Rock Lobster Enhancement and Aquaculture Subprogram Project 5: determination of the optimum environmental and system requirements for juvenile and adult rock lobster holding and grow-out
University of Adelaide
Mike C. Geddes
The need for a coordinated sub-program, and research projects focussing on collection and neutrality, nutrition, health and system design and handling has been outlined in the background to this submission. Further evidence of the need for this and the other sub-program projects includes: Project 1: COORDINATION AND SUB-PROGRAM MANAGEMENT: At a planning workshop in Hobart in 1997, an open forum of all participants identified 21 issues of concern to the aquaculture of rock lobsters. These were condensed into five major issues with each major issues condensed examined in detail by a discussion group. One of the five major issues was project management. Based on the range of research issues and other programs related to rock lobsters, well facilitated project management was considered a fundamental priority. With increasing demands being placed on scientists by their host organisations, the role of Sub-program Leader in addition to project commitments can be impossible to fulfil adequately. A dedicated Sub-program Leader will ensure the Sub-program runs effectively and objectives are delivered on time to the industry. Project 2: COLLECTION AND NEUTRALITY: Before any large scale commercial on-growing of postlarvae is permitted, it will be necessary to establish what effect large scale harvesting of pueruli might have on the wild stock. A second critical need to the success of any commercial venture into rock lobster postlarval growout is that techniques be developed to harvest huge quantities of healthy pueruli. Research is needed to estimate the likely impact of large-scale harvesting of puerulus on the commercial fishery and to establish methods and equipment necessary to catch large quantities of pueruli in the most cost-effective way. Project 3: NUTRITION: In Australia, opportunities to value add to the wild catch of lobsters or to on-grow juveniles taken from the wild is seriously constrained by the lack of a cost-effective and efficacious rock lobster feed. This contrasts with the developing industry in New Zealand where waste from the large mussel industry is an available and inexpensive source of feed. If feed comprises 40-50% of rock lobster production costs as is the case in other aquaculture industries (prawns, finfish), the development of a suitable manufactured feed is crucial for the successful establishment of rock lobster aquaculture in Australia. Project 4: HEALTH: Due to the infancy of rock lobster aquaculture, disease conditions associated with production are poorly understood. Similarly, the prevalence of disease conditions in wildstock and their likely impact in aquaculture systems or extended holding systems has yet to be determined. While other factors associated with the establishment of rock lobster aquaculture are perceived as a higher priority, it is recognised that health monitoring and the early identification of diseases that may affect production is critical. In the short term, there is a need to establish a mechanism for the monitoring of disease conditions of juvenile and adult lobsters in land-based and sea-based holding systems. This will not only provide industry with a means of assessment of moribund lobsters, but will facilitate the identification of health research priorities. Project 5: SYSTEM DESIGN AND HANDLING: Rock lobster fisheries throughout the world are generally fully or over-exploited while market demand remains very high with this product positioned at the premium end of the crustacean market spectrum. The proposed research will assist in increasing supply of this valuable product in a sustainable way and will consequently decrease pressure on wild populations. System design and basic husbandry information must be completed in conjunction with health and nutrition research as these factors combine to influence the efficiency of production.
1. Assess the interactions between stocking density and feed delivery system on maintaining and improving condition and on the growth performance of adult rock lobsters in existing sea-based holding systems in different seasons.
2. Determine the effects of temperature , salinity and photoperiod on the growth rate and survival of juvenile rock lobsters in existing land-based holding systems.
3. Determine the effects of stocking density and shelter on the growth rate and survival of juvenile rock lobsters in existing land-based holding systems.
4. Evaluate existing system design and management regimes for land-based captive grow out of juvenile rock lobsters and for sea-based holding of adult rock lobsters.
Principal Investigator: Michael Geddes
Key Words: aquaculture, southern rock lobster, tropical rock lobster, live-holding, moulting, juvenile growth, survival, salinity, temperature, density, photoperiod
Summary: There were three different components to this project. Component I of the project investigated the effectiveness of different ‘natural’ and manufactured diets in maintaining/improving condition and in promoting growth at moult in adult J. edwardsii held in sea-based and land-based systems. Trials were run over “summer” (November 1998 to March 1999) and “winter” (April to November 1999) on industry facilities at Port Lincoln and Kangaroo Island. These provided information on diets and feeding regimes, comparison of holding systems, the growth, mortality and biology of lobsters under long-term liveholding and the product quality of live-held lobsters. Component II of the project investigated the effects of temperature, salinity, and density/biomass on the growth and survival of juvenile P. ornatus. Component III of the project investigated the effects of temperature and photoperiod on the growth and survival of juvenile J. edwardsii.