Let's talk about eels & dams. 'Cause dams are a problem for eels now, but they haven't always been.
Eels can live out of water for a while, & travel overland. Young eels climb up & around small waterfalls as they migrate. And so many medieval dams weren't a problem for them. 1/7
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Eels can live out of water for a while, & travel overland. Young eels climb up & around small waterfalls as they migrate. And so many medieval dams weren't a problem for them. 1/7
🗃️🧪
Comments
These dams did block migration pathways for fish like salmon, though, with some interesting repercussions. 2/7
This shift from freshwater fish to marine fish is called the Fish Event Horizon! 3/7
But modern dams? That's a whole other story. They're too big for elvers to climb over easily, and hydroelectric turbines kill silver eels migrating back to sea. 4/7
These help, but not enough. And if they're not maintained then they don't do any good at all. 5/7
That's great. But them you also have to help them back to the sea later on. That's a lot of truckin'. 6/7
https://www.washingtonpost.com/climate-solutions/2020/09/17/climate-change-assisted-migration/
Modern dams are one of the greatest threats facing eels today. Just one more reason to move away from hydroelectric power. The eels will thank us. 7/7
In the wild, eels usually live 10-15 years before heading back to sea, and the number of eels being caught never really dropped for hundreds of years.
I know they can climb, we have videos of them climbing vertical dam walls!
In Sweden, many eels are 40+ when heading back to the Sargasso Sea (I’m an eel researcher too!)
Yeah...it's not always a great proxy for wild numbers, but the number of eels moving through the economy of medieval Engand doesn't really decline at all until the mid 14th century, when the Black Death radically changes huge parts of the society.
In medieval England, just about everyone ate them. King, bishops, peasants; everyone.