We studied behaviour pattern of anchovy (Engraulis japonicus) shoal by a method of shoal echo integration and tested species identification by a method of artificial neural network using the acoustic data collected in the East China Sea in March 1994 and in the southern coastal waters of the East Sea of Korea in March 1995. Between areas, frequency distribution of 10 shoal descriptors was different, which showed characteristics of shoal behaviour in size, bathymetric position and acoustic strength. The range and mean of shoal size distribution in length and height was wider and bigger in the southern coastal waters of the East Sea than in the East China Sea. Relative shoal size of China Sea. Fractal dimension of shoal was almost same in both areas. Mean volume reverbration index of shoal was 3 dB higher in the southern coastal waters of the East Sea than in the East China Sea. The depth layer of shoal distribution was related to bottom depth in the southern coastal waters of the East Sea, while it was between near surface and central layer in the East China Sea. Principal component analysis of shoal descriptors showed the correlation between shoal size and acoustic strength which was higher in the southern coastal waters of the East Sea, than in the East China Sea. Correlation was also found among the bathymetric positions of shoal to some degree higher in the southern coastal waters of the East Sea than in the East China Sea. The anchovy shoal of two areas was identified by artificial neural network. The contribution factor index (Cio) of the shoal descriptors between two areas were almost identical feature. The shoal volume reverberation index (Rv) was showed the highest contribution to the species identification, while shoal length and shoal height showed relatively high negative contribution to the species identification.

The authors have investigated three species of Clupeidae such as herring, Korean anchovy and large-eyed herring, belonging to the order Clupeiformes. The fish is also indigenous to some parts of the southern regions of the West Sea. Fishes are the most popular marine products in Korea because of their taste and nutritional value, and Koreans consume them in large quantities. Especially, Korean anchovy and large-eyed herring are widely distributed in the entirety of brackish-water habitats and seawater areas of the West Sea in the Korean Peninsula, as well as in several areas in China. However, in spite of their economic and scientific consequences, a little information currently exist regarding the physiological and ecological levels only of crab species in Korea. During the last two decades, environmental contamination and various environmental disruptions by industries and city sewage, have threatened the coastal fisheries, and then reduction of individual number of this fish is an increasing trend in the 2000s. This study attempt is to elucidate the genetic distances within and between herring, Korean anchovy and large-eyed herring population from the West Sea. Three species of herring (C. pallasii), Korean anchovy (C. nasus) and large-eyed herring (H. zunashi) were obtained in close vicinity to the West Sea in Korea. Three species of fish muscle was collected in sterile tubes, placed on ice immediately, and stored under refrigeration until needed. Genomic DNA was extracted and purified under the conditions described previously (Yoon and Kim, 2004). The degree of variability was calculated by use of the Dice coefficient (F), which is given by the formula: F = 2nab / (na+nb), where nab is the number of bands shared between the samples a and b, na is the total number of bands for sample a and nb is the total number of bands for sample b (Jeffreys and Morton, 1987; Yoke-Kqueen and Radu, 2006). Euclidean genetic distances within-and between-species were also calculated by complete linkage method with the help of the hierarchical dendrogram program Systat version 10. The genomic DNA isolated from herring (C. pallasii), Korean anchovy (C. nasus) and large-eyed herring (H. zunashi) in the West Sea, were amplified several times by PCR reaction. The dendrogram obtained by the seven primers indicates three genetic clusters as shown in Fig. 1. The hierarchical dendrogram indicates three main branches: cluster 1 (PALLASII 01, 02, 03, 04, 06 and 07), cluster 2 (NASUS 08, 09, 10 and 11), and cluster 3 (NASUS 12, 13 and 14, ZUNASHI 15, 16, 17, 18, 19, 20 and 21, PALLASII 05). The genetic distance among the three fish species ranged from 0.018 to 0.318. In three fish population, the shortest genetic distance displaying significant molecular difference was between individual PALLASII no. 03 and PALLASII no. 02 (0.018). Ultimately, individual no. 05 of the PALLASII herring was most distantly related to PALLASII no. 06 (genetic distance = 0.318). From what has been said above, the potential of this PCR analysis to identify diagnostic markers for the identification of three fish populations has been demonstrated. Generally speaking, this PCR analysis method has been applied to identify specific markers particular to line, species and geographical population, as well as genetic diversity/polymorphism in diverse species of organisms (McCormack et al. 2000; Yoon and Kim 2003).

웅어 Coilia nasus의 생식소중량지수(GSI), 비만도지수, 난소 발달, 군성숙도, 포란수를 2007년 1월부터 2007년 12월 까지 조직학적 관찰 및 형태 측정 분석에 의해 조사하였다. GSI와 비만도지수는 2월에 증가하기 시작하여 난소가 성숙해지는 6월에 최대에 이르며, 그 후 산란이 일어나는 7월에 급격히 감소하였다. 그러므로 GSI와 비만도지수의 월별 변화는 난소의 성숙 및 산란과 밀접한 관련을 갖는다. 암컷의 난소 발달 단계는 연속적인