THE WONDERFUL LIFE OF THE EEL.

Otago Daily Times, Issue 18746, 27 December 1922, Page 10

THE WONDERFUL LIFE OF THE EEL.

Marine zoologists have solved at last the ancient riddle of tho life history of tlie common eel. Dr Jobs. Schmidt, a Danish zoologist, has now filled up the last-of the gaps in the tale, ' and here it is (says the Manchester Guardian). The adult eels—a male eel is an adult at five or six years of age, and a female at anything from five to 20 —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 10 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 2000 miles south-west of England and 500 miles north-east of the Leeward Islands. There the larva: of the eel are bom in spring and early summer, apparently between 700 and 1000 feet below the surface. As they grow during that first summer they movo up towards the surface. Next summer the o ? e "i' eaT O mbuits are found in the centre of the Atlantic, some impulse urging them north-eastwards towards Europe. The suninisr after that they are off the coasts ° . Europe. For tho 10 months following tins third midsummer of their lives the larvae, now developing into elvers, seem to take no food at all. It is a period of some strain, for ft tbey have to make their wav up tho rivers, then up their tributaries, and so many of them—into remote inland pools, and at the same time they change their gear, as it were, from that of sea life to that of fresh 1 water. However, tho stout creatures ma.nage somehow to live on their fat. By the following April they 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 a breeding area used also by a slightly different species, the American eel. Tho ’larves of tho two species are found together, and are sometimes taken in the same net. Yet no American larva, as far as is known, makes for Europe, and no Emopean larva for America, Dp Schmidt discovered why; by following both crowds of larvsa up. The American kind, he found, completes its larval stage in one year—just long enough for it tq 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 coast, like a quarantined ship, for two years until its organism was qualified to go up a river. Either would perish. One stands amazed and awed at the perfect certitude of instinct which propels each kind of eel, unguided by any accompanying parent, along the proper route of its own pilgrimage. But amazement grows deeper, if possible, in presence of the apoarent enormity of Nature’s exaction of effort both from the emigrant parents and from the immigrant young. What, one wonders, can the physical circumstances of the world have been which evolved for tho sluggish-looking creature that we see lying motionless on the mud, under clear ice, conditions of racial continuance so much more exorbitant than those imnosed even upon migratory birds. Those who in earlv youth have stooped to the baseness of laying night-lines for eels may remember with some compunction the stony fortitude with which the hooked eel would wind himself tiyhtly round the base of the stout water-lily stems to resist tho tearing haul of the line. They need resolution, these eels.