now declining.[1] This diminution may well take place, for, according to Prof. Henry Woodward, of the common species Homarus vulgaris, as many as 25,000 live specimens "are often delivered at Billingsgate in one day. If only as many are eaten in the whole of England as in London, this would be at the rate of 50,000 per day, or 18,250,000 annually.... From Norway as many as 600,000 are received annually."[2] Marine animals commonly produce far more eggs than insects. The dangers of the shallow seas are so great that a small proportion only of the young animals come to maturity. Hence the enormous fertility of common marine animals, except such as are able to nourish or defend their young. Vast numbers of Zoœa are swept into mid-ocean or into tidal rivers, or are devoured. It is only a chance remnant that survives.[3] Prof. Möbius says that out of a million oyster embryos only one individual grows up, a mortality due to untoward currents and surroundings, as well as to hungry mouths.[4] Leuckart calculates that a tapeworm embryo has only about one chance in 83,000,000 of becoming a tapeworm.[5]
The fecundity of fish is shown by the following table of the number of ova in different species, as found by Frank Buckland's observations:—
| Name of Fish. | Weight of Fish. | No. of Eggs. | |
| lb. | oz. | ||
| Salmon. (The average num- ber of eggs in a Salmon is 850 to each pound weight) |
12 | 0 | 10,000 |
| Trout | 1 | 0 | 1,008[6] |
| Carp | 14 | 8 | 633,350 |
| Perch | 3 | 2 | 155,620 |
| ,, | 0 | 8 | 20,592[7] |
- ↑ 'Zoologischer Anzeiger,' xvii. no. 454; summarized in 'Nature,' vol. l. p. 553.
- ↑ 'Cassell's Nat. Hist.' vol. vi. p. 205; also cf. W.B. Lord, 'Crab, Shrimp, and Lobster Lore,' p. 95.—According to Bertram, 'As a general rule, the great bulk of Lobsters are not much more than half the size they used to be' ('The Harvest of the Sea,' p. 274).
- ↑ L.C. Miall, 'Nature,' vol. liii. p. 154.
- ↑ Cf. Thomson, 'The Study of Animal Life,' 2nd edit. p. 43.
- ↑ Ibid. p. 48.
- ↑ "There is not a living creature," said Mr. Francis Francis, "which inhabits the waters which does not prey more or less on Trout ova." ("The Trout" (Fur, Feather, and Fin Series), p. 171.)
- ↑ The number of eggs produced by this fish has been given as much greater by more recent writers. "Upwards of two hundred and eighty
