Measuring settlement intensity of abalone: Results of a pilot study

Abstract

Results of a pilot study to assess the utility of settlement collectors for measuring settlement intensity of abalone in the field are presented. The collectors, consisting of transparent PVC sheeting, were conditioned in sea water before being deployed on the seabed in habitat containing adult and juvenile abalone. Collectors were recovered and replaced at intervals of between one and eight weeks over a 12-month period. The optimum period was found to be between two and four weeks. Two discrete peaks in settlement were recorded, coinciding with the annual spawning activity of two species, Haliotis rubra and Haliotis laevigata. Intensity of settlement in each peak was equivalent to 114 m^-2 and 45 m² respectively.