A semi-submersible spar-type offshore fish farm for cultivating fish at open sea, comprising an elongated center column having one of a circular and polygonal cross-section. The elongated center column having a first end part and a second end part, a buoyancy sleeve and a harvesting sleeve that are coaxially arranged around the elongated center column, wherein the buoyancy sleeve is arrangeable at positions along the elongated center column between the first end part and the harvesting sleeve and the harvesting sleeve is arrangeable at positions along the elongated center column between the buoyancy sleeve and the second end part.

The invention relates to a method for controlling a concentration of dissolved oxygen in a volume (V) of water (W), wherein a device (1) for dissolving oxygen in water (W) is submerged in said volume (V) of water, wherein oxygen is injected by the device (1) with an adjustable flow rate into a main water stream (W′) sucked into a housing (100) of the device (1), and wherein the oxygen enriched main water stream (W′) is discharged by the device (1) out of the housing (100) of the device (1) into said volume (V) of water (W), and wherein a current concentration of oxygen dissolved in the sucked main water stream (W′) is measured with an oxygen probe (6) that is integrated into the housing (100) of the device (1), wherein said current concentration of dissolved oxygen is transmitted in a wireless fashion to a hand-held device (9) of an operator, and wherein the flow rate of the injected oxygen is controlled such that the measured current concentration of dissolved oxygen approaches a pre-defined reference value.

Aquatic structures with adjustable buoyancy constructed in part with a vent valve for a buoyancy control device suitable for divers, where the vent valve may be opened by any combination of over-pressure, manual pressure relief or a powered means, where a force to a valve plug is applied by means of a spring that is constrained to prevent entirely lateral and angular movement but in which movement of the plug in the axis of the seat is unconstrained.

Aquatic structures with adjustable buoyancy constructed in part with a vent valve for a buoyancy control device suitable for divers, where the vent valve may be opened by any combination of over-pressure, manual pressure relief or a powered means, where a force to a valve plug is applied by means of a spring that is constrained to prevent entirely lateral and angular movement but in which movement of the plug in the axis of the seat is unconstrained.

An aquaculture system includes a pen configured to be disposed in a body of water and configured to at least temporarily store aquatic animals during development. A control system is configured to receive electric power from a power source and is configured to provide electric power to a pumping mechanism coupled to the pen such that the pumping mechanism provides a flow of water through the pen. A set of buoyancy tanks are coupled to the pen. A portion of the control system is in fluid communication with the set of buoyancy tanks and is configured to adjust a volume of fluid in at least one buoyancy tank to move the pen from a first position in which the pen is partially submerged in the body of water to a second position in which the pen is fully submerged in the body of water.

An aquaculture system includes a pen configured to be disposed in a body of water and configured to at least temporarily store aquatic animals during development. A control system is configured to receive electric power from a power source and is configured to provide electric power to a pumping mechanism coupled to the pen such that the pumping mechanism provides a flow of water through the pen. A set of buoyancy tanks are coupled to the pen. A portion of the control system is in fluid communication with the set of buoyancy tanks and is configured to adjust a volume of fluid in at least one buoyancy tank to move the pen from a first position in which the pen is partially submerged in the body of water to a second position in which the pen is fully submerged in the body of water.

A mort trap assembly includes an upper ramp with a top end, a first bottom end, and an outer edge that is fixedly attached to an inner edge of a slide. A retaining chamber is located below the upper ramp and includes a first entry port located below the first bottom end of the upper ramp. A lower ramp has a top end spaced away from the upper ramp, and a first bottom end located at a bottom of the first entry port of the retaining chamber, and a purge pipe fluidly connected to the retaining chamber. The upper ramp is configured to receive morts from the slide, and the lower ramp is configured to receive the morts from the upper ramp and to direct the received morts into the first entry port.

A mort trap assembly includes an upper ramp with a top end, a first bottom end, and an outer edge that is fixedly attached to an inner edge of a slide. A retaining chamber is located below the upper ramp and includes a first entry port located below the first bottom end of the upper ramp. A lower ramp has a top end spaced away from the upper ramp, and a first bottom end located at a bottom of the first entry port of the retaining chamber, and a purge pipe fluidly connected to the retaining chamber. The upper ramp is configured to receive morts from the slide, and the lower ramp is configured to receive the morts from the upper ramp and to direct the received morts into the first entry port.

An automated oyster maturation system including a containment assembly rotatably disposed within a housing. The containment assembly includes a spiral construction that includes compartments that are in communication with one another, walls that define the compartments, and ramps. Openings disposed in the walls and ramps increase in size from the outer diameter to the inner diameter of the spiral construction so that, with every complete rotation of the containment assembly, every oyster will tumble further into the spiral construction and ascend from its original compartment into the adjacent inner compartment where opening size is larger than in the original compartment such that only oysters which have grown sufficiently can remain in the adjacent inner compartment while oysters that have not grown sufficiently yet will fall through the openings of the adjacent inner compartment into the original compartment.

An automated oyster maturation system including a containment assembly rotatably disposed within a housing. The containment assembly includes a spiral construction that includes compartments that are in communication with one another, walls that define the compartments, and ramps. Openings disposed in the walls and ramps increase in size from the outer diameter to the inner diameter of the spiral construction so that, with every complete rotation of the containment assembly, every oyster will tumble further into the spiral construction and ascend from its original compartment into the adjacent inner compartment where opening size is larger than in the original compartment such that only oysters which have grown sufficiently can remain in the adjacent inner compartment while oysters that have not grown sufficiently yet will fall through the openings of the adjacent inner compartment into the original compartment.