Hydrobiological Bulletin

, Volume 19, Issue 1, pp 29–36 | Cite as

Calculations of results in grazing experiments using the counting method

  • M. L. M. Tackx
  • E. M. Van De Vrie
Measurements in the Ambient Medium


Different formulae used in the literature for calculation of ingestion rates are reviewed. Their applicability is discussed in relation to two criteria: the occurrence of saturation of the feeding and/or growth of the food particles. It is shown by simulations that the differences in results obtained by calculating ingestion following a linear or an exponential model are restricted to a few percent. Calculation of ingestion rates by subtraction of particle concentrations from control and grazing bottles can result in substantial over- or underestimation depending on the growth constant of the food particles and the grazing time.

The formule l=Vk(Czt−Czoekt)/N(l−ekt) is proposed for the calculation of ingestion rates under saturated circumstances.

It is demonstrated that, with data obtained by multi-size class analysis, calculations on total particle concentrations are only feasible when growth constants and grazing coefficients are equal for all size classes considered.

Attention is drawn to calculation problems resulting from non-normally distributed results and from non equal particle concentrations in control and grazing bottles at the beginning of the experiment. For the latter problem, two correction methods are proposed.


grazing Coulter counter clearance rate ingestion rate 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. BARETTA, J.W. and J.F.P. MALSCHAERT, 1985. Experimental problems using electronic particle counters. Hydrobiological Bulletin 19: 21–27.Google Scholar
  2. FROST, B.W., 1972. Effects of size and concentration of food particles on the feeding behaviour of the planktonic copepodCalanus pacificus. Limnol. Oceanogr., 27: 805–815.Google Scholar
  3. GAULD, D.T., 1951. The grazing rate of planktonic copepods. J. Mar. Biol. Ass. U.K., 29: 695–706.Google Scholar
  4. MULLIN, M.M., 1963. Some factors affecting the feeding of marine copepods of the genusCalanus. Limnol. Oceanogr., 8: 239–250.Google Scholar
  5. PAFFENHOFER, G.A., J.R. STRICKLER and N. ALCARAZ, 1982. Suspension-feeding by herbivorous calanoid copepods: a cinematographic study. Mar. Biol., 67: 193–199.Google Scholar
  6. POULET, S.A., 1973. Grazing ofPseudocalanus minutus on naturaly occurring particulate matter. Limnol. Oceanogr., 18: 564–573.Google Scholar
  7. PRICE, H., G.A. PAFFENHOFER and J.R. STRICKLER, 1983. Modes of cell capture in calanoid copepods. Limnol. Oceanogr., 28: 116–123.Google Scholar
  8. RIGLER, F.H., 1971. Feeding rates-Zooplankton. In: EDMONDSON, W.T. and G.G. WINBERG e.d., 1971. Secondary Productivity in Fresh waters. Blackwell Scientific publications Oxford and Edinburg, p. 228–256.Google Scholar
  9. SHELDON, R.W., A. PRAKASH and W.H. SUTCLIFFE, Jr., 1972. The size distribution of particles in the ocean. Limnol. Oceanogr., 27: 327–340.Google Scholar
  10. VANDERPLOEG, H.A., 1981. Seasonal particle-size selection byDiaptomus sicilis in offshore Lake Michigan. Can. J. Fish. Aquat. Sci., 38: 504–517.Google Scholar

Copyright information

© Netherlands Hydrobiological Society 1985

Authors and Affiliations

  • M. L. M. Tackx
    • 1
  • E. M. Van De Vrie
    • 1
  1. 1.Delta Institute for Hydrobiological ResearchYersekeThe Netherlands

Personalised recommendations