Rock Lobster Enhancement and Aquaculture Subprogram: the nutrition of juvenile and adult lobsters to optimise survival, growth and condition
CSIRO Oceans and Atmosphere Hobart
Kevin C. Williams
Because Australia's rock lobster fisheries are at their maximum sustainable capacity, the value of the industry can be increased only through the development of aquaculture. In the immediate term, this could be achieved by on-growing of juveniles taken from the wild and the holding of adults for weight gain or niche marketing opportunities. In the longer term, domestication of the specie/s and hatchery propagation of the juveniles will enable a sustainable rock lobster aquaculture industry to develop. In Australia, these opportunities are 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 from 40 to 50% of rock lobster production costs as is the case for prawn and finfish grow-out operations, the availability of a suitable formulated pelleted feed is seen as a necessity for commercial production. Preliminary feed’s development work (FRDC 98/303) for juvenile and adult lobsters has been initiated in an 18-month project that terminated in December 1999. Although all lobster species consumed the developed dry feed pellets, the productivity of juvenile animals was inferior to the feeding of fresh mussels. However, with adult J. edwardsii held in sea cages, the pelleted diets were equal to fresh mussel in maintaining the condition (moult frequency, weight increase and survival) and colour of the lobsters The sub-optimal performance of the pelleted diets for the juveniles is thought to have been due to the reduced attractiveness and /or sub-optimal nutrient specifications of the diet for the lobsters. This project will seek to develop improved and more cost-effective pelleted dry lobster feeds for P. ornatus and J. edwardsii juveniles and to improve the feeds management of adult J. edwardsii. Dietary improvements made with the juvenile work will be applied to adult lobsters being held under commercial sea cage conditions in Professor Geddes’ ‘On-growing Project’ (98/305). A collaborative research approach involving CSIRO, TAFI and UA and other agencies in the RLEAS will give the best prospects for achieving our aims. The likelihood of the project being successful is high because: 1. The initial Feed’s Development Project has shown dry pelleted diets to be well accepted by the lobsters and further improvements are likely upon implementation of the proposed targeted research. 2. The project will build on the already established strong collaborative linkages between related rock lobster research being carried out at CSIRO, QDPI, TAFI, UA and by industry. 3. The assembled project team has considerable expertise and an established track record in delivery of successful feed development for other crustaceans (prawns) and finfish, and have established strong collaborative linkages with the aquafeed industry to aid the rapid commercialisation of the research.
1. Develop manufactured feeds for juvenile rock lobsters (ie puerulus - year 1 and beyond) that optimise survival and growth by: a) defining the chemicophysical cues that stimulate food consumption in juvenile rock lobsters, b) developing pelleted feeds that remain attractive to lobsters for periods in excess of four hours after immersion, and c) determining the optimum dietary specifications of selected nutrients required by juvenile rock lobsters for growth and development.
2. Develop manufactured feeds for adult lobsters for body maintenance and moult manipulation by a) determining the optimum pellet size and feeding frequency for maintaining the condition of adult rock lobsters and b) providing continued advice to project 98/305 on feeds development for adult lobster holding.
Research in FRDC RLEAS 98/303 established that tropical (Panulirus ornatus), southern (Jasus edwardsii) and western (Panulirus cygnus) rock lobsters readily consumed formulated pelleted dry feeds and exhibited a dose dependent growth response to dietary protein concentration. The derived optimum dietary crude protein dry matter specification was 49, 37 and 57% for tropical, southern and western lobsters, respectively. However, growth rates of lobsters fed diets of either fresh mussel or expensive (AUD$7,500/tonne) extruded kuruma shrimp (Penaeus japonicus) feed pellets were from one third to five-times better than for the laboratory-pelleted diets. The sub-optimal performance of the laboratory-pelleted diets was attributed to a loss of attractiveness of the food after 1–2 hours immersion in the water and/or a sub-optimal supply of nutrients critical to growth and development of the lobsters.
Based on these results, the focus of the research in this project (FRDC RLEAS 2000/212) was to enhance the lobster's acceptability of pelleted dry feeds and to advance knowledge on the animal's requirements for critical nutrients and the nutritive value of alternative protein ingredients. Additionally, research was carried out with adult southern rock lobsters to improve feeding and husbandry management practices.