  Using data taken as part of the Bluedisk project we study the connection
between neutral hydrogen (HI) in the environment of spiral galaxies and that in
the galaxies themselves. We measure the total HI mass present in the
environment in a statistical way by studying the distribution of noise peaks in
the HI data cubes obtained for 40 galaxies observed with WSRT. We find that
galaxies whose HI mass fraction is high relative to standard scaling relations
have an excess HI mass in the surrounding environment as well. Gas in the
environment consists of gas clumps which are individually below the detection
limit of our HI data. These clumps may be hosted by small satellite galaxies
and\or be the high-density peaks of a more diffuse gas distribution in the
inter-galactic medium. We interpret this result as an indication for a picture
in which the HI-rich central galaxies accrete gas from an extended gas
reservoir present in their environment.
