To the Editor of the "Gardener's Chronicle."
My attention has been called to a paragraph in a Worcester paper giving an account of a (so-called) discovery by Mr. Boccius, that Eels are propagated by spawn, like other fish, and that they are not brought forth alive, as had hitherto been supposed. This may be true, but before I can give an unqualified belief to the assertion, I should like to have a few questions answered by Mr. Boccius. Who saw the fish from which those thousands of eggs were extracted at the time this dissection was made? Are the parties who saw these eggs quite certain that the fish was an Eel and not a Lamprey? Who saw the eggs from which Mr. Boccius produced living Eels? Who beside Mr. Boccius ever saw Eel-fry in a pond which had no communication with a river? Will Mr. Allees and Mr. Reed (the gentlemen to whom the spawn was exhibited) say whether the ovary which was shown to them was pretty much of the same form as that of the Lamprey? and if not, in what respect did it differ?
I am induced to ask these questions, both because by inference they show my own opinions on the subject, and because I am led on undoubted authority to believe that Mr. Boccius is inclined to claim at _least_ all that belongs to him; and also because I have my doubts about the scientific attainments of Mr. Boccius in the Natural History of Fishes.
It is difficult to prove a negative. My never having seen the strange things above mentioned certainly does not prove that other people with better eyes and more discrimination have likewise failed to do so; but I can't help doubting, and I publish my doubts in the hope that the subject may be further inquired into. A true naturalist ought only to wish for the truth, without reference to his own preconceived notions; but so far as my examinations have gone, I have failed altogether to detect spawn in the fringes which I have fancied were the ovaria of the fish, or elsewhere, and I don't believe that Eels are bred in fresh water at all. I see the fry ascending from the sea in May and June by thousands and millions, but I never met with one of these in a pond having no communication with a river. I have little doubt that I shall be pronounced in error touching this matter, except perhaps by those who know how perseveringly these little Eels make their way up every stream, ditch, and driblet of water into which they can gain access. They penetrate into the water-pipes and pumps; they climb up the perpendicular faces of the rocks and weirs which obstruct the course of the rivers, even when they are only moist--adhering to the moss and stones like snails.
The downward migration of Eels is observed here from July to the middle of September, but in the Manchester market I find them up to this time (the end of November), and am informed that they are caught at the foot of Windermere in their downward migration.
Would a dissection of the Conger at various seasons throw any light on the propagation of Eels? One would think that in such large fish the ovaria would be much more easily distinguished than in smaller specimens. (November, 1850.)
_The above elicited the following reply:_--
T. G. denies the possibility of Eels breeding in fresh water. We have a pond here covering three or four acres which swarms with Eels of all sizes. I have caught them from the size of my little finger up to the weight of five pounds. The supply of water is from nothing else than land springs--there being no communication between the pond and any river. When much rain occurs I am obliged to put up a sluice-board, in order to prevent the banks from overflowing. I have taken from one to two hundredweight at a time from a box which the water flows through at the bottom of the sluice-board. The large quantity that has been taken out of this pond leaves no doubt that they breed there to a great extent, but whether they are propagated by spawn or brought forth alive I am unable to say.--G. H., _Finedon Hall_.
_Reply to the foregoing._
Your correspondent G. H. says T. G. denies the possibility of Eels breeding in fresh water. This is rather too strong. I don't deny the _possibility_ of Eels being bred in fresh water, I only deny the _probability_. The expression I used was that I did not believe they were bred in fresh water at all, and I distinctly stated that my not having seen these things (Eel spawn, &c.), did not prove that other people had not done so. But to the question. G. H. says that he has caught them of all sizes, from the thickness of his little finger to five pounds weight. No doubt he may have done so, but did he catch them of the thickness of a crow's quill, and three inches long? because that is the size at which they usually ascend rivers. He says his pond does not communicate with any river. Is there no escape of water from it? I mean, is the evaporation from its surface equal to the supply of water? If not, where does the surplus go to? Does it not directly or indirectly flow into a river or the sea? I am the more inclined to think that this is the case, because G. H. says he caught a hundredweight at a time from a box which the water flows through at the bottom of the sluice-board. This is exceedingly like what is done here and elsewhere from July to the end of November, when the Eels are on their downward migration. Will G. H. be kind enough to say whether he does not catch his about the same time? will he also say whether the Eels he catches are not Silver Eels? and will he also state whether he does not catch them principally after heavy rains have increased the flow of water out of the pond? If he answers these questions in the affirmative, I shall still think I am right, and request him to keep a sharp look-out after rains in May and June, when I think he would probably see the grigs passing through his box into the pond. If, on the other hand, there is no escape of water from the pond at any time, I must admit that I am wrong, but at present I don't know how to reconcile the impounding the water so completely with what he says about the flow of the water through the box at the bottom of the sill. Where does the water flow to, and for what is this sill?
_G. H. replied as follows._
T. G. asks if I have caught Eels of the size of a crow's quill. I have caught them of the size of a tobacco-pipe, and from three to four inches in length.
Our surplus water flows indirectly into the river Nene from our sluice. It supplies some stews where we have been in the habit of keeping reserve fish, and passing over several waterfalls, it enters into a ditch which is about three-quarters of a mile long, and then reaches the river I have just named.
The greatest take of Eels I have had was on the 23rd of December, but the time of the year is of little consequence with us, provided the water is thick and muddy and the weather rather warm, which, of course, only occurs during very heavy rains. If I were to draw all the water out of the pond when in a clear state, I should not catch a fish. The variety is the Silver Eel. Our pond is upwards of fifty miles from the sea; therefore how is it that those little Eels had got no larger during their long journey, interrupted as it is by numerous and almost insurmountable obstacles, before they could reach the little ditch, three- quarters of a mile long, that would conduct them to our pond? And, last of all, after this long and tedious journey, within a hundred yards of their destination they would have to climb four waterfalls and a perpendicular sluice-board. It appears to me they should have grown much larger than a common tobacco-pipe and longer than three or four inches in that time, but I will leave this point for T. G. to explain.--G. H., _Finedon Hall_.
_Reply to the foregoing._
Many thanks to G. H. for his second letter on this subject. It appears to me that we think very much alike about Eels.
He says his pond is fifty miles from the sea; "therefore, how is it that these little Eels get no larger in their long and tedious journey? interrupted as it is by numerous and almost insurmountable obstacles, before they could reach the little ditch, three-quarters of a mile long, which would conduct them to our pond? and last of all, after this long and tedious journey, within a hundred yards of their destination, they would have to climb four waterfalls and a perpendicular sluice-board. It appears to me they should have grown much larger than a common tobacco-pipe during that time; but I will leave that point to T. G. to explain."
This is so fairly put, that I will tell what I have seen, hoping that this will be a sufficient explanation.
In June, 1850, I chanced to go down to the bank of the Ribble, and there I saw a column of small Eels steadily making their way up the stream. I should suppose there might be fifty in every lineal yard, for they kept pretty close to the bank, apparently because they met with less resistance from the stream, and without pretending to accuracy I supposed they travelled at the rate of a mile an hour. This was about five o'clock in the afternoon, and I went to look for them about nine in the evening--they were still going in one unbroken column. How long they had been going when I first saw them, and how long they continued to go after my second visit, I don't know, but many thousands--perhaps millions--must have passed that day. At this rate (of a mile an hour) they would have required little more than two days to reach G. H.'s pond, fifty miles from the sea; but he says they had to pass over three or four waterfalls and a perpendicular sluice-board. If these waterfalls and the sluice-board were covered with moss, they would climb them as readily as a cat does a ladder. I have seen them in swarms at a perpendicular weir here, winding their way through the damp moss with which the stones are covered; but this was not all: where there was no moss, the little things seemed to have the power of adhering to the perpendicular face of the stones, like so many snails. I must not omit to remark, that although they seemed to choose the margin of the stream for the sake of easier travelling, yet they took care to keep in the stream, as I had a nice opportunity of observing.
At the point where I first saw them, the tail goit of a water- wheel had its junction with the river, but being Sunday there was no current there--not a single Eel took its course up the goit, although the water was deeper there than where they went. The water being low and perfectly clear, I could trace their course both above and below the place where I stood without any difficulty.
If we allowed that they travelled a mile in the hour, and that the obstructions of the waterfalls and sluice-board took as long to get over as all the rest of the journey, they would be able to reach G. H.'s pond in four days from the sea; and from what I have seen of their ability to surmount such obstructions, I am quite convinced that they would travel that distance in the time. But say they were a week--they would not grow much in that time, particularly if they had been travelling without food the whole of the distance, and that they must have done so, is proved to my mind by their keeping in column; for if they had dispersed to seek for food, by what contrivance were they marshalled into line again, to enable them to proceed? Now the place I saw them is forty miles from the sea, although not that distance from salt- water. T. says it is no proof that Eels are bred in fresh water because they may be found in ponds having no connection with a river--the proof required is _ab ovo_. If we wait for this proof I fear we will have to wait for some time, for I fancy that no one but Mr. Boccius ever saw the ova of Eels, and he will not condescend to enlighten us on the subject. At the same time I admit that finding them there is no proof that they were bred there, inasmuch as I have myself stocked such ponds for my friends, and what I have done may be done by others.
T. says further there is also room for inquiry into another curious subject--do Eels return to fresh water after having gone to the sea for spawning? In reply to this, I can only say, that no trace of such a migration is ever seen here, and I think if it existed at all, I should have observed it, for the following reasons.
The Ribble here supplies a large mill, the water-wheels of which are 150 horse-power; therefore, when they are at work in the daytime, the whole force of the river is often passing through the mill-lead (goit) and the bed of the river between the weir, and the tail goit in such times is left dry, except in a few pools. If there was a shoal of Eels between these two points it would have been seen at one time or another, and this has never happened, so far as I know. It may be said that they migrate singly, but they don't do so in their first migration, and, so far as I am aware, it is not the habit of any animal to do so. Herrings, Pilchards, Smelts, Flounders, Sturgeon, Bisons, Antelopes, Woodcocks, Swallows, Fieldfares, Locusts, and even Butterflies congregate together previous to migration.
NOTE.--The last paragraph requires some modification, as I have since proved that Eels migrate singly when going to the sea, as I have had occasion to know in a hundred cases when watching my Eel- trap, where every Eel may be seen as it descends into the trap.
_On the same subject._
I [Jeremiah Garnett, brother of the writer, and editor of the "Manchester Guardian,"] having noticed the communications on this subject which have recently appeared in your columns, am desirous of mentioning a fact which appears to me to throw some light upon the localities in which Eels are bred, though it leaves the question of the mode of generation precisely where it stood before.
Like your correspondent T. G., I have many times seen columns of small Eels ascending the Ribble and other rivers in the months of May and June, at considerable distances from the sea, but only on one occasion have I seen them under circumstances which evidently brought them near the place of their nativity.
I happened to be attending the Lancaster Spring Assizes in the month of March in the year 1826, and learning that there was a remarkably high tide in the estuary of the Lune, I walked down to the riverside about the time of high water, and found that the tide had covered the grass in many places; and as it began to ebb, I observed something moving in every small hollow which had been overflowed, and in which a little water had been left behind. On examination I found that the moving bodies were exceedingly diminutive Eels, rather less, to the best of my recollection, than three-quarters of an inch long, and almost transparent, but exhibiting in every respect the true form of the mature Eel. They had evidently followed the water to its extreme verge, where it could not have been more than an inch deep, and that they must have been very numerous was clear from the large numbers which were left behind and had perished--for that they did perish I found on the following day, when they were lying dead on the grass by hundreds. Some of your correspondents who reside in localities favourable for making observations on this subject may be induced to pay attention to it; the exact appearance may be ascertained, with probably other facts calculated to throw light on the obscure question of their generation.
[The end]
Thomas Garnett's essay: Eels