Mr. J. A. Harvie-Brown, F.Z.S., foremost and most versatile of authorities upon the salmon, entirely agrees with what we have stated. “The spring fish,” he says, “are vigorous younger fish and reach highest up the rivers, and can stay longer in the fresh water without hurt to themselves. The autumn fish are older, larger fish: and many begin to go out of condition before they leave the brackish, as they are less able to stay long in the fresh.”
In his book on “The Salmon,” the late Mr. Russell, of the Scotsman, argues “that the facts are at the least equally compatible with, and indeed entirely suitable to, the theory that the fish coming up all the year are the adults of various ages, and that those rushing up in a body in summer are the young of the same species. What are those clean salmon that run up the rivers in late winter or early spring? Where have they been in the preceding months? What do they want now? They cannot be wanting to spawn, for there is no spawning for at least six months to come. They cannot have spawned early in the preceding or rather present spawning season, gone down, recovered, and returned, for numerous experiments show that the period of return is about three months, and it is only about three months since the earliest fish had begun to spawn in the rivers which these are now ascending. They must have passed the autumn or earlier winter in the sea. Then they must have passed the winter without breeding.”
Briefly put, the views we hold concerning the whole matter (as regards long-seasoned rivers) are: That the early running salmon are fish that have not spawned in the immediately preceding season (the great majority, which are small fish, females preponderating, have passed their girlshood in the sea); that the late spring and early summer salmon, for the most part, are fish that have not been gravid in the preceding spawning season; that the salmon appearing later in the summer, say from June, represent the first-descended of the previous season’s spawners returning again to the rivers; that the grilse that arrive inshore in summer seeking the fresh water are the breeding portion of the stock of grilse for the year, as proved by their ova and milt, and that the autumn salmon, the great majority of which are large fish, are those that spawned latest in the previous season, or, as kelts, were exceptionally late in getting back to the sea.
What we have stated and emphasised above is expressly intended to show how untenable is the theory that spring and autumn salmon (or, as we should call them, if we are to speak accurately, spring-run and autumn-run salmon) are distinct and separate breeds.
We now come to give other strong reasons for discrediting the notion, theory or hypothesis, that there are different breeds of salmon in the Scottish rivers. Accordingly it is advisable to be specific, necessary to select certain rivers and state the facts. Our choice is the Don and the North Esk. Now as regards these rivers, what are the facts? First, that early every year thousands of salmon are netted at their mouths and in their tideways, and many thousands more above their tideways; second, that owing to the severe river netting plus the fixed obstructions which no fish can pass as long as the water has a low temperature, not a score, perhaps not half-a-dozen, pairs of so-called “spring fish” survive, and eventually reach the upper strath or glen sections. These are strictly facts, facts that cannot be disputed, facts that the Fishery Board for Scotland may conveniently verify. Now we should like to ask, is it at all likely that the many thousands of salmon that are netted in these rivers in spring are exclusively the progeny of three, six, or even a dozen pairs of spring-run salmon? We answer that it is not likely. We go farther and say it is impossible. But some one will query: Are there not in ten spawning salmon more thousands of potential salmon than the thousands that are caught annually in spring by the rods and nets conjointly? Quite true—say fifty thousand in a dozen fish of 8 or 9 lb. each (a good average weight in spring). But then the crucial question must be asked? What percentage, reckoning all the risks from frost, drought, spates, and so forth, hatches out? And what proportion, considering the scarcity of their food at recurrent periods, and all the perils and all the enemies to which they are exposed during the years of their growth in sea and river, survives to reach the adult stage? Let us suppose that 5 per cent. of the whole hatched ova—and this is a liberal estimate—advances through all the stages—parr, smolt, and grilse—till the adult fish is reached. On this calculation the mature progeny, resulting from a dozen pairs of spring salmon, would number two thousand five hundred.
No, we cannot accept the theory that spring salmon are a different breed from autumn salmon; nor can we agree with the dictum that they are to be preferred for hatchery purposes. No fish-culturist who has devoted himself with eminent success to the breeding of salmon, would ever dream of preferring the spawn of fish that have been ten or eleven months in the fresh water, to the spawn of fish that have been in the rivers only two. Numerous experiments have proved that of the ova of spring salmon about 75, and of the ova of autumn salmon about 95 per cent. is the average that hatches out and reaches the parr stage; and that as a particularly high percentage, 98 is more common in the latter than 78 in the former case. How, then, can it be contended that spring salmon are to be preferred for their ova? In conclusion, the whole argument may be clinched in a single sentence thus: If from twelve pairs of spring salmon, the maximum number of “escapes” in Don and North Esk annually, there survive to reach maturity a progeny of two thousand five hundred, are we not warranted in assuming that the grand result from the ova of the many thousands of fine large fish that ascend these rivers in autumn and early winter would be millions on millions of salmon, or more than the pools could comfortably hold? Enough! Enough! Informed opinion is against the theory of different breeds of British salmon with different inherited migratory instincts.
W. Murdoch.
VANGUARD RUNNING A FOX TO GROUND.
(From “The Foxhounds of Great Britain,” by permission of the publishers.)
[From a picture at Birdsall.