Atlantic herring (Clupea harengus) during a laboratory experiment at the University of Bergen (Norway) in April/May 2022. This experiment was associated to the KOSMOS 2022 mesocosm campaign. Herring larvae were held in 6 rearing tanks until 37 days-post-hatch (dph). Ocean alkalinity enhancement (OAE) was applied 18 dph to half of the tanks. At several time points, growth (increase in standard length), basic physiology (routine metabolic rate) and behavior (swimming/hunting) were assessed by subsampling several larvae from each tank. At the end of the experiment, long-term survival was assessed by counting all larvae remaining in the tanks. Methodological details in Goldenberg et al. (under review).