LIFE OF THE EEL.

Otaki Mail, 19 March 1923, Page 4

LIFE OF THE EEL.

Marine zoologists have solved at last the ancient riddle oi the life history of the common eel. Dr. Johs Schmidt, a Danish zoologist, has now filled up the last of the gaps in the tale, and here.it is. The adult eels—a male eel is an adult at five or six years of age, and a female at anything from five to twenty—from all the rivers, lakes, and ponds of Europe set out seawards in autumn and winter, resting by day and travelling by night, especially on moonless nights. They probably go about ten miles a night. Reaching the open sea they never return. But we know what becomes of them now. Their place of honeymoon and nursery is a limited tract of the North Atlantic, about 2500 miles south-west of England and 500 miles north-east of ihe Leeward IsladS. There the larvae of Hie eel are born in spring and early summer, apparently between 700 and 1000 feet below the surface. As they grow during that first summer they move up towards the surface. Next summer the one-year-old infants are found in the centre of the Atlantic, some impulse urging them northeastward towards Europe. The summer ctllor they ore off the coasts of Europe. For the ten months following this third midsummer of their lives the larvae, now developing ir-to elvers, seem to take no food at all. It. is a period of some strain, for they have to make their way up the rivers, then up their tributaries, and s0 —many of them—into remote inland pools, and at the same time they have to change their gear, as it were from that of sea life to that of the fresh wafer. However, the stout creatures manage somehow to live on their fat, By the following April 'hey are smaller than they were, but they have arrived.

To add an extra marvel to this three-year Odyssey of the baby eel. he comes from ;i breeding area, used also by a slightly different species, the American eel. The larvae of the two species are found together, and are sometime taken in the same net. Yet no American larva, as far as is known, makes for Europe and no European Inrvn for America. Dr. Schmidt discovered why. by following both crowds of larvae up. The Amerienn kind, lie found, completes its larval stage in one year—just long enough for it to reach the American coast before its constitution begins to cry out for fresh water and fresh water things. So if it made for Europe it would, at the end of the first year of the journey, be cast away in mid-Atlantic like a wrecked mariner, with water, water everywhere and not a drop to drink. If, on the other hand, a larva with a European pedigree struck out for America, it would have to hang about off the American const, like a quarantined ship, for two years until i f s organism was qualified to go up a liver. Either would perish. One stands amazed and awed at the perfect attitude of instinct which propels each kind or eel ungulded by any accompanying parent, along the proper route of its own pilgrimage. But amazement grows deeper, if possible, in presence of the apparent enormity of Nalurr's exaction of effort bcth from the emigrant parents and Tom the immigrant young.