Vertical Distribution and Biology of Micronektonic Fishes from Meso- and Upper Bathypelagic Layers in the Rockall Trough and Porcupine Seabight, Eastern North Atlantic Ocean

북대서양 Rockall Trough과 Porcupine Seabight에서의 중심층 및 상부점심층성 소형어류의 수직분포와 생물학적 특성

Eleven of 52 species were relatively abundant in the mesopelagic and upper bathypelagic layers in the Rockall Trough and Porcupine Seabight. The fish belonging to the families Gonostomatidae, Myctophidae and Sternoptychidae were the most abundant. During the daytime most members of these three family groups occurred in the depth of 300-900m. Over this depth range gonostomatids and sternoptychids were almost mutually exclusive while gonostom$\grave{a}$tids and myctophids showed much greater overlap, as did myctophids and sternoptychids. During the night the distribution of these three families were relatively well separated, myctophids occurring in the surface 100m, sternoptychids at 200-500m and gonostomatids at 500-900m. Generally vertical pattern in the number of species in both areas was similar through day and night with the highest number occurring at 500-900m. The numerical abundance in the epipelagic layer was greater at night than during the daytime, while it was greater in daytime in the upper mesopelagic layer. There was no great diel change in the lower mesopelagic layer. Most of diel migrators in the upper layers of waters at night appear to be mainly from the upper mesopelagic layer. In some species larger individuals tend to occur in the deeper water than smaller ones, suggesting habital segregation with size.

북동대서양의 Rockall Trough과 Porcupine Seabight에서 중심층 및 상부점심층성 어류 마이크로넥톤 52종이 채집 동정되었다. 이들 두 해역에서의 종조성과 출현양상은 비슷하였는데, 그중 앨퉁이과, 샛비늘치과 및 Sternoptychidae에 속하는 어류가 우점하였다. 이들 3과에 속하는 생물은 주간에는 서식심도에 중복되는 경향이 많으나, 야간에는 현저한 서식지 분할현상이 보였다. 양해역에 있어서 출현종수는 500-900m에서 많고, 개체수는 야간에는 표층 (10-200m)에, 주간에는 상부중심층 (200-500m)에 많았다. 하부중심층(500-900m) 및 그보다 깊은 곳 (900-190m)에서는 주야수직이동이 별로 없었다. 몇개의 주요종에 대해서는 성비, 성숙, 수심별 서식개체크기 등이 논의되었다.