Because, though attacked by man, and many animals, as the grampus, gulls, etc, it multiplies with astonishing rapidity. Its great and regular migrations, during summer, along the coasts of Europe, particularly the Orcades, Norway, etc. have given employment to many thousand people, from the 12th century. - Blumenbach.
It is, however, asserted, that "we have no satisfactory authority for believing that herrings breed in the northern seas, when they have never yet been observed in the real icy seas; nor have they even formed a fishery on the coast of Greenland and Iceland. When they first appear on the coast of Scotland, it is not in shoals, but in small numbers; and they are then taken with a feather, or fly, and a rod. There is nothing to indicate a migration from the north; on the contrary, there is every reason to believe they breed in our own seas: but, both the time of their breeding, and their visits, are irregular and capricious. Much good money has been sunk by erecting buildings, and establishing fishing stations, which the herrings afterwards abandoned." - Notes in Science, 1828.
Sir Humphry Davy says: " The great supposed migrations of herrings from the poles, to the temperate zone, have appeared to me to be only the approach of successive shoals from deep to shallow water, for the purpose of spawning." - Salmonia,
In a recent paper, in Jameson's Journal, Major W. M. Morrison supports that view of the migration of gregarious fish, which leads to the supposition, that they do not actually travel from north to south; but that, in accordance with climate, successive shoals approach the coasts for the purpose of spawning; and this view he supports by some interesting facts. The nets of Hastings are always cast north and south, in order that they may drift with the ebbing and flowing of the tide, which takes the direction of east and west in that part of the British Channel; and it is curious, that while those fish which are encumbered with roes, are caught in great numbers on the east side of the nets, they are not met with in a greater proportion than one in about one hundred without roes on the west side.
At Cairo, the Arab cooks are said to prepare the herring for the table, in such a manner, as to intoxicate the eaters.
Because its roe is poisonous, and has often given rise to dangerous symptoms when eaten.
Because it may, through this tube, throw water on the insects upon aquatic plants, so that they may fall and become its prey.
Because it kills insects and other prey,by ejecting, from its tubular mouth, single drops of water. Thus, when it spies a fly sitting on the plants that grow in shallow water, it swims 4, 5, or 6 feet from them, and then takes aim as above, when it rarely fails to strike the fly into the sea, where it soon becomes its prey.
Because its outline has the appearance of a broad crescent, in the centre of which, the tail, short and fan-shaped, projects like a leaf.