Suburban trout?

[Paul mabbott]

Not my line at all but curiosity has got the better of me. About seven years ago fish like these (perhaps the same ones, or their parents) appeared in a little stream nearby:

This is taken where the stream comes out of a tunnel uder the road and most of its route upstream is tunneled ... the stream then runs into Millhouses Park, over a weir and into the River Sheaf (which then runs into the Don, the Humber and the North Sea ...).

So, please, (a) are these trout? and (b) do they migrate?

[GuyF]

I think that that is a Brown Trout. I'm not sure, but if I'm right then there are some Brown Trout known as Sea Trout (possibly a different subspecies or race which lives in the sea for most of the year). The Sea Trout are the ones which do migrate and travel back to their place of spawning. Possibly otherwise Sea Trout are just mature Brown Trout and smaller ones stick in the river until they're older.
I think it might be the first answer, but I may be completely wrong altogether!
Guy

[Ukwildlifeo]

You first answer is correct GuyF. And I would say there brown trout aswell

[Paul mabbott]

Thanks - so it's not migratory? What do we southerners know about trout anyway? All the ones I've seen before have been nicely grilled .....

[GuyF]

Originally Posted by Paul mabbott

Thanks - so it's not migratory? What do we southerners know about trout anyway? All the ones I've seen before have been nicely grilled .....

It could be migratory if it's a Sea Trout, although I'm not sure what the visible differences are. I think Sea Trout are a lot larger, sometimes over 1 metre? And I think their also more silvery.
So it could be migratory, but it looks more likely that it's a normal Brown Trout which I don't think migrate.
Guy

[bugbotherer]

Nice to have in the stream as it probably means that there is plenty of invert food for them

[AndyC]

Originally Posted by Paul mabbott

So, please, (a) are these trout? and (b) do they migrate?

Yes they are brown trout.

They don’t migrate as such (by which I mean they don’t leave the river and go to the arctic circle or some sunny climate) but they can migrate within a river system. Typically they will tend to move upstream in late summer and autumn towards the higher reaches of rivers where they will spawn in winter. The juvenile fish will then drop back downstream over the next couple of years. In rivers which have suitable spawning habitat spread throughout their length this upstream movement may be very short or non existent, there is no point in swimming miles to do the business! However in some rivers the best spawning and juvenile habitat is found in the head waters and migrations of tens of miles are quite common. Even small brown trout are capable of jumping weirs if they get the right conditions, so yours may well have come from downstream or they may have simply dropped down from some point above the tunnelled section.

Sea trout.
The boffins tell us that they are genetically the same as brown trout but they do have a different lifestyle in that they migrate to and from the sea. The adult sea trout spawn in the same areas as brown trout and their young are indistinguishable from young brown trout. However after a year or two in the spring they take on a bright silver colouration (at which point they are called smolts) and drop downstream and go out to sea. There is still a bit of mystery about where they go next. The smolts from some rivers seem to hang around the estuaries and immediate coastline while smolts from other rivers have been found several hundred miles from their home river (they almost always return to the river where they were born). After a period (a few months or in some cases over a year) of feeding at sea they return to the river and migrate upstream to spawn. Once spawning is complete the adult sea trout return to sea and repeat the whole process each year.

The visible differences are as GuyF says that sea trout are silver in colour and sometimes (but sadly not often!) over 1 meter in length, 30cm - 60cm would be more typical.



Andy

[fisherontheriver]

Yes definatly a brown trout
and brown trout will migrate up strean to spawning areas. On many keepered rivers they are traped at that time and milked for future stocking programs.
brown trout will live in the full river system from sorce down to and including the estuarys. being able to live in the tidal near fully salt water zones these are fondly called slob trout(duno why) possibly the begings of the fully migrating sea trout or sewin if your in wales.

[seamusagleann]

slobs !!never heard them called that in years.exactly what we here call them .first run sea trout we call fannichs or scatan bhan , the blonde herring .

[Paul mabbott]

Originally Posted by bugbotherer

Nice to have in the stream as it probably means that there is plenty of invert food for them

This was what perplexed me - yes there are a few flies and things around - possibly more at night, possibly mayflies in the season of the year - but I have seen very little potential food for them. Presumably, they grow at the rate their food source allows?

With the heavy rainfall we've had recently (few intense downfalls which are not uncommon) but several days of continuous moderate rain (which flooded the River Sheaf for the first time in my experience) and the stream where these trout live was, for a couple of days, absoutely opaque with suspended clay - the increased water flow having scoured down to the subsoil, presumably. I've not seen the fish since - are they likely to have suffered from this turbidity?