Eel appears to have been considered a nourishing or medicinal food since ancient times, and the centuries-old custom of eating it at the height of summer survives in modern Japan. The Japanese may also assume that they are the only people who are interested in eating and studying the animal that is thought to have come into being about 100 million years ago probably in the waters near Borneo Island.
Aristotle (384-322 BC) mused that eels were “sexless creatures spontaneously emerging from the earth’s guts,” according to The New York Times (NYT) international weekly edition (December 27, 2015).
We know better than the Greek philosopher/scientist that eels spend time in all but two seas (East Pacific and South Atlantic Ocean). Japanese eels, which scientists call anguilla japonica, were once thought to be born in the waters off Okinawa or Taiwan. They now suggest that the spawning ground for those eels is likely to be in western Mariana Trench, not far from Guam Island.
Eels still remain enigmatic. Scientists do not fully agree on whether or not the fish spawn just once in its lifetime.
“Now, at least one eel enigma is finally a step closer to being solved,” thanks to research conducted by David Cairns, a research scientist at Canada’s Department of Fisheries and Oceans, NYT reported. “American eels spend their adult times, which range from three to 20 years, in rivers and estuaries from Greenland to Venezuela, but those far-flung populations share a single reproductive site in the Sargasso Sea.” This sea is off (east of) Florida.
Cairns and his team developed a tracking device, or aquatic satellite tags, which are small and lightweight enough to be attached to eels, NYT explained.
“From 2012 to 2014,” NYT said, “researchers released 38 satellite-tagged eels along the coast of Nova Scotia. They gathered data from 28, but one in particular stood out…the eel was tracked for 2,400 kilometers as it journeyed east from Nova Scotia toward the continental shelf off Newfoundland. There, it took a sharp right, crossed the Gulf Stream and headed straight for the Sargasso Sea.”
This particular eel required “just 45 days to complete its marathon run,” according to NYT.
The newspaper quoted Julian Dodson, a biologist at Laval University in Quebec as saying: “I’ve been studying fish migration for over 40 years, and I don’t think I’ve ever seen a track like that.”
Come August, you may eat a whole or part of an expensive Japanese eel, thinking about its long journey in the sea.
By Shota Ushio, freelance writer based in Tokyo