The present report deals with age and growth estimations based on ring marks on scales for Parapristipoma trilineatum (Pomadasyidae).Materials used in this study consist of 1170 individuals ranging from 49 to 355.7 mm in fork length.They were taken by set net, hook and line and gill net from coastal areas of Kumano-nada during the period from March, 1978 to April, 1979.A number of scales were taken from a row beneath the lateral line of the left side of the fish just posterior to the tip of the pectoral fin, and a scale of regular shape among them was selected and used for measurement. The results obtained are summarized as follows: 1) The relationships between the fork length (L in mm) and total length (TL in mm), standard length (SL in mm) and body weight (W in g) were shown by the following equations: logTL=1.01logL+0.019 logSL=1.02logL-0.106 logW=3.25logL-5.388 2) Ring marks on scales were formed twice in a year, both in summer and in winter.Of these two ring marks, the ring mark formed in the period from January to February was used for the estimation of age and growth of the fish.The other ring was considered to be the spawning mark, because the ring mark was inconspicuous in immature specimens and the time of ring formation in mature specimens corresponded to the spawning season from June to July. 3) An anti-Lee phenomenon was observed in the mean value of each ring radius.-Phenomenon may be attributable to the growth of old tissue of scale. 4) The relationship between the fork length and scale radius (R in mm) was shown by the equation log L=0.881 log R+1.842.The fork lengths at the time of ring formation were calculated using the above equation. 5) The results obtained from the Walford's growth transformation method indicated that the plots of ln+1 against ln fall on a straight line, given by the equation ln+i= 0.779ln+78.3. 6) Since the time difference between spawning and ring formation on scales was about 0.5 year, the Bertalanffy's growth equation for full age (t) in fork length (Lt) and weight (Wt) was given as follows: Lt=355 (1-e-0.249 (t+0.731) ) Wt=794 (1-e-0.249 (t+0.731) ) 3.25 7) There was no sex-associated difference in growth.
The effect of light on leucophores of an isolated scale from the wild-type medaka Oryzias latipes was investigated.Leucophores were directly exposed beneath a light source of 150 or 300 lux.Fully dispersed leucophores in a M/7.5 KC1 solution and fully aggregated leucophores in a physiological saline solution did not show any noticeable response under illumination except for a very active Brownian movement of leucosomes.On the other hand, leucophores aggregated under the effects of both a stimulant and an inhibitor of the adrenergic β-receptor, dispersed under illumination and this response was found to be reversible.From the above findings, it was concluded that light directly induces leucosome dispersion in leucophores without any mediation of the adrenergic β-receptor.
A mature female of the bramid fish, Taract-clnhrs longipinnis(Lowe)was caught by tuna long line from the T.V.Nagasaki-maru, Nagasaki University, at around 9°31'S, 118°50'E in the eastern Indian Ocean on August 8, 1966.The fish was 78 cm TL, 61 cm SL, about 10 kg BW, and the viscera weight was about 1.5 kg.The abdomen of the fish was scarcely swollen, but mature translucent eggs of a light yellow tint were squeezed from the fish.The eggs were spherical in shape and separately pelagic in the sea water at a temperature of about 26°C and a salinity of about 34.5‰.The eggs preserved in 5%formalin are 1.2mm in diameter with a conspicuous perivitelline space, a homogeneous 0.9 mm yolk, and a 0.3 mm oil globule. The mature ovaries of the fish were small and about 90 g in weight, and the GSI was less than I.The ovaries contained about seventy thousand mature eggs. It was considered that the mature female fish was hooked at a depth of 80-150 m.The ocea-nographic observation data suggest that the fish was living in the mid-layer of the ocean at tem-peratures of 11.10-.25.84°C and at salinities of 34.54-34.76‰.