Camilla With Fagerli // Norwegian Institute for Water Research Brian Tsuyoshi Takeda // Restorae Øyvind Stråbø // Trefadder Erling Natvig // Vår Energi A natural sea urchin predator The Atlantic wolffish (Anarhichas lupus) is a relatively stationary bottom-dwelling species commonly found along the entire Norwegian coast, typically at depths shallower than 150 metres. It mainly feeds on sea urchins but is also partial to mussels, snails, and crabs. The species reaches sexual maturity at 6–7 years of age and it can live up to 25 years. During the spawning season, male and female wolffish pair up and remain together at the spawning site until spawning. Unlike most other fish species, Atlantic wolffish has internal fertilisation. After the female lays her eggs, the male guards the egg mass for 9–10 months until hatching—a rare example of extended parental care among marine fish. In captivity, natural mating behaviour does not occur, so artificial fertilisation techniques must be used. Females are briefly removed from the water, anaesthetised, and stripped of eggs, which are then fertilised with milt taken from males. The eggs are incubated in seawater tanks where they adhere naturally to one another as they develop. Restoring ecological balance Small-scale experiments have...