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Marine Biology

, Volume 142, Issue 2, pp 263–270 | Cite as

Effects of food concentration on the behaviour of Oikopleura dioica

  •  E. Selander
  •  P. Tiselius

Abstract.

Feeding behaviour of the pelagic tunicate Oikopleura dioica presented with a range of food concentrations (FC, 4–670 µg C l–1) of the flagellate Isochrysis galbana was observed using video. Simultaneous bottle incubations provided clearance rate estimates. Tail beats per minute (TB), number of tail arrests or pauses (TA) and swimming speeds were recorded. TB decreased with increasing FC, from 521 to 355 min–1, while TA increased from 17 to 35 min–1. Aberrant behaviour with repeated TA was found if inlet filters were obstructed by larger particles or aquarium walls. Swimming speed was 1.0±0.4 mm s–1, and the time spent swimming decreased with FC from 38% to 11% of the time. Clearance rate decreased sharply with FC, from 4.3 to 0.11 ml ind.–1 h–1, resembling a type II functional response with Michaelis–Menten parameters Imax=113 µg C ind.–1 h–1 and Km=27 µg C l–1. Using TB, TA and a residual error term, a simple model to predict clearance rate from behavioural parameters was developed. Power functions of FC were fitted to each parameter, resulting in exponents of –0.047, –0.183 and –0.38, respectively. The error term includes passive clogging and food rejection at the mouth, and was according to the model the most important for shaping the functional response.

Keywords

Food Concentration Functional Response Clearance Rate Rate Estimate Swimming Speed 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  •  E. Selander
    • 1
  •  P. Tiselius
    • 1
  1. 1.Kristineberg Marine Research Station, Department of Marine Ecology, Göteborg University, 45034 Fiskebäckskil, Sweden

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