Both Lure Fjord and Lindåsosane to the inside give good living conditions for rare marine organisms: jellyfish, shellfish and fish. These include animals that migrated in after last the Ice Age, when the sea level was higher. Eventually, as the land rose, some of these populations became isolated.
There is a lot of trout and a large char population in Lake Rylandsvatnet. The lake was stocked with char, probably in 1907. The promoters of the project were the family Ameln, who owned eight mills in Rylandsvågen and parts of the Ryland farm.
When the debate about building a pontoon bridge over Salhus Fjord was raging, some were afraid that the bridge would disrupt the ecology of the fjord system inside. The worst predictions did not prove true, but it is easy to see that there was a change: the Puffins have gotten a new food platter after the Nordhordaland bridge was built. Its favourite meal, mussels, thrive on the pontoons that are the foundation for the bridge.
It is said that the salmon populations with the largest and the smallest salmon in the world both come from the waters that run out into the fjord system around Osterøy. Vosso is supposed to have the largest spawning salmon to be found in any river, whereas Lonelva is said to have the smallest.
In the late 1800s, Ekso was known among the nobility in England as having among the best salmon rivers. In summer the Lords could haul in big fish of up to 25 kg. In return, the townsfolk were paid for fishing rights, lodging and local assistance.