Dear colleagues, On behalf of my coauthors, I am happy to share the link to an open-access paper we published today in Scientific Reports: Kiszka, J.J., Caputo, M., Vollenweider, J., Heithaus, M.R., Dias, L.A. & Garrison, L.P. Critically endangered Rice's whales (Balaenoptera ricei) selectively feed on high-energy prey in the Gulf of Mexico. Scientific Reports, 13: 6710. Link to the paper: https://www.nature.com/articles/s41598-023-33905-6 Abstract: Determining the drivers of prey selection in marine predators is critical when investigating ecosystem structure and function. The newly recognized Rice’s whale (Balaenoptera ricei) is one of the most critically endangered large whales in the world and endemic to the industrialized Gulf of Mexico. Here, we investigated the drivers of resource selection by Rice’s whales in relation to prey availability and energy density. Bayesian stable isotope (δ13C, δ15N) mixing models suggest that Rice’s whales feed primarily on a schooling fish, Ariomma bondi (66.8% relative contribution). Prey selection using the Chesson’s index revealed that active prey selection was found to be positive for three out of the four potential prey identified in the mixing model. A low degree of overlap between prey availability and diet inferred from the mixing model (Pianka Index: 0.333) suggests that prey abundance is not the primary driver of prey selection. Energy density data suggest that prey selection may be primarily driven by the energy content. Results from this study indicate that Rice’s whales are selective predators consuming schooling prey with the highest energy content. Environmental changes in the region have the potential to influence prey species that would make them less available to Rice’s whales. Jeremy Kiszka, Ph.D. Assistant Professor Institute of Environment, Coastlines and Oceans Division Department of Biological Sciences Florida International University https://environment.fiu.edu Principal Investigator, Marine Conservation Ecology Lab. https://marineconservationecologylab.com 3000 NE 151 St., FL-33181, North Miami, USA. Office (direct): (305)-919-5234 [cid:be29e8a8-61eb-4421-a3af-fd09403863e6]