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Volume 25, Issue 2
Displaying 1-10 of 10 articles from this issue
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Takakazu Ozawa1978 Volume 25 Issue 2 Pages 79-88
Published: September 15, 1978
Released on J-STAGE: February 23, 2011
JOURNAL FREE ACCESSNotosudid larvae of two genera and five species, Ahliesaurus brevis, Scopelosaurus smithii, S.mauli, S.harryi and S.“sp.II”of Bertelsen et al. (1976), were recorded from the ocean of southern Japan.Japanese names are given to them, together with tropical Indo-Pacific species S.hoedti and except for S.“sp.II”whose species name is not erected due to the absence of metamorphosed specimens.The descriptions confirm those given by Bertelsen et al. (1976), providing some additional information, especially concerning the youngest stages.A marked change in larval pigmentation during notochord inflection is shown.A key to the notosudid larvae recorded from the waters of Japan is provided.View full abstractDownload PDF (1428K) -
Kouichi Kawaguchi, Basil G.Nafpaktitis1978 Volume 25 Issue 2 Pages 89-91
Published: September 15, 1978
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSA new lanternfish, Diaphus kuroshio, is described.This species is readily distinguished from its close relatives, D.aliciae, D.mollis and D.fulgens, in having higher total gill-raker counts of 22-25 (17?`20 in its relatives).D.kuroshio is abundant in the Kuroshio Waters off Japan, extending its distribution to the adjacent warm waters.View full abstractDownload PDF (2685K) -
Harumi Sakai, Fujio Yasuda1978 Volume 25 Issue 2 Pages 92-100
Published: September 15, 1978
Released on J-STAGE: July 04, 2011
JOURNAL FREE ACCESSThe development of eggs and larvae of the large-dark type B and that of larvae of the cross-band type of Rhinogobius brunneus were observed.Newly hatched larvae of both types were different in total length and also in the position of the anus.Some variations in the pigmentation of melanophores were observed in the larval development of the cross-band type.The larvae of the large-dark type B reached the juvenile stage and wholly abandoned their planktonic mode of life in 32 days after hatching at 21.0-27.5°C.Those of the cross-band type did so in 36 days after hatching at 19.9-22.8°C.View full abstractDownload PDF (2817K) -
Jack T.Moyer, Akinobu Nakazono1978 Volume 25 Issue 2 Pages 101-106
Published: September 15, 1978
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSPopulation structure and gonad histology were investigated in six species of the anemonefish genus Amphiprion occurring in Japanese waters.Species investigated included Amphiprion frenatus, A.clarkii, A.polymnus, A.perideraion, A.sandracinos, and A.ocellaris.All six species occur around their host anemones in small social groups that include a monogamous pair of sexually functional adults and from zero to three sexually non-functional subadults and juveniles.In all species, the single female in a particular social group is larger than her mate, considerably so in some species.Histological examination of gonads indicated that all individuals of all six species are ambosexual as juveniles.At first only testicular tissues mature.Under certain conditions these may later degenerate and the gonads change to ovaries.Field studies supported histological results.A strict dominance hierarchy exists in each social group.The largest fish is always the single female, and the second largest fish is invariably a functional male.Only the two largest fish are sexually functional.Two functional males of A.clarkii under study in the field changed to females after the loss of their previous mates.The six Amphiprion species in Japan present examples of socially controlled protandrous sex inversion.View full abstractDownload PDF (4931K) -
Akira Chiba, Yoshiharu Honma, W.J.R. Lanzing1978 Volume 25 Issue 2 Pages 107-114
Published: September 15, 1978
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThe present paper describes histological and cytological changes in the hypophysis and gonads of juvenile Tilapia (=Sarotherodon) mossambica exposed to the antigonadotropic drug methallibure (I.C.I.33, 828) by means of daily doses of 1 or 2 p.p.m.for 7 weeks.This treatment markedly prevented the process of maturation of gametogenesis in both sexes of fish, in addition to retardation of differentiation of interstitial cells and epithelial lining of the efferent duct of the testis.The polygonal basophils (gonadotrophs) located in the ventral portion of the proximal pars distalis of the hypophysis underwent a marked decrease in the cell size as well as in the amount of cytoplasmic granules of glycoprotein -aceous nature.Atrophy was manifested by the acidophils (somatotrophs) of the proximal pars distalis and the PAS positive cells of the pars intermedia, whereas no appreciable change was recognized in other cell types of the adenohypophysis.View full abstractDownload PDF (9191K) -
Akira Goto1978 Volume 25 Issue 2 Pages 115-123
Published: September 15, 1978
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSMonthly changes in the ovaries of the small-egg type (SE) and the large-egg type (LE) of Cottus nozawae were compared biometorically and histologically.The relative weight of ovaries (GSI) scarcely differed between two types for six months after spawning in May to November.The GSI values were slightly higher in the SE than in the LE during the period of December to January.In the spawning period (April), however, the relation was inverse, because of the rapid increase in the ovary weight of the LE since February.The diameter of ovarian eggs in the spawning period was significantly larger in LE than in SE.From a comparison of the monthly changes of egg sizes between the two types, it is definite that the difference was a result mainly of the rapid increase of egg sizes in the LE after March. Vitellogenesis in the LE became active in early August, and in mid September for SE.The beginning of formation of yolk globules also differed between LE and SE.
Thus, there are two types of C.nozawae, each with unique modes of ovarian development.The mode in the LE is not simply an extention of development in the SE.View full abstractDownload PDF (10105K) -
Katsumi Suzuki, Koji Kobayashi, Syozo Hioki, Takashi Sakamoto1978 Volume 25 Issue 2 Pages 124-140
Published: September 15, 1978
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (8537K) -
Kaneyoshi Yamashita1978 Volume 25 Issue 2 Pages 141-148
Published: September 15, 1978
Released on J-STAGE: July 04, 2011
JOURNAL FREE ACCESSDownload PDF (10249K) -
Kunio Amaoka, Kazuhiro Nakaya, Koji Abe1978 Volume 25 Issue 2 Pages 149-152
Published: September 15, 1978
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESS -
Wataru Takada, Teruya Uyeno1978 Volume 25 Issue 2 Pages 153-154
Published: September 15, 1978
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (2290K)
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