My suggestions, based on mosquitoe projects I've heard about in Sweden, would be to:
- Thin vegetation along the shores
- Remove accumulated detritus
- Manage grasslands along the shore, by grazing if possible.
The idea here is to remove the stagnant pools where mosquitoes develop, either coming from rainfall or spring flooding/snowmelt. By removing pools and increasing sun exposture you will probably decrease habitats and larval survival. Continously managing grasslands usually also helps, since it removes excess plant materials and kills mosquitoe larvae by trampling (if grazing is used). To introduce grazing by e.g. sheep (if possible) will probably also have positive conservation effects. Stocking of fish might help, but I suspect that the mosquitoes mainly comes from adjacent waters and edge pools and not the main water body. I doubt that bird and bats can control the mosquito population to any larger extent, but don't have anything specific to back-up this statement.
Also note that actions depend on the types of mosquitoes found in the area. There are both "forest mosquitoes" and "flood mosquitoes" in Sweden, but most perceived problems come from the latter kind, and since you are referring to mosquitoes from the lake/pond I suspect you are dealing with the latter kind. You should try to determine the most common species found there though. Treatment with Vectobac G (Bacillus thuringiensis israelensis) might be an option, but I don't know what kind of retrictions there are on using it privately.
You might be interested in this report from a Swedish county board, since it mentions ways to control mosquitos (in Swedish):
Lundqvist et al. 2013. Förslag till hur myggproblemet vid Nedre Dalälven kan hanteras på lång sikt. Länsstyrelsen Gävleborg ("Suggestions for how to handle the mosquito problem at Lower Dalälven over the long-term" freely translated).