Notes on relations between density, settling, and growth of two sympatric cockles, Cardium edule (L.) and C. glaucum (Bruguière)
Brock, V. (1980). Notes on relations between density, settling, and growth of two sympatric cockles, Cardium edule (L.) and C. glaucum (Bruguière), in: Christensen, A.M. et al. Proceedings of the 6th Symposium of the Baltic Marine Biologists: Relationship and exchange between the pelagic and benthic biota. Århus, Denmark, 20-26 August 1979. Ophelia. Supplementum, 1: pp. 241-248
In: Christensen, A.M.; Muus, K. (Ed.) (1980). Proceedings of the 6th Symposium of the Baltic Marine Biologists: Relationship and exchange between the pelagic and benthic biota. Århus, Denmark, 20-26 August 1979. Ophelia. Supplementum, 1. Marine Biological Laboratory: Helsingør. ISBN 87-981066-0-0. 304 pp., meer
In: Ophelia. Supplementum. Ophelia Publications: Helsingør. ISSN 0107-5896, meer
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Documenttype: Congresbijdrage
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| Trefwoorden |
Cardium edule Linnaeus, 1758 [WoRMS]; Cardium glaucum Bruguière, 1789 [WoRMS]
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| Abstract |
Density dependent survival, growth and settling in bottom cages was investigated during the growth
period, 1 April to 15 October 1978. The cages contained different densities of either Cardium
edule, C. glaucum or both. They were placed under natural conditions in a sublittoral locality in
the Limfjord, where the two closely related species occur in sympatry. The mortality of the cockles
placed in the cages was comparable to that of an undisturbed reference area at the locality.
Neither the initial density nor species combination in the cages did affect the growth of the
survived cockles. Only C. edule did settle in the area the year concerned. Settlement of this cockle
within the cages was inversely related to the density of the cockles already there, showing no
species specific preference. High densitites, up to 1648 indv. per m2 of newly settled cockles, were
found in the cages, while the densities outside, due to predation, was only 2 indv. per m2. The
growth of the newly settled cockles was similar at higher and lower cage densities, showing that
food was not the limiting factor, whereas density dependent regulation was found to act upon the
settling process of the young cockles. |
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