A submersible float assembly that is releasably attachable to a mooring line in a shellfish aquaculture system is disclosed. Submersible culture systems generally employ mechanical parts that require regular maintenance and servicing to ensure reliable operation, particularly in a marine environment. The invention disclosed has no moving parts and allows for the suspension of the float at any point on the mooring rope quickly and securely. The float has a float body (2) having a conduit (6) through which the mooring line (4) may pass and a retainer (3) that releasably engages with the mooring line to maintain the float body at a desired depth. The engagement is by way of a tapered fit between the retainer and the conduit where the retainer has a split so as to close on the mooring rope. Means (10) for retaining support lines (5) are also disclosed. A method of its use is also disclosed.
