  We present the detection of 89 low surface brightness (LSB), and thus low
stellar density galaxy candidates in the Perseus cluster core, of the kind
named "ultra-diffuse galaxies", with mean effective V-band surface brightnesses
24.8-27.1 mag arcsec$^{-2}$, total V-band magnitudes -11.8 to -15.5 mag, and
half-light radii 0.7-4.1 kpc. The candidates have been identified in a deep
mosaic covering 0.3 square degrees, based on wide-field imaging data obtained
with the William Herschel Telescope. We find that the LSB galaxy population is
depleted in the cluster centre and only very few LSB candidates have half-light
radii larger than 3 kpc. This appears consistent with an estimate of their
tidal radius, which does not reach beyond the stellar extent even if we assume
a high dark matter content (M/L=100). In fact, three of our candidates seem to
be associated with tidal streams, which points to their current disruption.
Given that published data on faint LSB candidates in the Coma cluster - with
its comparable central density to Perseus - show the same dearth of large
objects in the core region, we conclude that these cannot survive the strong
tides in the centres of massive clusters.
