A group-housing system for an artificial shark uterus

We developed an artificial shark uterus system that enables the simultaneous maintenance of multiple embryos within a single container. In previous designs, group housing of late-stage embryos was unsuccessful because the activation of one embryo stimulated others, triggering collective hyperactivity. This led to severe skin abrasions due to repeated contact with the rubber mesh covering the container opening. The key modifications and functional principle of the new system are as follows:•The rubber mesh was eliminated and replaced with an acrylic cylinder that provides vertical space above the incubation container.•This vertical space allows activated embryos to swim upward, reducing physical contact between active and inactive individuals.This method increases incubation density and broadens the applicability of artificial uterine technology to shark species with high fecundity.