Freshwater fish family diversity

Family richness of typical bony fishes (Actinopterygii) in inland waters, plotted as a world density surface. It is based on generalised range maps of 157 families. Colour depth represents the number of families, up to a maximum of 44, potentially present at any point. Two families of cartilaginous fishes (Elasmobranchii) that together have a very few inland water species are omitted. About a dozen families of bony fish that occur in coastal and estuarine waters but do not extend significantly into inland freshwaters are omitted. Several families range more or less widely in inland waters and also occur in coastal and estuarine waters around the continents, but this peripheral part of the range is in most cases not represented.
Source: produced by UNEP-WCMC, with support from DEFRA, using range maps prepared from information in Berra
Berra, T.M. 2001. Freshwater fish distribution. Academic Press, San Diego and London.