The Effects of Salinity on the Oxygen Consumption Rates of Juvenile Lumpfish

The lumpfish (Cyclopterus lumpus) is a commercially important species in Iceland and the Netherlands, where it is fished for roe which is used for caviar. Moreover, several recent studies have shown that lumpfish juveniles are useful ‘cleaner fish’ in the Atlantic Salmon aquaculture industry. Despite the importance of the species, little is known about its ecology. This study is examining how one environmental variable (salinity) impacts the oxygen consumption of juvenile lumpfish.  To determine this, juveniles were exposed to five salinity treatments (10, 15, 20, 25, 30 ppt) and oxygen consumption rates were measured. Standard metabolic rates (SMR) were calculated using SMR = (V*δC_wo2)/ (δt*M_f), where δC_wo2 is the slope of the decrease in dissolved oxygen, V is the volume of the respirometry chamber, δt is the change in time, and M_f is the mass of the individual fish.  Results showed that juveniles had higher SMR at both 20 and 25ppt. However, they were able to tolerate salinities down to 5ppt for a week without visual signs of stress. This information will be helpful in informing the management of coastal and fishery resources, as well as those who wish to use lumpfish in aquaculture operations.