PLEASE NOTE: In order to post on the Board you need to have registered. To register please email paul@sexyloops.com including your real name and username. Registration takes less than 24hrs, unless Paul is fishing deep in the jungle!
Temperature effects on Brown trout.
Re: Temperature effects on Brown trout.
Few past summers in here (Finland, close to arctic circle), we habe had water temps +22 c and even +23. When temps are more than +20 you can see how graylings (same go with trouts) start to have problems to recovering after fight, bigger the fish bigger the problem.
In Finland they start to close rivers when water is +20 or +21 celsius, depens about river. This goes more to mid Finland, in here and more north they don't have this closing process yet, it is partly because rivers starts from lakes which can be deep and cold so there is oxygen in water. This is just excuse to keep rivers open and get license money coming in.
Nowdays most of the flyfisher are stopping fishing when temp gets over +20, no later than +21. or they just stop releasing, that's the other story anyway.
Other interesting fact is.... we have running trout here, it is coming thru long and narrow lake which has dephts more than 100 meter, so water in lake is cold, in surface it can get +20 but... in depth where trouts are coming it is more like 16 celsius or less, that means two things for running.
First if water temp in river is 2 degrees warmer than lake water, trouts won't start they run. They either wait on lake that river water gets cooler or that they adapt themselves for river temp. If temp in river is more than 19 celsius, they wait. Haven't heard or seen any new runners on those temp.
Rain and thunder always launch runs, it means always cooler river water and fresher air all the way, so river water can easily drop from 21 to 18 celsius and because of rain lake water is also changing the temp so it always launch the run. That's why after heat waves and warm river water, when heavy rains comes... river is filling with fishermen and running trout. Pressure to get spawing area has been rising while waiting, you might know that feeling from your younger days.
Also cool august nights are doing more or less same than rain. In here big even 8K brownies might run in less than knee deep water in August at dark, do not wade.
Mika,
close from Arctic circle
In Finland they start to close rivers when water is +20 or +21 celsius, depens about river. This goes more to mid Finland, in here and more north they don't have this closing process yet, it is partly because rivers starts from lakes which can be deep and cold so there is oxygen in water. This is just excuse to keep rivers open and get license money coming in.
Nowdays most of the flyfisher are stopping fishing when temp gets over +20, no later than +21. or they just stop releasing, that's the other story anyway.
Other interesting fact is.... we have running trout here, it is coming thru long and narrow lake which has dephts more than 100 meter, so water in lake is cold, in surface it can get +20 but... in depth where trouts are coming it is more like 16 celsius or less, that means two things for running.
First if water temp in river is 2 degrees warmer than lake water, trouts won't start they run. They either wait on lake that river water gets cooler or that they adapt themselves for river temp. If temp in river is more than 19 celsius, they wait. Haven't heard or seen any new runners on those temp.
Rain and thunder always launch runs, it means always cooler river water and fresher air all the way, so river water can easily drop from 21 to 18 celsius and because of rain lake water is also changing the temp so it always launch the run. That's why after heat waves and warm river water, when heavy rains comes... river is filling with fishermen and running trout. Pressure to get spawing area has been rising while waiting, you might know that feeling from your younger days.
Also cool august nights are doing more or less same than rain. In here big even 8K brownies might run in less than knee deep water in August at dark, do not wade.
Mika,
close from Arctic circle
- whinging pom
- Posts: 332
- Joined: Sat Oct 02, 2021 5:18 pm
- Location: Oundle uk
Re: Temperature effects on Brown trout.
all best
pom
The Duffer of the Brook !
Nothing is Impossible: I do Nothing everyday .
Nothing is Impossible: I do Nothing everyday .
- whinging pom
- Posts: 332
- Joined: Sat Oct 02, 2021 5:18 pm
- Location: Oundle uk
Re: Temperature effects on Brown trout.
im not sure if anyones looking but ill post it anyway.
Its got all the signs of being a very short trout season this year for our club, im dreading telling the members.
Bugger!!
Pom
It shows that our little very early heat wave has put the temps in stream to over my 19c cut off for fishing and we haven't even made mid summer yet. the earliest in the year in the UK that temps have passed 30c on record.Its got all the signs of being a very short trout season this year for our club, im dreading telling the members.
Bugger!!
Pom
The Duffer of the Brook !
Nothing is Impossible: I do Nothing everyday .
Nothing is Impossible: I do Nothing everyday .
- Paul Arden
- Site Admin
- Posts: 19662
- Joined: Thu Jan 03, 2013 11:20 am
- Location: Belum Rainforest
- Contact:
Re: Temperature effects on Brown trout.
I guess at this rate Scotland will become inhabitable in a few years.
Re: Temperature effects on Brown trout.
That’s a bit depressing, I’ve misplaced my thermometer, seeing those records I must dig it out. Although I haven’t been tempted to head out this week, my local rivers need some rain urgentlywhinging pom wrote: ↑Tue Jun 13, 2023 9:09 pm im not sure if anyones looking but ill post it anyway.tin tag may -june 2023.jpg
It shows that our little very early heat wave has put the temps in stream to over my 19c cut off for fishing and we haven't even made mid summer yet. the earliest in the year in the UK that temps have passed 30c on record.
Its got all the signs of being a very short trout season this year for our club, im dreading telling the members.
Bugger!!
Pom
- whinging pom
- Posts: 332
- Joined: Sat Oct 02, 2021 5:18 pm
- Location: Oundle uk
Re: Temperature effects on Brown trout.
No instead of their palid skin turning white in summer from winter blue, the scots, in a few years of these summers will tan up and look like grumpy Mediterranean's!Paul Arden wrote: ↑Wed Jun 14, 2023 1:13 am I guess at this rate Scotland will become inhabitable in a few years.
Ive just heard from a river keeper up at the very top of Scotland that he's closed the fishing at a water temp hitting 26c today!! A highland freestone river coming down from the mountains.
( thankfully they have have more diurnal variation than us, so there will be some respite for the poor salmon).
He says there's people still fishing the adjacent posher waters , how they expect to safely release salmon caught is beyond me
I wonder Boisker if carrying thermometers with us will again become part of the regular kit.I have a digital in the car full time to spot read our brook whenever I cross by it, its interesting to start to see the trigger temperatures for mayflies etc
Im about to order more data loggers for our brook also so we can get a better picture of the entire system and of the ambient shade temp so we can see how it relates.
all best
WP
The Duffer of the Brook !
Nothing is Impossible: I do Nothing everyday .
Nothing is Impossible: I do Nothing everyday .
Re: Temperature effects on Brown trout.
I feel it with you guys!!!
Today they closed my local river for fishing, as the water temperature has been around 17,5 degrees Celsius for the last couple of days. According to the official rules, the river will be closed when the temperature hits 18 degrees Celsius (or more), but I guess they already closed it now, because of a “better safe than sorry” principle…
Just to clarify, my local river is the Varde River, located in western Denmark.
Anyway, the people on the news on the TV say we should expect some rain soon, but the temperature should keep climbing up… So who knows when the river will open again?
Cheers, Bendix
Today they closed my local river for fishing, as the water temperature has been around 17,5 degrees Celsius for the last couple of days. According to the official rules, the river will be closed when the temperature hits 18 degrees Celsius (or more), but I guess they already closed it now, because of a “better safe than sorry” principle…
Just to clarify, my local river is the Varde River, located in western Denmark.
Anyway, the people on the news on the TV say we should expect some rain soon, but the temperature should keep climbing up… So who knows when the river will open again?
Cheers, Bendix
Re: Temperature effects on Brown trout.
What loggers are you using?Im about to order more data loggers for our brook
Been thinking of trying to build my own Pi based one to test our lakes.
Alan
Cheers
Alan
bad and getting worse
Alan
bad and getting worse
- whinging pom
- Posts: 332
- Joined: Sat Oct 02, 2021 5:18 pm
- Location: Oundle uk
Re: Temperature effects on Brown trout.
Hi BendixBendix wrote: ↑Wed Jun 14, 2023 9:25 pm I feel it with you guys!!!
Today they closed my local river for fishing, as the water temperature has been around 17,5 degrees Celsius for the last couple of days. According to the official rules, the river will be closed when the temperature hits 18 degrees Celsius (or more), but I guess they already closed it now, because of a “better safe than sorry” principle…
Just to clarify, my local river is the Varde River, located in western Denmark.
Anyway, the people on the news on the TV say we should expect some rain soon, but the temperature should keep climbing up… So who knows when the river will open again?
Cheers, Bendix
How refreshing to read of a clear policy erring on the side of caution, I have members complaining that I should produce the temps and then they be allowed to use ‘common sense’ to choose if they fish or not
( common sense is an English concept of having very little knowledge and using it badly, while being able to maintain a moral high ground… Brexit was based on this quaint conceit )
Is this (18c ) a national policy or chosen by individual rivers or authorities.?
And do you know if there was a particular source for informing this decision.
Many thanks
WP
The Duffer of the Brook !
Nothing is Impossible: I do Nothing everyday .
Nothing is Impossible: I do Nothing everyday .
- Lasse Karlsson
- Posts: 5801
- Joined: Wed Jan 09, 2013 9:40 pm
- Location: There, and back again
- Contact:
Re: Temperature effects on Brown trout.
Hi Pom
Local policy, but basicly all the salmon rivers follow it. It is rooted in data like these:
https://pubmed.ncbi.nlm.nih.gov/26179562/
And being evaluated at least once a year. The river I fish most for salmon, Skjern closes at 18 degrees and opens again when the water temperature drops below 16,5 degrees. This can lead to weird scenarios, where the river opens and closes due to cold nights and warm days.
The freezer filling is on a quota, and this year they split it up in three batches, first one was fished up early May, and second starts tomorrow. Two days ago the water temperature was 17,8, right now its 15,87 so it will probably open.
https://skjernaasam.dk/uncategorized/va ... -den-16-6/
Common sense isn't so common here too, bitching about closure happens here too
Cheers
Lasse
Local policy, but basicly all the salmon rivers follow it. It is rooted in data like these:
https://pubmed.ncbi.nlm.nih.gov/26179562/
And being evaluated at least once a year. The river I fish most for salmon, Skjern closes at 18 degrees and opens again when the water temperature drops below 16,5 degrees. This can lead to weird scenarios, where the river opens and closes due to cold nights and warm days.
The freezer filling is on a quota, and this year they split it up in three batches, first one was fished up early May, and second starts tomorrow. Two days ago the water temperature was 17,8, right now its 15,87 so it will probably open.
https://skjernaasam.dk/uncategorized/va ... -den-16-6/
Common sense isn't so common here too, bitching about closure happens here too
Cheers
Lasse
Your friendly neighbourhood flyslinger
Flycasting, so simple that instructors need to make it complicated since 1685
Got a Q++ at casting school, wearing shorts
Flycasting, so simple that instructors need to make it complicated since 1685
Got a Q++ at casting school, wearing shorts