Norwegian Spring-Spawning Herring

The overwintering aggregation of Norwegian spring-spawning herring in Vestfjorden is one of the largest concentrations of any fish species on the planet, with biomass estimates reaching several million tonnes. Herring form tight defensive bait balls when threatened by orcas or other predators, and divers who enter these formations find themselves completely surrounded by a shimmering wall of silver fish that responds to movement like a single organism. The herring draw humpback whales, white-tailed eagles, and large tuna in addition to orcas, making Vestfjorden a multi-species pelagic experience unmatched in European waters.