Lakes & Reservoirs: Research and Management 2008 13: 215–220 © 2008 The Authors Doi: 10.1111/j.1440-1770.2008.00372.x Journal compilation © 2008 Blackwell Publishing Asia Pty Ltd Blackwell Publishing Asia Original Articles Comparison of electrofishing and gillnets Comparison of electrofishing and NORDIC gillnets for sampling littoral fish in boreal lakes Tapio Sutela, 1 * Martti Rask, 2 Teppo Vehanen 1 and Ari Westermark 2 1 Finnish Game and Fisheries Research Institute, Oulu Game and Fisheries Research, 90570 Oulu, Finland, 2 Finnish Game and Fisheries Research Institute, Evo Game and Fisheries Research, Rahtijärventie 291, Evo, Finland Abstract Parallel sampling of fish, using electrofishing and NORDIC multimesh gillnets, was performed in the littoral areas of e boreal lakes. Some fish species were caught only by electrofishing (e.g. bullhead, Cottus gobio (L.); burbot, Lota lota while some were caught only with gillnets (e.g. pikeperch, Stizostedion lucioperca (L.); smelt, Osmerus eperlanus (L.) The fish species that were caught with both methods (e.g. perch, Perca fluviatilis (L.) exhibited gear-specific distributions. A combination of NORDIC gillnetting (passive gear) and electrofishing (active gear) is suggeste reasonably well cover the entire species composition in the littoral zones ( ≈ 0–3 m depth) of boreal lakes. This gear combination is recommended for evaluating the ecological status of lakes within the European Water Framework Dire Key words electrofishing, fishing method, littoral, NORDIC gillnet, Water Framework Directive. INTRODUCTION The scientific study of fish populations in the littoral zone of lakes is hampered by a number of methodological problems, most arising from the shallowness and physical complexity that characterizes this habitat (Winfield 2004). A gillnet is a passive and selective gear (Hamley 1975; Kurkilahti et al. 2002). Only fish that actively swim into a gillnet and are retained in it are caught (Olin et al. 2004). By contrast, electrofishing also stuns inactive fish, or those hiding under stones or among macrophytes. Each gear type samplesa different composition, and presentsa partial view of the community (Weaver et al. 1993; Fago 1998). It can be speculated that a combination of a passive and an active gear results in a representative overview of the species richness and relative densities. Electrofishing is a widely used method in sampling littoral fish assemblages (e.g. Lewin et al. 2004). In contrast, gillnetting has seldom been used in sampling littoral fish species, particularly those fish species that live their entire life span in the littoral zone. However,minnows and bullheads have been caught by small meshed gillnets in the littoral zone (Hesthagen et al. 1992; Jørgensen et al. 1999). Relying on these studies, it could be possible to catch littoral fish species by gillnets set in littoral areas of a lake. The NORDIC multimesh gillnet is a standard monitoring gear of lake fisher communities in Finland, Sweden and Norway (Appelberg et al. 1995; Olin et al. 2004). This method has gained prominencein the assessment of the ecological status of lakes, according to the European Water Framework Directive (European Union 2000), in Central Europe as well. Diekmann et al. (2005) used NORDIC gillnets in the benthic and pelagic habitats of 67 German lowland lakes. They also electro- fished the littoral habitats of these lakes. These researchers strongly recommend littoral electrofishing as a supplemen- tary method to pelagic and benthic NORDIC gillnetting. They concluded that only simultaneous consideration of all these three habitats would fulfil the requirements of the Water Framework Directive for evaluating the ecological integrity of lakes. The objectives of this study were: (i) to test the suitability of the NORDIC gillnet in sampling littoral fish species (e.g. minnow; bullhead); (ii) to evaluate the overlap and combined coverage of electrofishing and NORDIC gillnet fishing in sampling littoral fish assemblages; and (iii) to compare the size spectrums within the fish species caught effectively by both methods. *Corresponding author. Email: tapio.sutela@rktl.fi Accepted for publication 7 June 2008.