DOI: DOI: 10.2478/cjf-2025-0006
Original scientific paper
Discrimination of morphological traits between Atlantic and Danubian brown trout lineages and their hybrids
2025, 83 (2) p. 43-53
Marina Piria, Ivan Špelić, Tamara Kanjuh, Ana Marić, Predrag Simonović
Abstract
Brown trout of non-native lineages (e.g., Atlantic) have been stocked into Croatian streams and rivers primarily to meet anglers’ demand, resulting in the presence of admixed populations at many locations. The clear, easily distinguishable morphological differences between brown trout of the introduced Atlantic (AT) and indigenous Danubian (DA) lineages, as well as their hybrids (HY), were unknown. Therefore, the aim of this study was to identify classical morphometric and meristic traits that can differentiate them. Brown trout were collected by electrofishing during 2017 and 2018 from 10 streams in three mountain areas: Gorski Kotar, Mt. Žumberak, and Mt. Papuk. Additionally, 10 specimens belonging to the AT lineage were obtained from a fish farm in continental Croatia. In total, 90 fish specimens were analysed: 17, 22, and 51 specimens of AT, DA, and HY, respectively. The results revealed the most prominent differences in head features of the AT compared to the DA lineage and their HY. Discriminant analysis demonstrated that eye diameter and postorbital length were significantly smaller whereas interorbital width and head height were significantly greater in the AT lineage. These findings suggest the need for a detailed head morphometry analysis to identify distinctive morphological traits that will be able to differentiate brown trout lineages and detect their hybrids.
Keywords
salmonid fish, hybridization, meristic, morphometric, Black Sea Basin