The dorid nudibranchs <i><scp>P</scp>eltodoris lentiginosa</i> and <i><scp>A</scp>rchidoris odhneri</i> as predators of glass sponges

Abstract

Abstract The dorid nudibranchs P eltodoris lentiginosa and A rchidoris odhneri were found on glass sponges (Porifera, Hexactinellida) during remotely operated vehicle surveys of three reefs in the S trait of G eorgia, British Columbia , C anada. Eight nudibranchs were sampled from 2009 to 2011. Identification of sponge spicules found in their gut and fecal contents confirmed the nudibranchs to be predators of the reef‐forming hexactinellids A phrocallistes vastus and H eterochone calyx , as well as of the demosponge D esmacella austini, which encrusts skeletons of the glass sponges. Four of five nudibranchs dissected for gut content analysis had stomachs containing sponge spicules. Counts from high‐definition video footage taken during systematic surveys done in 2009 showed that nudibranchs were found in only two of the three glass sponge reefs. These data provide the first quantitative evidence of a molluscan predator on glass sponges found outside of A ntarctica, and establish the first trophic link between glass sponges and their associated community of animals in a sponge reef ecosystem on the western C anadian continental shelf.