Dear MARMAM community, We are pleased to share our recent publication: Shaff JF, Baird RW. Diel and lunar variation in diving behavior of rough-toothed dolphins (*Steno bredanensis*) off Kauaʻi, Hawaiʻi. Mar Mam Sci. 2021;1–16. https://doi.org/10.1111/mms.12811 Abstract: Observational studies describe rough-toothed dolphins (*Steno bredanensis*) actively foraging during the day on epipelagic species. Using data from depth-transmitting satellite tags deployed on nine individuals off Kauaʻi, we investigated diving behavior and the effects of lunar phase and solar light levels on vertical movements. Overall, tagged rough-toothed dolphins primarily used near-surface waters, spend- ing between 83.6% and 93.7% of their time in the top 30 m of the water column. When diving, grand mean, median, and maximum dive depths were 76.9 m, 67.5 m, and 399.5 m, although individuals were in water with depths from approximately 700–1,450 m. Dive rates varied by time of day, being lowest during the day and at dawn and highest at dusk and night. Dives were deepest (M = 133.7 m, SD = 52.6 m, median = 106.5 m) and longest (M = 4.0 min, SD = 0.4 min, median = 4.0 min) at dusk, suggesting dolphins were taking advantage of prey rising to the surface in response to reduced light levels. Lunar phase indirectly affected diving, with deeper and longer dives occurring with increasing illumination. The variations in dive behavior across solar and lunar cycles indicate diving patterns shift based on the distribution of prey. For more information on our Hawaiʻi research efforts: https://www.cascadiaresearch.org/hawaiian-cetacean-studies/publications Kind regards, Jacquelyn Shaff -- Jacquelyn Shaff She/her Graduate Student Research Assistant School of Marine and Environmental Affairs University of Washington jacquelynshaff@gmail.com