Foto: Erling Svensen, CC BY 4.0
Blue jellyfish
Cyanea lamarckii
Jellyfish in our great hallThe tentacles of the blue jellyfish are grouped into eight clusters along the edge of the bell. Each cluster consists of 40–60 tentacles. They contain venom that causes a sharp, stinging sensation. The species is common along the coast of southern Norway, but in recent years the blue jellyfish has been observed along the entire Norwegian coastline. Researchers point to rising sea temperatures, particularly in winter, as the cause.
Diett
Zooplankton and fish eggs
Hvor lever de
Pelagic and coastal sea
Størrelse
Up to 20 cm
Breeding
The blue jellyfish has a complex life cycle that includes both a free-swimming medusa stage – the jellyfish we see in summer – and a stationary polyp stage that overwinters on the seabed. These polyps remain on the seabed throughout the winter and give rise to a new generation of jellyfish the following summer. The temperature of the seabed during winter is a crucial factor in determining how many blue jellyfish appear the following spring.