Food intake and growth of Sarsia tubulosa (Sars, 1835), with quantitative estimates of predation on copepod populations
Daan, R. (1986). Food intake and growth of Sarsia tubulosa (Sars, 1835), with quantitative estimates of predation on copepod populations. Neth. J. Sea Res. 20(1): 67-74
In: Netherlands Journal of Sea Research. Netherlands Institute for Sea Research (NIOZ): Groningen; Den Burg. ISSN 0077-7579; e-ISSN 1873-1406, meer
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| Abstract |
In laboratory tests food intake by the hydromedusa Sarsia tubulosa, which feeds on copepods, was quantified. Estimates of maximum predation are presented for 10 size classes of Sarsia. Growth rates, too, were determined in the laboratory, at 12°C under ad libitum food conditions. Mean gross food conversion for all size classes averaged 12%. From the results of a frequent sampling programme, carried out in the Texelstroom (a tidal inlet of the Dutch Wadden Sea) in 1983, growth rates of Sarsia in the field and population densities are derived. Growth in the field equalled maximum growth under experimental conditions, which suggests that Sarsia in situ can feed at an optimum level. Two estimates of predation pressure in the field matched very closely and lead to the conclusion that the impact of Sarsia predation on copepod standing stocks in the Dutch coastal area, including the Wadden Sea, is generally negligible. |
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