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Facts on Salmon.
Facts on Salmon 1. Salmon and grilse invariably spawn in fresh water if possible both the eggs and the young fry whilst in the parr state being destroyed by contact with salt water. 2. The eggs are usually deposited on gravelly shallows where they hatch in from eighty to one hundred and fcrty days, according to the temperature of the water. Eggs remaining unhatched beyond the latter period will seldom hatch at all 3. The eggs deposited by the female will not hatch under any circumstances unless vivified, after exclusion, by the milt of the male ; and at least up to the period of migrationthere is no difference whatever in fry bred between salmon only, between grilse only, between salmon and grilse between salmon and parr, or between grilse and parr. [Note. Usually the female parr cannot spawn ; but the male parr can, and constantly exercises the power of vivifying salmon and grilse eggs, attaining to the breeding stage at about eighteen months.] 4. The fry remain one, two, and, in some cases, three years in the rivers as parr before going down to the sea about half taking their departure at one year, nearly all the Others at two years, and the remainder (which are exceptional) at three years old. In this last case the female parr may spawn. 5. All young salmon fry are marked with bluish bars on their sides until shortly before their migration, up to which period they are. Parrs ; they then invariably assume a more or less complete coating of silvery scales and become smolts the bars, or parr marks, however, being still clearly discernible on rubbing off the new scales. 6. The young of all the species of our salmon and trout, migratory and non-migratory, have at some period of their existence these bluish bars ; and consequently such marks are not by themselves proofs that fry bearing them are the young of the true salmon (Salmo sala?'). 7. Unless the young fish put on their smolt dress in May or early in June and thereupon go down to the sea, they remain as parrs another year ; and without smolt scales they will not migrate, and cannot exist in salt water. 8. The length of the parr at six weeks old, is about an inch and a half or two inches ; and the usual weight of the smolt before reaching the tidal wave from one to two ounces. 9. In at least many cases, smolts thus migrating to the sea in May and June return as grilse, sometimes within five, generally within ten weeks, the increase in weight during that period varying from two to ten pounds, the average being from four to six pounds ; and these grilse spawn about November or December go back to the sea and (in many cases) reascend the rivers the next spring as salmon, with a further increase of from four to twelve pounds. Thus, a fish hatched in April 1854, and marked when migrating in May 1855, was caught as a salmon of twenty-two pounds weight in March 1856. 10. It appears certain, however, that smolts do not always return during the same year as grilse, but frequently remain nine or ten months in the sea, returning in the following spring as small-sized salmon. [Note. It will thus be seen that the fry of salmon are called parrs until * they put on their migratory dress, when they become smolts and go down to the salt water ; grilse if they return from the sea during the first year of their migration ; and at all other periods salmon. ] 11. It has also been clearly proved that, in general, salmon and grilse find their way back to spawn to the rivers in which they were bred sometimes to the identical spots spawn about November or December and go down again to the sea as * spent fish,' or ' kelts,' in February or March returning, in at least many cases, during the following four or five months as 1 clean fish,' and with an increase in weight of from seven to ten pounds. [Note. Shortly before spawning, and whilst returning to the sea as kelts, or spent fish, salmon are unfit for food, and their capture is then illegal. ' Foul fish ' before spawning are, if males, termed red fish, from the orange-coloured stripes with which their cheeks are marked and the golden orange tint of the body ; the females are darker in colour, and are called black fish.] The foregoing still represents, in a condensed form, our positive knowledge as regards the leading facts of salmon history. The irregular return of salmon from the sea, which, I believe, I was the first to call attention to, will be found to explain many apparent anomalies and irregularities in the habits of salmon in different rivers as observed and chronicled by local fishermen and others ; and the time may come when under a more minute and complex system of salmon legislation it will be found to have an important bearing upon the regulation of our fisheries. In tracing the history of the salmon we will begin with the adult fish on their ascent from the sea, whether as salmon or grilse. At varying periods during spring and summer months a proportion at least of salmon in the bays and estuaries of the coast make their way up the rivers for the purpose of spawning their general colouring at this period being a brilliant silvery white, merging into a bluish black with a few dark spots on the upper part of the body and head. When first ascending from the sea, salmon are termed 1 fresh-run ' fish, and are then in the most perfect condition both for the rod and the table. A fresh-run salmon may not only be generally known by the bright silvery hue on the belly and sides, but also, when just up from the sea, by a species of parasite, or sea louse, which may be frequently found attached to the fish. These, however, are killed by a few hours' contact with fresh water, but the salmon exhibit for some time after the marks or scars left by the parasite. The periods of ascent and spawning of salmon differ in different rivers are earlier or later, that is, in point of time. Streams issuing from large lakes, in which the water has previously undergone a sort of filtering process, and has become warmer, owing to the greater mass and higher temperature of its source, are often what would be described in angling parlance as ' early rivers ; ' whilst, on the contrary, streams which are liable to be swollen by the melting of snows, or cold rains, or which are otherwise bleak and exposed, are frequently later in season, and yield their principal supply when the great Lake rivers are beginning to fail. Of these operating causes two of the Sutherland streams afford good examples. One, the Oikel, springs from a small exposed alpine pool some half mile in breadth ; the other, the Shin (a branch of the Oikel), takes its rise in the deep sweeping waters of Loch Shin and its tributary lakes. The Shin joins the Oikel about five miles from the sea. Early in the spring, all the salmon entering this common mouth diverge at the junction, pass up the Shin, and thus return, it would appear, to their own warmer stream ; whilst very few keep the main course of the Oikel until a much later period. Nor does it appear that these operative causes and their resultant effects are confined to Scotland. An analogous instance, indirectly traceable to the same cause, has been pointed out by Dr. Heysham, in his * Catalogue of Cumberland Animals,' as observable in several of the rivers of that county : The salmon, during winter and spring, evidently prefer the Eden to either the Esk, Caldew, or Peteril, although the Eden and the Esk pour their waters into the same estuary, and, in fact, are only separated at their mouths by a small promontory. There is hardly an instance, Dr. Heysham asserts, of a salmon entering the Esk until the middle of April or beginning of May a circumstance always referred by local fishermen to the difference in temperature between the two streams. The waters of the Eden, they allege, are considerably warmer than those of the Esk, which, from the shallow and rocky character of the bed of the Esk, appears not improbable. Be this as it may, it is an indubitable fact that snow water prevents salmon from running up even the milder stream of the Eden. The Caldew and the Peteril, again, pour their waters into the Eden, the one at, and the other a little above Carlisle ; yet up neither of these rivers do salmon ever run, unless at the spawning season, and then but in small numbers. The rule, however, which would appear to be inferred from some instances quoted is far from being invariable ; and as it has been found that the time of salmon ascending and spawning frequently differs in neighbouring rivers of the same district in some cases even where their sources and channels are apparently of a similar nature it is very possible that we have yet to arrive at the whole truth respecting the causes of these variations.
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