Interestingly this thinking has carried over to the UK. And as is often the case, people don't consider the scale changes and second order effects.
'Removing barriers to salmon migration' became a huge deal about 20 years ago, with conservation bodies removing weirs. Yes weirs not dams. Old Mill weirs, for instance, that were there when salmon stocks were high.
A lot of money has been spent, especially in the River Wye, which wriggles between Wales and England. The salmon stocks have plummeted, and got worse since they started.
The thing is Salmon could jump weirs in a flood. That is their evolutionary advantage. They had access to tributaries that no other fish could get too. Now Salmon can get their, along with Barbel, who eat fish eggs... and are not native to the Wye. Just saying.
One 'expert' (at fundraising at least), said 'Salmon could only cross these barriers in high flows' which is fine, because Salmon only run the river at all at high flows.
Weirs also provided varied habitat, and more oxygenated water... that is now lost.
I went to a seminar lead by two of these groups. One gave a presentation about all the dead trees they had removed from the river to 'remove barriers'. The second speaker talked about the dead trees they put in the river to create fish nurseries. I seemed to be the only person that find this absurd.
Now the barrier removal people are claiming success. As in they successfully raised the money and removed the 'barrier', one presumes. Salmon stocks have got worse.
There is more, but that was sad enough on its own
'Removing barriers to salmon migration' became a huge deal about 20 years ago, with conservation bodies removing weirs. Yes weirs not dams. Old Mill weirs, for instance, that were there when salmon stocks were high.
A lot of money has been spent, especially in the River Wye, which wriggles between Wales and England. The salmon stocks have plummeted, and got worse since they started.
The thing is Salmon could jump weirs in a flood. That is their evolutionary advantage. They had access to tributaries that no other fish could get too. Now Salmon can get their, along with Barbel, who eat fish eggs... and are not native to the Wye. Just saying.
One 'expert' (at fundraising at least), said 'Salmon could only cross these barriers in high flows' which is fine, because Salmon only run the river at all at high flows.
Weirs also provided varied habitat, and more oxygenated water... that is now lost.
I went to a seminar lead by two of these groups. One gave a presentation about all the dead trees they had removed from the river to 'remove barriers'. The second speaker talked about the dead trees they put in the river to create fish nurseries. I seemed to be the only person that find this absurd.
Now the barrier removal people are claiming success. As in they successfully raised the money and removed the 'barrier', one presumes. Salmon stocks have got worse.
There is more, but that was sad enough on its own