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The research lakes have been SW Pyhäjärvi (Säkylä), Puulavesi, Päijänne (Tehinselkä and Northern Päijänne), Ruotsalainen, Southern Konnevesi, Keitele, Puruvesi,SE Pyhäjärvi, Paasivesi, Onkamo, Höytiäinen, Oulujärvi and Kitka. In some years, comprehensive monitoring has included the following measures annually on some lakes: estimating the density of larvae, determining the growth of the first summer, determining the recruitment in the fall (echo sounding, test trawling, other catches), fishing effort and catch monitoring, collecting population samples, estimating the size of the spawning stock, and fisher surveys. In most cases, however, only part of the annual work has been carried out. The largest lakes are limited to either one or a few sub-areas of around 100-200 km2.