NEWS
In the brackish water environment, the pike is known to have two different strategies for spawning. Some stay in the brackish water environment when spawning, while others show a homing behaviour similar to salmon. In Petter Tibblins thesis he proves that subpopulations adapt genetically to the environment in the spawning area, even if they live in a merged population a greater part of the year.
Petter Tibblin. Photo: Kristina Viklund.
Pike, Esox lucius, is one of the most common predatory fish, and play an important role in the ecosystem of lakes, streams and coastal areas of the Baltic. In the brackish water environment, it is known to have two different strategies for spawning. Some stay in the brackish water environment when spawning, while others show a homing behaviour similar to salmon, and migrate to freshwater streams for spawning. The juveniles hatched in freshwater will stay there for a couple of weeks before returning to the sea, and will return to the same stream to spawn three to four years later. They will thereafter return for spawning for a couple of weeks every spring.
In Petter Tibblins thesis he discusses how these short, annual periods of time will influence the pike. There are differences in morphology and life-traits between subpopulations which can be explained by which spawning area the pikes are hatched in. Studies in the thesis proves that the differences between subpopulations are a result of natural selection, even if the period of time when the pikes live in the spawning area is very short. The subpopulations live in a merged population a greater part of the year, but still adapt genetically to the environment in the spawning area. Altogether, the thesis shows the importance of considering fine spatial scale population structures in management and conservation of biodiversity in the Baltic Sea.
