Bulletin of the Hiroshima University Museum Issue 10
2018-12-25 発行

瀬戸内海周防灘中津干潟における絶滅危惧種アオギス Sillago parvisquamis(キス科)の危機的な生息状況(2016-2018年)

Critical Population Trend of the Small-scale Sillago Sillago parvisquamis (family Sillaginidae) at Nakatsu Tidal Flat, Suo-nada Sea, Western Seto Inland Sea, Japan, 2016-2018
Shigeta, Toshihiro
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abstract
The small-scale sillago Sillago parvisquamis (family Sillaginidae) has been evaluated as one of the endangered species in Japan. The only largest local population exists at Nakatsu tidal flat in the southern part of the Suo-nada Sea (Buzen-kai Sea), Seto Inland Sea. The population structure of the species on the tidal flat was investigated in 2016-2018 to determine recent population trends. As a result, no dominant year class was observed in the population. Catch per unit effort (CPUE) (indiv./3 hours/person; mean ± SD) by rod and line fishing during the spawning seasons in 2016, 2017 and 2018 showed low values, at 0.80 ± 1.3 (n = 13), 4.3 ± 2.9 (n = 18) and 0.33 ± 0.65 (n = 9), respectively. Histological examination of ovaries of the females captured in 2018 indicated that spawning had occurred as yet. These findings suggest that the small-scale sillago stock has decreased to a critical level in Japan.
subject
アオギス
キス科
絶滅危惧種
中津干潟
Sillago parvisquamis
endangered species
Nakatsu tidal flat
Sillaginidae
small-scale sillago
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