Effects of ocean acidification on the larval growth of olive flounder (Paralichthys olivaceus)

Abstract. Little is known about how marine fishes respond to the reduced pH condition caused by the increased CO₂ in the atmosphere. We investigated the effects of CO₂ concentration on the growth of olive flounder (Paralichthys olivaceus) larvae. Newly hatched larvae were reared in three different concentrations of CO₂ (574, 988 and 1297 μatm CO₂) in temperature-controlled water tanks until metamorphosis (4 weeks). Body lengths, weights, and the concentration of some chemical elements in larval tissue were measured at the completion of each experiment, and experiment was repeated three times in May, June, and July 2011. Results indicated that body length and weight of flounder larvae were significantly increased with increasing CO₂ concentration (P < 0.05). Daily growth rates of flounder larvae were higher (0.391 mm) from the high CO₂ concentration (1297 μatm) than those (0.361 mm and 0.360 mm) from the lower ones (988 and 574 μatm).The measurement on some chemical elements (Ca, Fe, Cu, Zn and Sr) in fish tissue also revealed the increasing tendency of element concentration with increasing CO₂ in seawater, although statistical significance cannot be tested due to the single measurement. It suggests that there are enrichment processes of these cations in larval tissue in the low pH condition.