西部太平洋における稚魚の研究-I : カツオの後期仔魚
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概要
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1. In 1949-1952, 466 collections were made in the Western Pacific Ocean with larva nets. Ten post-larvae, supposedly of Katsuwonus pelamis with the body length 5.1-9.0mm, were obtained from the sea near Mariana and East Caroline Islands, the Kurosio Current near Japan, and the sea south-east of Okinawa. 2. The transparent specimens were prepared from these post-larvas by the Hollister method. They were identified as Katsuwonus pelamis by morphological observations especially from the following characteristics. The upper jaw was longer than the lower. They had 42 myotomes. There were 2 rows of bony spines on the surface of preoperculum; they consisted of 3 small bony spines on the front row and 7 larger ones on the rear row in the case of the larva with the body length 9.0mm. The head-top, operculum, tip of the lower jaw, and peritoneum of the abdominal sac were pigmented with scattered, small black chromatophores. Th??re were characteristic small black spots on the ventral midline immediately anterior to the caudal peduncle (nearly on the 35th myotome) and on the rear portion of the hypural bone. 3. It was presumed from the appearance of post-larvae and young fish that this fish made spawning and growth in a wide range from the east to the west in tropical and subtropical zones. In the sea near Japan a small number of the post-larvae were obtained from the Kurosio Current. However it was asummed from the state of maturation of the eggs in the ovary that the spawning was made only rarely in the southern sea of Okinawa.
- 公益社団法人 日本水産学会の論文