NORTH-WESTERN JOURNAL OF ZOOLOGY 13 (2): 311-319 ©NwjZ, Oradea, Romania, 2017 Article No.: e161704 http://biozoojournals.ro/nwjz/index.html Comparative diet analysis of the Eurasian otter (Lutra lutra) in different habitats: Putna - Vrancea Natural Park and Lower Siret Valley, south-eastern Romania George BOURO޹,* and Dumitru MURARIU² 1. Faculty of Biology, University of Bucharest, Splaiul Independenţei, no. 91–95, 050095, Bucharest, Sector 5, Romania. 2. Institute of Biology, Calea 13 Septembrie, no. 13, Splaiul Independenței, no. 296, 060031, Bucharest, Sector 6, Romania. * Corresponding author, G. Bouroș, E-mail:
[email protected] Received: 10. February 2016 / Accepted: 26. August 2016 / Available online: 09. September 2016 / Printed: December 2017 Abstract. The otter (Lutra lutra) in Romania uses a wide range of habitats: highland and lowland lakes, rivers and streams, as well as marshes, riparian forests, delta and coastal areas. These habitats lead to a high variability of otter’s prey. From December 2012 until July 2014, diet of Eurasian otter was studied based on spraint analysis in Putna-Vrancea Natural Park (n=118 samples) and Lower Siret Valley Natura 2000 Site (n=56 samples), south - east Romania. The Percentage of Occurrence (PO), Relative Frequency of Occurrence (RFO) and Percentage Frequency of Occurrence (PFO) were calculated. Fish (PO = 56.1%) and amphibians (PO = 22.5%) were the primary diet components of otters in Putna-Vrancea, while in Lower Siret Valley, fish (PO = 36.7%) and crayfish (PO = 32.6%) formed the mass of the diet. Fish consumption was all seasons high in Putna-Vrancea, except in winter. In Lower Siret Valley, the highest fish consumption was in the autumn and the lowest in the summer.