Effect of temperature on the gastric evacuation in sprat Sprattus sprattus

Authors

  • M. Bernreuther,

    Corresponding author
    1. Institute of Hydrobiology and Fisheries Science, University of Hamburg, Olbersweg 24, D-22767 Hamburg, Germany
      Tel.: +49 40 38905 238; fax: +49 40 38905 263; email: matthias.bernreuther@vti.bund.de
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      Present address: Federal Research Institute for Rural Areas, Forestry and Fisheries, Institute of Sea Fisheries, Palmaille 9, D-22767 Hamburg, Germany.

  • A. Temming,

    1. Institute of Hydrobiology and Fisheries Science, University of Hamburg, Olbersweg 24, D-22767 Hamburg, Germany
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  • J.-P. Herrmann

    1. Institute of Hydrobiology and Fisheries Science, University of Hamburg, Olbersweg 24, D-22767 Hamburg, Germany
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Tel.: +49 40 38905 238; fax: +49 40 38905 263; email: matthias.bernreuther@vti.bund.de

Abstract

Gastric evacuation of groups of juvenile (mean 63 mm total length, LT, 0·283 g dry mass, MD) sprat Sprattus sprattus feeding on brine shrimp Artemia sp. nauplii was studied at six temperatures (7·5, 10, 13, 16, 19·5 and 21·5° C) in the laboratory. Gastric evacuation was best described with a general model: inline image, with St = stomach content at time t, S0 = stomach content at time 0, t = time , R, B = constants. The shape parameter was estimated as B = 0·668. For comparison with other studies, an exponential model was fitted also to the data. The evacuation constant (R) of the general gastric evacuation model increased exponentially with temperature between 7·5 and 16° C. The slope of the increase was reduced between 16 and 19·5° C and a slight decrease was observed between 19 and 21·5° C. Additionally, the effect of mean MD (range 0·286 – 1·025 g) was examined. A simple power function (inline image ) described the influence of predator mass on exponential evacuation constant with C = 0·503. The results of this investigation were integrated into a consumption model for the calculation of daily rations of S. sprattus: inline image, with T = ambient temperature (°C) and inline image of field stomach contents (g dry) individually raised to the power of 0·668.

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