EELS AND THEIE WAYS.

Otago Witness, Issue 2690, 4 October 1905, Page 67

EELS AND THEIE WAYS.

By Dinoenis.

A week or two since someone — " Magister." I think — wrote asking for information about the breeding habits and mode of development of the eel. As no one has come forward in response, perhaps the following gleanings may prove of some use : — Until quite recently the early history cf the eel tribe (both fresh and saltwater species) remained enshrouded in complete mystery. Like many other such puzzles, this one has only yielded its solution to patient and long-continued observation. It was believed that the fresh-water eel bred in the places frequented by it during adult life. Upon this error there has been piled up a marvellous assortment of fanciful and superstitious notions about the genises of eels, to which I may refer further on.

It is well known now that the eel forsakes the fresh water for the salt when about to make provision for the future generation. As early as 186* an English zoologist (M.r Gill) had fairly well demonstrated that certain very curious, rare, and

very delicately-framed fishes, which had long been a stumbling-block to scientists, were none other than the long-sought-for larval eels These curious organisms had (under the impression of their being defined species) already received the name of Leptocephali, but were regarded as monstrosities, the victims of uncongenial surroundings. Thus Dr Gunther, ons of the most profound authorities of our time on all matters pertaining to fishes, wrote of them: — "We must come to the conclusion that the Lepfcocephalids are the offspring of various kinds of marine fishes, representing" not a normal stage of development (larvae), but an arrest of development at a very early period of their life; they; continue to grow to a certain size without corresponding development of their internal organs, and perish without having attained the characters of tho perfect animal." It was not, however, till 1896 that two Italian naturalists (Drs Grassi ancl Colandruccio), by a very careful and exhaustive study of a large "series of Leptocephalids, were enabled to establish beyond fear of dispute that these remarkable and puzzling fish were larval eels— not only of fresh water, but marine forms also. The study of these larvae, furthermore, brought to light some very extraordinary facts, one of the most important of which concerns the law of growth. Thus they go on increasing in size and favour daily, up to a certain point, when they i actually begin to grow " backwards — that is to say, they decrease in size from day to day up to a certain point, then growth recommences; with this »ew growth they assume the characteristic round, eel-like form, ascend to the surface of the sea, and, in tile case

of fresh- water species, make their way with all speed up the rivers. The parent eels never return to fresh-water haunts, and it is considered likely that they die soon after depositing the ova and sperma. When the eel-larva has completed the first stage of its growth it ceases to feed, and it is then that it rapidly loses bulk. At this stage its condition is reminiscent of the pupal, or chrysalis, period in insect development. Other changes that now take place bear out the analogy. It develops what has hitherto been lacking— pigment or colouring matter, — then it discards is larval teeth, and replaces its soft membranous backbone by a series of hard and complicated bones. Thcsa baby eels seem to frequent deep water, but particulars as to the actual zone favoured by them are yet to bo added. The Ita'ian naturalists studied their subject by direct observation in the Gulf of Messina, and also upon living specimens kept in an aquarium. The manner of capture of these living fish is curious. The majority are procured from the Straits o£ Messina by a series of fortunate accidents, which are constantly repeated. These "accidents'" are due to the fact that mighty currents every now and then boil up in the straits, bringing with them the strange inhabitants of these unexplored regions— eggs, larvae, and fishes of many kinds, besides other forms .ot animal life. Some are got by dredging with fine nets, and others are procured j from the stomach of that grotesque monster the sunfish, of which a nob'e specimen j is to be seen in the Otago . Museum. The larval eel is small— two or three inches at full growth,— -extremely delicate in bodily , substance, and quite transparent. It spends two years in completing its metamorphosis and getting ready for lite in a new environment. j When eel migration sets in in earnest the sight is an astonishing one. In England and Scotland during summer they ascend rivers in incredible numbers, overcoming all obstacles, ascending vertical walls or floodgates, entering every larger and smaller tributary, and making their way even over terra firm a to waters shut off from all communication with rivers. As a humourist has said, the eel, like the famous American river steamer, can go where it is damp. That is true— of the eel,— but stories like that of the gardener who declared he had caught eels in the kitchen garden stealing his young peas must Ire accepted with reserve In England such immigrations have been long known by the name cf "eel fairs," and tons of the "elvers" are captured as they make their ) way up stream. Somebody interested in the subject once studied the spring movement iii the Thames, jle calculated that 50,000 were passing up stream every hour, and this continued during several days. Upwards of three tons of " elvers " were despatched in one day from the Gloucester district in the spring of 1886, and it las been estimated that over 14,000 of these elvers go to make a pound weight. In 1885 the annual consumption of grown e<ls in England was estimated at a-- minimum of 1650 tons, with a total yaks of £130.000. It is a curious fact that the eel is very cordially disliked in Scotland.' It has been said that a Scottish cook will not cook an eel, and if she would, her employer would not eat it. Generally speaking, that is quite true.

My remarks upon eel-superstitions must be cut short, these notes having been drawn out somewhat more than' was intended. Evolutionists are still occasionally reproached by misguided indiyidiials for holding- that all species of living things have coihe to be what they are by gradual processes of development. If such individual's would but glance back at the beliefs of their ancestors, they wcvld find that these beliefs were, in thousands of instances, of an irrational quality almost beyond conception. It i=s amazing: that a whole population supposed to be steeped in orthodoxy, including the orthodox view of Creation, should have invented and clung- to belief in endle&s instances of spontaneous generation. One such belief was that vhich declared eels to be developed from horsehairs dropped in water. After long soaking they were supposed to become ei.dowed

I with life, and turned into worms. These worms, almost hair-like in thinness, were known as "hair-cols," and they in course of time completed the wondrous transformation by developing into true eels! This crazy belief is by no means defunct in some parts of the Home lands even i ow, and I have known it to be upheld in the newspapers not so very long ago. Absurd as it appears, this freakish superstition has an elemental trace of truth 'Underlying it. This truth is represented in so much as concerns the hair-eels. They exist in plenty, and I have seen many of them in swampy meadows and water-filled hoofmar'ks in Scotland. But the " hair-eel " is only one of a group of commonly parasitic nematoid worms, the early stages of existence of which are passed within the bodies of aquatic insects, from which they ultimately emerge to pass the adult condition as freo swimming; organisms. These worms look very like horsehair, arc slender, hard, and shining black in colour. Given the old-time love of the fantastic, and readiness to accept without question any hypothesis, however barren of credentials, ancl we have all that is necessary to account for this widely-held and venerable suoerstition. Another of these venerable errata was that two turf rods, wet with May dew. would engender quantities of "elver" if placed for the night in a stream. Some eel-loving gourmets may be intei*esfced by the statement of an old English witer, who says they " cause ague, sharpen the gout, and fill the body with many diseases. Tr-ey are worst in summer, but never wbolesome"; while breeders or sellers of horses i may not know that ia iha olden time

"horse-coursers" gave young eels to horse* to make them more lively