The only other areas in the world where glass sponges grow shallower than 50m are in Antarctica, southern New Zealand, and a few caves in the Mediterranean. Deep surveys of British-Columbia fjords by the manned submersible ‘Pisces IV’ indicate that highest abundances coincide with seawater containing high levels of dissolved silicate, low light levels, reasonably high oxygen levels, temperatures between 9-10oC, and low amounts of suspended sediments.