European sea bass, <i>Dicentrarchus labrax</i>, in a changing ocean

Abstract

Abstract. Ocean acidification, caused by rising concentrations of carbon dioxide (CO2), is widely considered to be a major global threat to marine ecosystems. To investigate the potential effects of ocean acidification on the early life stages of a commercially important fish species, European sea bass (Dicentrarchus labrax), 12 000 larvae were incubated from hatch through metamorphosis under a matrix of two temperatures (17 and 19 °C) and two seawater pCO2 levels (ambient and 1,000 μatm) and sampled regularly for 42 days. Calculated daily mortality was significantly affected by both temperature and pCO2, with both increased temperature and elevated pCO2 associated with lower daily mortality and a significant interaction between these two factors. There was no significant pCO2 effect noted on larval morphology during this period but larvae raised at 19 °C possessed significantly larger eyes and lower carbon:nitrogen ratios at the end of the study compared to those raised under 17 °C. Similarly, when the incubation was continued to post-metamorphic (juvenile) animals (day 67–69), fish raised under a combination of 19 °C and 1000 μatm pCO2 were significantly heavier. However, juvenile D. labrax raised under this combination of 19 °C and 1000 μatm pCO2 also exhibited lower aerobic scopes than those incubated at 19 °C and ambient pCO2. Most studies investigating the effects of near-future oceanic conditions on the early life stages of marine fish have used incubations of relatively short durations and suggested that these animals are resilient to ocean acidification. Whilst the increased survival and growth observed in this study supports this view, we conclude that more work is required to investigate whether the differences in juvenile physiology observed in this study manifest as negative impacts in adult fish.

Ocean warming has a greater effect than acidification on the early life history development and swimming performance of a large circumglobal pelagic fish

“…However, other species appear much more tolerant to the direct lethal effect of elevated p CO 2 , with no effect on larval survivorship reported in Baltic cod (Frommel, Schubert, Piatkowski, & Clemmesen, ), Atlantic herring (Franke & Clemmesen, ) and walleye pollock (Hurst, Fernandez, & Mathis, ). Survivorship even increased at 1,000 μatm p CO 2 in European sea bass (Pope et al., ). In winter flounder, there was a strong effect of elevated p CO 2 (≥1,800 μatm) on prehatching survival, but no effect on survivorship after hatching (Chambers et al., ).…”

European sea bass show behavioural resilience to near-future ocean acidification

“…Fertilized D. labrax eggs from a mixed spawn (multiple males and females) were incubated in water at 19°C and 585 µatm p CO 2 (ambient) or 1000 µatm p CO 2 (for full details of rearing conditions, see the electronic supplementary material and Pope et al [24]); n  = 180 fish from 585 µatm p CO 2 conditions (mean length ± s.d. = 32.34 ± 3.12 mm), and n  = 90 fish (mean length ± s.d.…”

An updated synthesis of the observed and projected impacts of climate change on the chemical, physical and biological processes in the oceans

“…Recent work continues to highlight the effects of secondary drivers such as ocean acidification, hypoxia and food availability on the capacity of an organism to adapt to changing temperatures and increasing numbers of recent studies are highlighting the interactive effects of temperature and secondary drivers (Vehmaa et al, 2013;Ko et al, 2014;Mackenzie et al, 2014b,c;Madeira et al, 2014;Pope et al, 2014). A recent study has demonstrated that trans-generational plasticity can mediate the effects of warming in a fish species (Shama et al, 2014); however, there remains low confidence in our understanding of the potential evolutionary adaptation to warming.…”