Rasping in the dark: First evidence of sound production in a polar marine invertebrate, the snow crab ( Chionoecetes opilio )

Sound production is prevalent among marine invertebrates, yet acoustic behavior remains largely undocumented in polar species. Here is reported the first evidence of acoustic emissions in the snow crab Chionoecetes opilio, a commercially important crustacean inhabiting cold and deep marine environments. Using synchronized passive acoustic recordings and miniaturized carapace-mounted accelerometers, the study demonstrates that snow crabs emit broadband pulse trains, termed rasps. Laboratory experiments revealed a strong effect of light conditions, with rasps detected only under dark conditions. Some snow crabs produced long and highly repetitive rasp sequences (up to 200 rasps in 1 h), resulting in sustained emission rates that, as far as can be determined, have not been described at this temporal scale in marine invertebrates. A complementary field experiment confirmed rasp production in situ, and accelerometer recordings allowed attribution of signals to a single individual within a group, highlighting strong inter-individual variability. The temporal structure of rasps was comparatively irregular, suggesting that internal friction-based mechanisms, such as gastric mill activity, may be involved. While the ecological role of snow crab rasps remains unknown, these findings expand current knowledge of crustacean acoustic behavior and provide a foundation for future research on sound production and its ecological relevance in polar marine invertebrates.