food; and it is well known to fly-fishers that they do not catch
many fish in the streams if they begin early, say in February. It
is proverbial here that fish begin to stream when the great grey,
or what is called in other districts the devil or dule crook, and
in March brown or brown drake, comes upon the water; and I have
seen Trout by scores leaping at a weir in the beginning of May,
whether in search of food or an instinct implanted in them to keep
all parts equally stocked with them, I do not know; but it has
certainly nothing to do with their spawning. Is it presumptuous to
suppose that God in His providence has implanted this instinct in
Salmon for our good, that we might have a supply of excellent
food, which without this would be in a great measure unattainable?
Whether this is the true cause, and the only one, I am unable to
determine; but this is the effect produced, and in the absence of
other reasons it is, in my opinion, one that ought to be admitted.
Another reason why fish ascend rivers is their impatience of heat.
I speak now more particularly of Grayling; if the weather is very
hot at the end of May or the beginning of June, the Grayling in
the Wharfe (they are almost unknown in this part of the Ribble)
ascend the mill streams by hundreds, and go up the wheel races as
far as they can get, and stay there until the stoppage of the
wheels (many a ducking have I had in pursuit of them), when they
are obliged to beat a retreat, and this often proves a disastrous
one to many of them. The ascent of young Eels by millions, and the
ascent of the Flounder, are neither of them connected with the
propagation of their kind, and though I cannot say for what
purposes they do ascend, I am, I think, justified in doubting
assertions which seem to have nothing to support them but the
positive manner in which they are made.