Tracing the colonization process of non-native gobies into a large river: the relevance of different dispersal modes

Abstract

Ponto-Caspian gobies have invaded many river systems in the northern hemisphere, but their colonization patterns often remain unrecognized at the early stages of invasion. Here, we analyzed the ongoing invasion of the round goby Neogobius melanostomus (Pallas, 1814) in the Elbe River (Germany) by combining literature research with electrofishing and environmental DNA (eDNA) sampling. Along the surveyed 517 km, abundances peaked in the upper and lower sections, while low or no goby abundances were detected in the middle section. Combining the results of the field survey and literature data, we inferred four dispersal modes, jointly appearing during the colonization. (1) Human mediated transport, which was responsible for the initial colonization of the tidal Elbe and for a jumpy expansion to the upstream sections. (2) Fast downstream colonization, which was particularly observed for juvenile individuals. (3) Slow upstream migration, which was also recorded for another goby species, the bighead goby Ponticola kessleri (Günther, 1861) and (4) Lateral invasion via a major shipping canal in the middle river section. The eDNA analyses generally supported these conclusions and showed a high sensitivity and thus increased detection strength at low goby densities. Our study showed that the location of the first occurrence, as well as the dispersal mode, strongly determines the invasion process of non-native gobies.

The functional ecology of four invasive Ponto–Caspian gobies

“…Goby species have migrated through three invasion corridors identified by Bij de Vaate et al (2002) and have invaded major European river systems, i.e. the Rivers Danube, Rhine, Moselle, Meuse, Vistula, Elbe, Nemunas, Neva, Volga (Slynko et al 2012;Roche et al 2013;Manné et al 2013;Rakauskas et al 2018;Nogueira Tavares et al 2020). They have become established in large and small rivers, streams, dam reservoirs, lakes and artificial canals and occur locally at high density (Erős et al 2005;Polačik et al 2009;Borcherding et al 2011), sometimes comprising more than 70% of all fish sampled (Cerwenka et al 2018).…”

Dietary partitioning of six co‐occurring Ponto‐Caspian gobies in the Dnieper River basin

“…Several species considerably expanded their range from the Black Sea, Sea of Azov and Caspian Sea to many European rivers, and even reached North American freshwaters (Copp et al, 2005). Their ability to spread and establish populations outside of their native range has attracted considerable attention from fish biologists and conservationists (Copp et al, 2005; Nogueira Tavares et al, 2020; Piria et al, 2016; Płąchocki et al, 2020; Rakauskas et al, 2018).…”

An Interdisciplinary Approach to Evaluating Native and Invasive Fish Connectivity and Spatial Ecology in Canada’s Historic Rideau Canal Waterway

“…In 2020 and 2021, the two years following our telemetry tracking study, free diving and snorkel surveys were conducted in the region downstream of Edmonds Lockstation and a higher abundance of round goby were observed near the station 500 m from the original site of capture, indicating downstream dispersal is occurring as expected. We did not track movements of juveniles (<50 mm), and given that juvenile round goby have been documented to disperse downstream rapidly (Tavares et al 2020), we may have missed key insights into range expansion. However, the number of round goby observed markedly decreased close to Kilmarnock Lake (Online Resource 1, Fig.…”