What happens to salmon who escape from the fish farms when they become old enough to ‘return to the source’? Where do they go?

Good question.

Yes, a good question!

I wonder if they their instinct is to swim upstream? Against the flow? Towards the fresher/colder water?

At least an escaped salmon might have some direction to go, what about the farmed ones that can’t make a journey?

>At least an escaped salmon might have some direction to go,

but i am assuming that they won’t find scotland.

>what about the farmed ones that can’t make a journey

from what i read the salmon don’t become fully sexualised until they are well on their journey home.
(which makes me wonder what they do to the salmon to get roe on the fish farm.)

but i assume most of these salmons would be dead before they got the idea of a caledonian excursion.

They might find it hard to find enough food just to stay put, let alone embark on migrations.

http://www.marineharvestcanada.com/farming_escaped_farmed_salmon.php

http://www.bellona.org/aquaculture/tema_aquaculture/Escapes

i would guess it would be more of a concern in the N hemisphere. i don’t think salmon migrate from near australia so mixing might not be so much of a problem. yet.

Escapee Salmon that don’t fall prey to seals and other predators die sad, lonely and unfulfilled. Unlike trout, they will not breed in Tasmanian waters. Salmon have been repeatedly introduced into a number of Tasmanian waterways since the mid to late 1800’s with no sign of establishment.

Originally, the assimilation societies and what later became the Inland Fisheries Service were attempting to establish a local population. In this they failed spectacularly and expensively. The populations of Atlantic salmon in Tasmania’s fresh water are maintained through stocking programs.

Salmon maintain a “scent picture” of the streams they were spawned in. They use this to navigate back to the same place when it is their time to spawn, detecting odours in almost homeopathic concentrations. I know Tassie has beautiful water, but for salmon it’s not quite home.

>Salmon maintain a “scent picture” of the streams they were spawned in.

Why can’t they be spawned in a Tassie river?

How would you get the original spawning pair to breed in the river when they’ve not been spawned from there?

I was thinking of an artificial means.

Can’t that be done?

Like transplanting fertilised eggs into a virgin stream?

It’s currently done by physically stripping eggs and milt from the fish. Fertilisation and then rearing through the juvenile stages.

There were studies done in the 1970’s on imprinting on young fish so they would home on an artificially introduced scent.

Why would you want to change the breeding behaviour of Salmon? Having yet another exotic mouth full of teeth splashing around and establishing a population doesn’t seem like a good idea to me.

With salmon, we have an easily manipulated animal that can’t run feral. The few escapees that do get away don’t appear to persist in the environment for very long.

Teleost said:

Why would you want to change the breeding behaviour of Salmon?

Because we like messing with nature, of course.

:)

okay. thank you all. i think it makes me happy.

(‘ceptin’ all the local fisherpeoples swear that it is near impossible to catch native fish in our area but it is quite easy to catch salmon and i am pretty sure the waters aren’t clean and green. actually i am not sure anything here in tas is clean.)