Temperature and Water Elemental Concentration Affecting Strontium Incorporation into Otoliths in Larval-Juvenile Flounder Paralichthys olivaceus

Abstract:

An understanding of the effects of aquatic environmental factors on elemental incorporation into otoliths is fundamental for reconstructing life and environmental histories of fish using otolith microchemistry analysis. This study investigated the effects of temperature (16℃, 19℃, and 22℃) and water elemental concentration (1×, 2×, 3× Sr ambient baseline, 6.5 mg/L) on the otolith elemental incorporation of Sr in larval-juvenile flounder, Paralichthys olivaceus (15~93 days post hatching). The results revealed that the otolith incorporation of Sr (Sr∶CaOtolith) was positively dependent on ambient Sr concentration (Sr∶CaWater) as well as water temperature. Sr∶CaOtolith values were significantly higher at 22℃ than at 16℃ and 19℃ at all Sr concentrations. Partition coefficient of Sr (DSr, Sr∶CaOtolith/Sr∶CaWater) tended to decrease with increasing Sr∶CaWater but remained stable when Sr∶CaWater reached a certain level at each temperature. Sr was incorporated into the otoliths more efficiently at 22℃ than at the lower temperatures. It appeared that the otolith elemental incorporation of Sr was closely related to the ambient elemental concentration and, thus, could reflect the water chemistry that fish experienced, suggesting that Sr could be used as an elemental fingerprint to reconstruct the life and environmental histories of the flounder during its early life stage in nature.