Autumn migration and vertical distribution of the brown shrimp Crangon crangon L. in relation to environmental conditions
Boddeke, R. (1975). Autumn migration and vertical distribution of the brown shrimp Crangon crangon L. in relation to environmental conditions, in: Barnes, H.B. (Ed.) Ninth European Marine Biology Symposium. pp. 483-494
In: Barnes, H.B. (Ed.) (1975). Ninth European Marine Biology Symposium. European Marine Biology Symposia, 9. Aberdeen University Press: Aberdeen. IX, 760 pp., meer
In: European Marine Biology Symposia., meer
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Crangon crangon (Linnaeus, 1758) [WoRMS]
Marien/Kust |
| Abstract |
The seasonal migration of C.crangon is wellknown phenomenon. Different reasons for, and explanations of, this migration are given in the literature, including the search for better feeding grounds, the migration in winter to waters with a higher salinity, the influence of the water temp on the migration, and the osmoregulatory ability. A description and explanation of the autumn migration is given based on data collected over a period of 14 yr of both lab research and field work in the various coastal waters of the Netherlands. It has become evident that there is no relation between salinity or the absolute water temp and this seasonal migration. The autumn migration, and partially also the vertical distribution, are induced by the fluctuations of the water temp especially those in the tidal zone, which are caused by the seasonal differences between air and water temp. Sexually mature shrimps are more sensitive to temp fluctuations than sexually more immature animals. The autumn migration runs parallel with a period of increasing sexual activity and appears to be a very regular process in which waves of shrimps in decreasing stages of sexual ripeness migrate to the open sea one after another. Every wave includes male, berried female, and non-berried female. Among both the berried and the non-berried female of each wave a high measure of synchronization could be demonstrated in respect to the moulting cycle. By this rigid patterned process of migration the density of the inshore population is reduced in a regular way, leaving the sexually least mature animals in the areas with the richest food supplies and returning the sexually more mature animals to more or less the same area where they hatched. |
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