The silver of the sea swims in the laboratory's tanks

For herring, timing is everything. Reproducing at the right time of year is crucial to give the next generation the best possible chance of survival. As the climate changes, the conditions in the sea change as well. This makes the question of what controls the timing of herring spawning more important than ever.

Researchers already know that genes play an important role. By mapping the genomes of thousands of herring from the Baltic Sea and the Atlantic Ocean, they have identified several genetic differences between spring-spawning and autumn-spawning populations. However, exactly how these genes interact with changes in light, temperature, and other environmental factors remains an unanswered question.

Researchers from Uppsala University now hope that the herring at BalticWaters Fish Laboratory will help fill these knowledge gaps and provide a better understanding of what actually happens in the fish’s brain and reproductive organs as it prepares to spawn.

The herring in the laboratory, which comes from the local Södermanland archipelago off Studsvik, give researchers a unique opportunity to follow the same fish over time. Through repeated sampling before, during, and after the spawning period, the researchers hope to track the biological changes that occur as the fish prepares for reproduction and investigate how genes and environmental factors interact.

The study has the potential to provide new fundamental knowledge about reproduction in vertebrates, while also improving our understanding of how climate change may affect the adaptive capacity of herring. In the long term, the results could contribute to more sustainable management of one of the Baltic Sea’s most important fish species.