Animals: Eel Secrets

Some 2,200 years ago Aristotle dignified the lowly eel by puzzling about the mystery of its life. Following him came scores of scientists who jousted with the problem with no success. All knew the mature eel, the smaller elver. None, until lately, ever saw the larvae on the spawning ground. None knew where eels went to breed.

As the two-masted, 138 ft. Dana, one-time British minesweeper in the Baltic, slipped into Naples last week, the solution of the eel mystery was held in notebooks which she carried. Dr. Johannes Schmidt, Denmark’s famed ichthyologist, had cruised 40,000 mi. about the globe tracking down the eel.

Dr. Schmidt’s findings included the fact that eels from the eastern U. S. and western Europe all spawn in the Sargasso Sea. When eels feel the procreative urge they leave their freshwater homes, start for this vast backwater of the Atlantic east of the Antilles. It is a one-way journey for them, for once their function is performed they die.

Some theorists have guessed that female eels lay their eggs at great depths, diving down until the pressure forces the eggs out of their bodies, then expiring. The male is then pictured as swimming rapidly over the floating eggs, fertilizing them, expiring in turn.

Dr. Schmidt’s announcements last week did not touch on these matters. But he did reason that the necessity for warm, deep, still salt water was an explanation for the choice of the Sargasso Sea as a breeding place.

Each female eel lays some ten million eggs. As soon as they hatch, the landward journey of the larvae must start. If dilatory they will outgrow their salt water days, perish before they reach fresh water. In the larvae form eels grow to a length of about twelve inches, transparent, gelatinous creatures of which the only substantial parts are two disembodied eel eyes like mother of pearl.

When the Atlantic eel larvae hegira reaches a point about the latitude of Bermuda, the great stream divides into eastbound and westbound branches. Soon the twelve-inch larvae shrink to two-inch elvers which have much the same characteristics as the adult.

Toward the freshwater streams from which their mothers came the progeny direct themselves. Once in the parental river they seek out the spot from which their mothers came, settle there to carry on eel family history.

Eels from other parts of the world spawn in two great centers. One is off Australia, the other in Indian waters. To discover these facts Eelman Schmidt banded thousands of eels, tracked them about the seas. Because they look like snakes, eels are not a popular fish, but Dr. Schmidt avers “they are more nourishing than salmon. . . . A profitable industry awaits the man with enough enterprise to catch elvers alive . . . stock rivers and lakes with them, keep them until they reach maturity [up to 40 lb.] and then catch them for the market.”