The Book of Household Management by Mrs. Beeton

208. THE FECUNDITY OF FISHES has been the wonder of every natural

philosopher whose attention has been attracted to the subject. They are in general oviparous, or egg-producing; but there are a few, such as the eel and the blenny, which are viviparous, or produce their young alive. The males have the _milt_ and the females the _roe_; but some individuals, as the sturgeon and the cod tribes, are said to contain both. The greater number deposit their spawn in the sand or gravel; but some of those which dwell in the depths of the ocean attach their eggs to sea-weeds. In every instance, however, their fruitfulness far surpasses that of any other race of animals. According to Lewenhoeck, the cod annually spawns upwards of nine millions of eggs, contained in a single roe. The flounder produces one million; the mackerel above five hundred thousand; a herring of a moderate size at least ten thousand; a carp fourteen inches in length, according to Petit, contained two hundred and sixty-two thousand two hundred and twenty-four; a perch deposited three hundred and eighty thousand six hundred and forty; and a female sturgeon seven millions six hundred and fifty-three thousand two hundred. The viviparous species are by no means so prolific; yet the blenny brings forth two or three hundred at a time, which commence sporting together round their parent the moment they have come into existence.