ittle eels, according to his observation, are
produced within reach of the tide, and climb round falls to reach fresh
water from the sea. I have sometimes seen them in spring, swimming in
immense shoals in the Atlantic, in Mount Bay, making their way to the
mouths of small brooks and rivers. When the cold water from the autumnal
flood begins to swell the rivers, this fish tries to return to the sea;
but numbers of the smaller ones hide themselves during the winter in the
mud, and many of them form, as it were, masses together. Various authors
have recorded the migration of eels in a singular way; such as Dr. Plot,
who, in his History of Staffordshire, says they pass in the night across
meadows from one pond to another; and Mr. Arderon, in the Philosophical
Transactions, gives a distinct account of small eels rising up the
flood-gates and posts of the water-works of the city of Norwich; and
they made their way to the water above, though the boards were smooth
planed, and five or six feet perpendicular. He says, when they first
rose out of the water upon the dry board, they rested a little--which
seemed to be till their slime was thrown out, and sufficiently
glutinous--and then they rose up the perpendicular ascent with the same
facility as if they had been moving on a plane surface.--There can, I
think, be no doubt that they are assisted by their small scales, which,
placed like those of serpents, must facilitate their progressive motion;
these scales have been microscopically observed by Lewenhoeck. Eels
migrate from the salt water of different sizes, but I believe never when
they are above a foot long--and the great mass of them are only from two
and a half to four inches. They feed, grow, and fatten in fresh water.
In small rivers they seldom become very large; but in large, deep lakes
they become as thick as a man's arm, or even leg; and all those of a
considerable size attempt to return to the sea in October or November,
probably when they experience the cold of the first autumnal rains.
Those that are not of the largest size, as I said before, pass the
winter in the deepest parts of the mud of rivers and lakes, and do not
seem to eat much, and remain, I believe, almost torpid. Their increase
is not certainly known in any given time, but must depend upon the
quantity of their food; but it is probable they do not become of the
largest size from the smallest in one or even two seasons; but this, as
well as many other pa