Contents lists available at ScienceDirect Fisheries Research journal homepage: www.elsevier.com/locate/ fishres Recreational trolling effort and catch of Atlantic salmon and brown trout in Vänern, the EU’s largest lake Andersson A a , Greenberg L.A. a , Bergman E a , Su Z b , Andersson M c , Piccolo J.J a, * a River Ecology and Management Group, Department of Environmental and Life Sciences, Karlstad University, S-651 88 Karlstad, Sweden b Institute for Fisheries Research, Michigan Department of Natural Resources and University of Michigan, NIB G250, 400 N. Ingalls, Ann Arbor, MI 48109-1084, USA c SLU, Swedish University of Agricultural Sciences, Department of Aquatic Resources, Institute of Freshwater Research, Pappersbruksallén 22, SE‐702 15 Örebro, Sweden ARTICLE INFO Editor: Vañas J Keywords: Angler survey Atlantic salmon Brown trout Complemented survey Lake vänern Recreational fisheries ABSTRACT Recreational fishing has grown substantially worldwide; for some recreational fisheries both catch and economic value now exceeds that of commercial fisheries. Monitoring of recreational fisheries effort and catch is therefore important for sustainable fisheries management. We developed and implemented an angler survey to estimate effort and catch for the recreational trolling fishery for landlocked Atlantic salmon (Salmo salar) and brown trout (S. trutta) in Lake Vänern, Sweden. Major challenges were the large spatial scale and dispersed fishing effort, a lack of revenue from fishing licence sales, and a lack of catch reporting requirements. We developed a com- plemented roving/mail-in survey to estimate effort and catch during the main fishing periods, spring and fall, 2014. Instantaneous counts from major access sites were used for effort estimates, and mail-in surveys were used for catch rates. Our results show that Vänern supports a salmon and trout fishery of some 28.7 ± 3.3 tonnes per year. Fishing effort was higher in the spring than in the fall, and there were seasonal differences in catch rates for trout but not for salmon. Estimates show that the recreational trolling fishery now harvests more salmon and trout annually than do the commercial and subsistence fisheries combined. This highlights the importance of continuing an angler survey program for Vänern as a key element for sustainable fisheries management, and can serve as a model for other recreational fisheries at large spatial scales. 1. Introduction Recreational fisheries worldwide have grown in importance in re- cent decades, with many inland and coastal recreational fisheries now exceeding commercial fisheries in catch and economic value (McPhee et al., 2002; Cooke et al., 2015). Managing for sustainable fisheries, therefore, requires accurate estimates of recreational fishing effort and catch; for many recreational fisheries these estimates are lacking (McPhee et al., 2002; Post et al., 2002; Cooke and Cowx, 2006). Angler (or creel) surveys are the primary method for collecting the data used to estimate effort, harvest and released catch in most recreational fisheries (Jones and Pollock, 2012). Contrary to many commercial fisheries, where catch reporting is mandatory, angler surveys are typically carried out by contacting anglers on site or through various off-site methods (Jones and Pollock, 2012). Obtaining accurate and unbiased data through angler surveys, however, is methodologically-challenging and it can be very costly (Jones and Pollock, 2012; Su and Clapp, 2013). In particular, fisheries that are highly dispersed in time or space require the development of effective methods that can accurately estimate effort and catch. Large-scale angler surveys often employ off-site or complemented on/off site methods. These offer greater opportunities to contact anglers who are dispersed over large geographical areas, and they are less ex- pensive to perform than are on-site methods (Pollock et al., 1994; Henry and Lyle, 2003; Jones and Pollock, 2012). Although off-site methods such as telephone and mail surveys are clearly the most cost- effective, complemented surveys, wherein more than one contact method is used, can reduce bias and expand spatial scales to better estimate catch and effort (Pollock et al., 1994, 1997). Complemented angler surveys can take a variety of forms, employing various types of both on-site and off-site methods (Jones and Pollock, 2012); these have now been developed for a number of important large-scale recreational fisheries worldwide, improving fisheries conservation efforts (Dauk and Schwarz, 2001; Vølstad et al., 2006). Our study system, Lake Vänern, Sweden, is the largest lake in the European Union (EU). Vänern is home to at least 34 native fish species (Degerman et al., 2001; Nilsson, 2014), and it has supported commer- cial, recreational, and subsistence fisheries for centuries. Among these https://doi.org/10.1016/j.fishres.2020.105548 Received 3 February 2019; Received in revised form 17 February 2020; Accepted 22 February 2020 ⁎ Corresponding author. E-mail address: john.piccolo@kau.se (P. J.J). Fisheries Research 227 (2020) 105548 Available online 05 March 2020 0165-7836/ © 2020 Elsevier B.V. All rights reserved. T