The effect of turbidity and illumination on the reaction distance and search time of the marine planktivore Gobiusculus flavescens |
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Authors: | A. C. W. Utne |
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Affiliation: | Department of Fisheries and Marine Biology, University of Bergen, Bergen High Technology Centre, N-5020 Bergen, Norway |
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Abstract: | Both reduced illumination and increased turbidity caused a significant reduction in reaction distance of Gobiusculus flavescens . The longest reaction distance, 18.9 cm for larger prey (Calanus finmarchicus) , occurred at a light level of 80 μmol m −2 s −1 compared to 12.9 cm for a smaller prey (Acartia clausi) at 8 μmol m−2 s−1. Above a light saturation level of 10 μmol m−2 s−1, additional light had little influence on reaction distance. In the turbidity experiments, the longest reaction distances were measured at turbidity levels of 10–20 JTU. Prey size influenced reaction distance at all tested light levels. Search time was influenced by prey size only at low illumination. With increasing turbidity, reaction distance to a group of prey was longer than to one prey. |
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Keywords: | Gobiusculus flavescens reaction distance prey size turbidity light intensity |
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