The increased demand for seafood such as octopus and lobster over the past decade has resulted in efforts for further research and development into octopus and lobster aquaculture. Whilst closing the life cycle of species with planktonic larvae stages has yet to be achieved on commercial scale, the 'ranching' of octopus and lobster has increased in popularity and developed into a potential solution to fill the shortfall in supply.
Octopus
Commonly, the grow-out systems involve the use of 'hides', usually PVC pipes that provide shelter to individual octopus. Although positive growth has been achieved and marketable individuals obtained, these grow-out methods have several limitations including attainment of relatively low biomass (up to 15 kg/m3), difficulty to clean and harvest, and promotion of territorialism and cannibalism amongst individuals.
During the past five years, advanced systems and ranching protocols for Octopus tetricus juveniles on commercial scale have been developed. These systems and protocols have eliminated the need to use shelters in tanks, which has significantly reduced cannibalism and territorialism, subsequently tanks are extremely easy to clean and harvest. These advances have resulted in the ranching of octopus juveniles from as little as 50 gr at a biomass upwards of 54 kg/m³. New and easy to use solutions were developed to retain the octopus in the tanks, thus, eliminating escaping events, while reducing the need for caging or fencing the tank.
Commercial Return on Investment (ROI) was developed for the ranching of O. tetricus and a commercial project involving artesian fisheries in several countries are currently in development.
Lobsters
Tropical rock lobster (Panulirus ornatus and P. homarus) ranching is already established in several South-east Asian countries including Vietnam, Indonesia, Philippines, Malaysia. The industry relies on wild caught puerulus (post larvae).
Lobsters are grown in shallow submerged cages and are grown to 1kg (P. ornatus) or 500g - 1kg (P. homarus). Lobsters are fed 'trash fish' caught nearby. Survival varies significantly between 5-70%. There are large variations in systems, methods and returns between countries. In some countries, poor handling, holding and transport resulted in high mortality of wild caught puerulus (up to 70%). Some of the issues for lobster ranching include:
Ranching of 'hard to breed' organisms such as octopus and lobsters can present new, successful and sustainable opportunities - if developed properly and can bridge between traditional fishing and aquaculture.