Dear colleagues, The following paper was recently published in Royal Society Open Science: Wild L.A., Mueter F.J., Witteveen B., Straley J.M. 2020. Exploring variability in the diet of depredating sperm whales in the Gulf of Alaska through stable isotope analysis. Royal Society open science 7: 191110. http://dx.doi.org/10.1098/rsos.191110 Abstract: Sperm whales interact with commercially important groundfish fisheries offshore in the Gulf of Alaska (GOA). This study aims to use stable isotope analysis to better understand the trophic variability of sperm whales and their potential prey, and to use dietary mixing models to estimate the importance of prey species to sperm whale diets. We analysed tissue samples from sperm whales and seven potential prey (five groundfish and two squid species). Samples were analysed for stable carbon and nitrogen isotope ratios, and diet composition was estimated using Bayesian isotopic mixing models. Mixing model results suggest that an isotopically combined sablefish/dogfish group, skates and rockfish make up the largest proportion of sperm whale diets (35%, 28% and 12%) in the GOA. The top prey items of whales that interact more frequently with fishing vessels consisted of skates (49%) and the sablefish/dogfish group (24%). This is the first known study to provide an isotopic baseline of adult male sperm whales and these adult groundfish and offshore squid species, and to assign contributions of prey to whale diets in the GOA. This study provides information to commercial fishermen and fisheries managers to better understand trophic connections of important commercial species. The paper is available freely to download at: http://dx.doi.org/10.1098/rsos.191110 Please contact with any questions: lauren.a.wild@gmail.com Lauren Wild PhD - Fisheries University of Alaska Fairbanks College of Fisheries and Ocean Sciences lauren.a.wild@gmail.com www.seaswap.info (907)747-7789 - office (907)738-5315 - cell