A pneumatically controlled shellfish aquaculture apparatus is provided. A frame has containers for holding shellfish secured to the top side of the frame and tanks secured to the bottom side of the frame. Each tank has an air supply line connected to the tank and an opening on the bottom side of the tank. Each air supply line is connected to a manifold for controlling airflow to the tanks. Air is used to displace water in the tanks by pushing the water out of the openings in the bottom of the tanks in order to float the frame. To submerge the frame, the tanks are depressurized to allow water to displace the air in the tanks. When floating, the tanks lift the frame and the containers out of the water to allow air desiccation in order to prevent bio-fouling of the equipment and shellfish.

A floatable frame structure has concatenated frame modules, each formed of columns arranged substantially vertically. Neighboring columns are interconnected by upper and lower tie bars and form module sections. The connections between the tie bars and columns have rotary joints arranged at upper and lower nodes on the columns. At least one horizontal rotation joint is arranged for each column in the connection to an associated tie bar, and at least one spherical rotary joint or elastic rotary joint is arranged for each tie bar. Each module section is provided with elastic tensile elements secured to diagonally opposite upper and lower nodes, nodes lying diagonally opposite each other in the same horizontal plane and in the same frame module being connected by elastic tensile elements. Some columns form containers with submersible portions with positive buoyancy, and adjacent frame modules sharing at least one column.

A mortality trap (150) for a spar buoy fish pen (100) is configured to receive and trap deceased fish, or morts (M), that sink from the fish pen. The mortality trap attaches to a lower portion of the spar buoy (110) to define a first passage (90). The sinking mort passes into an upper receiver portion (150U) of the mortality trap, and encounters a sloping transverse panel (154). Gravity causes the mort to continue through a second passage (B) into a lower entrapment portion (150L), and further into a region underlying the transverse panel (154) preventing the mort from escaping if it becomes positively buoyant. The entrapment portion optionally includes a converging channel into a valved port, to permit extraction of morts. The mortality trap may be located on the distal end of the spar buoy, or at an intermediate location on the lower portion of the spar buoy.

A mortality trap (150) for a spar buoy fish pen (100) is configured to receive and trap deceased fish, or morts (M), that sink from the fish pen. The mortality trap attaches to a lower portion of the spar buoy (110) to define a first passage (90). The sinking mort passes into an upper receiver portion (150U) of the mortality trap, and encounters a sloping transverse panel (154). Gravity causes the mort to continue through a second passage (B) into a lower entrapment portion (150L), and further into a region underlying the transverse panel (154) preventing the mort from escaping if it becomes positively buoyant. The entrapment portion optionally includes a converging channel into a valved port, to permit extraction of morts. The mortality trap may be located on the distal end of the spar buoy, or at an intermediate location on the lower portion of the spar buoy.

An offshore farming system comprising an elongated vertical support column floating vertically in water with a larger extension below sea surface than above the sea surface, and a rigid cage structure enclosing the elongated vertical support column in circumferential direction and arranged movable in longitudinal direction of the elongated vertical support column.

An offshore farming system comprising an elongated vertical support column floating vertically in water with a larger extension below sea surface than above the sea surface, and a rigid cage structure enclosing the elongated vertical support column in circumferential direction and arranged movable in longitudinal direction of the elongated vertical support column.

An outlet basin for a fish pen is provided with at least one outlet hose extending from the outlet basin to a surface. The outlet basin includes a cylinder-shaped housing which is provided, at its upper portion, with a mounting collar arranged to be attached to a bottom portion of the fish pen, and which is provided, at its lower portion, with a through opening. The outlet basin further includes a cylinder-shaped outlet channel which, in a portion, is housed in the housing, the outlet channel is provided, at its upper portion, with a strainer covering the cross section of the outlet channel, an elongated annular space between the housing and the outlet channel, a slanted grating covering the entire annular space, the lowermost portion of the slanted grating being positioned just below the opening of the housing, a slanted bottom plate sealingly covering the entire annular space, and a lower through opening at the lowermost portion of the bottom plate.

An outlet basin for a fish pen is provided with at least one outlet hose extending from the outlet basin to a surface. The outlet basin includes a cylinder-shaped housing which is provided, at its upper portion, with a mounting collar arranged to be attached to a bottom portion of the fish pen, and which is provided, at its lower portion, with a through opening. The outlet basin further includes a cylinder-shaped outlet channel which, in a portion, is housed in the housing, the outlet channel is provided, at its upper portion, with a strainer covering the cross section of the outlet channel, an elongated annular space between the housing and the outlet channel, a slanted grating covering the entire annular space, the lowermost portion of the slanted grating being positioned just below the opening of the housing, a slanted bottom plate sealingly covering the entire annular space, and a lower through opening at the lowermost portion of the bottom plate.

An apparatus for cleaning nets underwater formed from a propeller housing with a centrally disposed axis with a plurality of blades extending therefrom. An outer perimeter ring secured to an outer tip of each blade with a plurality of knuckles secured to the outer perimeter ring. Each knuckle including a curved surface constructed and arranged to be forcefully presented to the aquaculture net upon rotation of said blades for removal of growth by impact and shaking of the aquaculture net. An elastomeric hub prevents spike loads.

An apparatus for cleaning nets underwater formed from a propeller housing with a centrally disposed axis with a plurality of blades extending therefrom. An outer perimeter ring secured to an outer tip of each blade with a plurality of knuckles secured to the outer perimeter ring. Each knuckle including a curved surface constructed and arranged to be forcefully presented to the aquaculture net upon rotation of said blades for removal of growth by impact and shaking of the aquaculture net. An elastomeric hub prevents spike loads.