On the use of Lloyd’s index of patchiness

Lloyd’s index of patchiness, and to a lesser extent, of mean crowding, are often applied to (fish or ichthyoplankton) densities, although they were designed for use with counts of individuals. The consequences of this erroneous application are described with examples. Alternative statistics are presented for application to densities. Like the mean crowding, these statistics are robust against zeroes and cannot be considered as spatial statistics.