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No. 79: Jan-Feb 1992

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Those slippery (adult) eels

Every year untold millions of adult eels swim down the rivers of the continents toward the sea, where they are literally swallowed up. They are never seen again! In the Atlantic, the oft-told sci-entific tale is that all the adult eels from Europe and eastern North America converge on the Sargasso Sea. Here, they mate and die. It is in this area of the Atlantic that one finds high concentrations of eel larva, called leptocephali; and this alone is why the eels are thought to spawn here.

In a long article in Science News, E. Pennisi is the latest to wonder where the adult eels are. She relates how, despite several ambitious expeditions well-armed with nets, traps, and sundry eel-catching devices, "...no one has ever spotted adult eels in the spawning grounds."

Actually, Pennisi's article focusses on the Pacific and a 1991 Japanese expedition that searched for the spawning grounds of Anguilla Japonica, the Japanese eel. Earlier searches had been in conclusive. The 1991 attempt, after arduous labors and 16,000 kilometers of cruising, found the highest concentrations of leptocephali east of the Philippines. But, as in the Atlantic, even though many larvae were captured, no adult eels turned up in the nets. (Pennisi, Elizabeth; "Gone Eeling," Science News, 140:297, 1991.)

Comment. It is our understanding that adult eels are never caught anywhere once they leave their home rivers. Can anyone refute this?

From Science Frontiers #79, JAN-FEB 1992. 1992-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:


  • "A sourcebook of unexplained phenomena is therefore a valuable addition to a collection of scientific literature. William R. Corliss has provided this in the past with his source books of scientific anomalies in several subjects, and now he has provided it for astronomy. He has done an excellent job of collecting and editing a large amount of material, taken in part from scientific journals and in part from scientific reporting in the popular or semi-scientific press." -- "The Mysterious Universe: A Handbook of Astronomical Anomalies", reviwed by Thomas Gold, Cornell University, in Icarus, vol.41, 1980

  • "An interesting, systematic presentation of unusual weather [..] This book is recommended for a general audience" --"Corliss, William R., Tornados, Dark Days, Anomalous Precipitation, and Related Weather Phenomena, Sourcebook Project, 1983.", revieweed in Choice, September 1983
  • "..the science is necessarily somewhat speculative, but Corliss's symthesis is based on reputable sources." -- "Corliss, William R. (Compiler). Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena" reviwed by Joseph M. Moran, Univ. of Wisconsin in Science Books and Films, Sep/Oct 1983

  • "Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 (1987), p. 24., 02/1987