Freshwater Lobster Breeding And Hatchery

Captive breeding of P.homarus, P. polyphagus, P. ornatus. P. longipes and P. versicolor has been achieved by different laboratories in India. Adult lobsters maintained in broodstock holding system mate and breed when optimum environmental conditions and feed are provided. Repetitive breeding is reported in P. Homarus.

Juveniles of P. homarus and P. ornatus were reared to maturity in captivity and successful breeding achieved. Egg bearing lobsters procured directly from fishermen are also suitable for egg hatching and rearing. However berried lobsters procured from secondary holding centres are often infected and not suitable for hatchery operations.

Phyllosoma larvae of P. homarus have been reared to stage 6 in 60 days. Recently larvae were reared to stage 8 in 42 days on a mixed diet of Artemia and plankton. Similarly larvae of P. ornatus, P. polyphagus and P. versicolor have also been reared through early stages.

Significant advances have been made in Japan, Australia and New Zealand in culture of phyllosoma larvae of a number of temperate and semi-tropical species of lobsters to settlement. Japanese were the first to succeed in completing the larval phase of five temperate species and one semi-tropical species.

Larvae took 132 to 319 days to complete the larval phase in different species. The number of instars was 17 for Jasus spp., 9 for Palinurus elephas has 25 (estimated) for Panulirus japonicus. Survival ranged from o.01 to 10%. Phyllosoma larae of P. Cygnus and J. verraeuxi were also reared to settlement by the Australians and the New Zealanders.

The method developed in northern Japan to culture phyllosoma larvae of five species of cool-temperate spiny lobsters combines the features of upwelling water, co-cultured microalgae and use of mussel gonad as food. The feeding behaviour of phyllosoma larvae shows that they are primarily predators.

Recent work has shown that the contamination of culture water by microorganisms such as the fouling protozoans Vorticella sp. can greatly reduce phyllosoma survival. Feeding with fish larvae reduced the larval period by half (65 days) in P. elephas.

However, commercial feasibility of seed production technology is still doubtful for most of the species because of the prolonged larval phase (> 300 days) and poor survival. Until hatchery technology is perfected, lobster farming will have to depend upon naturally available seeds.

Freshwater Lobster Breeding And Hatchery

Collection and ongrowing of puerulii

Spiny lobsters after completing its long larval life metamor phoses into postlarvae (puerulus),which swims towards the shore and settle in nearshore seagrass/seaweed habitats. They transform into postpuerulus and settle into benthic dwelling juvenile lobster.

In the wild, levels of puerulii settlement vary depending on the species and geographic area, which also depends on the spawning stock. Commercial harvest of puerulii and early juveniles from the wild as suggested by the Australians may be possible where there is heavy settlement in the inshore habitat. However, the feasibility of such a proposal is to be examined in other areas, as there is apprehension that this will have serious long-term implications on sustainability of wild resources.

Partial harvesting of puerulii from dense settlement areas is suggested as high mortality rates were experienced by juvenile lobsters between settlement and entry into the commercial fishery. This will benefit the wild resource as well as those interested in farming of lobsters.

Commercial collection of southern rock lobster puerulii for aquaculture has already commenced in Tasmania. In India, studies conducted off Kovalam near Chennai show that puerulii of three species, P. homarus, P. polyphagus and P. ornatus settle in rocky areas. However, the intensity of settlement is not very high enough to suggest harvesting for ongrowing. There is no information on settlement density of puerulii anywhere along the Indian coast.

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