Shipping and natural environmental conditions determine the distribution of the invasive non-indigenous round goby Neogobius melanostomus in a regional sea

Infection rates and prevalence of metazoan parasites of the non-native round goby (Neogobius melanostomus) in the Baltic Sea

“…The populations differ as to the time of invasion: the Lithuanian population around Klaipeda was discovered in 2002 (Sapota, 2011) and the population in Muuga, Estonia (Gulf of Finland) was discovered two years later in 2004 (Ojaveer, 2006). The first records of the round goby from Guldborgsund (GBS), Denmark, are from 2008 (Azour et al, 2015) and the population in Mariehamn, Å land islands, was first recorded in 2011 (Kotta et al, 2016).…”

“…The sampling was conducted in June 2015 using identical trap assays at each site (see below). The sites were chosen based on the previous observations of the round goby as these are the locations where the species was first discovered and populations are established and round gobies are abundant (Sapota, 2004;Ojaveer, 2006;Azour et al, 2015;Kotta et al, 2016). The habitat at all sampling locations consisted of vegetated sandy bottoms, except in Finland and Estonia where the bottom substrate consisted mainly of coarse gravel and rocks interspersed with sandy patches.…”

“…The northernmost observations to date were made in 2013 outside the town of Raahe (about 64°4 0 N) in the Bothnian Bay. Currently, the species has been observed along the coasts of all Baltic sub-basins, except for the Swedish coast of the Bothnian Bay (Kotta et al, 2016). Although originating from the brackish waters of the Black Sea and Sea of Azov, the species has also established viable and flourishing populations in many freshwater areas throughout European river systems (e.g.…”

“…They have a very different invasion history primarily in terms of time since introduction: the most recent introductions and oldest ones are more than 20 years apart (Sapota, 2011;Kotta et al, 2016). Also, the populations are exposed to very different abiotic conditions due to the pronounced gradients in both salinity and temperatures in the Baltic Sea and, therefore, different local parasite assemblages.…”

“…The round goby (Neogobius melanostomus (Pallas, 1814) is one of the most widespread non-native fish species in the Baltic Sea (Kotta et al, 2016), with reported detrimental biological impacts in many locations (Ojaveer & Kotta, 2015;. Following its initial detection in the Gulf of Gdansk in 1990 (Skora & Stolarski, 1993), it spread throughout the southern Baltic Sea, eastward to the Vistula lagoon and river system (Mierzejewska et al, 2011), westward to the German and Danish coastal areas and further north along the southeastern coast of Sweden (Florin & Karlsson, 2011;Sapota, 2011).…”