In order to establish the basic data for the growth of fish in the aquaculture industry, the behavior analysis of rockfish (Sebastes inermis) depending on the temperature and LED lights was conducted. In this study, water temperatures were set from 3℃ to 30℃ were used. One red light (wave length: 622 nm; light power: 811 mW) and one green lights (wave length: 518 nm; light power: 648 mW) were used. Behavior of the rockfish was expressed as average moving distance (AMD) for 1 minutes and a rate of movement. The mean AMD depending on the temperature was 1.0 m and the mean rates of movement was 50%. The mean AMD were 1.5 m, 1.9 m and 0.7 m in the red LED light, green LED light and control condition respectively. The mean rates of movement were 54%, 65% and 45% in the red LED light, green LED light and control condition respectively.

In order to establish the basic data for the active use of the LED light source in the aquaculture industry, the experiment about the behavior of rockfish (Sebastes inermis) corresponding to the LED light was conducted by image analysis. LED lights for the experiment were one red light (wave length: 622 nm; light power: 811 mW) and two green lights (wave length: 518 nm; light power: 648 mW, wave length: 518 nm; light power: 810 mW). Behavior of the rockfish was analyzed using a moving distance (MD5) for 5 minutes where MD5s during the period of feeding were 20.0 m, 19.6 m, 16.3 m and 20.5 m in the ch1, ch2, ch3 and ch4. At the sunrise, mean MD5 of the entire channel about right before and right after were 6.3 m and 8.2 m. At the sunrise, mean MD5s of the entire channel about right before and right after were 13.6 m and 12.0 m. In the ch1, ch2 and ch3, mean MD5s during the period of 24 hours were 13.2 m, 9.6 m and 6.8 m at experiment 1and 5.2 m, 3.8 m and 2.9 m in the experiment 2.

Experiments designed to measure the effect of LED (light–emitting diode) light wavelength on the growth of fingerling rockfishes (Sebastes inermis) were conducted. Fingerling rockfishes (average body weight of individual: 1.13g) were divided into two groups by wavelength of the LED light [light power: 1,620 mW; wavelength: 518 nm (green color), 622 nm (red color)]. Triplicate groups of 180 individuals were reared over 7 weeks. Lighting duration was 14 hours from 06:00 to 20:00. A water tank exposed on the natural light in a room through the windows was used as a control. At results of the first experiment [initial average body weight (BW) of individual: 1.13 g; standard deviation (SD): 0.13 g], the final individual BW exposed on the green color was increased 0.39 g than the red color, and decreased 0.12 g than the natural light in the room. At results of the second (initial individual BW: 5.07 g; SD: 0.70 g) and the third experiment (initial individual BW: 10.67 g; SD: 0.67 g), the final individual BW exposed on the green color was increased 1.07 g and 2.55 g than the red color, respectively, and increased 0.57 g and 0.84 g than the natural light, respectively. The relative growth rate of the green color was higher about 8% significantly (p<0.05) than the natural light. In the case of the red color the relative growth rate was lower significantly (p<0.05) than the natural light.

The characteristics of aquatic light fields are generally reflected in the visual systems of fishes inhabiting them. Therefore, research on light sensitivity of fish is useful to explain the correlation between the visual function and habitat, behavior and distribution of fish. Rockfish is an important species in coastal ecology and also one of the main species for culturing in Korea. To make a contribution on the maintenance of the fish resources and understanding the ecology of the rockfish, the visual spectral sensitivities of the dark-adapted rockfishes were measured in the range of visible light (405~660 nm) using a light source of light-emitting diodes (LEDs). In order to assess electrophysiological response of the fish, the ERGs (electroretinograms) of the dark-adapted rockfishes were recorded on a data logger (12 bits) and a laptop computer. Juvenile (n=5; weight: 20.3±5.2 g; total length: 10.3±0.7 cm) and adult (n=5; weight: 87.8±21.8 g; total length: 18.1±1.3 cm) rockfishes were used in experiment. The visual threshold of juvenile and adult rockfish were 11.66 (log quanta/cm2/s) and 11.81 (log quanta/cm²/s) in 574 nm, respectively. The peak wavelength of the spectral sensitivity in the dark-adapted juvenile and adult rockfish was commonly 551 nm (series of green color). Collectively, these results demonstrate that the rockfish has suitable visual capabilities for inhabiting coastal water in Korea.

Morphological properties of dark banded rockfish (Sebastes inermis) were analysed to investigate its acoustic scattering characteristics. Total of 18 live samples was prepared for X-ray photos and collected morphological coordinates of their body and swim bladder shapes. Kirchhoff-ray mode model was used to calculate acoustic scattering pattern for broad-band frequency range. Inclination of swim bladder ranged from 17 to 30 and the averaged value was about 25.2° (S.D.(standard deviation)=3.15). There were no any tendency of increase or decrease in volume and area ratio of swim bladder to fish body and ranged from 2.2 % to 4.43 % and 14.85 % to 21.31 %, respectively. The averaged value of volume and area ratio was 3.13 % (S.D.=0.52) and 17.6 % (S.D.=1.5). b20 values were –69.01 for 38 kHz, –69.83 for 70 kHz, –70.17 for 120 kHz and -70.93 for 200 kHz, recpectively. Broadband acoustic patterns of dark banded rockfish for 20 ~ 200 kHz were similar among samples and they reflected size and morphological properties of fish species.

Characteristics of age and growth of the black rockfish, Sebastes inermis sampled in the Jeonnam Marine Ranching Area (JMRA) around Geumo Islands south of Yeosu were investigated using 642 otoliths from March 2009 to February 2010. The opaque zone was formed in September once a year and hence it was used as an annulus. The parturient period was December to January, and therefore the duration from fertilization to the complete formation of the opaque zone was nineteen months. From the parameters calculated using the average length when the year ring was formed, growth of S. inermis were expressed by von Bertalanffy growth equation as Lt=23.267 (1-e-0.4406(t+1.1971)) for females and Lt=22.030 (1-e-0.5312(t+0.6834)) for males when is total length in age t. Through the growth equations, the maximum length was determined as 23.27cm for females and 22.03cm for males and the growth factor as 0.4406/yr and 0.5312/yr, respectively. Finally, the growth of female S. inermis is larger than the one of male S. inermis.

어류의 성 결정(sex determination)은 유전적인 요인 외에 부가적으로 서식 환경 요인(수온, pH 등)에 의해서도 영향을 받으며, 이 중 수온에 의한 성 결정(temperature dependant sex determination, TSD)은 많은 어류에서 보고된 바 있다(Noh et al., 1997; Baroiller & D'Cotta, 2001). 볼락은 방류 목적으로 인공종묘생산이 활발히 이루어지고 있는 어종으로서, 생산 기간의 단축을 위해 산출 자어시기부터 자연 해수온 보다 높게 유지하면서 사육하고 있다. 이에 따라 방류 후 생태계 내 성비의 불균형에 따른 우려가 제기되고 있어, 방류 목적으로 인공종묘 생산되고 있는 볼락의 성비를 조사하기 위하여 이 연구를 수행하였다. 2002년부터 2006년까지 경상남도에 소재한 지자체 및 민간 종묘배양장에서 인공 생산한 후 방류 전 해상 가두리에서 중간육성 중인 3～7개월령의 볼락을 대상으로 생식소를 적출한 후 조직학적 분석 또는 squash method에 의해 암수를 판정하였다. 그리고 방류 해역에서 성비 조사를 위해 통발 등으로 볼락을 수집하여 앞서와 동일한 방법으로 암수를 판정하였다. 모든 성비 data는 χ2 test를 실시하여 볼락의 자연 성비(♀1:♂1, Chang et al., 1995)와 비교하였다. 2002년부터 2006년까지 4곳의 종묘배양장에서 인공 생산한 볼락 종묘의 암컷율은 45.7～66.0%로서, 암컷율이 높았다. χ2 test 결과 모두 15회 중 6회에서 자연성비와 유의한 차이가 있었다. 분석한 모든 볼락(1,728마리)의 성비는 1.38♀: 1.00♂이었다. 방류한 해역에 서식하는 볼락의 암컷율은 52.3～55.8%였으나 χ2 test 결과 자연 성비와 유의한 차이는 없었다. 자원 조성을 위한 방류용 종묘는 생태계에서 성숙 및 번식에 의한 제2차 생산력이 매우 중요하다. 그러나 방류 집단의 성비가 자연 성비와 달리 어느 한쪽으로 치우치게 되면, 암수간 성비 불균형으로 인해 정상적인 번식이 이루어지지 않는다. 특히, 유전적인 성과 생리적인 성이 서로 다른 경우에는 자연 수계에서 유전적인 교란이 발생하게 된다. 예를 들면 암컷동형접합성(female homogamety, XX-♀:XY-♂) 어종에서 인공종묘생산 시 고수온에 의해 암컷이 100% 출현하였을 경우 이중 50%는 유전적으로 수컷(XY)이면서 생리적으로 암컷으로 간주할 수 있다. 이 경우 자연 수계에서 다음 세대 자손의 성비는 정상적인 1:1 성비에 어긋나게 되며, 이러한 과정이 여러차례 반복되면 자연 수계에서의 성비는 수컷 편중이 되어 자원 감소를 초래하게 된다. 따라서 볼락을 포함한 어류 방류 시에는 성비조사가 선행되어야 할 것으로 판단된다.

어류의 시각 구조와 시각 기능 연구에 있어서 행동적 요인이나 환경적 요인의 중요성은 시각생태학에서 매우 중요하게 다루어지고 있으며, 볼락, Sebastes inermis에 관하여는 아직까지 초기 눈의 성장 및 발달에 관한 발생생물학적 연구가 이루어진 바가 없음을 고려하여 이에 대한 연구를 수행하였다. 볼락의 전장, 두장, 두고, 눈의 직경과 수정체 직경은 산출 직후부터 산출 후 60일까지의 단계에서 양성의 상관관계(positive allometry)를