Lobster Farming

Farming technologies Spiny lobster grown in captivity could fetch high price through production of suitable size animals. Live spiny lobsters are sought especially in Japan and Southeast Asian countries. Japanese prefer live lobsters of 200-300 g with deep red external colour.  No countries except India could supply as the legal size of most species is above this size. The puerulus after moulting to juvenile takes many months to reach marketable size. Australia, New Zealand, Taiwan and Vietnam harvest puerulii for commercial on growing. Technologies to harvest puerulii have been developed. Unlike the  American lobster, Homarus americanus, cannibalism is much less in spiny lobsters and they can be cultured communally. There are currently no land-based lobster grow out facilities in India. Smallscale experimental grow out of lobsters has been attempted with some level of success in various marine culture systems including flow through, semi circulation and full circulation.

On-growing of puerulii and post-puerulii

Newly settled  puerulus is a non-feeding stage and they start feeding after the first moult. A biomass production of 4.7 kg/m2  was attained in P. ornatus juveniles stocked at 43/m2 and fed on natural and artificial feed and estimated that production of 1 kg can be achieved in 18 months. Early studies in Australia (Chittleborough, 1974)  reported 2 years for puerulii to reach a marketable size of 60 mm CL at 25° C.  P. homarus juveniles was reported to take 12-15 months to reach marketable size of 250 g in laboratory.  P. polyphagus puerulii took 2.5 years to reach 200 g. P. ornatus has been grown to 300 g in 10 months in Hawaii. In Taiwan, wild caught animals stocked at 25 g mean weight reached 330 g in 16 months in 200 m2 ponds.

Fattening of low value and undersize lobsters for product enhancement

Ongrowing wild caught seed lobsters are widely practiced in Vietnam, the Philippines and Indonesia. Farming is typically on a subsistence scale (limited by the availability of seed) although the magnitude of production in Vietnam is collectively very large (1000 tonnes annualaly).   In Australia and New Zealand, lobster seed cannot be taken for aquaculture except under strict and limited pilot license conditions. However, there is some in sea and on land holding of legal size lobsters for weight gain and/or more favourable (niche) marketing. In India there being no restriction on fishing, large quantities of juveniles and undersize lobsters are caught and marketed. Though there is good potential for fattening to legal size, there is very little attempt. While some entrepreneurs have shown interest, availability of healthy, quality seed is a major constraint. Ongrowing involves holding undersized lobsters, which fetch low price or not accepted legally for export, for short period until they attain legal size These lobsters could be held in tanks, ponds or cages fed with natural or artificial feed. Growth could be further enhanced remarkably through eyestalk ablation and by proper feed and water management. Since live lobsters fetch high market value, these can be marketed to targeted markets in Southeast Asian countries.

Seed availability

For the present, capture-based culture of spiny lobsters is only possible. Collection of   wild-caught peurulii and collection techniques have been developed and standardized and it could become an economically viable approach by refining the techniques further.    Studies in Australia and USA show that nearly 95% mortality of puerulii occur

rates of juvenile lobsters, except if collected in extremely large numbers from a particular area.    An efficient puerulus collector , sandwich collector, was developed by Fisheries Western Australia and tested its efficiency. Catches of individual collectors set in areas along the Western Australian coast where settlement of Panulirus cygnus is high,   was an average 100  animals per collector per month. Jeffs and Davis (2003) estimated that,  commercial scale collection by Witham collectors is possible  at an estimated cost of $0.05 to 0.30 per seed lobster. This estimated cost is dependent upon the number of puerulii available at a given time and region and thus may vary greatly. Studies along the Chennai coast show only low settlement of puerulii. Collection by collectors developed locally was not economical and therefore not recommended. New type of collectors need to be developed and standardized  and sites of collection    identified. However, commercial fishing using gill nets and trammel nets bring large number of juvenile lobsters  as incidental catch,  which fetches low price and this resource can be the source for lobster farming if collection , holding and transportation protocols are  properly developed and executed.

Collection and transportation

In India,  in spite of Minimum Legal Size  for export  is notified by Government of India, undersize lobsters were brought and sold  by fishermen  and  are exported by various means. There is no restriction on fishing of undersize lobsters unlike other lobster fishing nations, and   therefore, fishermen bring   these animals   to the shore. These undersize lobsters are held in small holding tanks in high densities by middlemen until purchased by the exporters. Due to poor water quality   in the holding tanks and    stock management these lobsters become weak and become highly vulnerable to the bacterial disease.  The seed lobsters in general are unsuitable for farming as they develop gaffkemia, the highly contagious bacterial disease, and  die within 2-3 days. The lobster traders give little care to the undersize lobsters as they fetch low price and become highly stressed during holding and transportation. A proper collection, holding and transportation protocol needs to be developed to use these valuable seed sources for fattening programme.

Lobster fattening in indoor grow-out systems

On-growing of juveniles in indoor tanks was developed by CMFRI and Tuticorin Fisheries College. Seed lobsters can be procured from fishermen or from lobster suppliers as explained above.    Juveniles are more susceptible to adverse environmental conditions. High levels of haemolymph ammonia and lactic acid have been observed in holding lobsters. Lobsters under stress are likely to be infected by opportunistic pathogens.  In P. homarus stressed lobsters have reddish exoskeleton compared to  greenish colour in healthy lobsters. Weak lobsters are further stressed during faulty transportation for long duration.  If the juveniles are healthy, dry packing and transportation is safe.  Safe transportation time (maximum) is 10 hours.  During wet transportation high levels of ammonia in the tank water, low DO levels and high temperature can lead to mortality.  The stocking density and  environmental parameters in tank water  recommended during transportation are:

Stocking : 0.1 kg/l; Temperature : 20-22°C (use synthetic ice bags) ; DO (mg/l) : 4.0 and above ; Ammonia : < 1 mg/l

The seed lobsters are to be kept under quarantine for 48 hours.  Healthy lobsters (active movement) may be treated with 50 ppm formalin for 1 hour before transferring to grow-out tanks. For on-growing in indoor systems, circular cement tanks  are preferred; however, for economy, serially constructed square tanks of about 9m2  each are ideal. Either flow-through, stagnant or recirculation system can be used depending upon the availability of seawater  Sand filtered or seawater pumped from a bore with a salinity of 30-38 ppt, pH 7.8-8.4 and hardness between 100-200 ppm can be used. Central drainage pit connected to the external drainage canal with a pipe and a stand-pipe outside will remove all wastes during flow through. A flow through system with self cleaning facility was developed at Calicut Research Centre of CMFRI.

In recirculation system, external biological filters are preferred.  pH  in recirculation systems is to be regularly monitored. Juvenile lobsters of < 100 g may be stocked at @ 1.0 kg/m2.  Shelters may be provided. Ambient light inside the  culture facility may be maintained at < 500 lux.

Tolerance limits for various water quality parameters  for the culturable species of lobsters

Food and feeding

Although accept a wide range of animal food, lobsters prefer shellfish. Mussels and soft clams (information on optimum size that can be cracked is available) can be fed as whole.  Trash fish may be chopped into a suitable size. Lobsters being nocturnal, food may be supplied at dusk. Mean gross conversion ratios of  5.0 for mussel,  5.8 for clams, 6.6 for fish and 4.8 for a mixed diet was obtained  from experimental studies.  Better conversion (3.5-4.0 for mussel) was obtained   during pilot scale farming at Calicut.

Growth in captivity

P. homarus weighing 80 g attained 330 g in 12 months on an exclusive diet of mussel. Minimum exportable weight of 200 g was achieved in 130 days. Growth enhancement can be achieved by eyestalk ablation. Ablated P. homarus gained a weight increase of 3  to 7 seven times more than the normal.  If initial weight is considered as 80 g ablated animals of P. homarus can achieve an estimated 749 g in one year. In P. ornatus 100 g  lobster attained 1.5 kg in 8 months.

Lobster culture in cages

In Philippines, P. ornatus, P. versicolor and P. longipes  are cultured in floating cages. Initial size preferred for stocking was 100-300 g and in 6-15 months harvest weight of 800-1300 g was achieved with 90% survival. Trash fish is the  main feed, which was procured at US $ 0.13-0.22/kg.  Live lobsters were sold at US $ 21-31/kg. In Vietnam, P. ornatus is the most preferred species. Floating cages made of nylon material were fixed at a depth of 10-20 m. The size of wooden fixed cage was 20-40 sq.m. Submerged cages were also used. Seed lobsters of 25-30 mm TL were initially  stocked at 100 to 200 per submerged cage and grown to 50 g. Those lobsters  were then stocked in fixed cages until a harvest weight of 800-1000 g is achieved. Lobsters were fed with chopped trash fish (lizard fish or other fishes) or shell fish. Conversion ratio was high at around 17-30 (fresh weight basis). Finfish comprise about 70% of the diet and rest by shellfish. Disease problems were erupted due to increase in number of cages, feeding with trash fish and consequently increase in total nitrogen content in water.  Treatment with 100 ppm formalin for 3-5 minutes was practised. Average annual production was 1500 t.  Farm-gate price of live lobster was US $ 26.75/kg.  The average profit margin was estimated as 50%. Cage culture experiments were conducted by NIOT, Chennai at Tuticorin. Stocking density in the fixed cages was  at 15-20 nos/m².  Lobsters were fed with mussels and clams.

Disease

Though no major diseases were encountered, stocking highly stressed seeds can invite disease. ‘Gaffkemia’ - like disease was reported during fattening in indoor system.     Juveniles lobsters kept in poor water quality  are infected This disease is highly infectious and infected lobsters  exhibit   lethargy and poor intake of feed   during later stages. P. homarus homarus lobsters loose their green colour and the shell becomes reddish. Maintaining the lobsters at lower temperature (24^oC) was found to reduce the severity of the infection. Isolation of infected stocks is necessary to stop spread of the disease. Tail fan necrosis and shell disease are also found in captive indoor stock. Good hygiene of the bottom of the tank and maintenance of water quality and sanitation in the culture facility are very crucial.