<story><title>Fish Doorbell</title><url>https://dutchreview.com/news/fish-doorbell-utrecht/</url></story><parent_chain><item><author>zck</author><text>For places humans have dammed a river, a fish ladder can be installed to let fish continue to swim upstream: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Fish_ladder&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Fish_ladder&lt;/a&gt;. I wonder why that&amp;#x27;s not used here.&lt;p&gt;Perhaps it&amp;#x27;s related to this being a _lock_, not a dam. In addition to having water loss from the lock, the middle part of the lock goes up and down, so you&amp;#x27;d have to have separate fish ladders for each part.&lt;p&gt;For the most fun fish transport I&amp;#x27;ve seen, check out the Salmon Cannon: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.youtube.com&amp;#x2F;watch?v=nopg9JSTTzg&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.youtube.com&amp;#x2F;watch?v=nopg9JSTTzg&lt;/a&gt; and &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.youtube.com&amp;#x2F;watch?v=eGzdOpCisnQ&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.youtube.com&amp;#x2F;watch?v=eGzdOpCisnQ&lt;/a&gt;. It uses a pressurized tube to transfer salmon from the low to high side. In the second video, the distance is over a kilometer.</text></item></parent_chain><comment><author>crote</author><text>It&amp;#x27;s a tiny monumental lock dating back to the middle ages. It has a history going back to the 1300s, as do the buildings around it.&lt;p&gt;Adding a traditional fish ladder isn&amp;#x27;t really a realistic option at this location.</text></comment>
<story><title>Fish Doorbell</title><url>https://dutchreview.com/news/fish-doorbell-utrecht/</url></story><parent_chain><item><author>zck</author><text>For places humans have dammed a river, a fish ladder can be installed to let fish continue to swim upstream: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Fish_ladder&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Fish_ladder&lt;/a&gt;. I wonder why that&amp;#x27;s not used here.&lt;p&gt;Perhaps it&amp;#x27;s related to this being a _lock_, not a dam. In addition to having water loss from the lock, the middle part of the lock goes up and down, so you&amp;#x27;d have to have separate fish ladders for each part.&lt;p&gt;For the most fun fish transport I&amp;#x27;ve seen, check out the Salmon Cannon: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.youtube.com&amp;#x2F;watch?v=nopg9JSTTzg&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.youtube.com&amp;#x2F;watch?v=nopg9JSTTzg&lt;/a&gt; and &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.youtube.com&amp;#x2F;watch?v=eGzdOpCisnQ&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.youtube.com&amp;#x2F;watch?v=eGzdOpCisnQ&lt;/a&gt;. It uses a pressurized tube to transfer salmon from the low to high side. In the second video, the distance is over a kilometer.</text></item></parent_chain><comment><author>wunderflix</author><text>From the Wikipedia article you referenced to:&lt;p&gt;&lt;i&gt;&amp;gt; Fish ladders have a mixed record of effectiveness. They vary in effectiveness for different types of species, with one study showing that only three percent of American Shad make it through all the fish ladders on the way to their spawning ground&lt;/i&gt;&lt;p&gt;I guess that’s what they call artificial selection pressure.</text></comment>