KOYA Yasunori

J-GLOBAL         Last updated: Jan 7, 2020 at 14:06
KOYA Yasunori
Gifu University
Faculty of Education

Research Areas


Academic & Professional Experience

助教授, Gifu University Faculty of Education, 理科教育(生物学)


Graduate School, Division of Fisheries, Hokkaido University
Faculty of Fisheries, Hokkaido University

Published Papers

Genetic population structure of eight-barbel loach, Lefua echigonia, in the Ise Bay region, a single paleo-river basin in central Honshu, Japan
Gen Ito, Yasunori Koya, Shigeru Kitanishi, Tokumasa Horiike, Takahiko Mukai
Ichthyological Research   55 411-416   2019   [Refereed]
Hypertrophy and polysaccharide production in the kidney associated with sexual maturation of male small-egged Kajica, Cottus pollux SE
KOYA Yasunori, FUJII Ryoji, YAMBE Hidenobu, TAHARA Daisuke
Ichthyological Research   63 260-266   2016   [Refereed]
KOIKE Yukari,, KOYA Yasunori
Japanese Journal of Ichthyology   61(1) 4-25   2014   [Refereed]
Host selection and the evolution of ovipositor morphology in nine sympatric species of sculpins that deposit their eggs into tunicates or sponges
AWATA Satoshi, SASAKI Haruka, GOTO Tomohito, KOYA Yasunori, TAKESHIMA Hirohiko, YAMAZAKI Aya, MUNEHARA Hiroyuki
Marine Biology   166 59-72   2019   [Refereed]


Yasunori Koya, Takako Itazu, Mutsumi Inoue
Ichthyological Research   43(3) 241-248
To clarify the annual reproductive cycle of wild female mosquitofish, Gambusia affinis, in Mie Prefecture, central Japan, changes in ovarian histology were investigated. Female mosquitofish kept in aquaria under constant temperature (25°C) and pho...
Yasunori Koya, Marta Muñoz
Ichthyological Research   54 221-230   Aug 2007
The reproductive modes of the Scorpaenidae are extremely varied: oviparity, viviparity, and even spawning of internally fertilized eggs or embryos (zygoparity or embryoparity), as in Helicolenus, are known. The ovarian structure of this family is ...
H. Munehara, Y. Koya, K. Takano
Journal of Fish Biology   45 1105-1111
Takahiro Matsubara, Yasunori Koya, Yasunori Koya
The Journal of Experimental Zoolgy   278 189-200
Proteolytic degradation of three classes of vitellogenin-derived yolk proteins (lipovitellin, phosvitin, and β-component) was quantitatively examined during oocyte maturation in barfin flounder, Verasper moseri, a marine teleost which spawns pelag...
Say Sawaguchi, Y. Koya, T. Matsubara
Fish Physiology and Biochemistry   28 363-364
Three distinct forms of vitellogenin (Vg), 600 kDa VgA and VgB and 400 kDa Vg, were discovered biochemically in estrogen treated female plasma. By sequencing of the three Vg DNAs, the VgA and VgB were recognized as complete Vgs having all yolk pro...
Yasunori Koya, Mutsumi Inoue, Terumasa Naruse, Sayumi Sawaguchi
Fisheries Science   66 63-70
The present study investigates the dynamics of oocyte and embryonic development between two successive parturitions (about 22-day interval) under 16 Light:8 Dark photoperiod at 25°C, in order to develop criteria for the ovarian cycle in the vivipa...
Yasunori Koya, Hiroyuki Munehara, Kazunori Takano, Hiroya Takahashi
Comparative Biochemistry and Physiology -- Part A: Physiology   106 25-29   Jan 1993
1. 1. The motility of spermatozoa in several marine sculpins, which exhibit a special reproductive manner of the internal gametic association, was measured in various artificial solutions, ovarian fluid and seminal plasma. 2. 2. In the elkhorn scu...
Yasunori Koya, Sanae Ishikawa, Sayumi Sawaguchi
Japanese Journal of Ichthyology   51 43-50
Mosquitofish, Gambusia affinis, repeat parturition at constant intervals under constant temperature and photoperiod. Although the intervals change with rearing condition, it is unclear whether or not environmental factors affect the process from v...
Y. Koya, S. Sawaguchi, K. Shimizu, A. Shimizu
Fish Physiology and Biochemistry   28 349-350
We examined short-term changes in neuroendocrine function during the onset of vitellogenesis by introducing female mosquitofish into a warm environment. Activation of FSH cells occurred prior to vitellogenesis, which was characterized by the produ...
Yasunori Koya, Eriko Kamiya
Journal of Experimental Zoology   286 204-211
To clarify the environmental factors regulating the annual reproductive cycle of the female mosquitofish, Gambusia affinis, a viviparous teleost, histological changes of the ovary in natural population, and laboratory experiments were examined. Th...
Hiroyuki Munehara, Yasunori Koya, Youichi Hayakawa, Kazunori Takano
Journal of Experimental Marine Biology and Ecology   211 279-289
Conditions for the initiation of fertilization and the initial fertilization process were investigated using histological observations of eggs of Hemitripterus villosus (Pallas), an oviparous fish that undergoes internal insemination. Eggs obtaine...
Tomomi Saito, Yasunori Koya
Zoological Science   18(4) 567-576
Development of the gonads and embryo in the deep-sea sponge-associated shrimp, Spongicola japonica Kubo, was observed based on field samples collected from July 1993 to June 2000. Histological observation of gonads revealed that the gonadal maturi...
Marta Muñoz, Yasunori Koya, Margarida Casadevall
Journal of Experimental Zoology   292 156-164
The bluemouth rockfish, Helicolenus dactylopterus dactylopterus (De la Roche, 1809), is a zygoparous species with internal fertilization. The male urogenital papilla acts as the copulating organ, and the females retain the spermatozoa in their ova...
Yasunori Koya, Ryoji Fujii, Hidenobu Yambe, Daisuke Tahara
Ichthyological Research   
© 2015 The Ichthyological Society of Japan Although renal hypertrophy during the reproductive period has been reported previously in species of Cottus, the function of the kidney in reproduction remains unknown. In order to clarify the role of the...
Yasunori Koya, Ryoji Fujii, Hidenobu Yambe, Daisuke Tahara
Ichthyological Research   63 59-67   Jan 2016
© 2015, The Ichthyological Society of Japan. We found that male small-egged Kajika, Cottuspollux SE sensu Yokoyama and Goto (2005), retained a large volume of urine (approximately, 1 % body weight) in their urinary bladder while nesting under spaw...
Yasunori Koya, Hiroyuki Munehara, Kazunori Takano
Journal of Morphology   233(2) 153-163
The morphology of female sperm storage during the spawning period and the morphology of sperm degradation after the spawning period were investigated by electron microscopy in a copulating teleost, Alcichthys alcicornis. The spermatozoa were maint...
Yasunori Koya, Hiroyuki Munehara, Kazunori Takano
Journal of Experimental Zoology   292 145-155
Elkhorn sculpin, Alcichthys alcicornis, is a marine teleost with a unique reproductive mode called "internal gametic association," in which sperm introduced into the ovary by copulation enter the micropylar canal of ovulated eggs in the ovarian ca...
Hiroyuki Munehara, Kazunori Takano, Yasunori Koya
Japanese Journal of Ichthyology   37 391-394
In the copulating cottid species, Blepsias cirrhosus, the point at which fertilization occurred was determined experimentally. Ovulated eggs were obtained directly from the ovary of impregnated females. Eggs maintained in ovarian fluid did not sho...
Copulation in Marine Sculpting
Animals and Zoos   46(7) 12   1994
Internal gametic association and external fertilization in the elkhorn sculpin, ┣DBAlcichthys alcicornis(/)-┫DB
Copeia   1989(3) 673   1989
Hiroyuki Munehara, Kazunori Takano, Yasunori Koya
Japanese Journal of Ichthyology   37(4) 391-394   1991
Ultrastructural observations on sperm penetration in the egg of elkhorn sculpin, ┣DBAlcichthys alcicornis(/)-┫DB, showing internal gametic association
Zoological Science   10(1) 93   1993
The reproductive cycle of female ┣DBZoarces elongatus(/)-┫DB, a viviparous teleost
Bulletin of the Hokkaido National Fisheries Research Institute   (57) 9   1993
Testicular development and sperm morphology in the viviparous teleost, ┣DBZoarces elongatus(/)-┫DB
Bulletin of the Hokkaido National Fisheries Research Institute   (57) 21   1993
Yasunori Koya, Hiroyuki Munehara, Kazunori Takano
Japanese Journal of Ichthyology   40(2) 199-208   1993
Effects of extracellular environments on the motility of spermatozoa in several marine scullions with internal gametic association
Comparative Biochemistry and Physiology   106A(1) 25   1993
Yasunori Koya, Hiroyuki Munehara, Kazunori Takano
Japanese Journal of Ichthyology   41(1) 39-45   1994
Testicular development of male ┣DBSebastolobus macrochir(/)-┫DB in the Pacific coast of southeastern Hokkaido
Bulletin of the Hokkaido National Fisheries Research Institute   (58) 1   1994
Yasunori Koya, Toshitaka Ikeuchi, Takahiro Matsubara, Shinji Adachi, Kohei Yamauchi
Japanese Journal of Ichthyology   41(3) 338-342   1994
Annual changes in fine structure of the inner epithelial lining of the ovary of a marine sculpin, ┣DBAlcichthys alcicornis(/)-┫DB(Teleostei : Scorpaeniformes), with internal gametic association
Journal of Morphology   223(1) 85   1994
Ultrastructural observation on the inner ovarian epithelia of kichijirockfish Sebastolobus macrochir with special reference to the production of gelatinous material surrounding the eggs.
Bulletin of Hokkaido National Fisheries Research Institute   (59) 1-17   1995
Yasunori Koya, Hiroyuki Munehara, Kazunori Takano
Japanese Journal of Icthyology   42(1) 45-52   1995
Reproductive cycle and embryonic growth during gestation of the viviparous teleost, Zoarces elongatus.
Proceedings of the Fifth International Symposium on the Reproductive Physiology of Fish   237   1995
Proteolytic cleavage of yolk proteins during oocyte maturation in barfin flounder.
Proceedings of the Fifth International Symposium on the Reproductive Physiology of Fish   372   1995
Fish fauna of the Ijira River, branch of the Nagaragawa River, Gifu Prefecture
Science Reports of the Faculty of Education Gifu University(Natural Science)   22(1) 7-12   1997
Obsevation method for mating and spawing behavior in medaka fish
Science Report of the Faculty of Education GIfu University (Natural Science)   26, 19-22    2002
Sperm stprage and motilify in the ovary of the marine sculpin Alcichtys alcicornis(Taleostei:Scorpaemformes),with internal gametic association
Jounal of Experimental Zoology   292,145-155    2002
Annual reproductive cycle of black rockfish Sebastes schlegeli , in captivity
Fisheries Science   69, 908–921    2003
Fish Physiology and Biochemistry   28, 349-350    2004

Books etc

Fish Reproduction
Yasunori Koya (Part:Contributor, Reproductive Physiology on Viviparous Teleosts)
Science Publishers   2008   ISBN:978-1-57808-331-2

Research Grants & Projects

Japan Society for thePromotion of Science: Grants-in-Aid for Scientific Research
Project Year: 2014 - 2016
Ministry of Education, Culture, Sports, Science and Technology: Grants-in-Aid for Scientific Research(基盤研究(C))
Project Year: 2010 - 2012    Investigator(s): Yasunori KOYA
The temporal water area formed by rainfall provides important breeding environmentfor some fishes. Environmental research of the temporal water area and maturationinvestigation of fishes were conducted for the purpose of grasping the environmental...
Study on Reproductive Ecology and Gamete Characteristics of Fish
Study on Reproduction in Viviparous Teleosts