Seabream Larval Physiology under Ocean Warming and Acidification

Abstract

The vulnerability of early fish stages represents a critical bottleneck for fish recruitment; therefore, it is essential to understand how climate change affects their physiology for more sustainable management of fisheries. Here, we investigated the effects of warming (OW; +4 °C) and acidification (OA; ΔpH = 0.5) on the heart and oxygen consumption rates, metabolic enzymatic machinery—namely citrate synthase (CS), lactate dehydrogenase (LDH), and ß-hydroxyacyl CoA dehydrogenase (HOAD), of seabream (Sparus aurata) larvae (fifteen days after hatch). Oxygen consumption and heart rates showed a significant increase with rising temperature, but decreased with pCO2. Results revealed a significant increase of LDH activity with OW and a significant decrease of the aerobic potential (CS and HOAD activity) of larvae with OA. In contrast, under OA, the activity levels of the enzyme LDH and the LDH:CS ratio indicated an enhancement of anaerobic pathways. Although such a short-term metabolic strategy may eventually sustain the basic costs of maintenance, it might not be adequate under the future chronic ocean conditions. Given that the potential for adaptation to new forthcoming conditions is yet experimentally unaccounted for this species, future research is essential to accurately predict the physiological performance of this commercially important species under future ocean conditions.

Larval Development in Tropical Gar (Atractosteus tropicus) Is Dependent on the Embryonic Thermal Regime: Ecological Implications under a Climate Change Context

“…This is the case of studies focused on establishing the potential effects of the climate change over fish species. Most studies on this issue exposed contemporary populations of fishes to global warming (higher mean water temperature and ocean acidification) that progressively will take place in the coming years [14][15][16][17][18]37], neglecting the capacity of fish species to adapt to this environmental condition through the different generations. Here, we explored the effect of a more extreme event (although shorter in time, only lasting some days) related to climate change, the heat waves, a contemporary event which frequency and intensity are predicted to be increased [1].…”

Impact of chronic exposure of rainbow trout, Oncorhynchus mykiss, to low doses of glyphosate or glyphosate-based herbicides

“…Some tendencies were observed when CS/CCO and LDH/CS ratios of activities were considered but further studies are needed to confirm these results. Higher LDH/CS could indicate a transition from aerobic to anaerobic metabolism [70], while a lower CS/CCO ratio could reveal mitochondrial dysfunction [35]. Craig et al [14] observed that Cu exposure affected this ratio in the liver of the gilthead seabream (Sparus aurata) and suggested that it could, therefore, affect normal mitochondrial biogenic processes.…”

The effects of the “deadly trio” (warming, acidification, and deoxygenation) on fish early ontogeny

“…Ten larvae per replicate (n= 30 per treatment) were placed after hatch in sealed water-jacketed respirometry chambers, lled with seawater from the respective treatment (according to Pimentel et al 2019). Water volumes were adjusted to allow routine activity and to minimize larval stress.…”

“…Water volumes were adjusted to allow routine activity and to minimize larval stress. Routine heart rates measurements were taken at the end of the experiment under a stereoscope (Leica S6D, Leica Microsystems), and de ned as the number of heart beats per unit of time when larvae were not swimming (according to Pimentel et al 2019).…”