Fish resource surveys were conducted near Jeju Island in June, August and October 2021 using an underwater camera monitoring system, fish pots, and SCUBA diving methods. The efficiency of the methods used to survey fish resources was compared using the number of individuals compared to area per unit time (inds/m3/h) and the number of species compared to area per unit time (spp./m3/h). As a result of comparing the number of individuals compared to the area per unit time (inds/m3/h), the order was underwater camera 214.69, SCUBA diving 124.62, and fish pots 0.57 inds/m3/h. The number of species compared to area per unit time (spp./m3/h) is in the following order: SCUBA diving 0.85, underwater camera 0.38, and fish pots 0.01 spp./m3/h. The fish resource monitoring method using underwater cameras was found to be more efficient in individual counts, and the SCUBA diving method was found to be more efficient in species counts. When considering cost and survey efficiency, the fish resource survey method using underwater cameras was judged to be more effective. The results of this study are expected to be widely used in estimating the population density of fish, which is the core of future fisheries resource surveys.

본 연구에서는 부유토사로 인한 탁도 증가가 어류에게 미치는 영향에 대해 실험실 모의실험을 수행하였다. 국내 강 또는 호소에서 출현 비율이 높은 붕어, 잉어, 송사리를 대상으로 수정란 부화율 평가를 수행한 결과 붕어, 잉어는 4,040 NTU 수준까지 수정란 부화에 미치는 영향이 없었지만, 송사리는 254 NTU 이상의 구간에서 부화율이 저해되는 영향을 보였다. 붕어, 잉어, 송사리 치어의 4일간 노출 결과 생존에 미치는 영향은 없었다. 반면 성장률 결과에서 잉어와 붕어는 7일, 14일, 21일 모두 143 NTU 구간부터 성장저해 영향을 보였다. 송사리는 14일 노출 시 254 NTU, 21일간 노출 시 501 NTU 구간부터 성장저해 영향을 보였다. 따라서 강 또는 호소에서 143 NTU 이상의 탁도가 발생할 경우 붕어, 잉어의 성장을 저해시킬 수 있고, 250 NTU 이상의 탁도는 송사리와 같이 민감 어종의 부화율이 저해될 수 있을 것으로 사료된다.

The biomass of Ulva mats was surveyed in a lower rocky shore of the southern coast of Korea during the 1998-1999 winter. The population selected for the present study was located on the tidal zone ranging from 118 cm to 130 cm below mean sea level (MSL),

DNA damage such as genotoxicity was identified with comet assay, which blood cell of a marine parrot fish (Oplegnathus fasciatus) was exposed to an acidified seawater, lowered pH gradient making of CO2 gas. The gradient of pH were 8.22, 8.03, 7.81, 7.55 with control as HBSS solution with pH 7.4. DNA tail moment of fish blood cell was 0.548 ± 0.071 exposed seawater of pH 8.22 condition, on the other hand, DNA tail moment 1.601 ± 0.197 exposed acidified seawater of pH 7.55 lowest condition. The approximate difference with level of DNA damage was 2.9 times between highest and lowest of pH. DNA damage with decreasing pH was significantly increased with DNA tail moment on blood cell of marine fish (ANOVA, p < 0.001). Ocean acidification, especially inducing the leakage of sequestered CO2 in geological structure is a consequence from the burning of fossil fuels, and long term effects on marine habitats and organisms are not fully investigated. The physiological effects on adult fish species are even less known. This result shown that the potential of dissolved CO2 in seawater was revealed to induce the toxic effect on genotoxicity such as DNA breakage.

Chronic effects such as reproduction and population dynamics with elevated CO2 concentration were evaluated using two representative marine benthic species, copepod (Tisbe sp.) and amphipod (Monocorophium acherusicum) adopting long-term exposure. Juvenile copepod and amphipod individuals were cultivated in the seawater equilibrated with control air (0.395 mmol CO2/air mol) and high CO2 air having 0.998, to 3.03, 10.3, and 30.1 mmol CO2/air mol during 20 and 46 days, respectively. After the exposure period, the number of benthic invertebrate was counted with separate larval and juvenile stage such as naupliar, copepodid and adult for copepod, or neonate and adult for amphipod, respectively. The individual number of both test species at each life-stage was significantly decreased in seawater with 10.3 mmol CO2/air mol or higher. Recently, the technology of marine CO2 sequestration has been developed for the reduction of CO2 emission, which may cause climate change. However, under various scenarios of CO2 leaks during the injection process or sequestrated CO2 in marine geological structure, the potential risk to organism including various invertebrates can be expected to exposure. So the results of this study suggested that the detailed consideration on the adverse effect with marine ecosystem can be prerequisite for the marine CO2 sequestration projects.