Original scientific paper
VARIATIONS IN OTOLITH AND SCALE SHAPE OF THE INVASIVE ROUND GOBY Neogobius melanostomus POPULATIONS FROM DIFFERENT HABITATS OF THE SAVA RIVER BASIN, CROATIA
2023, 81 (3) p. 0-0
Valentine Planchet, Ivan Špelić, Marina Piria
Abstract
Round goby Neogobius melanostomus is one of the three invasive Ponto-Caspian gobies found in the Sava River Basin in Croatia. It has a negative effect on the native ecosystems through high invasive potential that enables its rapid spread upstream in the inland watercourses. The objective of this study was to determine the differences in sagittal otolith and scale shape of the frontal and established populations of the N. melanostomus in two different habitat types. At two sampling sites in the main course of the Sava (Babina Greda, Slavonski Brod) and modified habitat (Sava Odra canal) 20 individuals of N. melanostomus were collected and analysed. Geometric morphometric method, together with Procrustes analysis of variance, canonical variate analysis and discriminant function analysis were used to analyse the otolith and scale shape. The significant differences in both otolith and scale shapes between settled (Babina Greda) and frontal populations (Slavonski Brod) from the main course of the Sava River were identified. The main differences were wider anterior part of the scales and more pronounced open indentation in right-side otolith in Babina Greda population. Settled population in the Sava-Odra canal was significantly different in otolith shape from the Babina Greda population but not from the Slavonski Brod population, which suggest that upstream migration likely consist of individuals od specific phenotype and genotype. Otoliths generally expressed more shape variability than scales and thus could be more useful for the differentiation on a finer scale, between close populations. The results of the study show that the geometric morphometry approach can be applied for better understanding of the expansion of N. melanostomus in novel freshwater aquatic habitats.
Keywords
geometric morphometry, shape, frontal and settled populations, river, canal