I am a bit baffled by this, as they they used to breed in areas surrounding the River Chess.

Does anyone have a view or even a theory as to why these fish only choose Derbyshire as opposed to other areas.

I would be grateful for your replies and apologise if this subject has risen before.

__________________
[COLOR="Blue"]"A fish seen is a fish nearly caught"[/COLOR]

Perhaps they liked it there and decided to stay?

Although the Wye certainly suited the fish that were imported in the 1890's, I think the circumstances that brought about their introduction and subsequent release into the river proper from Ashford Dam, held paramount importance.

Let me explain:

The original Wye fish came from a watershed and hatchery very different from later imports. Most significant was that they were spring spawning, where as the Shasta's from the McCloud River, spawn well before Christmas. This makes them ultimately successful because their eggs do not sit in the gravel all winter, with their biological clocks turned off due to low water temperatures. Our spring spawning fish hatch in no time and although they appear from very small eggs, they swim-up into water that has developed, as far as zoo plankton is concerned.

I also believe that the broodstock played a vital role too. Surely, as fish farming was in its infancy, brood fish were caught up rather than being held. This gave their babies a good chance of inheriting the genes that would help them recognise spawning cues, when the time came.

Four years into their life in the lake at Ashford they were able to get out following periods of exceptionally high water. Coming from water with a temperature and pH very much like the Wye (Frost) and being liberated when they were all sexually mature (and understanding spawning cues) they spawned and the rest is history.

I wasn't ever able to ascertain whether the Misbourne and Chess rainbows were spring spawning through my correspondence with F.J.Taylor but I do know that the river and a lake on the Misbourne (name escapes me) were stocked with Shasta's from the local fish farm after a severe drought. Those fish never spawned and died out.

It is possible for Shasta babies, released accidentally from fish farms, to spawm when they get older, as is the case on the nearby River Dove. Historically these fish die out after a few generations but I don't know why.

Occasionally we see fish that have such tremendous scale adhesion, they are almost like enamel.



But the average fish are much most spotty. Here's Gareth with a cock fish...

Warren,

Were the original Wye fish S. Gairdnerii?

__________________
“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

No, Salmo Irideus.

Warren,

I'm a little confused.

According to one taxonomic reference the following are all species or sub species of rainbow trout:

Salmo gairdnerii gairdnerii
Salmo gairdnerii irideus
Salmo gairdnerii shasta
Salmo irideus shasta
Salmo irideus

Which of the above are those in the Wye?

Are some of the above alternative ways of referring to the same species?

__________________
“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

http://en.wikipedia.org/wiki/Steelhead


How about their correct taxonomic name: Oncorhynchys mykiss


Hugh

Be fair to the lads, the name was only changed in the 1980s.

__________________
"In wine there is wisdom. In beer there is strength. In water there is bacteria." - German proverb
JH based near Southampton

Warren,
I don't see how either using fresh brood stock or held fish would influence their genes as by there very nature genes are hereditary. I don't thing genes are reactive to environmental stimuli unless we are talking Darwinian time scales.

Frank

__________________
Frank Williams APGAI

See Classified for;

Flouro Drop Style Indicators ¦ French/Czech nymphing leaders ¦ Hi-Vis tippet for indicators ¦
Kamoufil leader material ¦
Stroft ABR & GTM

Sponsored Kilimanjaro climb

Fair enough but it still doesn't help much as the first fish in Warren's post looks an absolute ringer for Oncorhynchus mykiss gairdnerii according to the photos in the Wikipedia entry whereas the other fish looks more like Oncorhynchus mykiss irideus. There is no mention of the shasta sub-species. I was however aware of autumn and spring spawning strains and of the Shasta strain and also Wikipedia isn't 100% reliable.

The fish that I have caught in the Wye looked more like the top fish in Warren's post.

__________________
“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