アリューシャン水域に於けるギンダラの仔稚魚

抄録

Some specimens of the sablefish, Anaplopoma fimbria (P_ALLAS), were collected by a larva net, from aboard the training ship “Oshoro Maru” of Hokkaido University, in 1955 and 1956. The results obtained from observations on these samples revealed the following facts.
1. Sixteen specimens of larvae and youngs of the sablefish were collected from nine stations of the sea off the Aleutian Islands.
2. These specimens were collected from July 8th to August 13 th, in two successive years. They were 11.3-30.2mm in total length. The minimum specimen of 11.3mm was collected on-July 8th, and the maximum one of 30.2mm on August 13 th.
3. The rate of increase of head is about 0.3mm to 1mm in total length. Head length is about 24% of total length in the specimen of about 20mm overall length. Anus takes the place nearly in the middle of body, and the increase of the distance from the tip of snout to anus is about 0.5mm to 1mm in total length.
4. The minimum specimen of 11.3mm in total length has larval fin form, but in the speci-men of about 18mm in total length, fin rays have developed in the second dorsal and anal. At the stage of ca. 22mm in total length, fin rays are developing in the first dorsal fin, and number of fin rays of the second dorsal, anal and pectoral fins have reached their full number. The ventral fin developed when specimen reached about 18mm, rays were ascertained at ca 25mm, and their full number was attained at about 30mm in total length, respectively. Fin rays of the first dorsal reach the full number at maximal total length of 30.2mm, but they are of unfinished form.
5. Body color is blackish-brown, and becomes darker as the specimen grows older. Espe-cially, the latter half of pectoral fin turns jet-black; this is a distinguishing trait.