Experience enough to keep this expectation active is perhaps necessary to full enjoyment on the wild water; but the angler need not be highly skilled. Success with the salmon depends upon conditions different from those of success with the trout. In trout fishing you must be able to tell, by intuition or from experience, where fish are likely to be hovering, and you must be nimble in the use of rod and line and flies; but in salmon fishing the boatmen provide the knowledge of the haunts, and it is self-control in excitement, rather than dexterity, that does the rest. Indeed, it may be said that all men are equal on a salmon loch. The lines of all are baited with minnows, the various types of which are chosen more by fancy than by science; the lines, instead of being cast as in fly-fishing, are trailed behind the boats; and the boats, as a rule, are rowed in courses which the professional attendants think best. That is the practice. I am not certain that it is the only way in which salmon in still waters could be sought successfully. Often, on almost any loch which holds them, you will see the fish rising briskly; not infrequently, when casting for trout you will hook a salmon. Is it to be taken for granted, then, that salmon flies would be useless on the lochs ? One can, it is true, perceive a reason why a salmon fly on a loch would be not so effective as the same lure on a stream. The stream helps you in the process of getting the fly away from yourself a goodly distance ; but in a loch it lies where it falls until you begin to drag it, which can only be towards the boat. This, however, is not a complete proof that casting a salmon fly on a loch would of necessity be a futile endeavour towards refinement of the sport. Salmon are not sharper in eyesight than trout are, and trout are not prevented from rising at a fly by the proximity of a boat. On the other hand, there may be an important difference between the position of salmon and that of trout. When the trout-creel is filling quickly, the trout are feeding, and when they are feeding they are poised only a few inches below the surface of the water; but, although salmon often leap into the air, their normal position is much below the surface. That being so, one can understand why fly-fishing for salmon on a loch would probably yield comparatively poor results. The salmon and the trout stand in relation to the boat at widely different angles. As the eyes of both salmon and trout look up, besides looking in other directions, the fish that are well below the surface will see the boat long before it comes within the range of vision of the fish that are poised high. Thus it would appear that, though not uncommon, the rising of a salmon at a trout fly is an exceptional incident. Bringing fierce joy and much alarm, it happens only when the fly chances to fall over a salmon that is at once looking away from the boat and is in a humour to snap at the lure.
It seems probable, then, that the professional attendants are right in believing that a minnow trolled behind a boat is the best lure on a loch. Is it equally probable that they are right in believing that the boat, instead of being rowed straight forward, should go forward in a series of curves ? I am not sure that they are. The reason for the usage is obvious. If the boat goes straight forward, the lure, trolled behind, will always be in water that has been disturbed by the craft and the oars; it seems reasonable to suppose, indeed, that, if the water is not very deep, every fish that lay in what has become the track of the boat must be scared off*. On the other hand, if the boat goes forward in curves, the lure, at the end of forty or fifty yards of line, instead of following the curves, touches your track at intervals only, and for the rest is spinning through water that has not been disturbed. The gillie has implicit faith in this procedure. " It's aye at the turn ye hook a fish," he assures you, meaning that it is only when the minnow has come into one of the undisturbed bits of water that you have a chance. One is obliged to respect the gillie. His theory looks eminently reasonable; and, to carry it out, by rowing in cunning curves he puts himself to considerable pains. Still, I cannot be so confident as he is. Often you hook a salmon when, the day being nearly over, you are going directly to the landing-stage. If the straight course is the wrong course, how does that happen ?
This is an interesting problem. I perceive three suggestions towards solution. One of these, which I shall mention last, has been, in Trout Fishing, offered by myself. Each of the others is wholly original, and will probably be considered untenable by such as are given to quick judgments.
In the first place, I can conceive it possible that in water about thirty feet deep, or deeper, a boat might be rowed right over a salmon at the bottom without the fish seeing it. Any one who has studied the ways of salmon in a river must have noticed signs of certain peculiarities of their vision. If by any means, such as by being in the stream, you can approach a salmon straight in the face, you may get within three or four yards of him before he sees you and flashes off; this indicates that, though the fish does see in front of him, he does not see far in that direction. If you approach sideways, as from the bank of the stream, he darts off much sooner, though not so soon as a trout would; this indicates that his lateral line of vision is longer than his line of vision to the front. As we have already had occasion to note, he sees upward also; but how far upward does he see? Hitherto anglers generally seem to have taken it for granted that fish of the salmon-kind, howsoever deep may be the water in which they are lying, see straight upwards into the air; but this assumption is questionable. Does not one of the characters in Aylzvin, that witching romance, begin his preparations for trout fishing in a Welsh tarn by anchoring his coracle in one of the deepest parts? He does; he is about to fish with worms, too; from which it is obvious that Mr. Watts-Dunton believes it possible, where the water is deep enough, to catch fish of the salmon-kind from a perpendicular position, just as the seaman catches cod. We must not, however, give much weight to this evidence. Perhaps the passage referred to is one of the accomplished writer's lapses from accuracy, which are rare. More conclusive is the fact that if, instead of approaching your salmon from the front or from the side, you approach him from above, he is unconscious of your presence until you are very near. The position is difficult to get into; but it may be roughly attained, sometimes, by standing on a bridge over a stream. Is there a salmon just below the rim of the bridge ? You will not scare him if you hang over the rim and wave your arms. His upward line of vision does not reach you. Why, then, should our gillie be certain that the boat is seen by a salmon lying thirty feet, or more than that, below ? Although he may be unconscious of the presence of the boat, the fish may see the minnow which is following in the depths.