This may help a little.

In Michigan lakes with slow-growing
bluegill populations, the mean bluegill length at
first annulus (Figure 8) is often larger than the
mean lengths used in our pond studies. In
samples from 16 lakes over several years, most
young bluegill were 25-60 mm TL during their
12
first winter. A 25-mm bluegill is predicted to
have a maximum body depth of 6.3 mm
(Equation 12). Therefore, to ingest that bluegill
a walleye needs to be at least 63 mm (EMw) and
a yellow perch needs to be at least 78 mm (EMp)
or 72 mm (MMp). A 60-mm bluegill has a body
depth (17.9 mm) equal to the estimated mouth
width of a 158-mm walleye and a 193-mm
yellow perch. However, the majority of age-0
bluegill are less than 50 mm and could be
ingested by any walleye likely to be present and
by any yellow perch over 158 mm. \:\)