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Observations on the Growth of the Claspers and Cloaca in Raia clauata Linnaeus

Published online by Cambridge University Press:  11 May 2009

G. A. Steven
Affiliation:
Assistant Naturalist at the Plymouth Laboratory

Extract

In the course of work on the life-history and biology of the Raiidæ in the English Channel, and especially of R. clavata, the most important species commercially (4, p. 9 et seq.), it has been found necessary to attempt to disentangle the migrations of sexually mature fishes from those of juvenile individuals by means of marking experiments. In both sexes sufficiently small individuals could with safety be written down as juveniles and the largest of both sexes as adults. There remained, however, a considerable but ill-defined range of sizes (different in the two sexes) within which might be found fishes of all stages—juveniles, adolescents and adults.

Type
Research Article
Copyright
Copyright © Marine Biological Association of the United Kingdom 1934

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References

LITERATURE CITED

1.Clark, Robert S.Rays and Skates—A Revision of the European Species. Fisheries, Scotland, Sci. Invest., 1926, I. (1926.)Google Scholar
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3.Malm, A. W. Goteborgs och Bohusläns Fauna, Ryggradsdjuren. Goteborg, 1877.Google Scholar
4.Steven, G. A.Rays and Skates of Devon and Cornwall. II. A Study of the Fishery; with Notes on the Occurrence, Habits, and Migrations of the Species. Journ. Mar. Biol. Assoc., N.S., Vol. XVIII, 1932–33, p. 1.CrossRefGoogle Scholar
5.Steven, G. A. Rays and Skates of Devon and Cornwall. III. The Proportions of the Sexes in Nature and in Commercial Landings, and their Significance to the Fishery. Idem, p. 611.CrossRefGoogle Scholar