Changing ecosystems promote generalism and enhanced heterogeneity in diet composition in the endangered St. Lawrence Estuary beluga.

ABSTRACT: Changes in trophodynamics may affect trophic niche both at the individual and population levels. Using stable isotope ratios, we showed how contrasting oceanographic and trophic conditions in 1997-2003 and 2015-2020 have altered the diet and degree of individual specialization of St. Lawrence Estuary beluga (Delphinapterus leucas). The trophic niche of all sex and age classes changed over time, with beluga consuming more small pelagic prey during the first than the second period. Adult male diets differed from that of adult females and juveniles during the first period due to the other prey that were consumed. In 2015-2020, diet contributions by small pelagic prey decreased in all segments of the population and led to marginally significant differences in diet between adult males and femal

SUBMITTER: Cabrol J 

PROVIDER: S-EPMC11842592 | biostudies-literature | 2025 Feb

REPOSITORIES: biostudies-literature