Description: Water parameters in the 2 years before spawning of F0 (08.02.2016-06.03.2018) and during larval and juvenile phase of F1: Larval period until 17.05.2018 (48 dph, 900 dd) and 01.06.2018 (63 dph, ~900 dd) for warm and cold life condition respectively, for the juveniles until 28.09.2018 (180 dph, ~4000 dd) and 12.02.2019 (319 dph, ~5100 dd) for warm and cold conditioned fish respectively. Means ± s.e. over all replicate tanks per condition. Temperature (Temp.), pH (free scale), salinity, oxygen and total alkalinity (TA) were measured weekly in F1 and monthly in F0; sea water (SW) measurements were conducted in 2017 and 2018. Water parameters during larval and early juvenile phase of F0: Larval period until (45 dph, 900 dd, 06.12.2013), early juveniles until 1.5 years. Means ± s.e.m. over all measurements per condition (triplicate tanks in larvae, single tanks in juveniles). Temperature (Temp.) and pH (NBS scale) were measured daily. pH (total scale), salinity, phosphate, silicate and total alkalinity (TA) were measured once at the beginning and once at the end of the larval phase and 9 times during juvenile phase; PCO2 was calculated with CO2sys; A–Ambient PCO2, D1000 –ambient + 1000 µatm CO2, L – Larvae, J – Juveniles.

Description: Temperature dependent cell respiration and energy expenditure for protein synthesis were determined in primary hepatocytes of different fish species of the South Atlantic: the circumpolar-distributed Antarctic eelpout Pachycara brachycephalum (sampling location: 62°19′S; 58°33′W) and, of two notothenioids the sub-Antarctic Lepidonotothen squamifrons (sampling location: 53°24′S; 42°40′W) and the high-Antarctic icefish Chionodraco hamatus (sampling location: 70°19′S; 10°22′W). We used intermittent-flow respirometry and closed system respirometry to analyse cellular response to acute warming.

Description: The world's oceans are acidifying and warming as a result of increasing atmospheric CO2 concentrations. The thermal tolerance of fish greatly depends on the cardiovascular ability to supply the tissues with oxygen. The highly oxygen-dependent heart mitochondria thus might play a key role in shaping an organism's tolerance to temperature. The present study aimed to investigate the effects of acute and chronic warming on the respiratory capacity of European sea bass (Dicentrarchus labrax L.) heart mitochondria. Broodstock fish were caught in the Gulf of Morbihan, France. Larvae were raised at the aquaculture facility Aquastream (Ploemeur-Lorient, France) and obtained at 2 dph (20 January 2016). European sea bass were reared in the laboratory in six ocean acidification and warming (OAW) conditions: two temperatures (warm and cold life condition) and three PCO2 conditions (control, Δ500 and Δ1000). Conditions were chosen to follow the predictions of the IPCC for the next 130 years: ΔT = 5°C and ΔPCO2 = 500 and 1000 µatm, following RCP 6.0 and RCP 8.5 respectively. The fish were reared under these conditions from 3 dph (days post hatch) until mitochondrial respiration measurements at 3700 to 4100 dd (degree days, 183–199 dph and 234–249 dph in warm and cold life conditioned fish, respectively). During the experimental period, fish of all three PCO2 conditions of the respective temperature were used for mitochondrial respiration measurements on permeabilized heart fibres. Fish were not fed for 2 days prior to the experiments. Two batches of eight fish each were processed per day. Juveniles were randomly caught from their tanks and anesthetized with MS-222. Mass, fork length and body length were directly determined with a precision balance (Mettler, Columbus, OH, USA) and a calliper, to the nearest 0.01 g and 0.01 mm, respectively. Afterwards, fish were killed by a cut through the neck, and the heart was completely dissected from the fish, followed by excavation and permeabilization of the ventricle. Tissue from a whole ventricle was used for respiration measurements in each respiration chamber of the oxygraphs and respiration rates were normalized to ventricle mass. During the permeabilization step, the livers and the carcasses of the fish were weighed to calculate the hepatosomatic index (HSI) and condition factor (K). Mitochondrial respiration of the permeabilized heart fibres was measured using four Oroboros Oxygraph-2K respirometers with DatLab 6 software (Oroboros Instruments, Innsbruck, Austria). Permeabilized fibers have the advantage of resembling the living state as closely as possible, while still allowing control of the supply of substrates and inhibitors to the mitochondria (Saks et al., 1998; Pesta and Gnaiger, 2012). Measurements were conducted at 15 and 20°C for all treatments to determine the effect of acute temperature changes on mitochondrial metabolism in vitro. A standard substrate–uncoupler–inhibitor titration protocol was employed to measure the respiration rates of the different complexes. Residual respiration after antimycin A addition was used to correct all mitochondrial respiration rates.

Description: Ongoing climate change is leading to warmer and more acidic oceans. The future distribution of fish within the oceans depends on their capacity to adapt to these new environments. Only few studies have examined the effects of ocean acidification (OA) and warming (OW) on the metabolism of long-lived fish over successive generations. We therefore aimed to investigate the effect of OA on larval and juvenile growth and metabolism on two successive generations of European sea bass (Dicentrarchus labrax L.) as well as the effect of OAW on larval and juvenile growth and metabolism of the second generation. European sea bass is a large economically important fish species with a long generation time. F0 larvae were produced at the aquaculture facility Aquastream (Ploemeur-Lorient, France) and obtained at 2 days post-hatch (dph). From 2 dph F0 larvae were reared in the laboratory in two PCO2 conditions (ambient and Δ1000). Larval rearing was performed in a temperature controlled room and water temperatures were fixed to 19°C in F0. In juveniles and adults, water temperatures of F0 sea bass were adjusted to ambient temperature in the Bay of Brest during summer (up to 19°C), but were kept constant at 15 and 12°C for juveniles and adults, respectively, when ambient temperature decreased below these values. F1 embryos were obtained by artificial reproduction of F0 broodstock fish. Fertilized eggs were incubated at 15°C and at the same PCO2 conditions as respective F0. Division of F1 larvae from egg rearing tanks into experimental tanks took place at 2 dph. F1 larvae were reared in four OAW conditions: two temperatures (cold and warm life condition, C and W) and two PCO2 conditions (ambient and Δ1000). Larval rearing was performed in a temperature controlled room and water temperatures were fixed to 15 and 20°C for C and W larvae, respectively. In juveniles, water temperatures of F1 sea bass were adjusted to ambient temperature in the Bay of Brest during summer (up to 19°C), but were kept constant at 15°C when ambient temperature decreased below these values. F1-W was always 5°C warmer than the F1-C treatment. OAW conditions for F0 and F1 rearing were chosen to follow the predictions of the IPCC for the next 130 years: ΔT = 5°C and ΔPCO2 = 1000 µatm, following RCP 8.5. We analysed larval and juvenile growth in F0 and F1. Larval routine metabolic rates (RMR, in F1), juvenile standard metabolic rates (SMR, in F0 and F1) and juvenile critical oxygen concentrations (PO2crit, in F0 and F1) were obtained on individuals via intermittent flow-respirometry. Measurements were conducted at the rearing conditions of the respective larva or juvenile. Fish were fasted for 3h and 48-72h for larvae and juveniles, respectively. After the respirometry trial, larvae were photographed to measure there body length and frozen until measurement of dry mass. Juveniles body length and wet mass was directly determined with calipers and a balance.

Description: Ongoing climate change is leading to warmer and more acidic oceans. The future distribution of fish within the oceans depends on their capacity to adapt to these new environments. Only few studies have examined the effects of ocean acidification (OA) and warming (OW) on the metabolism of long-lived fish over successive generations. We therefore aimed to investigate the effect of OA on larval and juvenile growth and metabolism on two successive generations of European sea bass (Dicentrarchus labrax L.) as well as the effect of OAW on larval and juvenile growth and metabolism of the second generation. European sea bass is a large economically important fish species with a long generation time. F0 larvae were produced at the aquaculture facility Aquastream (Ploemeur-Lorient, France) and obtained at 2 days post-hatch (dph). From 2 dph F0 larvae were reared in the laboratory in two PCO2 conditions (ambient and Δ1000). Larval rearing was performed in a temperature controlled room and water temperatures were fixed to 19°C in F0. In juveniles and adults, water temperatures of F0 sea bass were adjusted to ambient temperature in the Bay of Brest during summer (up to 19°C), but were kept constant at 15 and 12°C for juveniles and adults, respectively, when ambient temperature decreased below these values. F1 embryos were obtained by artificial reproduction of F0 broodstock fish. Fertilized eggs were incubated at 15°C and at the same PCO2 conditions as respective F0. Division of F1 larvae from egg rearing tanks into experimental tanks took place at 2 dph. F1 larvae were reared in four OAW conditions: two temperatures (cold and warm life condition, C and W) and two PCO2 conditions (ambient and Δ1000). Larval rearing was performed in a temperature controlled room and water temperatures were fixed to 15 and 20°C for C and W larvae, respectively. In juveniles, water temperatures of F1 sea bass were adjusted to ambient temperature in the Bay of Brest during summer (up to 19°C), but were kept constant at 15°C when ambient temperature decreased below these values. F1-W was always 5°C warmer than the F1-C treatment. OAW conditions for F0 and F1 rearing were chosen to follow the predictions of the IPCC for the next 130 years: ΔT = 5°C and ΔPCO2 = 1000 µatm, following RCP 8.5. We analysed larval and juvenile growth in F0 and F1. Larval routine metabolic rates (RMR, in F1), juvenile standard metabolic rates (SMR, in F0 and F1) and juvenile critical oxygen concentrations (PO2crit, in F0 and F1) were obtained on individuals via intermittent flow-respirometry. Measurements were conducted at the rearing conditions of the respective larva or juvenile. Fish were fasted for 3h and 48-72h for larvae and juveniles, respectively. After the respirometry trial, larvae were photographed to measure there body length and frozen until measurement of dry mass. Juveniles body length and wet mass was directly determined with calipers and a balance.