Specimens (F1) of the marine calanoid copepod Acartia tonsa were exposed for five days under laboratory conditions to the isolated or combined effects of hypoxia and a marine heatwave. Then, their offspring (F2) were returned to control conditions (C: 18 °C, 100 % O₂ sat.) for the rest of their life cycle to simulate a recovery period. This dataset follows the physico-chemical parameters of the aquaria holding the copepods during the recovery phase.

The experiment was conducted in the Marine Ecological and Evolutionary Physiology Laboratory (MEEP) at the University of Quebec in Rimouski (UQAR), Rimouski, QC, Canada. Copepods of the species Acartia tonsa were maintained following the stock culture culturing protocol described in Dam et al. 2021 (https://doi.org/10.1038/s41558-021-01131-5). Namely, copepods were kept in three 5 L aquaria filled with artificial seawater kept at a salinity of 28.4 ± 0.5. The physicochemical parameters of the seawater were the following: temperature of 18 ± 0.4 °C, oxygen saturation of 93.7 ± 6.0 %, and pH NBS of 8.20 ± 0.09 before the experiment. The photoperiod was kept at 13h light: 11 h dark. Copepods were fed ad libitum with a mixture of three phytoplankters: Tetraselmis sp., Thalassiosira weissflogii and Rhodomonas salina. Parents (F1) were transferred in 2 L aquaria placed in an experimental system during the 5-d exposure to the isolated and combined effects of hypoxia and MHW conditions. Once the parents (F1) were removed, their offspring (F2) were kept in the same 2 L aquaria and exposed to the control condition to simulate a recovery period until they reached sexual maturity. All traits were measured on F2 adult individuals. For all F1 traits measured during the exposure phase, please refer to the following database: https://doi.pangaea.de/10.1594/PANGAEA.967352.--- This study was additionally supported by the FIR UQAR grant of the Université du Québec à Rimouski.