Author:
Balazy Kaja,Trudnowska Emilia,Wojczulanis-Jakubas Katarzyna,Jakubas Dariusz,Præbel Kim,Choquet Marvin,Brandner Melissa M.,Schultz Mads,Bitz-Thorsen Julie,Boehnke Rafał,Szeligowska Marlena,Descamps Sébastien,Strøm Hallvard,Błachowiak-Samołyk Katarzyna
Abstract
AbstractTwo Calanus species, C. glacialis and C. finmarchicus, due to different life strategies and environmental preferences act as an ecological indicators of Arctic Atlantification. Their high lipid content makes them important food source for higher trophic levels of Arctic ecosystems including the most abundant Northern Hemisphere's seabird, the little auk (Alle alle). Recent studies indicate a critical need for the use of molecular methods to reliably identify these two sympatric Calanus species. We performed genetic and morphology-based identification of 2600 Calanus individuals collected in little auks foraging grounds and diet in summer seasons 2019–2021 in regions of Svalbard with varying levels of Atlantification. Genetic identification proved that 40% of Calanus individuals were wrongly classified as C. finmarchicus according to morphology-based identification in both types of samples. The diet of little auks consisted almost entirely of C. glacialis even in more Atlantified regions. Due to the substantial bias in morphology-based identification, we expect that the scale of the northern expansion of boreal C. finmarchicus may have been largely overestimated and that higher costs for birds exposed to Atlantification could be mostly driven by a decrease in the size of C. glacialis rather than by shift from C. glacialis to C. finmarchicus.
Funder
Polish National Agency for Academic Exchange
Polish National Science Centre
Polish National Scientific Centre and Polish Ministry of Science and Higher Education
Publisher
Springer Science and Business Media LLC