HABITS OF TROUT.
A knowledge of the habits of trout is very essential, and this knowledge can only be acquired by careful observation. The largest fish are generally to be found where they can obtain the best supply of food—such points as just below sharp bends of the stream, behind large stones or other obstructions, at the head or tail of deep pools, and on the margin of swift currents, or under overhanging banks; and, if you take a good fish at any particular spot, you will probably find, a day or two afterwards, that the next best fish in that locality has taken the place of the one you captured. It has often occurred to me that there are several reasons why brook trout do not thrive in the lower part of rivers communicating with the sea. One thing is, to my mind, very certain—they do not feel at home in salt, or even brackish, water, and do not seek it of their own accord. Having lived many years within sight of a point where a fresh water stream flows into salt water, I have had perhaps exceptional opportunities of observing them, and forming an opinion on the subject; and, although I have lately seen an apparently well-supported contrary opinion strongly expressed, I am not yet convinced, thinking that probably some error may have crept in as to the kind of fish, or some disturbing cause taken place in the state of the water. Occasionally they get washed down by floods, or by the breaking away or uplifting of hatches or gates; but, as soon as the rush of water subsides, they begin to work their way up again, and if there is an obstacle to their ascending, such as a weir or mill, they are sure to be found close up to it, having got as far as they can. They always seem prompted by instinct to work upwards into shallow rapid water, where the bottom is gravelly, and, I believe, for the following reasons: They can there deposit and cover up their ova, and, when hatched, the young fry can get protection among it from their numerous enemies in their early days; and, although food may be plentiful in muddy sluggish streams near salt water, it is not of the kind that trout delight in. Larva, flies, and minnows abound in clear bright streams, and there the trout can clean themselves from their parasites, and, with healthy bodies and abundance of the food they enjoy, come into condition early, and become lusty and strong.
In the breeding time they, like many other animals, lose their usual caution and shyness, and when performing their natural functions seem to take no notice of what is passing around them; and thus very many of the best fish are captured in shallow water, and the streams almost depopulated. The greatest vigilance should be exercised in the spawning time to prevent poachers, both human and others, from preying upon them. In addition to men, swans, ducks, otters, herons, pike, perch, &c., &c., all prey on the luckless trout and its ova and fry, and the wonder is that the stock is so well maintained as it is. Otters and herons in particular appreciate this dainty, and either of them will travel across country many miles to get to a well-stocked trout stream. So strong is the instinct of the trout to get into shallow streams to deposit their spawn, that they will leap waterfalls several feet in height, or wriggle up over gravel where there is not half enough water to cover them, and where it is frequently impossible for them to get back again, and there they are often destroyed.