Arctic Comb Jelly

Mertensia ovum

Mertensia ovum is a distinctive ctenophore characterized by its oval shape and light pink coloration. It features eight rows of cilia, which create a rainbow effect as they move, propelling the jelly through the water. This species is typically found in the Arctic and adjacent polar seas, residing mostly in surface waters down to a depth of 50 metres. It prefers colder environments, unlike many other ctenophores that thrive in warmer waters. Divers may encounter this jelly in pelagic zones, where it can be seen drifting gracefully through the water column. Feeding primarily on small crustaceans and copepods, Mertensia ovum uses its long, sticky tentacles to capture prey. These tentacles are retractable and equipped with specialized structures that release an adhesive substance to ensnare their food. The diet of this species includes large copepods, amphipods, and krill, making it an important predator in its ecosystem. Mertensia ovum is hermaphroditic, reproducing both sexually and asexually. It releases eggs and sperm into the water, leading to the development of planktonic larvae. Adult specimens can grow up to 10 centimetres in length. Encounters with this jelly during dives can be intriguing, as its bioluminescence may create a captivating display in the water, particularly at night. The conservation status of this species is not evaluated, and it has been recorded at various dive sites across the Arctic region.