水槽内で観察されたシラウオの産卵行動  [in Japanese] Spawning behavior of shira-uo Salangichthys microdon in captivity  [in Japanese]

水槽に50個体のシラウオ成魚を収容し,その産卵行動をVTRに記録,分析した。シラウオは雄の吸盤状の尻鰭鱗で雌雄が互いの体を密着させ,体を震動させつつ放卵放精を行うというユニークな産卵行動を示した。その配偶行動は,底層に降下した雌に雄が群がって争い,ペアが形成されるというものであった。その後,ペアは上昇して放卵放精に至るが,ペア形成が必ず放卵放精に至る訳てはないことから,雌による配偶者選択も示唆された。さらに配偶過程の繰り返しから,雌が少数ずつ産卵を繰り返していたことが示唆された。

Video recordings of the behavior of 50 adult shira-uo Salangichthys microdon in an aquarium were analyzed to reveal their spawning behavior. Shira-uo showed unique spawning behavior that a pair shake their bodies, with the male sticking his gonopore into the female's one using the anal fin scales as a sucker. The mating behavior was that a female descended from the usual circular swimming in the upper layer to the bottom layer, males checking each other there crowded around the female and exchanged body charges to compete for the female, and a pair formed as a result of the male-male competition. The paired female led the male upward, and they spawned and ejaculated. However the pair did not always succeed in spawning and ejaculation and the low success rate may be due to the female's choice of mate. Furthermore, it was suggested that the female repeatedly snawned a small number of eggs with every spawning success by reiterating the process of mating.