Calanus finmarchicus

Jellyfish invaders: Trondheim Fjord in transition

Jarle Mork has spent the last 40 years of his career studying Trondheim Fjord and its finned inhabitants. Warmer waters and the arrival of new creatures are bad news for the fjord’s cod population, he says. But other fishing practices are problematic, too.

An acidic ocean may mean less fish

Calanus finmarchicus makes up about 90 per cent of the bottom of the food chain in northern oceans, and is eaten by fish and baleen whales alike, but as the ocean becomes more acidic due to CO2 emissions, populations may decrease dramatically.