CONTROL OF WATER QUALITY AROUND A CAGE FISH FARM IN THE NORRBY ARCHIPELAGO (NORTHERN BOTHNIAN SEA)

The concentrations of oxygen, nitrate, phosphate, particulate organic matter and planktonic algae around a cage fish farm during an annual cycle showed values similar to the concentrations in the water of the surrounding sea area. There was no increase of nutrients and no denser growth of algae in the cage fish farm. The concentration of oxygen was always rather high in the farm.