Journal of Marine Science: Research & Development
Open Access

Abstract

The effect of pH due to the increased CO2 on body and otolith growth during the early growth stages of fish was determined by the rearing experiments of chum salmon Oncorhynchus keta and olive flounder Paralichthys olivaceus . Fertilized salmon eggs were reared in 5 chambers of the pH ranges between 6.9 and 7.5 ( p CO 2 800 ∼ 2300 μmol) at the ambient temperature between 6 to 13 oC. pH was controlled by the successive aeration, and measured every day at 10:00 AM. Relationship between pH and CO 2 was estimated using the data obtained from the direct p CO 2 measuring system. Salmon eggs were hatched ca. 48 d after fertilization. Average total length was longer and otolith diameter was wider for hatched fish in the lower pH, and these differences maintained to the emerging stage (ca. 40 d after hatching). Fertilized eggs of olive flounder were reared by supplying the CO 2 gas from the tanks of 400, 800, 1600 and 3200 μmol. Experimental water maintained a water temperature of 18 ∼ 19oC and a salinity of 31.5 ∼ 32.0 psu. Eggs were hatched ca. 2 d after fertilization. Rotifer was fed 3 d after hatching. Larvae were sampled at 5 d and 10 d after hatching. Average total length was longer and otolith diameter was wider for larvae in the lower pH.

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