Abstract: A pen system is for farming aquatic organisms. The pen system has an outer surrounding rigid structure and an internal, closed enclosure. The outer surrounding rigid structure forms an upper portion and a lower portion. The pen system further has: an internal surrounding connecting element, the closed enclosure being attached to the connecting element; and a heave-compensation system having a plurality of fluid-filled cylinders, each fluid-filled cylinder being hingedly attached, in a first end portion, to the connecting element, and being hingedly attached, in a second end portion, to the inside of the rigid structure.

Abstract: A sea-pen arrangement is for farming fish. The sea-pen arrangement has a service unit with a plurality of shafts projecting downwards and a pontoon at their lower portions. The shafts define an inner area. A net forms a closed enclosure. The sea-pen arrangement further includes at least one sea pen positioned in an outer area on the outside of two shafts. A frame structure has an upper frame with a first fastening portion and a second fastening portion, a bottom frame, and a fence fastened to the upper frame and the bottom frame. The frame structure is fastened to the service unit at the fastening portions, and the frame structure surrounds the at least one sea pen in the outer area.

Abstract: A pen system is for farming aquatic organisms. The pen system has an outer surrounding rigid structure and an internal, closed enclosure. The outer surrounding rigid structure forms an upper portion and a lower portion. The pen system further has: an internal surrounding connecting element, the closed enclosure being attached to the connecting element; and a heave-compensation system having a plurality of fluid-filled cylinders, each fluid-filled cylinder being hingedly attached, in a first end portion, to the connecting element, and being hingedly attached, in a second end portion, to the inside of the rigid structure.

Abstract: A sea-pen arrangement is for farming fish. The sea-pen arrangement has a service unit with a plurality of shafts projecting downwards and a pontoon at their lower portions. The shafts define an inner area. A net forms a closed enclosure. The sea-pen arrangement further includes at least one sea pen positioned in an outer area on the outside of two shafts. A frame structure has an upper frame with a first fastening portion and a second fastening portion, a bottom frame, and a fence fastened to the upper frame and the bottom frame. The frame structure is fastened to the service unit at the fastening portions, and the frame structure surrounds the at least one sea pen in the outer area.