Hostname: page-component-848d4c4894-wzw2p Total loading time: 0 Render date: 2024-06-12T16:59:42.844Z Has data issue: false hasContentIssue false
  • English
  • Français

Rays and Skates of Devon and Cornwall. II. A Study of the Fishery; with Notes on the Occurrence, Migrations and Habits of the Species

Published online by Cambridge University Press:  11 May 2009

G. A. Steven
G. A. Steven
Affiliation:
Assistant Naturalist at the Plymouth Laboratory.
Get access Rights & Permissions [Opens in a new window]

Extract

1. Until the beginning of the present century there was little demand in this country for Rays and Skates. This fishery is now of major importance both nationally and within the Devon and Cornwall area.

2. Of the eleven species of Raia present in the western area of the Channel, R. clavata makes the greatest numerical contribution (37%) to the total landings in Devon and Cornwall. The composition of the catches obtained by different methods of fishing varies greatly.

3. R. clavata is the most widely distributed species in the Channel area at all depths and on all kinds of sea bottom.

4. In a series of trawl hauls off the west coast of Ireland R. clavata was most numerous in the catches down to about 100 fm. From that depth down to about 170 fm. (the greatest depth fished) R. fullonica was most numerous.

5. Unispecific and even unisexual shoals of at least three species of Raia—R. clavata, R. brachyura, R. fullonica—occur.

6. When more than one species of Raia is present within the same area at the same time, the members of the different species have been found not to mix indiscriminately.

7. R. clavata appears to hatch out in shallow water close inshore and gradually move seawards into deeper water as it grows.

8. Adult R. clavata show definite migratory movements, though the full extent of their wanderings is not yet known. There is an inshore migration in early spring of adult fish to a small part of the coast near Plymouth. The first fish to appear are females, males appearing later.

9. There is evidence of somewhat similar migratory movements by R. brachyura.

10. R. clavata—and possibly also R. brachyura and R. batis—at times may feed almost entirely on Herrings.

11. Large R. batis feed to no inconsiderable extent on other species of Eaia.

12. In foraging for their food Rays and Skates depend upon some sense other than sight.

13. There has been in recent years a steady decline in the landings of Rays and Skates from the English Channel—probably due to depletion of the available stock of fish.

Type
Research Article
Information
Journal of the Marine Biological Association of the United Kingdom , Volume 18 , Issue 1 , May 1932 , pp. 1 - 33
Copyright
Copyright © Marine Biological Association of the United Kingdom 1932

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

XI. LITERATURE CITED

1.Clark, Robert S.Rays and Skates (Raiæ). No. 1—Egg-Capsules and Young. Jour. Mar. Biol. Assoc., N.S., Vol. XII, p. 577. 1922.Google Scholar
2.Clark, Rsobert S.Rays and Skates; a Revision of the European Species. Fisheries, Scotland, Sci. Invest. 1926, I. (1926.)Google Scholar
3.Couch, Johnthan. A History of the Fishes of the British Islands. 4 Vols. London. I, 1864; II, 1863; III, 1864; IV, 1865.Google Scholar
4.Day, F. The Fishes of Great Britain and Ireland. 2 Vols. London. I, 1880; II, 1884.Google Scholar
5.Meek, A. The Migrations of Fish. London. 1916.Google Scholar
6.Murie, James. Report on the Sea Fisheries and Fishing Industries of the Thames Estuary. Pt. I. London. 1903.CrossRefGoogle Scholar
7.Steven, G. A.Bottom Fauna and the Food of Fishes. Jour. Mar. Biol. Assoc., N.S., Vol. XVI., p. 677. 1930.CrossRefGoogle Scholar
8.Steven, G. A.Rays and Skates of Devon and Cornwall. Methods of Eapid Identification on the Fishmarket. Jour. Mar. Biol. Assoc., N.S., Vol. XVII, No. 2, p. 367. 1931.CrossRefGoogle Scholar