or can be big variations year by year there is a downward trend in both smolts and returners. With adult female return rate at 1% and assuming the same rate for males that would mean that you need an extra 200 smolts to produce one pair of Salmon, if you increased the survival rate of the smolts (2000 conservative) that leave the burn by the same 2% that gives you 20 pairs of Salmon.
Although survival rates/returns will depend on the length of river migration, as CharlieH alluded to it would need a helluva lot of extra smolts to make any significant difference to the total run of Salmon on the Dee. But all improvements to habitat and food availability should also be done.
If tracking Salmon smolts in river or at sea can lead to an increase of just 1% or 2% survival rate that would make a huge difference.

file:///home/chronos/u-7465ee8fa961ef8c625d55c4861bf467a0d3c824/MyFiles/Downloads/girnock-baddock-fish-traps%20(2).pdf
I don't want to be a bore because yes it would be great to be able to magically increase marine survival but the adult returners to Girnock are only in small part derived from smolt emigrants and no one knows how many smolts return to other part of the catchment. Therefore there is no way anyone can claim it takes 100 smolts out for 1 adult.

I think it would fantastic to have a smoking gun but there are many easier and cheaper ways to get evidence. Tag 2 large batches of smolts from a river like the Laxford. Release one batch in the river and the other batch at sea. Count relative returns and repeat for 5 to 10 years. Do the same concurrently with a river without a salmon farm in the estuary and that should give you some pretty good evidence of the impact of salmon farming in the estuary.
 

SOS

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But they already have sufficient evidence for the Lochy.
Fish farms appeared on linnie and the salmon disappeared.
They experimented with fallow periods and the salmon came back.
They then stopped fallow periods and salmon disappeared.

But the good news is,
The aquaculture industry, pay the lochy scientist, to turn salmon originally of norwegian and farmed mixed genes, magically into idiginous fish, to go to sea and still disappear.

As per that science, i do not believe it will be effective in removing one salmon farm.
But it will enable the placing of even more salmon farms, where there is a slightly less number of smolts going to be killed by the lice soup.

Money would be far better spent, simply policing current lice numbers on farms.
So yes that might be a culdesac for the Lochy, but without tracking the evidence is less than it would be.
I doubt if a fish farm on Loch Linnie would have an effect on east coast rivers, but one in Shetland might, and if so pressure can be put on the owners to relocate. That is what all the Salmon conservation bodies should and could be doing if they find evidence through tracking.
 

SOS

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I don't want to be a bore because yes it would be great to be able to magically increase marine survival but the adult returners to Girnock are only in small part derived from smolt emigrants and no one knows how many smolts return to other part of the catchment. Therefore there is no way anyone can claim it takes 100 smolts out for 1 adult.

I think it would fantastic to have a smoking gun but there are many easier and cheaper ways to get evidence. Tag 2 large batches of smolts from a river like the Laxford. Release one batch in the river and the other batch at sea. Count relative returns and repeat for 5 to 10 years. Do the same concurrently with a river without a salmon farm in the estuary and that should give you some pretty good evidence of the impact of salmon farming in the estuary.
If there are straying from the Girnock to other parts of the Dee or indeed other rivers there will also be strays entering the Girnock from other areas.
As for the size matters suggestion from the Frome meaning better return rates, that would mean that as the juvenile population of the Girnock decreases the size of the parr and smolts should increase, unless there is less food for some reason which can be remedied through various methods.
 

mows

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If there are straying from the Girnock to other parts of the Dee or indeed other rivers there will also be strays entering the Girnock from other areas.
As for the size matters suggestion from the Frome meaning better return rates, that would mean that as the juvenile population of the Girnock decreases the size of the parr and smolts should increase, unless there is less food for some reason which can be remedied through various methods.
I seem to remember that in storm frank year, the par numbers were reduced, but because of this the smolts were bigger that summer.
 

SOS

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SOS,
am I right in thinking that the Girnock's figures are more in decline than the Baddoch's?
Which figures? output or returner.

file:///home/chronos/u-7465ee8fa961ef8c625d55c4861bf467a0d3c824/MyFiles/Downloads/girnock-baddock-fish-traps%20(2).pdf
These links do not seem to copy and paste, but if you put in the file names you should be able to download them.
 
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keirross

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How do you propose research is done to investigate the persistent low marine survival of Atlantic salmon in the early stages of their oceanic migration to feeding grounds in the North Atlantic?

I seem to remember that in storm frank year, the par numbers were reduced, but because of this the smolts were bigger that summer.
 

SOS

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On the subject of straying
Although this document does not rule out straying there is an interesting point.
"So far no Girnock tagged fish has entered the Baddoch or vice versa indicating the precision of their homing"
Page 11 including introductions, or page 5 proper, para 5

I know I keep referring to the Girnock and Baddoch, but it is only because there have been dozens if not hundreds of studies done on these two burns.

 
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On the subject of straying
Although this document does not rule out straying there is an interesting point.
"So far no Girnock tagged fish has entered the Baddoch or vice versa indicating the precision of their homing"
Page 11 including introductions, or page 5 proper, para 5

I know I keep referring to the Girnock and Baddoch, but it is only because there have been dozens if not hundreds of studies done on these two burns.

That's a great point. Well spotted.
 
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keirross

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SOS,
am I right in thinking that the Girnock's figures are more in decline he Girnoch used to feature quite

My point was that without these tracking studies and knowing the migration routes it would be very difficult to go the authorities and say we THINK that the Salmon smolts are dying because of XYZ, where as if we had the data then it would be easier to argue the point.

I have just been looking at the smolt output and adult return rates for the Girnock burn and although there are or can be big variations year by year there is a downward trend in both smolts and returners. With adult female return rate at 1% and assuming the same rate for males that would mean that you need an extra 200 smolts to produce one pair of Salmon, if you increased the survival rate of the smolts (2000 conservative) that leave the burn by the same 2% that gives you 20 pairs of Salmon.
Although survival rates/returns will depend on the length of river migration, as CharlieH alluded to it would need a helluva lot of extra smolts to make any significant difference to the total run of Salmon on the Dee. But all improvements to habitat and food availability should also be done.
If tracking Salmon smolts in river or at sea can lead to an increase of just 1% or 2% survival rate that would make a huge difference.

file:///home/chronos/u-7465ee8fa961ef8c625d55c4861bf467a0d3c824/MyFiles/Downloads/girnock-baddock-fish-traps%20(2).pd
 

SOS

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I would love to reply to your post quoting my post, but I have no idea what I would be replying to without text.
 

SOS

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I seem to remember that in storm frank year, the par numbers were reduced, but because of this the smolts were bigger that summer.
So where is the increase of returners?.
It is my opinion that to increase the amount of returners the output has to also increase, but because the input and output are in reverse the numbers will continue to decline no matter the size of the smolts.
 

MCXFisher

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SOS,
your first statement is entirely correct: the key to success is the maximisation of smolt output from rivers, because once they're out at sea there's nothing much we can do but sit and wait for them to return. So that requires the largest possible suitable spawning areas and fry/parr nurseries with ample food supplies. Any interruption of the critical inputs - gravel, invertebrates etc - will have serious impacts on smolt production.
If by intervening in the headwaters we can increase egg to smolt survival from 2% to 3%, then on average each mature hen salmon will be sending an additional 60 smolts into the migration process (i.e. from 120 to 180, based on 6,000 eggs). With a sea survival rate of 3-4%, that brings 5-7 back per spawning hen.
Of course the maths aren't that simple, because there's no 'average' hen. Most produce few or no surviving smolts, while a few deliver lots: it's a skewed distribution. Nevertheless it's good enough to demonstrate the advantage to maximising output.
It stands to reason that we should look out for sources of exceptional losses at sea, and wherever possible seek to eliminate them, but we shouldn't allow that hunt to divert attention and resources from the vital work in the headwaters.
 

Jockiescott

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I've said before on the forum about the massive flood my river had in 2017 where homes and businesses were flooded and we lost bridges and weirs that had stood for well over a century. Because of the localised nature of the intense rain, there were only 2 rivers that suffered from the really bad floods.

After the flood, the fields were littered with fish at every stage of the life cycle. It was sickening and we really feared the worst.

However, the entire river became one massive spawning bed with the big boulders washed away and almost the entire river was left with lovely gravel.

We caught fish every year after the flood and last year, three years since the flood, our counter recorded its highest numbers in years. In fact, I don't think any other river on the entire Foyle system, of around 20 rivers, recorded more than the Faughan.

Whether this was due to the gravel or easier access to the upper reaches with the Weir washed away, we really don't know. Maybe it had something to do with far less juveniles competing for foods after the flood and being able to grow bigger and stronger? We really don't know that either. However, last year was certainly an improvement, numbers wise, than many years in the past.
 

mows

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So where is the increase of returners?.
It is my opinion that to increase the amount of returners the output has to also increase, but because the input and output are in reverse the numbers will continue to decline no matter the size of the smolts.
there wasnt an increase in numbers, but there also wasnt the huge anticipated decrease in numbers.
It isnt either or!
You need plenty smolts, but the quality also makes a big difference.
 
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Salmo salar

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I don't want to be a bore because yes it would be great to be able to magically increase marine survival but the adult returners to Girnock are only in small part derived from smolt emigrants and no one knows how many smolts return to other part of the catchment. Therefore there is no way anyone can claim it takes 100 smolts out for 1 adult.

I think it would fantastic to have a smoking gun but there are many easier and cheaper ways to get evidence. Tag 2 large batches of smolts from a river like the Laxford. Release one batch in the river and the other batch at sea. Count relative returns and repeat for 5 to 10 years. Do the same concurrently with a river without a salmon farm in the estuary and that should give you some pretty good evidence of the impact of salmon farming in the estuary.
Yes you could do that and use a helicopter or barge to bring smolts far out to sea to avoid potential estuarine/bay mortality and compare to river run smolts. This was an experiment completed many times in different rivers and in different countries - all with the same result. Smolts brought out to sea simply strayed all over the place on their return. Their return to their natal river also slowed making them more susceptible to near shore predation. To run such an experiment on wild salmon today would (or should) be impossible in terms of fish welfare. But yes you are right scientists should think outside the box as with this tracking programme. Looks like there are zones in the marine that are critical to Salmo salar survival so let's pin those down.
 
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Inisisle

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I've said before on the forum about the massive flood my river had in 2017 where homes and businesses were flooded and we lost bridges and weirs that had stood for well over a century. Because of the localised nature of the intense rain, there were only 2 rivers that suffered from the really bad floods.

After the flood, the fields were littered with fish at every stage of the life cycle. It was sickening and we really feared the worst.

However, the entire river became one massive spawning bed with the big boulders washed away and almost the entire river was left with lovely gravel.

We caught fish every year after the flood and last year, three years since the flood, our counter recorded its highest numbers in years. In fact, I don't think any other river on the entire Foyle system, of around 20 rivers, recorded more than the Faughan.

Whether this was due to the gravel or easier access to the upper reaches with the Weir washed away, we really don't know. Maybe it had something to do with far less juveniles competing for foods after the flood and being able to grow bigger and stronger? We really don't know that either. However, last year was certainly an improvement, numbers wise, than many years in the past.
It was certainly an improvement, Jockie, and the Faughan Counter originally recorded a run of over six thousand fish at the end of 2020. This counter always gives the bare minimum of fish that run through.
However, earlier this year the Loughs Agency suddenly reduced this number by over two thousand fish.
Why? I have never seen any published scientific reason.

And this year the run is only sixty-nine fish - well according to the counter, that is.
The date of the last reading is given as 21st May, 2021.
So the whole of the summer run, and part of the autumn run, is not recorded.

Personally, I believe those who say that the river is "stuffed with fish".
And long may it continue.
 
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