613244 Disclosed are a fish pen (100) for aquaculture and a method of retaining fish in open water. The mobility of conventional fish pens in water is dependent upon the spacing of individual spar buoys. Such fish pens do not provide easy access for the extraction of fish from the pen. The fish pen (100) comprises an elongate centre spar buoy (110) a reserve buoyancy buoy (120) lower (130) and upper (140) rim assemblies a plurality of first (150), second (152) and third (154) tension members a netting assembly (160) and first and second interior panels. The plurality of first tension members (150) including a first end are attached to a lower portion of the spar buoy (110) and a second end is attached to the lower rim assembly (130). The plurality of second tension members (152) including a first end is attached to the lower rim assembly (130) and a second end attached to the upper rim assembly (140). The plurality of third tension members (154) including a first end are attached to one of the upper rim assembly (140) and a second end attached to an upper portion of the spar buoy (110). The netting assembly (160) defines an enclosed volume and comprises a floor portion and a wall portion. Each of the first and second interior panels has a lower edge inner edge and outer edge. The first and second interior panels are configured to define a smaller operable volume within the netting assembly (160). The outer edge of the second panel is pivotable about the spar buoy (110).
