Canadian researchers are working on a new method to assess the diets of grey seals in the northwest Atlantic in order to better understand their influence on fish populations. The grey seal population grew as cod levels collapsed, since seals fed on high-quality forage fish. This study, coordinated by Sara Iverson and Suzanne Budge of Dalhousie University, examines the kinds and quantities of fatty acids found in seal blubber. They are also investigating the use of stable isotopes to distinguish between prey species. The project’s goal is to improve diet estimations in grey seals and to apply the findings to other ecosystems and species.
Researchers in the United States have also utilized DNA metabarcoding to study seal feces and identify different fish species in their diet. The study gave fresh insights into the grey seal’s nutrition by combining these methodologies. However, fatty acids retained in blubber offer a more extensive record of nutrition, perhaps extending months.
When compared to scat and stomach content analyses, which only represent their most recent meals, fatty acid analysis reveals a more extensive nutritional history for seals. A little blubber sample collected from a grey seal during the breeding season can reveal information about the seal’s diet over the previous four months.