Herring in the Archipelago Sea

Baltic Herring: A Vital Baltic Ecosystem Player

Baltic herring (Clupea harengus membras L.) plays a crucial role in the Baltic ecosystem. It’s a significant food source for predatory fish like Baltic cod and salmon, while also acting as a predator itself, feasting on zooplankton and nektobenthos. Thanks to its broad tolerance for varying salinity levels, Baltic herring thrives and reproduces across nearly every corner of the Baltic Sea.

A Commercially Valuable Species

Despite fluctuations in its abundance and biomass, Baltic herring has sustained commercial exploitation for decades. In Finland, herring represents about 90% of the total fish catch by volume in the sea area. The Baltic herring is the most important species commercially (ca. 17 million euro).

The Archipelago Sea: A Vital Spawning Ground

The Archipelago Sea, located off the southwest coast of Finland, serves as the primary spawning area for Baltic herring along the Finnish coast. This vast coastal sea region is characterized by over 40,000 islands, a complex coastline, and shallow waters (with an average depth of approximately 20 meters). It boasts an extensive littoral area with diverse vegetation, including macroalgae like Fucus, Cladophora, Enteromorpha, Pilayella, and Ectocarpus, as well as vascular plants like Potamogeton and Ranunculus, and occasionally Zostera. Several rivers, including Aurajoki, Mynäjoki, and Paimionjoki, discharge freshwater into the area, with sheltered and productive estuaries.

Exploring Baltic Herring Research

On these pages, you’ll discover valuable insights into the spawning areas, spawning populations, reproductive success, and trap net fishery of Baltic herring in the northern Baltic Archipelago Sea. This information draws extensively from research conducted by the herring research group since the 1980s.