An Eel Swims in the Bronx
In the annals of natural history, there is perhaps no fish so singularly unusual, even mysterious, as Anguilla, the eels. Unlike every other migratory fish on Earth, they spawn in the open ocean and mature inland, in lakes and streams—an elementary fact, yet it took centuries for scientists to discover. They didn’t realize that larval eels, which resemble translucent cherry leaves, were actually eels.
Even with this knowledge, nobody has ever actually seen eels mate. Instead they’ve inferred its occurrence from the oceanic distribution of larvae. The youngest American) are found in the Sargasso Sea, part of the northern Atlantic Ocean near Bermuda. From there they drift on the Gulf stream up the eastern coast of North America, eating plankton and becoming more eel-like, though still translucent. At some point they encounter, hundreds of miles from shore, a part-per-trillion chemical trace of fresh water and instinctively follow it back to the source.
