Seawater carbonate chemistry and reproduction of fish

• Main Authors: Nagelkerken, Ivan, Alemany, Tiphaine, Anquetin, Julie M, Ferreira, Camilo M, Ludwig, Kim E, Sasaki, Minami, Connell, Sean D
• Format: Dataset
• Language: English
• Published: PANGAEA 2021
• Subjects: Alkalinity; total; standard deviation; Animalia; Antioxidant capacity; per protein mass; Aragonite saturation state; Attack rate; Behaviour; Bicarbonate ion; Calcite saturation state; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Chordata; CO2 vent; Coast and continental shelf; Experiment; Field observation; Figure; Fish; Foraging rate; Forsterygion lapillum; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Gastropoda; mass; Gonad mass; per size; Growth; Growth/Morphology; Individuals; Liver mass; Male; Malondialdehyde; Nekton; Notoclinops segmentatus; Notoclinops yaldwyni; Number of prey; OA-ICC; Ocean Acidification International Coordination Centre; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.930727; https://doi.org/10.1594/PANGAEA.930727

Ocean acidification affects species populations and biodiversity through direct negative effects on physiology and behaviour. The indirect effects of elevated CO2 are less well known and can sometimes be counterintuitive. Reproduction lies at the crux of species population replenishment, but we do not know how ocean acidification affects reproduction in the wild. Here, we use natural CO2 vents at a temperate rocky reef and show that even though ocean acidification acts as a direct stressor, it can indirectly increase energy budgets of fish to stimulate reproduction at no cost to physiological homeostasis. Female fish maintained energy levels by compensation: They reduced activity (foraging and aggression) to increase reproduction. In male fish, increased reproductive investment was linked to increased energy intake as mediated by intensified foraging on more abundant prey. Greater biomass of prey at the vents was linked to greater biomass of algae, as mediated by a fertilisation effect of elevated CO2 on primary production. Additionally, the abundance and aggression of paternal carers were elevated at the CO2 vents, which may further boost reproductive success. These positive indirect effects of elevated CO2 were only observed for the species of fish that was generalistic and competitively dominant, but not for 3 species of subordinate and more specialised fishes. Hence, species that capitalise on future resource enrichment can accelerate their reproduction and increase their populations, thereby altering species communities in a future ocean.