Yellow clay dispersion has been applied to minimize fisheries impact by the red tide Cochlodinium polykrikoides blooms in Korean coasts since 1995. The present preliminary study documents the effect of yellow clay on Korean rockfish, Sebastes schlegelii, in terms of oxygen consumption rate (OCR). The OCR in the low clay suspension (0.05 and 0.23 %, w/w) showed normal level compared to the control. In contrast, the OCR for each one of three replicates in the high clay suspension (1.16 and 5.58 %, w/w) was not returned to the previous level that clay was not treated, indicating that high clay suspension (≥1.16%, w/w) might give negative effect on Korean rockfish. Overall, this result suggests that field application of clay to control Harmful Algal Blooms (HABs) may not give impact on Korean rockfish once the clay is dispersed in a low concentration (≤0.23%). In order to understand the changes of OCR in the repeated exposure to clay, it is required to do further studies on the changes of OCR when the fish is exposed to clay repeatedly after recovery in the normal seawater.

Oxygen consumption has been regarded as a useful indicator for assessment of mammalian embryo quality. This study was performed to investigate whether oxygen consumption reflects morphological grade of in vivo derived bovine blastocyst-stage embryos (blastocyst). The oxygen consumption of in vitro produced blastocyst was compared to its total cell number. In addition, pregnant rate was measured after transplantation of in vivo blastocysts with different oxygen consumption. The quality of blastocyst collected on day 7 after artificial insemination was categorized as grade I and II (G I and G II) based on microscopic observation of the morphology. Oxygen consumption of blastocyst was measured using a scanning electrochemical microscopy (SECM) and total cell number of in vitro blastocyst was enumerated by counting cells stained by propidium iodide. Pregnancy of recipient cow was confirmed with rectal palpation after 60 days of embryo transfer. The oxygen consumptions of G I blastocysts were significantly higher than those of G II blastocysts ( versus , p<0.05). Total cell numbers of in vitro blastocysts were 74.8, 90.7, and 110.2 in the oxygen consumption of below 10.0, 10.0~12.0, and over respectively. Total cell number was significantly increased in embryos with high oxygen consumption (p<0.05). Pregnant rate in recipient cow was 0, 50, and 85.7% in the transplantation of embryo with the oxygen consumption of below 10.0, 10.0~12.0, and over , respectively. These results suggest that measurement of oxygen consumption may help increase the pregnant rate of bovine embryos.