They do not inhabit saltwater. Mosquitoes are important because of their blood-feeding behavior. This makes them major nuisances as well as disease carriers. Only the females suck blood - the males are nectar feeders. The females need the protein in blood to produce viable eggs.
More money is spent on mosquito control than on control of any other insect.
Smaller cities and towns most often have programs using personnel with other duties in addition to mosquito control. In Mississippi there are an estimated 200 mosquito control programs. The one thing all mosquitoes have in common is water. The female mosquito lays her eggs in water or in places where water will be eventually. Examples of the latter include low places which will become puddles after rain and containers which hold water after rain.