Maturation and spawning processes of anadromous and resident pond smelt in lake ogawara |
| |
Authors: | Satoshi Katayama Yoshio Sugawara Michio Omori Akihiro Okata |
| |
Institution: | (1) Department of Applied Bio-science, Faculty of Agriculture, Tohoku University, 1-1 Tsutsumidori, Amamiyamachi, Aoba-ku, 981-8555 Sendai, Japan;(2) Department of Biotechnology, Sensyu University of Ishinomaki, 1 Shinmito Minamisakai, 986-0031 Ishinomaki, Japan;(3) Laboratory of Hydrospheric Ecology, 1-2-6 Ushirono, 312-0014 Hitachinaka, Japan |
| |
Abstract: | Pond smelt,Hypomesus nipponensis McAllister, in Lake Ogawara demonstrate alternative life history strategies, as evidenced by the coexistence of anadromous
and resident fish. However, it is unknown if anadromous and resident groups interbreed. In this study, maturation and spawning
processes were examined and compared between anadromous and resident groups. Histological observations indicated negligible
variation in the maturational stage composition of oocytes, the frequency of oocyte diameter being unimodal for all specimens
at different maturational stages. Oocytes were absent in the ovaries of spent fish. Accordingly, the species can be considered
a semelparous spawner with unimodal oocyte diameter distribution. Temporal changes in the proportion of spent fish were compared
between anadromous and resident groups. Spawning of both groups began in late March and peaked over April 8–12. Although both
groups did not differ significantly in the period of peak spawning, anadromous fish finished spawning earlier than resident
ones. Anadromous fish were not able to spawn upon migration into Lake Ogawara, and quickly matured after immigration, contrasting
with resident fish. |
| |
Keywords: | Pond smelt maturation spawning anadromy residence |
本文献已被 SpringerLink 等数据库收录! |
|