title: Effects of sampling techniques on population assessment of invasive round goby Neogobius melanostomus.
abstract: In this study, a comparison of point abundance sampling (PAS) electrofishing, angling with two different hook sizes and trap-based fishing was performed in a non-wadeable river to analyse their effects on catch per unit effort (CPUE) and population characteristics of invasive round goby Neogobius melanostomus. PAS electrofishing was identified as the most effective (mean ± s.e. CPUE = 57 ± 4 N. melanostomus min(-1) ) and least selective method in terms of size, feeding status and species composition. Angling had the second highest CPUE, but was more size selective and resulted in a higher proportion of males compared to electrofishing [overall sex ratio angling (female:male) = 1:0.92, electrofishing 1:0.65]. Owing to low CPUE (0.012 ± 0.004) and low frequency of occurrence, minnow traps were least suitable for N. melanostomus population assessment. The results of this study suggest that a higher degree of standardization and inter-calibration is useful to achieve better comparability of population data of invasive N. melanostomus and other benthic fish species.
authors.affiliation: Aquatic Systems Biology Unit, Technische Universität München, Center of Life and Food Science Weihenstephan, Department of Ecology and Ecosystem Management, Freising, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Brandner
authors.forename: J
authors.initials: J
authors.lastname: Pander
authors.forename: M
authors.initials: M
authors.lastname: Mueller
authors.forename: A F
authors.initials: AF
authors.lastname: Cerwenka
authors.forename: J
authors.initials: J
authors.lastname: Geist
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D049628:Body Size; D004463:Ecology / Q000379:methods; D005260:Female; D008297:Male; D010473:Perciformes / Q000502:physiology*; D011156:Population Density; D011157:Population Dynamics; D012107:Research Design; D045483:Rivers; D012744:Sex Ratio