Observations on the spawning behavior, egg masses and paralarval development of the ommastrephid squid Todarodes pacificus in a laboratory mesocosm
Observations on the spawning behavior, egg masses and paralarval development of the ommastrephid squid Todarodes pacificus in a laboratory mesocosm
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DOI：
10.1242/jeb.127670
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发表时间：
2015-12-01
影响因子：
2.8
通讯作者：
Sakurai, Yasunori
中科院分区：
文献类型：
--
作者：
Puneeta, Pandey;Vijai, Dharmamony;Sakurai, Yasunori
乌贼的产卵行为在自然条件下从未被观察到。以前对日本飞鱼(Todarodes Pacphaus)的实验室观察表明，典当前的雌性可能会在大陆架或斜坡上休息，然后才会上升到跃层以上产卵，卵团可能会在跃层中安顿下来。在这里，在一个6米深的300m(3)水箱中进行了两个中温层实验来研究这一假说。在第一个实验中，通过创建一个热分层(17-22摄氏度)水柱，在水箱中建立了一个温跃层(2.5-3.5米)。在第二个实验中，所有深度的温度都是均匀的(22摄氏度)。在产卵之前，雌性不会在水箱地板上休息。在分层水柱中，卵块仍然悬浮在温跃层中，而在非分层水柱中，它们停留在池底，坍塌并受到微生物的侵扰，导致异常或无法存活的胚胎。11只雌虫共产卵18枚(直径17-80厘米)，表明雌虫在胁迫下可以多次产卵。副翼幼虫在30/31阶段孵化，存活了10天，使我们能够观察到圈养中副翼幼虫最高级的阶段。副翼幼虫在消耗了内蛋黄后存活了下来，这表明它们可能是在鱼缸里进食的。
The spawning behavior of ommastrephid squids has never been observed under natural conditions. Previous laboratory observations of Japanese flying squid (Todarodes pacificus) suggest that prespawning females might rest on the continental shelf or slope before they ascend above the pycnocline to spawn, and that the egg masses might settle in the pycnocline. Here, two mesocosm experiments were conducted in a 300 m(3) tank that was 6 m deep to investigate this hypothesis. In the first experiment, a thermocline (2.5-3.5 m) was established in the tank by creating a thermally stratified (17-22 degrees C) water column. In the second experiment, the temperature was uniform (22 degrees C) at all depths. Prior to spawning, females did not rest on the tank floor. In the stratified water column, egg masses remained suspended in the thermocline, but in an unstratified water column, they settled on the tank bottom, collapsed and were infested by microbes, resulting in abnormal or nonviable embryos. Eleven females spawned a total of 18 egg masses (17-80 cm in diameter), indicating that females can spawn more than once when under stress. Paralarvae hatched at stage 30/31 and survived for up to 10 days, allowing us to observe the most advanced stage of paralarvae in captivity. Paralarvae survived after consumption of the inner yolk, suggesting they might have fed in the tank.