Publications by authors named "Dharmamony Vijai"
The spawning behavior of a Japanese flying squid (Todarodes pacificus) is described based on up-close observation of a captive female. The squid was first transferred from a 10-ton tank to a polystyrene plastic box containing 45 liters of seawater. About one hour later, the mantle-contraction rate increased rapidly, followed by a brief convulsion of the mantle and arms and a whitening of the body.
View Article and Find Full Text PDFSquid embryos develop in the perivitelline fluid inside the chorion, which is an envelope secreted by the ovarian follicle. The onset of hatching initiates local dissolution of the chorion when the hatching gland enzyme facilitates the release of the developed paralarvae. In the present study, we investigated the pre-hatching behavioral patterns of Todarodes pacificus embryos and their responses to light after hatching.
View Article and Find Full Text PDFArticle Synopsis
- The Japanese flying squid, Todarodes pacificus, lays neutrally buoyant egg masses that float at the interface of water layers with different densities, affecting their vertical distribution and drift.
- Experiments in a thermally stratified tank helped characterize the density of these egg masses and their buoyancy, with findings showing the outer jelly of the egg masses being denser than surrounding water.
- It is proposed that these egg masses remain suspended above the pycnocline layer in the Tsushima Strait, allowing them to maintain a stable location essential for embryo survival and recruitment.
Article Synopsis
- The spawning behavior of ommastrephid squids, specifically Japanese flying squid, had not been observed in natural settings, leading researchers to investigate their spawning habits in controlled experiments.
- In a 300 m³ tank, two experiments were conducted: one with a thermocline to imitate natural conditions and another with uniform temperature, revealing that egg masses behaved differently in each setup.
- The study found that females spawned multiple times under stress, and the resulting paralarvae survived for up to 10 days, indicating potential feeding behavior in captivity.