Can a stocked Brown turn Ferox?
I think you can draw a distinction between "Cannibal" and "Ferox", so the stocked brown may try a bit of the former without becoming the latter? :worms
Yeah
My observations and readings lead me to conclude that pretty much all fish are opportunist feeders. I base a lot of this on personal findings on the Eyebrook reservoir near "little Scotland"(Corby).This man made reservoir was made by throwing a dam over a river(a bit like the Backwater up here) but as well as wild Brownies and stockies,there was a huge population of course fish.I observed piscivarous behaviour by all the species over the years,even the Carp eat fish fry. On the Hampshire Avon anglers after Salmon frequently caught very big Barbel on Devon Minnows,fairly caught in the mouth.Good feeding in rich waters gives you diversity,poorer waters create (in troots)either a migratory fish or if landlocked a fish eater.Where available Ferox will eat other species like Char and in the Lake District,Wales and the odd Scottish Loch, coarse fish and the "white fish" like Vendace.
I can't recall the name of the syndrome,but fish do get"stunted" in small poor environments and several species have been known to turn to eating anything they can lay their teeth on.
I guess what I'm saying is I think food(or the lack of it) creates this rather than genetics.
Ferox are genetically separate from "standard" brown trout, although there is always a lot of discussion about it.
Some info;
http://www.fisheriesireland.ie/Projects/ferox-trout-project.html (http://www.fisheriesireland.ie/Projects/ferox-trout-project.html)
Nah!
Ferox switch to an almost exclusively piscivorous diet at a certain age, although they have been known to eat frogs, newts and even lemmings in Scandinavian countries. This is down to genetics and is why they live to such a long age and why they pack on tremendous weight.
A stocked brown trout which lacks the ferox gene will become an opportunistic feeder, especially in a big reservoir like Eyebrook, it would make sense for them to exist mainly on other fish when they reach a certain size but they don't have the ferox gene so they wouldn't be ferox trout and wouldn't be able to "go ferox" - it's a genetic distinction. It's well known that rainbows feed almost exclusively on fry at certain times of the year in these big reservoirs, I would liken a stocked brownie existing on fry to one of these rainbows rather than class it as a ferox.
That article opens with the unsubstantiated statement and then shows the evidence of some good science as to where the big trout spawn.Have they tagged smaller,non Ferox fish to see if they spawn in the same places?,this is work in progress,but not conclusive and I've seen no genetic science to prove that Ferox or Migratory trout are different to any other Brown Trout.
I read an article of American origin where studies were done on Steelheads and Rainbows and that was inconclusive too.
Indeed, there is a lot of discussion.
http://www.wildtrout.org/content/ferox-trout (http://www.wildtrout.org/content/ferox-trout)
http://www.scotland.gov.uk/Resource/Doc/295194/0100051.pdf (http://www.scotland.gov.uk/Resource/Doc/295194/0100051.pdf)
There was a train of thought for many years that Loch Leven trout were also a different species,obviously all species develop differently in different environments,just look at the shapes and colours of humans. I do agree to some extent there must be a difference in some species,I'm definately not from the same species as Tories,SNP followers or Weegies :8)
One fairly common difference is that Ferox live longer than other trout. You can find big piscivorous brown trout in lots of places, ( a "cannibal" is something that eats its own species), but they are not as long lived as Ferox.
The Marine Scotland link in Mike's post (above) makes the most sense to me.
I do not doubt the "genetically different" comment but a lot more research will be required to demonstrate that a "ferox gene" exists (present in ferox, absent in brown), whether this is a dominant or recessive gene, whether hybrids exist, and how this gene manifests itself in the life of the trout. That plus habitat and range need to be considered.
In the meantime, release them carefully.
Edward Fahy explained this I think in the best way. You can divide groupings of trout in many ways one of the ways is life span.
He split trout up into long-lived and short lived groupings.
Long lived life strategies include
* Ferox
* Burn trout (though not all burn trout are of the long lived strain these are again unusual in that they produce much larger and much fewer eggs than normal
* Long lived seatrout - not all systems have these but those that do tend to produce much bigger seatrout. There are quite a few of these longlived seatrout fisheries in Wales and Scotland but Ireland only a few.
The long lived trout actually have a genetic component called LDH-5(100) allele - the short lived trout instead have LDH-5(90) allele. I'm sure Mr Fachan will be along soon to explain further as it was he who put me onto this in the first place.
As well as this Ferox are unusual in that they only spawn every second year and spawn in different places - normally in outflows - although that's not prescriptive.
Alan,
My reply as to whether Ferox can come from stocked fish was rather short but they did this in Norway when they hatched and stocked ferox. Ron Greer reports this in his excellent book on Ferox Trout and Arctic Char. This is one of the best books I've ever read.
Quote from: Malcolm on December 29, 2012, 02:48:12 PM
Ron Greer reports this in his excellent book on Ferox Trout and Arctic Char. This is one of the best books I've ever read.
It is a superb book written by a man who knows what he's talking about.