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The Reproduction of the Lobster

Published online by Cambridge University Press:  11 May 2009

E. J. Allen
E. J. Allen
Affiliation:
Director of the Plymouth Laboratory
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Extract

Amongst the numerous subjects which have occupied the attention of the fishery authorities of the United States, that of the great decline in the productiveness of the lobster fishing industry has received much consideration, and several competent naturalists have, in consequence, devoted themselves to a scientific study of the habits and life-history of the American species. This species (Homarus Americanus) is so nearly allied to the European lobster (Homarus vulgaris), that the results arrived at for it, with regard to such questions as the time of year at which spawning takes place, the length of time during which the eggs are carried by the female attached to the under side of the abdomen, and the time of year at which the eggs are hatched, might be expected to apply, to some extent at least, to the latter. That this is so, appears to be abundantly proved by Dr. Ehrenbaum's study of the lobsters which frequent the shores of Heligoland, and certain observations which I have been able to make on lobsters taken in the neighbourhood of Plymouth during the last two years, in the course of my work on the nervous system of the embryo, also tend to confirm this view.

Type
Research Article
Information
Journal of the Marine Biological Association of the United Kingdom , Volume 4 , Issue 1 , May 1895 , pp. 60 - 69
Copyright
Copyright © Marine Biological Association of the United Kingdom 1895

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References

page 61 note * Johns, HopkinsUniv. Circulars, vol. x. no. 87, and Zool. Anzeiger, nos. 361 and 362.Google Scholar

page 61 note † Zool. Anzeiger, 08, 1894, and 06, 1895.Google Scholar

page 61 note ‡ Nielsen states that, in Newfoundland, the larger lobsters spawn from the middle of June till the middle of August, whilst the smaller do not lay until the latter part of October and November. (Annual Report, Newfoundland Fisheries Commission, 1889, p. 12.)Google Scholar

page 62 note * In the sixth Annual Report of the Fishery Board for Scotland, p. 196, Prof. Ewart and Dr. Fulton state that in Rothesay Aquarium, a female, with ova, being placed in the tanks in August, 1886, hatching was only completed in August, 1887, some of the young lobsters being hatched as early as April. It seems fairly certain from this result, that confinement tends to produce an abnormal rate of development, as, in the case of lobsters captured when the eggs are nearly ready to hatch and placed in the tanks of the Plymouth Laboratory, hatching is usually completed within a week, at most, from the time it commences.

page 64 note * Herrick found, however, among about 3,000 animals, a slight excess of females.

page 64 note † Herrick (Zool. Anz. 1891, p. 134) has given a similar table, which, however, does not give the same result.

page 65 note * “A false interpretation of the facts can only be possible in so far that perhaps, sometimes, females may have been counted as ‘not egg-bearing,’ although they were slightly under 24 cm. (9½ inches) long, and therefore not yet capable of reproduction. So far as could be judged by the eye, however, the young animals not yet capable of reproduction during the enumeration, were always left on one side.”

page 67 note * In comparing Ehrenbaum's figures with those of Herrick, it must not be forgotten that those of the latter author are based on an examination of nearly a thousand individuals, whilst those of the former are in each case the result of counting the eggs of a single female.

page 68 note * It may, of course, be maintained that the capture of other fish has tended to reduce he number of enemies of the larvæ.