A method and system for removing tunicates (sea squirts) and other bycatch from a population of cultivated shellfish such as mussels involves providing a liquid flow medium to a bed of shellfish 5 within a vessel 1 via an inlet 16, perturbing or fluidising the bed of shellfish with a source of energy such as the flow of liquid so as to dissociate the tunicates from the shellfish and removing the shellfish and/or the tunicates. Enables efficient removal of saleable shellfish product whilst at the same time allowing immature shellfish to be safely recovered and re-used in cultivation. May be used as part of a de-roping and tubing method. The vessel may be fitted on a boat.
