A device for colonizing and harvesting marine hardground animals in an underwater region of a ground-based offshore edifice includes at least one rail device configured to extend vertically on the offshore edifice along a height of the underwater region to above a waterline. The device also includes a netting array including a habitat carriage having a habitat and trapping basket that is adapted to contain the hardground animals. A lifting device is configured to move the netting array along the at least one rail device. Additionally, the device includes a scavenging carriage including a basic unit and a running unit that is configured to detachably couple the scavenging carriage with the at least one rail device so as to be movable thereon. The scavenging carriage is configured to detachably couple with the habitat carriage and the lifting device.