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大村湾内カタクチイワシの産卵生態


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Title: 大村湾内カタクチイワシの産卵生態
Other Titles: Breeding habits of Anchovy in Ômura-Bay
Authors: 山田, 鉄雄
Authors (alternative): Yamada, Tetuo
Issue Date: 28-Feb-1958
Publisher: 長崎大学水産学部
Citation: 長崎大学水産学部研究報告, v.6, pp.73-82; 1958
Abstract: The author has studied the breeding habits of Anchovy, Engraulis japonica (HOUTTUYN), in Ômura-Bay by their sex maturity and their ova which sampled in the sea surface throughout a year. Anchovy in the Bay spawn their ova from April to December, and the peaks appear in Spring and in Autumn, but one more small peak occurs in August when the water temperature in the Bay is at their highest. According to the body length frequency distribution of them, the author has assumed these spawning groups are both one year fish about 90mm~100mm in body length. The spawning time is supposed from 11p.m. to 4a.m. according to the investigation of the floating ova. The spawning of parent-fish both of Spring and Autumn will be commenced at such sea condition as the water temperature of surface and bottom become almost equal by overturning of the sea water. / 大村湾において,表層曳プランクトン網によるカタクチイワシ卵の時空的分布と,生殖腺熟度の調査結果から,湾内カタクチの産卵生態について考察した.産卵は冬季(12月~3月)を除いて周年行われているが,盛期は春(5,6月)秋(10~12月)の二季である.その産卵親魚の体長はいずれも90~100mm(満1年)で,明かに別群である.即ち春季産卵群と秋季産卵群があり,それぞれ年1回の産卵を行う.これが湾内の主群を形成し,満1年以上のものは極めて少ない.海況との関係では,湾内水温の成層が破れて上下混交がはじまり,上下の水温差のほとんどなくなるころから産卵盛期となる.即ち春は4月(16℃),秋は10月(23℃)産卵盛期に入る.水温最高期(ca.30℃)の8月中下旬にも一つの短期間の産卵の山があることは,産卵生理上注目される.採集卵中,放卵直後のものを調べ,産卵時刻は23~4時位の間と推測した.産卵場所の中心は湾央であるが,大串,小串の両湾や川棚沖に卵の密集しているのを見ることがある.
URI: http://hdl.handle.net/10069/31928
ISSN: 05471427
Type: Departmental Bulletin Paper
Text Version: publisher
Appears in Collections:第6号

Citable URI : http://hdl.handle.net/10069/31928

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