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mals form an important portion of the food of the herring in particular sea
A stomach of a herring, caught in the Frith of Forth this summer (1837), containing this species of food, is on the table, No. 7.
Mr Mackenzie further states, that, "in regard to the food of the herring, it has been frequently observed that the small fry suck their nutrition out of the marine alge, or from some matter adhering to them." This observation is borne out by the fact of many marine animals depositing their ova on the sea-weed, and by the fact of ova of fishes, and even those of their own species, being found in the stomach of the herring. Mr Mackenzie also mentions that "it has been ascertained by fishermen that herrings will swallow a clear unbaited hook, such as is used for catching haddocks, when tied to a fine line; a device which has been often successfully adopted when the herring fishery is carried on in deep water, in order to discover the arrival of the shoals. It seems certain, therefore, that the herrings take these hooks for such animalcules as they, at least, sometimes feed upon.”—(II. 313, 314.)
In the same volume is a paper, by the Rev. James Headrick, on the fisheries of Scotland, which Dr Knox has also quoted as proving the food of the herring to be unknown. But, as the Doctor has only given a portion of the paragraph on the subject, and founded on it as a distinct proposition, it is necessary to give the whole statement in connexion. "With regard to their mode of feeding," says Mr Headrick, "it is, in all probability, similar in the salmon and the herring. I suppose they live chiefly on water, and on small insects which abound both in the sea and in rivers. I have been told of the fry of smaller fishes found in the stomachs of salmon; but such instances never occurred to me, and I never heard of any animal being found in the stomach of a herring."
Here Dr Knox's quotation stops, lest the explanation which follows might lessen the value of his assumed discovery. But Mr Headrick continues thus:-" This," says he, “ may be owing to the strong digestive powers, which speedily convert into chyle the food received into the stomach. In all the experiments I have heard narrated, with a view to ascertain on what the herring feeds, it appeared that a considerable time was allowed to elapse between its being killed and cut up. Now, such an experiment is not fair. In man and other animals the power of the gastric juice is known to continue after death, so as not only to liquify the contents of the stomach, but even to corrode the stomach itself. The only way to know on what a herring feeds, is to cut it up immediately after it has enjoyed a full meal. Both the salmon and the herring leap at flies and other winged insects.' Trans. High. Soc. II. 444, 445.
In regard to what is stated by Dr Walker and Mr Headrick as their own opinion, that opinion is corroborative of what had been before discovered as to the food of the herring. As to their ignorance of what had been previously observed and recorded upon this subject, I cannot pretend to account. But their want of knowledge by no means proves, in the face of evidence to the contrary, that such knowledge did not exist. I am aware that, from the interruption of intercourse occasioned by the wars of the French Revolution, there was difficulty in getting books from the Continent; and a great degree of ignorance seems to have prevailed in Scotland as to the progress of the natural sciences in foreign countries, and even in England. But for Dr Knox and Professor Rennie there is not the same excuse; and the only conclusion that can be drawn from the statements of these gentlemen is, that when they penned them they were not aware of what had been previously written.
II. FOOD OF THE SALMON.-(Salmo Salar, Lin.)
I now come to the third point, on which I have to make a few observations, tending to show that the food of the salmon was perfectly well known to Naturalists before the publication
Dr Knox's as
of Dr Knox's paper. sertions, however, are as confidently made with regard to his discovery of the food of the salmon, as they were with regard to the food of the herring,
and, as I shall endeavour to show, equally unfounded.
"The nature of the food of the her. ring, Coregonus, and salmon" (says he)," was not to be stumbled on by accident. I feel happy in having to offer it as a direct result of patient scientific enquiry."(P. 463.)
"As a proof of the difficulty of the enquiry, it being unnecessary to cite more here, I shall content myself with quoting a passage from a very recent work (1833) on natural history. The Complete Angler of Izaak Walton edited by Mr Rennie, Professor of Zoology, King's College, London. In 1653, Walton found nothing in the stomach of the Fordige trout; and in a note, in the year 1833, Mr Rennie adds, “The same is true of the salmon, which has never any thing besides a yellow fluid in his stomach when caught." (P. 467.)
“The true salmon prefers a peculiar kind of food, the ova of the Echinodermata, and takes with great reluctance any other."
"When the salmon first takes to the estuary and to the river, whether beyond or within the influence of the tide, he does not feed, unless the estuary should happen to contain this peculiar kind of food.”—(P. 468.)
"I have opened the stomach of a. fish killed by the poacher in the month of October, nearly 100 miles from the ocean, with the peculiar food, and none else, in the intestines."-(P. 470.)
This peculiar food-on reading the first part of his paper, Dr Knox restricted to the ova of the ECHINODERMATA, and nothing else.
The genera of the first order of this class are ASTERIAS, ENCRINUS, ECHI NUS of Linnæus, and HOLOTHURIA. But only one species of the first genus, Asterias glacialis, is particularly men. tioned as affording this food; and we are not informed how the ova of this genus, when separated from the animal, is to be distinguished from that of the other genera of the order. It would be information, indeed, to learn that Encrini were so abundant on our
coasts, that their spawn afforded the salmon its peculiar food. On reading the second portion, he added another article to the salmon's bill of fare in "some of the crustacea." But in the abstract drawn up by himself, the food is limited to the Echinodermata, as if these animals deposited
their spawn at all seasons, and in sufficient quantity, to feed the family of British salmon. There is not a doubt, that if Dr Knox had examined the stomachs of salmon at different periods, and on different stations, he would not only have found the ova of the starfish (for that is the only echinodermatous animal stated as supplying the peculiar food), but also the starfish itself, the smaller crustacea, and the small fishes which abound on the coasts which salmon frequent. But of this afterwards.
In the years 1824 and 1825, a Committee of the House of Commons was appointed to investigate the modes of carrying on the principal salmon fisheries in the kingdom, for the purpose of framing an Act of Parliament that should regulate that fishery, for the advantage of the river and coast proprietors and the public. A valuable body of evidence was thus procured regarding the habits of the salmon ; the period of its ascending the different rivers for the purpose of spawning; the deposition of the ova in the spawning beds; the descent of the young to the sea; and the food of this fish both in the sea and in rivers, &c. But though this enquiry was made with great ability on the part of the committee, and although the witnesses examined included practical fishermen, tacksmen of fisheries, river and shore proprietors, and scientific men of the first eminence, Dr Knox, upon what principle it is difficult to conceive, characterises the results of the whole minutes of evidence as "below criticism" (P. 500);-" the persons offering the testimony and evidence, without any exception, incompetent to the task, the greater part being the evidence of individuals, to whom it would be impossible even to explain the care and precision and extent of direct evidence, requisite to arrive at a correct scientific conclusion"—(P. 500); and "none was found, throughout their most extended inquiry, who could offer a rational conjecture (founded on facts) personally known and understood (the result of positive research, by a competent naturalist and physiologist), as to the food of the salmon, its habitat while in the ocean, and its feeding ground."—(P. 496.)-The whole, in short, is" an inextricable mass of confusion and error."(P, 463.)
Among the witnesses whose evidence is thus characterised, are Sir Humphry Davy, Sir Henry Fane, Viscount Forbes, Mr Spring Rice Sir George Rose, Mr Home Drummond, George Hogarth, jun., William Stephen, George Little, John Halliday, Murdoch Mackenzie, and our most respectable and learned associates, the Rev. Dr Fleming, and James Jardine; besides numerous other educated and respectable men, many of whom had spent the best part of their lives in the daily observation of the fisheries of salmon, in different parts of the United Kingdom.-The names of these individuals were warrant to the public that they were competent to form a rational conjecture; their sources of information, that they were capable of giving direct evidence; and their education and rank in life were warrant for their possessing at least some knowledge of the nature of testimony. And when, on the other hand, it is considered that what is termed the natural history of the salmon in this memoir, is rested on a single experiment, made in a hurried visit to a salmon river-and the nature of the food at all seasons and in all places peremptorily determined, from. cutting up one or two stomachs at one period of the year, and at one station, it would not be difficult for the least versant in the nature of testimony to say on which side the incompetency was likely to be found.
Having made these preliminary remarks, I now proceed to show, from these much abused "Minutes of Evidence," and other sources, that the claims of the author of the memoir as a discoverer, rest merely on his own assertions; and that the main points upon which he claims merit were just as well known before the appearance of his memoir as since that period. In this case, however, I shall not detain the society with many quotations from writers on natural history as to the food of the salmon, either when in the sea or when found in rivers. The evidence taken before the Committee of the House of Commons narrows the enquiry as to this point; and I shall therefore avail myself of this evidence to corroborate what had been previously stated on the subject.
Professor Rennie, of the King's College, London, it has been stated,
found nothing in the stomach of the salmon but a "yellow fluid;” and Dr Knox asserts that this opinion must be "quite peculiar to Professor Rennie, as he knew of no author in which such a fact is mentioned." But this fact is not peculiar to the learned professor, notwithstanding Dr Knox's assertion that it is so; for it is repeatedly men. tioned in Sir Humphry Davy's work, entitled Salmonia, published a year before Professor Rennie's Walton appeared. And stranger still, this book is quoted, and a passage from the very page in which the "yellow fluid” is mentioned, animadverted on by Dr Knox. The following is the passage: The stomach of the salmon, you perceive, contains nothing but a little yellow fluid; and though the salmon is twice as large, does not exceed much in size that of the trout.". (P. 129--And again, in the following page "I have opened ten or twelve, and never found any thing in their stomachs but tape-worms, bred there, and some yellow fluid; but I believe this is generally owing to their being caught at the time of their migration, when they are travelling from the sea upwards, and do not willingly load themselves with food. Their digestion appears to be very quick."-(Salmonia, p. 130.)
In corroboration of Sir Humphry Davy's remark as to less food being found in the stomach of the salmon at the period of its annual migration, I may mention, that more than one naturalist has noticed the fact, that as the generative organs increase much, there seems less disposition in fishes to feed, and that their sto mach in such cases is generally found empty, or nearly so. John Monipennie, also, in his description of Scotland, published in 1612, mentions what I have no doubt was a fluid of the same nature, though he does not mention its colour; for, says he, "Finally, there is no man that knoweth readily whereon this fish liveth, for never was any thing yet found in their bellies, other than a thick slimy humour."
According to Bloch, (v. 245), “the salmon feeds on little fishes, insects, and worms." According to Lacepede, it "lives on insects, worms, and the fry of fishes." (Hist. Nat. des Poissons, xii. 135.) According to Bose, "it is upon insects, worms, and small fishes, that it feeds." (Nouv. Dict. xxx. 251.) Hyppolyte Cloquet
states that it feeds upon worms, insects, and small fishes; and in Turton's translation of Gmelin's edition of the Systema Naturæ, the salmon is said to "feed on fishes, worms, and insects." "It is evident," says Pennant, "that at times their food is both fish and worms; for the angler uses both with good success; as well as a large gaudy artificial fly, which probably the fish mistakes for a gay Libellula, or dragon-fly." (Brit. Zool. iii. 387); and Dr Fleming states that "their favourite food in the sea is the sand-eel." (Brit. Animals, 179.) Dr Fleming's means of knowledge I may, in passing, remark, were a residence of, I believe, fifteen years within sight of extensive salmon-fisheries on the Frith of Tay, and an extensive and minute acquaintance with all the branches of British Zoology. And it may be a sufficient answer to the contemptuous allusions by Dr Knox to that deservedly eminent individual, to say that his writings are referred to as authoritative by almost every author who treats of the subjects which have been illustrated by his pen.
It is necessary again to mention, that by insects, in these passages, is meant the class of animals included under that name by Linnæus, which extended to all annulose animals; and the whole modern class Crustaceæ, including minute crabs, shrimps, &c., as well as the divisions of Enchinodermata and Entomostraca. By worms is also meant the class Vermes of Linnæus, which included not only the naked but testaceous Mollusca; and it is in reference to these extended classes that the terms used by the writers of the period are to be understood.
the friths, where sand-eels are used as
So much for the statements of systematic writers as to the food of the salmon. I shall now give some extracts from the papers in the second volume of the Highland Society Transactions, regarding the salmon fisheries of Scotland, as to the food of the salmon. In fresh water, according to Dr Walker, "little is found in the stomach except slime, or some half-digested, and some half-entire insects."-" It is probable that they receive, in the sea, a more copious food, and of a different kind; but the precise nature of this food is unknown," i. e. to Dr Walker. (P..364 )
Mr John Mackenzie says, "It is probable they live on the fry, or young of other fishes. It is well known that when in fresh water, they feed on animalcules, flies, small trouts, &c." (P. 384.)
Later writers confirm the observations of the older authors as to the food of the salmon. Thus Mr Yarrell, Mr Alexander Morrison says, "I in his History of British Fishes, pub- have taken salmon within flood-mark, lished in 1835, has the following pas- some of which had two, and others three sage relative to the food of this fish-full-sized herrings in their stomach. "Faber, in his Natural History of the Fishes of Iceland, remarks, 'the common salmon feeds on small fishes and various small marine animals.' Dr Fleming says,Their favourite food in the sea is the sand-eel;' and I myself," says Mr Yarrell, "have taken the remains of sand-launce from the stomach. Sir William Jardine says," continues Mr Yarrell, "In the north of Sutherland a mode of fishing for salmon is sometimes successfully practised in
When salmon enter rivers, where but a small quantity of the fry of fish (on which they usually feed) is to be found, they evidently become worse in the course of twenty-four hours. From this it may be inferred, that salmon not only require a considerable quantity of food, but that their stomachs dissolve it in a very short period." (P. 392.)
Mr Archibald Drummond, after stating that when in the river they eat every thing with voracity, notices the
common saying of the fishermen, that nothing is ever found in their stomach.
In these papers there is only one fact stated, on the personal knowledge of one of the writers, Mr Morrison, who has himself taken from their stomachs full-sized herrings. The others only state their conjectures, or opinions. None of them refer to previous writers, either British or foreign, on the natural history of the salmon.
I now turn to the minutes of evidence before the Committee of the House of Commons, for facts upon the subject of the food of the salmon. In the Report of 1824, John Halliday gives his evidence as to their food in these words:" I have had thousands of them dissected, when I have seen small fish in their stomachs. I have seen thousands of fish opened in the boilinghouse, and I have seen small things like a worm, and skeddens, in the stomach of the salmon, or a small fish like a minnow."-(P. 90.) "I have observed more of this worm and small sen-fish in those fish we get from particular parts of the sea-shore."-ib.
Mr Moir states the chief food of the salmon to be sand-eels. "As all the fish were cut up," says he, "for the purpose of being preserved in a fresh state, I had an opportunity of examining their stomachs. I never could detect food of any kind in the stomachs of salmon taken in the upper riverfishings; whereas those taken in the sea were frequently gorged with food, which was principally sand eels." "I strongly suspect that the salmon frequent the flat sands between the Don and Ythan for the purpose of feeding;" and "a very successful stake-net fishery is carried on, on the sands at Musselburgh, and another at Aberlady. These sands abound with sand-eels. The one station is thirty, the other forty miles from a spawning river."(Report, 1825, p. 171, 172.)
This last gentleman is, I conceive (for Dr Knox very prudently does not mention his name), the person whom he accuses of making the statement I have read," in open defiance of truth and daily observation, ," when he averred, on his own knowledge, that the sand-eel formed a principal part of
the salmon's food. But Mr Moir is not singular in his opinion; for the Rev. Dr Fleming asserts the same fact from his own knowledge; and on the evidence of these two gentlemen alone, the fact of the salmon feeding much on sand-eels might at once be admitted. Dr Knox is equally virulent against another person, whom he does not name, for asserting what was consistent with his own knowledge, that he had seen small fishes in the stomachs of the thousands of salmon opened in the boiling-house. He alludes, I presume, to Mr Halliday, in these terms.
"One practical fisher and tacksman of salmon fisheries of vast extent, was so ignorant of every fact in natural history, that he mistook the tapeworm (a parasite infesting certain parts of the intestinal tube of the salmon) for the food of the salmon." (P. 499.) The inference Dr Knox wishes to be drawn from this circumstance (granting, for the sake of argument, that it is as he states it), is, that Mr Halliday's evidence as to food is good for nothing, because he saw, without knowing it was so, a tape-worm amongst the small fishes in the stomachs of the salmon opened. But this is neither fair to Mr Halliday nor right in itself. There can be no doubt of the fact of fishes, and a worm, being found in the stomachs alluded to, for it is a common occurrence; and Mr Halliday may be quite right as to the plain matter of fact, when he states what he had seen, while his opinion as to this fact or the nature of the substances, may be disregarded. But no one can mistake Mr Halliday's description of the worm alluded to, who had ever seen one. He describes it as like a "crimped straw." If this rule were applied generally to Dr Knox's own paper, there would be found, I am afraid, evidence of deficient information sufficient to discredit the whole of his statements.
In ordinary cases, where an observer states a fact as coming under his own observation, any opinion he may form upon that fact is a separate thing from the fact itself, and does not necessarily detract from its truth. Others, better informed, may draw a
The specimen, No. 3, now on the table, contains the vertebral remains of some small fishes. The same specimen contains in its intestinal canal the tape-worm which is usually found there.
VOL. XLIV. NO. CCLXXIV.