One tested species, commonly called the ‘chicken kidney sponge’ proved especially hardy when transplanted to a busy polluted recreational port near Girona, Spain. The authors had shortlisted five candidates, all abundant at low depths off Santa Anna Point, 30km from Marina Palamós: Corticium candelabrum, Crambe crambe, Scalarispongia scalaris, Ircinia oros, as well the chicken kidney sponge. “Unlike many sponges, the chicken kidney sponge can ‘creep’ away if local conditions deteriorate – for example, when nearby organisms compete. “But we will also continue testing more sponge species.” Image credit: Carlota EscarréSpecimen of Chondrosia reniformis transplanted into the harbor attached to an experimental plate used as the substratum.