View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Repository of the Academy's Library Hydrobiologia (2019) 846:147–158 https://doi.org/10.1007/s10750-019-04060-9 (0123456789().,-volV)( 0123456789().,-volV) PRIMARY RESEARCH PAPER Habitat use of invasive monkey goby (Neogobius fluviatilis) and pumpkinseed (Lepomis gibbosus) in Lake Balaton (Hungary): a comparison of electrofishing and fyke netting István Czeglédi . Bálint Preiszner . Zoltán Vitál . Bernadett Kern . Nóra Boross . András Specziár . Péter Takács . Tibor Erős Received: 5 February 2019 / Revised: 23 August 2019 / Accepted: 26 August 2019 / Published online: 6 September 2019 © The Author(s) 2019 Abstract Detailed knowledge on the habitat pref- assessing habitat use and population structure of erence of invasive fishes and the bias of different invasive fishes. fishing methods in determining their population dynamic parameters are essential in fisheries man- Keywords Non-native fish · agement, ecology and conservation. This study was Anthropogenic habitat degradation · conducted to determine the habitat use and length Sampling methods · Habitat preference · frequency distribution of the invasive monkey goby Large lakes and pumpkinseed in the littoral zone of Lake Balaton (Hungary) using two different sampling methods, electrofishing and fyke netting. In general, both Introduction species preferred anthropogenically modified habitat types (rip-rap shorelines and harbours) compared Biological invasions are major contributors to the loss with natural reed habitats with silty-sand bottom. of biodiversity and the homogenisation of biota Length frequency distribution data showed significant worldwide (Rahel, 2000; Clavero & Garcı´a-Berthou, between-gear differences, since electrofishing 2005; Dudgeon et al., 2006). Human activity is resulted in the capture of larger individuals in greater rapidly transforming natural ecosystems and habitats proportion than fyke nets for both species. This study, which alterations often facilitate the spreading of which includes the first detailed data about the habitat non-native species (Byers, 2002; Johnson et al., use of the highly invasive monkey goby in lakes, 2008). Fishes are amongst the most common intro- suggests that invasive species may benefit from the duced taxa worldwide, mainly for societal demands alteration of the littoral zone. It also highlights that of fish products, angling and ornamental market reliance on single gear surveys can be misleading in (Gozlan, 2008). However, introduction of non-native freshwater fishes can often cause catastrophic eco- logical consequences (Vitule et al., 2009). Lakes are Handling editor: Fernando M. Pelicice particularly vulnerable to introduction of non-native fishes and these ecosystems often maintain several I. Czegle´di (&) · B. Preiszner · Z. Vita´l· unique endemism. For instance, the introduction of B. Kern · N. Boross · A. Speczia´r · P. Taka´cs · T. Ero˝s Nile perch [Lates niloticus (Linnaeus, 1758)] along Balaton Limnological Institute, MTA Centre for with several tilapiine species into Lake Victoria Ecological Research, TihanyKlebelsberg K. u. 3, 8237, Hungary caused dramatic reductions of the previously abun- e-mail: [email protected] dant endemic haplochromine species (Hughes, 1986; 123 148 Hydrobiologia (2019) 846:147–158 Ogutu-Ohwayo, 1990; Witte et al., 1992). For pumpkinseed [Lepomis gibbosus (Linnaeus, 1758)] predicting the ecosystem impacts of non-native are the most dominant invasive species (Speczia´r, species and developing more effective management 2010). However, compared to watercourses, few strategies to control their negative impacts and detailed data exist about their abundance and habi- spreading, detailed information about their spatial tat-use patterns in this and other European lakes (e.g. distribution and habitat preference is a prerequisite Neophitous & Giapis 1994; Vila-Gispert & Moreno- (Cooper et al., 2009; Verhelst et al., 2015). Amich, 1998; Dembski et al., 2008; Didenko, 2013). Identifying effective sampling techniques of non- The monkey goby is a small, invasive benthic fish, native fishes is crucial to estimate their abundances, from the Ponto–Caspian region, which was first and also for feasible population control measures documented in Lake Balaton in 1970 (Bı´ro´, 1971). (Trebitz et al., 2009; Collins et al., 2015). It is known Previous studies suggested that monkey goby prefers that different sampling gears can provide different inshore habitats with finer substrata (i.e. silty sand, estimations of the abundance of a given species even sand, small gravel) in rivers (Ero˝s et al., 2005; in the same location, which complicates the choice of Ada´mek et al., 2007;Cˇ a´pova´ et al., 2008; Borcherd- an appropriate sampling method (Johnson et al., ing et al., 2013). The habitat use of the species is 2005; Brandner et al., 2013). Moreover, fish size understudied in lakes, although Didenko (2013) selectivity and sampling cost and effort could also found most of the adult and sub-adult individuals differ between sampling methods (e.g. Ero˝s et al., on sandy bottoms. The pumpkinseed is a centrarchid 2009; Ribeiro et al., 2015). Although electrofishing is fish (sunfish) native to North America. In several the most commonly used method in the routine European countries (including Hungary), it has monitoring of fish assemblages in the littoral zone of become widely established and form invasive popu- lakes (Minns et al., 1994; Pierce et al., 2001; CEN, lations in many, but not all cases (Cucherousset et al., 2003; Eggleton et al., 2010), several studies empha- 2009; Copp et al., 2017). The species inhabits both sise the use of complementary sampling methods for lentic and lotic environments (Robinson et al., 2000; a more complete estimation of fish assemblage Fox & Copp, 2014) and has various negative impacts structure (e.g. Weaver & Magnuson, 1993; Clark on native fauna (Tomecˇek et al., 2007; Van Kleef et al., 2007; Bonvechio et al., 2014; Hinlo et al., et al., 2008). According to Bı´ro´ (1997), pumpkinseed 2017). Unlike other gears, fyke nets may be univer- began to colonise Lake Balaton presumably from a sally applicable for monitoring fish communities in a nearby fishpond between 1904 and 1908. Nowadays, wide variety of littoral meso-habitats. In fact, several it has stable and self-sustaining populations in the studies indicated that fyke nets were highly effective whole lake and its drainage (Bı´ro´ et al., 2003). in catching small-bodied fishes and tended to collect Although these two fish species may seriously impact more individuals and more species of fishes than food web in the littoral zone of the lake via the other gears (Weaver & Magnuson, 1993; Clark et al., competition of food resources and space with native 2007; Eggleton et al., 2010). Nevertheless, less fishes (Speczia´r, 2010), no study to date examined research has been devoted to compare the habitat their habitat-use patterns, especially with different use and population dynamic parameters of non-native sampling methods, which may halt effective man- fish species using different sampling methods (but agement measures. see, e.g. Trebitz et al., 2009; Bauer-Haa´z et al., 2014). This study was conducted to determine the habitat Several non-native fishes settled in European use and length frequency distribution of the monkey lakes, which may threaten biodiversity and ecosystem goby and the pumpkinseed in the littoral zone of Lake functioning (e.g. Musil et al., 2010; Ciutti et al., Balaton using two different sampling methods, elec- 2011; Ferincz et al., 2016; Taka´cs et al., 2017). Yet trofishing and fyke netting. We hypothesised that data are sporadic about their abundance and habitat- both non-native species might prefer anthropogeni- use patterns, which may hinder the determination of cally modified habitat types (rip-rap shorelines and population trends and eradication strategies. In the harbours) to natural reed covered areas with silty- littoral zone of Lake Balaton, which is the largest sand bottom. We were especially interested to shallow lake in Central Europe, the monkey goby compare whether the two different sampling methods [Neogobius fluviatilis (Pallas, 1814)] and the characterise the habitat-use patterns of the two 123 Hydrobiologia (2019) 846:147–158 149 species consistently. Finally, regarding the length Fish sampling frequency distribution of the species, we predicted that fyke netting would catch smaller individuals, and We sampled fishes during three sampling periods in electrofishing would catch larger individuals, and 2017: (1) spring (from 24 April to 04 May), summer hereby complement each other on the size-structured (from 12 July to 19 July), and autumn (from 18 habitat use of the two species (see e.g. Chick et al., September to 11 October). Three distinct mesohabitat 1999; Ruetz et al., 2007; Warry et al., 2013; Francis types can be distinguished in the littoral zone of the et al., 2014 for other small-bodied species). lake: (1) semi-natural reed covered areas, (2) rip-rap shoreline and (3) harbours. Reed habitats had a depth of 40–140 cm and had silty-sand bottom. Reed strip Materials and methods width along the shoreline varied between 8 and 40 m. The rip-rap shorelines consisted of large rocks and Study area boulders with diameter size of 20–40 cm. They had a depth of 35–140 cm and they gradually sloped. The Lake Balaton (Hungary) is the largest lake (surface harbours could be characterised by deep water (110– area: 593 km2; mean depth: 3.2 m) in Central Europe 330 cm) and heavy boat traffic. Most part of the (Fig. 1). The lake is mesotrophic (Istva´novics et al., shoreline of this habitat type was strengthened by 2007). About 40% of the littoral zone is covered by concrete which was usually perpendicular to the common reed [Phragmites australis (Cav.) Trin. ex bottom creating a concrete “wall”. Substrate of the Steud.] (Speczia´r et al., 2013), but the rest of the harbours consisted of silty sand. Electrofishing and shoreline is anthropogenically modified (mainly rip- fyke netting were performed in reed and rip-rap rap sections, beaches, and harbours).