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The growth and morphological development of larval and juvenileEpinephelus bruneus were examined in a hatchery-reared series. Average body length (BL) of newly-hatched larvae was 1.99 mm, the larvae growing to an average of 3.96 mm by day 10, 6.97 mm by day 20, 12.8 mm by day 30, 22.1 mm by day 40 and 24.7 mm by day 45 after hatching. Newly-hatched larvae(More)
The gonadal sex differentiation in red sea bream, Pagrus major, which is one of the most important species for aquaculture in Japan, was revealed histologically. The suitable conditions for induction of all-male groups in the fish were investigated, and functional males were induced by the conditions of oral administration of 17α-methyltestosterone. The sex(More)
Transgenic technology has been widely applied to a variety of freshwater fish species. However there are few reports on the use of this technology in commercially important marine species. In this study, the construction of expression vectors containing the β-actin promoter region for use in the red sea bream Pagrus major, a species of considerable(More)
Human melanocytes respond to UV irradiation by increasing the synthesis of melanin. While much is now understood of the pathways governing this process and the nature of the melanin synthesized, little is known of melanins produced by lower vertebrates and their capacity to respond to UV. Here we report that a fish, red seabream, can undergo 'suntanning'.(More)
In bluefin tuna aquaculture, collision of juveniles with the tank or net walls is a major cause of high mortality. This problem may be related to color sensibility of the visual mechanisms of this species. As a first step in understanding of color vision of Pacific bluefin tuna Thunnus orientalis, we applied a molecular technique and histology to study cone(More)
We studied the profiles of 3,5,3'-l-triiodothyronine (T3), thyroxine (T4), and thyroid hormone receptors (TRs) in Pacific bluefin tuna (Thunnus orientalis) during embryonic and post-embryonic development. Both T3 and T4 were detected in embryos just before hatching, and it was found that the levels of both were increased in postflexion fish. The thyroid(More)
Bluefin tuna maintain a higher body temperature than ambient sea water. Body heat is derived mainly from metabolic heat to elevate and maintain regional body temperature that is higher than the ambient, while heat loss is caused by heat transfer throughout the whole body surface and gills. Retention of high body temperature is thought to differ at each(More)
Stable reproduction is essential for supplying artificially hatched fish to tuna aquaculture. We observed testes maturation in reared Pacific bluefin tuna (PBT) Thunnus orientalis at 2+ years of age. The incidence of males with mature testes was 25.0%, and 40% of the males had developing testes that contain spermatozoa, while oocytes of the same aged(More)
The ontogenetic changes in the growth potential of larval and juvenile laboratoryreared Pacific bluefin tuna were examined based on RNA-DNA and protein-DNA ratios. Experimental fish were reared at the Ohshima Experiment Station of Kinki University Fisheries Laboratory in August 2002. Samples were taken from 13 to 35 days after hatching (DAH). Metamorphosis(More)
Chromatophoromas in the croaker nibe, Nibea mitsukurii, are common neoplasms in feral fish which inhabit the shallow water in a unique geographic distribution along the Pacific coast of Japan. We undertook surveys of the epizootiology of tumor-bearing fish at 25 sites. The highest tumor incidence occurred at the station near the mouth of the Kumano river(More)