Otto Muck, in his book 'The Secret of Atlantis' Collins:1978, was a catastrophist and though his theory was overtaken by other ideas, on the fate of Atlantis and the expansion of the Atlantic Ocean, he came up with a novel explanation for the behaviour of eels, drifting as larvae on the Gulf Stream with an origin in the Sargasso Sea. He visualised this area of the Atlantic was at one time, at the end of the Cretaceous, the only part of that ocean that existed – and the ocean has since expanded causing the eels to migrate further and further away, born on the Gulf Stream to Europe, and wherever that stream of warm water went (which would include parts of N America).
The ecology of the eel is fascinating – and they have been in existence for a very long time. It was the one part of Otto Muck's grand idea that stuck in my head – as we are talking about a book written 37 years ago.
At http://phys.org/print362817897.html … we have some recent ocean research and we see that eels have adapted to a modern hazard – the drowining of the continental shelf off the east coast of Massachusetts and Maine. The American eel is also carried as larvae on the Gulf Stream and it needs to enter estuaries to swim up rivers just as they do in Europe. Floating on the Gulf Stream the juvenile eels are carried over the top of the shelf by what is called 'Pinocchio's Nose Intrusions' -introducing infusions of warm water into the colder waters of this part of N America. Without the help of the Gulf Stream eels would not make landfall – but they were migrating this way long before the continental shelf was inundated (as the rivers would have extended out to the shelf boundary).
Eels are so fascinating. Unfortunately, modern farming methods are not kind to eels – or river management systems. Eels are in short supply in the UK. At one time they were an abundant food source – in the Middle Ages.
Eels return to the tropics to breed and die. Conger eels in the Caribbean can be very big and fearsome creatures – nothing like the juvenile fish that used to be caught in their thousands at river mouths in special nets.