-Pikeperch Sander lucioperca is an economically important fish which depleted populations need intensive management and supplemental stocking. We aimed to assess the relative influence of various pikeperch stocking strategies in Lake Balaton, Hungary, and tested 60 stocking set-ups (two seasons  three lake areas  shore vs. offshore release  five size groups) by releasing 3000 tagged yearlings. Anglers reported data of 522 recaptures within four years after stocking. Recapture rate was highest in stocking of the most productive lake area, increased with fish size, was higher in shore than offshore releases, but did not differed between stocking seasons. Fish stocked to oligotrophic areas travelled longer distances and dispersed more than those stocked to the mesotrophic area. Fish size had little effect, whereas season and method of stocking had no effect on dispersal of fish. To conclude, in pikeperch, autumn stocking with large yearlings released directly from the shore is recommended over other set-ups. Stocking quotas may be concentrated in space in low productivity areas, but should be dispersed between multiple sites in food rich areas to attain complete dispersal. This study provides a framework for testing fisheries management alternatives and behaviour of stocked fish in intensively utilized habitats.Keywords: angling / fisheries management / mark and recapture / Sander lucioperca / stocking strategy Résumé -Gestion de l'empoissonnement de sandre dans le lac Balaton: effet de la saison, de la localisation, de la taille du poisson et de la méthode de déversement sur le taux et la distribution des recaptures. Le sandre Sander lucioperca est un poisson économiquement important dont les populations appauvries ont besoin d'une gestion intensive et d'un empoissonnement de soutien. Nous avons cherché à évaluer l'influence relative de diverses stratégies d'empoissonnement de sandre dans le lac Balaton, en Hongrie, et nous avons testé 60 configurations d'ensemencement (deux saisons  trois zones lacustres  zone riveraine  zone de remise à l'eau au large  cinq groupes de taille) en relâchant 3 000 animaux d'un an marqués. Les pêcheurs à la ligne ont apporté des données sur 522 poissons recapturés dans les quatre ans suivant le déversement. Le taux de recapture était le plus élevé dans la zone lacustre la plus productive, il augmentait avec la taille des poissons, était plus élevé sur le rivage que dans les eaux hauturières, mais ne différait pas d'une saison à l'autre. Les poissons déversés dans les zones oligotrophes ont parcouru de plus longues distances et se sont dispersés davantage que ceux déversés dans la zone mésotrophe. La taille du poisson a eu peu d'effet, alors que la saison et la méthode de mise à l'eau n'ont eu aucun effet sur la dispersion du poisson. Pour conclure, pour le sandre, il est recommandé de faire des empoissonnements d'automne avec de grands alevins de l'année relâchés directement du rivage plutôt que d'autres solutions. Les quotas de mise en charge peuvent être concentrés...

It is hypothesized that stocking procedure influences survival, growth and distribution of 19 introduced fishes; however, there is still limited information on the effect of various stocking 20 strategies on recaptures in natural freshwaters. The present study aimed to investigate how the 21 rate and distribution of anglers' common carp (Cyprinus carpio) catches vary with the 22 stocking season (i.e. spring, summer and autumn), lake area, method (i.e. shore and offshore 23 releases) and fish size (i.e. ≤500 g and >500 g) in large and shallow Lake Balaton, Hungary. 24In 2010, 4500 two-summer old, individually tagged common carp were stocked to test 36 25 releasing set-ups (i.e. three seasons × three lake areas × two methods × two size groups). 26Anglers reported date, location and fish size (standard length and weight) on 787 recaptures 27 within two years after the release. Recapture rate was highest in summer and lowest in 28 autumn stockings, but it was not affected by the stocking area, method and fish size. 29Recaptures dispersed most in space in stockings carried out in autumn and the centre of the 30 lake, but movement of fish was not influenced by stocking method and fish size. To conclude, 31in summer, stocking quotas should be evenly distributed along the entire shore line, while 32 early spring stockings may be optimized for transport cost and concentrated by each lake 33 basin. Late autumn stockings should be avoided, and the capacity of effective wintering ponds 34 developed. This study also provides a good framework for testing fisheries management 35 alternatives in other intensively fished habitats. 36 37 Keywords: angling, Cyprinus carpio, fisheries management, game fishes, mark and recapture, 38 stocking strategy. 39 3 Introduction 40Recreational fishery (i.e. angling) is displacing commercial fishery from freshwater habitats 41 in developed countries, especially in Central and Western Europe and North America 42 (Hickley, 2009). Intensive angling requires specific fisheries management. In general, anglers 43 are selective and fish for a few valuable species, putting unbalanced pressure on fish 44 assemblages (Vostradovský, 1991; Arlinghaus and Mehner, 2003; Hickley, 2009). 45Consequently, maintaining high angling activity in freshwaters generally requires stocking of 46 the most important game fishes, especially in areas where captured fish are not returned to the 47 water and natural recruitment is unsatisfactory. 48In some European and Asian countries, common carp, Cyprinus carpio L., is a much 49 preferred commercial and game fish (e.g. Czech Republic: Vostradovský, 1991; Germany: 50 Arlinghaus and Mehner, 2003; United Kingdom: Linfield, 1980; Poland: Wolos et al., 1998). 51Unfortunately, due to human-induced habitat alterations, wetland draining, floodplain 52 isolation by dykes, overfishing and intensive stocking of domesticated strains, most native 53 wild common carp populations have become endangered (e.g. River Danube subpopulation 54 listed as critically endangered in the IUCN Red Lis...

Common carp Cyprinus carpio and pikeperch Sander lucioperca are widely distributed and economically important freshwater fishes. Because these species are extensively stocked both within and outside of their native ranges, it is important to assess the effect of these actions. We aimed to analyse growth rate and its variability related to stocking strategy (season × lake area × habitat × fish size) in common carp and pikeperch in Lake Balaton (Hungary), based on cooperative tagging experiments with anglers. In both species, length increment was more closely associated with thermal time (degree-day sum) over 8 °C threshold water temperature than calendar time. Except a marked decrease with increasing fish size, stocking parameters had little effect on length increment. Growth models based on the GROTAG method and the von Bertalanffy's asymptotic length (L∞) and growth rate (K) are provided. Compared to other habitats, estimated growth rate proved to be high in common carp (128 mm year−1 at 300 mm standard length) and modest in pikeperch (61 mm year−1 at 250 mm standard length). We concluded that stocking rate even might be increased in common carp, while management of the pikeperch population should rather be based on catch restriction measures than intensified stockings.