Exposure to elevated carbon dioxide does not impair short-term swimming behaviour or shelter-seeking in a predatory coral-reef fish.

Adult bluespotted rockcod Cephalopholis cyanostigma, a coral-reef grouper, were acclimated to either ambient (mean ± s.d. 406 ± 21 μatm; 1 atmos = 101325 Pa) or high pCO2 (945 ± 116 μatm) conditions in a laboratory for 8-9 days, then released at the water surface directly above a reef (depth c. 5 m) and followed on video camera (for 191 ± 21 s) by scuba divers until they sought cover in the reef. No differences were detected between groups in any of the six measured variables, which included the time fish spent immobile after release, tail beat frequency during swimming and the time required to locate and enter the protective shelter of the reef.