If you get a cod on the hook in the Baltic Sea, you will most likely be met by a sad sight, a very small and excellent specimen of the most important predator fish of the Baltic Sea.

But there is one exception: the Åland cod.

 - In these waters the fish is large, healthy and has smaller parasites than in the rest of the sea. The kind of fish that could be found throughout the Baltic Sea in the 1980s, says Ulf Bergström, who researches the Baltic Sea's habitats and is at the end of a study on the cod in the Åland Sea.

"Can open new areas"

The reason that cod is so good is the deep, cold and oxygen-rich sea. But living is one thing, being able to be born another. The sea is not enough salt for the eggs to hatch.

In the past, it has been thought that the salt content needs to be about eleven per thousand, levels found only south of the Baltic Sea. But there the cod have less food and lack of oxygen-rich water.

But the study that Ulf Bergström participated in and conducted on the abundant Åland cod has given positive indications:

- In some individuals we have seen successful fertilization down to 9-10 per thousand. If the game can succeed in that salt content, it opens up new areas where there could be play.

No guarantee for richer stocks

There are at least two important lessons to be learned from the study, says Ulf Bergström: That the cod's eggs can be hatched at lower salinity levels and that it becomes extra important to protect the Åland cod as it appears to tolerate lower salinity levels and is large-grown and produces more offspring.

- We want to save this cod. It is unique with a large cod that seems to have found an optimal area to live in.

He is also careful to point out that it is not possible to see the study's results as a clear turning point for cod survival:

- We have just scratched the surface and there are incredibly large knowledge gaps. But the result is interesting and provides knowledge to build upon.