Triple stable isotope analysis to estimate the diet of the Velvet Scoter (Melanitta fusca) in the Baltic Sea

Rasa Morkūnė; Jūratė Lesutienė; Julius Morkūnas; Rūta Barisevičiūtė

doi:10.7717/peerj.5128

Triple stable isotope analysis to estimate the diet of the Velvet Scoter (Melanitta fusca) in the Baltic Sea

PeerJ. 2018 Jun 27:6:e5128. doi: 10.7717/peerj.5128. eCollection 2018.

Authors

Rasa Morkūnė¹, Jūratė Lesutienė¹, Julius Morkūnas¹, Rūta Barisevičiūtė²

Affiliations

¹ Marine Research Institute, Klaipeda University, Klaipeda, Lithuania.
² Center for Physical Sciences and Technology, Vilnius, Lithuania.

Abstract

This study quantifies contributions of different food sources in the winter diet of the Velvet Scoter (Melanitta fusca) in coastal waters of the Lithuanian Baltic Sea using non-lethal avian sampling. We highlight the application of stable sulphur isotope ratios as complementary to stable carbon and nitrogen isotope analysis in order to discriminate sandy bottom macrozoobenthos organisms as potential food sources for the Velvet Scoter. Selection of the most relevant trophic enrichment factors and Monte Carlo simulations in order to choose the best fitted model were undertaken. The stable isotope mixing model revealed the main contributions of a group of bivalves, Mya arenaria and Cerastoderma glaucum, to be 46-54%, and while the crustacean, Saduria entomon, comprised 26-35% of the diet.

Keywords: Carbon; Gut content; Mixing models; Monte Carlo simulations; Nitrogen; Soft bottom macrozoobenthos; Sulphur; Trophic enrichment factors.

Grants and funding

This study was supported by Klaipėda University and the project Lithuanian Maritime Sector’s Technologies and Environmental Research Development (No VP1-3.1-ŠMM-08-K-01-019). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.