The power law in particle size analysis for aquacultural facilities

Fine particles tend to accumulate in recirculating aquacultural facilities, which can lead to serious fish health problems. The literature indicated t hat in many particle systems, the particle size distribution may be accurat ely represented by a two-parameter, hyperbolic power-law function, dN/dl = Al-beta. The purpose of this paper is to investigate whether this observation holds for aquacultural facilities. Particle size distribution data from four rese arch establishments were examined, using 14 data sets, comprising 11 aquacu ltural systems, and covering three species of salmonids and one of striped bass. In the data examined, the exponent, beta, varied from 2.9 to 4.6, wit h one sample reaching as high as 6.3. Correlation coefficients varied from 0.998 to 0.975. Larger exponents, indicating a greater number of fine parti cles, appear to dominate recirculating aquaculture systems. The results strongly suggest that a hyperbolic distribution is valid for aq uaculture systems. The usefulness in this technique is that once a worker h as established the exponent from the distribution of particle sizes at any given point in his facility, an estimate of particulate contributions by si ze to the total particle number, surface area and volume/mass concentration can be obtained. (C) 1999 Elsevier Science B.V. All rights reserved.