Fisheries Techniques 2d pg. 468. PSD = Proportional Stock Density = [ # of fish > or = minimum quality length divided by # of fish > or = minimum stock length ] X 100. See also Relative Stock Density = RSD which is the % of fish of any designated length-group in a sample. Without getting to complicated these have been refined to 5 catagories , stock , quality, preferred ,memorable and trophy lengths. Table 15.2 has these for 39 taxa.

This is the only AFS study using the words " proportional size distribution ".

Black Bass Length Limits by Design: A Graphic Approach

The bass proportional size distribution presented
in the wing graph is similar to the proportional
stock density (PSD) concept of Anderson 1976 .
Had we chosen CPUE of bass 8 in and
longer as the JV-axis and CPUE of bass 12 in and
longer as the X-axis, the slope of a line from the
origin to a given point would equal the PSD for
that population. The PSD is a useful concept for
fisheries management, especially as related to angler-
caught fish; however, we have found that PSD
based on electro fishing data can be overly sensitive
to annual changes in recruitment. A large increase
in abundance of 8-in bass can inflate the denominator
of the PSD equation and thus reduce PSD
substantially, even though the abundance of larger
bass remains unchanged. Therefore, we agree with
Dent (1986a) that PSD information should be used
in conjunction with CPUE data by si/e-group. Another
limitation of PSD is that it does not include
largemouth bass less than 8 in. The product of
total bass CPUE and PSD is of little value by itself.
Total bass CPUE and the CPUE of bass 15 in and
longer is much more useful. The larger bass are
needed to sustain population biomass, predatory
pressure and the quality of fishing.