Improved collector design for the capture of tropical spiny lobster, Panulirus homarus and P. ornatus (Decapoda: Palinuridae), pueruli in Lombok, Indonesia

The literature on late-stage larval and puerulus settlement of tropical spiny lobsters suggests that a broad range of visually-assessed variables may play a role in the selection of settlement substrates. These variables include light level, luminosity, degree of exposure, and the availability of edges, crevices and clefts. A fishery has developed in Indonesia, that captures pueruli for grow-out purposes, along the entire southern coastline from Java to Sumbawa. The present study builds on knowledge gained on the behaviour and substrate preferences of settling pueruli by examining aspects of collector design and substrate surface characteristics in regard to catch rates. A series of tank-based experiments were used to examine preferences for various attributes of collector materials, and preferred material characteristics were then tested in a field experiment to verify the laboratory results. In the tank experiment the most preferred substrate was cement bag paper, followed by insect mesh, weed netting, PVC rubber and cement bag plastic. Crevice angles of 10° and 20° were significantly preferred over 30°. The substrate level and other substrates had less influence on settlement. However, both the lunar phase and type of materials tested in the field had a significant effect on settlement. Significantly greater numbers of pueruli were caught at the time of the new moon than at other moon phases. Cement bag paper was the most preferred material in the field, followed by cement bag plastic, insect mesh, weed fabric, and PVC rubber.