The biology and ecology of a brackish lagoon bivalve, Cerastoderma glaucum Bruguière, in an English lagoon, The Midwater, Sussex
Ivell, R. (1979). The biology and ecology of a brackish lagoon bivalve, Cerastoderma glaucum Bruguière, in an English lagoon, The Midwater, Sussex. J. Moll. Stud. 45(3): 383-400
In: Journal of Molluscan Studies. Oxford University Press: Reading. ISSN 0260-1230; e-ISSN 1464-3766, meer
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Cerastoderma glaucum (Poiret, 1789) [WoRMS]
Brak water |
| Abstract |
Data are presented on population and individual parameters for a population of Cerastoderma glaucum Bruguière living in a small, almost closed mixohaline lagoon in southern England. The bivalve occupies two discrete niches, a benthic one and a semi-pelagic one, where juveniles are suspended in the floating alga Chaetomorpha linum Kutz. During the study year (1972) there was no growth in the benthic population. This was shown to be an unusual occurrence by comparing growth data obtained by several different techniques, including the microscopic examination of shell growth lines. Reproductive condition followed the monocyclic pattern already established for this species in northern localities, with spawning taking place in May. Ash content, water content and calorific content all varied in correspondence with the level of starvation, which proceeded with insignificant mortality until body weight was reduced to about a quarter of that at the beginning of the year. At this point calorific values as low as 3.5 kcal/g were measured. Possible causes for the anomalous negative production are considered. The most likely factor responsible would appear to be the high production of the alga Chaetomorpha linum which would effectively compete out the phytoplankton food of the Cerastoderma population. |
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