Design, use, and effectiveness of collectors for catching the puerulus stage of spiny lobsters

Abstract

Abstract Collectors have been used successfully to catch the puerulus stage of spiny (rock) lobsters to provide animals for study in the laboratory, to investigate levels of puerulus settlement, and for mariculture purposes. Different types of collectors have been developed for different species and different areas. We focus mainly on the use of artificial seaweed collectors for Panulirus cygnus in Australia and crevice types developed for Panulirus argus in the U.S., and Jasus edwardsii in New Zealand. Workers in other countries, including Antigua, Bermuda, Cuba, Grenada, India, Jamaica, Japan, Mexico, and St. Paul and Amsterdam Islands have also used collectors to catch the puerulus stage of Panulirus and Jasus spp. Collectors of various shape and size have been constructed from a range of materials. The biological response to collectors appears to vary among species, and the most appropriate collector is unknown for any species. Collectors are usually set in localities where juveniles occur in large numbers, but they have been used throughout the water column. The type of mooring depends on the type of collector and the depth. Most collectors have been set inshore (within 2 km of shore), where best catches have been made, either at the surface or near the sea floor at depths down to 12 m. Those near the surface require protection from the full force of waves and swell. Some collectors require conditioning before they are fully effective. The saturation level is unknown for any collector, but high catches on some suggest it is seldom approached. Lobsters remain on collectors for various times according to species and collector type. Where puerulus catches are being used in analyses of stock dynamics, a standard procedure for checking collectors and identifying pueruli must be established. The number of collectors required at each locality to obtain an adequate measure of puerulus settlement depends on several factors: (1) the area available, (2) the settlement levels, G) the variability of catches, and (4) the degree of precision required in fishery prediction. Data on puerulus catches of P. cygnus in Western Australia have been used successfully to predict the commercial catch 4 years in advance. Similar attempts to use puerulus catches for catch prediction are being made in New Zealand and Cuba.