Dear MARMAM community, On behalf of my co-authors and me, I am very pleased to share our latest publication in *Endangered Species Research*: Zeppetelli-Bedard L, Sherrill M, Ewald J, Pang Z, Cabrol J, Lesage V, Michaud R, Verreault J (2026) Comparative non-targeted lipidomic profiles in blubber of endangered St. Lawrence Estuary belugas and their potential prey. Endang Species Res 60:esr01501 https://doi.org/10.3354/esr01501 ABSTRACT: The St. Lawrence Estuary (SLE) belugas *Delphinapterus leucas* are a small and isolated population listed as endangered in Canada. Profound changes in the SLE ecosystem and a parallel deterioration in SLE beluga body condition suggest a potential decline in the quality and/or quantity of their prey. Using a non-targeted screening approach, this study aimed to gain insights into the blubber lipid profiles of SLE belugas and their potential prey, and to examine variations among beluga males and females and age classes, as well as among prey taxa and sampling seasons. Ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) was used to analyze 71 SLE beluga blubber biopsies (outer blubber layer) and 126 prey homogenates from 10 fish and 2 invertebrate species. Over 10383 features were detected across SLE beluga and prey samples, highlighting structural lipids such as glycerolipids, sphingolipids, and glycerophospholipids as the predominant components. Distinct lipid profiles were found between SLE beluga males and females, suggesting potential differences in diet and lipid metabolism, thus underscoring the importance of considering sex-specific lipid variations in beluga blubber. Prey species displayed unique lipid fingerprints, clustering according to phylogeny, diet, and trophic guilds. Significant seasonal variations in lipid composition were also observed in prey sampled across seasons. This study constitutes a critical first step toward assessing beluga–prey ecological interactions and lipid composition in the SLE food web, as well as how lipid composition influences energy allocation and storage. Cheers, Laura Zeppetelli-Bédard, MSc., University of Quebec in Montreal, Canada Aquatic science technician at Fisheries and Oceans Canada Laura.zeppbed@gmail.com or laura.zeppetelli-bedard@dfo-mpo.gc.ca Tel.: (514)-691-9712