A total of 2,256 juveniles of the mud spiny lobster, Panulirus polyphagus with a mean carapace length

of 40.44 mm and mean body weight of 67.83 g after acclimatization for a period of twelve weeks

in 8000 litres FRP tanks were stocked in open sea cage near Veraval on the coast of Gujarat, India

at a density of 12.4 m-3. The lobsters were fed twice daily with fresh fish and mollusc meat at 10%

of lobster biomass per day. Monitoring of the water quality parameters in the vicinity of the cage

found that they were well within the favourable ranges for shellfish culture indicating that the cage

has not made any adverse impact on the local environment. The lobsters were harvested from the

cage after 120 days at a mean wet weight of 212.65 g. Survival was 86.1 %. The results of this

preliminary experiment indicate that there is commercial potential for the development of sea cage

culture of Panulirus polyphagus in Gujarat

Ghosh, Shubhadeep

Mohamed, Gulshad

Rao, G Syda

CMFRI Digital Repository

316Journal of the Marine Biological Association of India (2010)Gulshad Mohammed et al.J. Mar. Biol. Ass. India, 52 (2) :  316 - 319, July - December 2010IntroductionThe state of Gujarat contains about 20% of India’scoastline, 33% of the continental shelf area (1,64,000sq. km) and over 2,00,000 sq. km of EEZ and rankssecond among India’s nine maritime states in marinefish production. However, intensive and uncontrolledfishing pressure in the coastal waters of the state hasresulted in major shifts in the marine ecosystem ofthe State (Mohanraj et al., 2009).  In recent timesthe bulk of the fish catch of Gujarat has beencomposed of low value species, which are sundried,or block frozen and exported to China and SoutheastAsian countries (Mohanraj et al., 2009). Theproduction of larger sciaenids and perches, as wellas pomfrets, threadfins, penaeid prawns, lobsters,eels, clupeids and mullets is declining fast and hasreached a critical level (Mohanraj et al., 2009).Some of the valuable fishes like large sharks andwhitefish had completely vanquished from thefishery of the state.  The fishery at present isdominated by low value fin fish and shell fish, suchas smaller croakers, carangids, Bombay duck,ribbonfishes, threadfin breams, lizardfishes, flatfishesAquaculture of spiny lobsters in sea cages in Gujarat, India*Gulshad Mohammed, 1G. Syda Rao and Shubhadeep GhoshVeraval Regional Centre of CMFRI, Matsya Bhavan, Veraval - 362 269, Gujarat, India.*E-mail: gulshadm62@gmail.com1Central Marine Fisheries Research Institute, Cochin-18, Kerala, India.AbstractA total of 2,256 juveniles of the mud spiny lobster, Panulirus polyphagus with a mean carapace lengthof 40.44 mm and mean body weight of 67.83 g after acclimatization for a period of twelve weeksin 8000 litres FRP tanks were stocked in open sea cage near Veraval on the coast of Gujarat, Indiaat a density of 12.4 m-3.  The lobsters were fed twice daily with fresh fish and mollusc meat at 10%of lobster biomass per day.  Monitoring of the water quality parameters in the vicinity of the cagefound that they were well within the favourable ranges for shellfish culture indicating that the cagehas not made any adverse impact on the local environment.  The lobsters were harvested from thecage after 120 days at a mean wet weight of 212.65 g.  Survival was 86.1 %.  The results of thispreliminary experiment indicate that there is commercial potential for the development of sea cageculture of Panulirus polyphagus in Gujarat.Keywords:  Spiny lobsters, sea cages, aquaculture, Saurashtra coastand nonpenaeid prawns.  It was therefore felt to bea necessity to revitalize the dwindling fishery of theState.  Capture based aquaculture (CBA) is perhapsthe best alternative to augment the low catches andlow economic returns in recent times. In this context,open sea cage culture offers much promise inallowing fishermen to maximize their economicreturns.Lobsters (both spiny and slipper varieties) formone of the most important natural resources ofGujarat.  Spiny lobsters are particularly expensive,fetching a price depending on size, from Rs. 600 toRs. 800 kg-1 (US $ 13.3 to 17.8 kg-1).  In terms ofseed availability, pueruli and early post-pueruli spinylobsters are abundantly available in nearshore watersalong the Saurashtra coast in the post-monsoonmonths (from September onwards).  The mud spinylobster species Panulirus polyphagus was selectedfor stocking in sea cages.Material and MethodsThe most important factors determining thesuccess of cage culture is the design of the cages317Journal of the Marine Biological Association of India (2010)Aquaculture of spiny lobters in sea cagesand the selection of an appropriate site for installationof the cage. As part of the project “Open Sea CageCulture Demonstration Farms in India” funded byNational Fisheries Development Board, a 6 mdiameter cage was fabricated and launched (Fig. 1)in January 2009 off  Sutrapada Village, 18 km southof Veraval in Gujarat.  The project was facilitatedby involving the local “Sagar Fishermen’s Co-operative Society” and to this end a Memorandumof Understanding was signed with their officialsrelating to the site chosen for the project.  Thisprevented disputes concerning navigational routesand property rights in relation to the experimentalsea cage.  The water quality parameters viz.,temperature, salinity and pH were monitored onweekly basis.  Dissolved oxygen content, totalammoniacal nitrogen, nitrate nitrogen, phosphatephosphorus and total bacterial load were analysedfortnightly (APHA, 1998).The cage was made of 140 mm HDPE materialand was provided with a railing of 1 m.  The netsfor the sea cage were made up of nylon (20 mm)and were attached to 10 m diameter ballast at thebottom.  The cage was 6 m in height and was heldin position by attached floats, Gabion boxes andshock absorbers.  It was also provided with 1.3 mcatwalk to provide working space for the fishermento complete their daily work.  An additional velonscreen was provided at the bottom and a bird’s net(80 mm mesh size) on top of the cage.  The totalvolume of net cage was 182 m3.A total of 2,256 juveniles and sub-adults of P.polyphagus of mean carapace length (CL) of 40.44mm, total length (TL) of 124.72 mm and mean bodyweight (BW) of 67.83 g, were stocked in cage inat Sutrapada in January, 2009 after acclimatizationfor twelve weeks during October – December, 2008in 8000 litre FRP tanks.Lobsters were selected based on their externalappearance with all appendages and exoskeletonintact exhibiting good pigmentation. Before stocking,morphometric data such as carapace length (CL),total length (TL) and body weight (BW) of randomsamples of lobsters (n=100) were recorded. Thelobsters were fed daily with a mixture of fish andmolluscan meat in 1:1 ratio at 10% of the biomassdistributed evenly in morning and evening hours.Frequent observations were made on the growthrate of caged lobsters by randomly sampling thepopulation with cast net fortnightly to ascertain theirhealth status and adjusting their feeding ration inaccordance to the changes in the biomass of thecaged population. The nets were cleaned on alternatedays to remove the unconsumed feed, clogging withsilt and fouling with barnacles.  The cage washarvested in May, 2009 after 120 days of culture.After harvesting, CL, TL and BW of randomsamples of lobsters (n = 100) were recorded whenthe  lobsters were harvested.  Growth parameterswere estimated using the formulae given below:Mean final wet weight –Mean initial wet weightBody weight gain (%) = –––––––––––––––––––x 100Mean initial wet weightMean final total length –Mean initial total lengthTotal length gain (%) =––––––––––––––––––– x 100Mean initial total lengthMean final carapace length –Mean initial carapace lengthCarapace length gain (%) = ––––––––––––––– x 100Mean initial carapace lengthNumber of lobsters survivedat the end of the experimentMean survival (%) =––––––––––––––––––––– x 100Number of lobsters stockedat the start of the experimentln Wt - ln WoSpecific growth rate =–––––––––––––––––––– x 100 (SGR) Days of cultureWt = Final average wet weight (g), Wo = Initialaverage wet weight (g)Results and DiscussionThe cage structure used in the present study wasfound to be sturdy and durable and had not madeany adverse impact on the local environment.  Similarfloating net cages (5 m x 7 m x 4 m) provided withadditional velon screen at bottom and hideouts forpreventing cannibalism were used for rearing spinylobster, P. homarus at Vizhinjam Bay (Syda Rao etal., 2010).318Journal of the Marine Biological Association of India (2010)Gulshad Mohammed et al.Puerulii and post-puerulii, early juveniles andsub-adults of the spiny lobster, Panulirus homarusand juveniles of P. ornatus were grown in differentfloating sea cages along the southeast coast of India(Vijayakumaran et al., 2009) made of galvanizediron pipe frame (2 m x 2 m x 1.2 m) with steelwoven mesh and four inner detachable compartments(0.75 m x 0.75 m x 1.10 m). In Vietnam, varioussizes of floating cages (3.5 m x 3.5 m x 1.5 – 4 m;4 m x 4 m x 1.5 – 4 m and 3 m x 4 m x 1.5 – 4m) were used to grow, P. ornatus (Tuan et al., 2000).However in New Zealand and Australia, smallersubmerged cages were used for growing spinylobster, Jasus edwardsii (Jeffs and James, 2001;Bryars and Geddes, 2005).All the water quality, nutrient and bacteriologicalparameters recorded from the cage in the presentstudy were well within the optimum rangesrecommended for lobster culture (Table 1). Theoptimal environmental requirements for lobsterfarming are temperature (26-33oC), salinity (25-35ppt), pH (6.8-8.5), dissolved oxygen (>3.5 ppm),ammonia (<0.1 ppm) and nitrate (<0.1 ppm) (Philipset al., 1980; Van Olst et al., 1980; Kittaka, 1994;Vijayakumaran et al., 2009).Table 1. Water quality, nutrient and bacteriologicalparameters recorded from cage during lobstercultureWater quality parameters RangeTemperature (OC) 26.5 - 27.7pH 8.1 - 8.2Salinity (ppt) 34.7 - 35.1Dissolved Oxygen (ml l-1) 4.38 - 5.34Ammonia (μg. at. NH4 – N l-1) 0.139 - 0.307Nitrate (μg. at. NO3 – N l-1) 4.22 - 6. 1Phosphate (μg. at. PO4 – P l-1) 0.022 - 0.088Total microbial count (log cfu ml-1) 4.37 - 4.89Juveniles/ sub-adults of P. polyphagus havingmean CL of 40.44 mm, mean TL of 124.72 mm andmean BW of 67.83 g after rearing for twelve weeksin FRP tanks during October – December, 2008reached on an average 50.89 mm CL, 144.39 TL and114.12 gm BW. The same were stocked in the cageat Sutrapada and after culturing for 120 days hadgrown to mean CL of 65.68 mm, mean TL of 178.23mm and mean BW of 212.65 g.  A sizeable proportionof the lobsters reached 300 g body weight at thetime of harvest. The percentage increments in bodyweight, total length and carapace length in cageswere 86.34, 23.44 and 29.06, respectively.The survival rate was 86.1% in cage and SpecificGrowth Rate was 0.519.  The biomass productionand total production of P. polyphagus was 143 kgand 308.6 kg from the cage. The results of thepresent study are in full agreement to Syda Rao etal. (2010), who recorded a survival of 75%, weightincrement of 0.82 g per day and SGR of 0.50 in cagereared spiny lobsters P. homarus at Vizhinjam Bay.Vijayakumaran et al. (2009) reported that sub-adultsof P. homarus with an average weight of 123.61 greached 341.25 g in 225 days at a stocking densityof 21 m-2 with a survival of 73% in floating seacages along the southeast coast of India.  Theirgrowth rate was 0.97 g per day with a SGR of 0.43which are comparable to the present study.Sreekrishnadas et al. (1983) recorded 0.6 g growthper day with survival rate of 57.5% for P. homarusfrom open sea net cage at Tuticorin Harbour.  Thesurvival rates recorded was similar to 70 – 95 %recorded for P. homarus by lobster growers inVietnam (Tuan et al., 2000). There was no incidenceof disease in cages during the experimental period.Another important role of cage in sea is that itcan function effectively as a fish aggregating device.It was observed at Sutrapada, that the fish and lobsterpopulation around the cage increased and werefeeding on the feed thatwas leaching from the cage.The structure of cage is efficient in attracting pelagicfishes which move in shoals.  Hence, the fishermencan travel directly to the site of the cage and fishwhich will save fuel and labour charges at the sametime will increase the quantum of catch.AcknowledgementThe authors express their sincere thanks to theNational Fisheries Development Board, Hyderabadfor financing the study.319Journal of the Marine Biological Association of India (2010)Aquaculture of spiny lobters in sea cagesReferencesAPHA/AWWA/WEF, 1998. Standard Methods for theExamination of Water and Wastewater, 20th Edition, AmericanPublic Health Association/American Water WorksAssociation/ Water Environment Federation. Washington,DC. p. 4-99 to 4-125.Bryars, S. R. and M. C. Geddes. 2005. Effects of diet on thegrowth, survival and condition of sea-caged adult of southernrock lobster, Jasus edwardsii. N. Z. J. Mar. Freshwat. Res.,39: 251-262.Jeffs, A. G. and P. James. 2001. Sea-cage culture of the spinylobster Jasus edwardsii in New Zealand. Mar. Freshwat.Res., 52(8): 1419-1424.Kittaka, J. 1994. Culture of phyllosomas of spiny lobster and itsapplication to studies of larval recruitment and aquaculture.Crustaceana, 66: 258-270.Mohanraj, G., K. V. S. Nair, P. K. Asokan and S. Ghosh. 2009.Status of marine fisheries in Gujarat with strategies forsustainable and responsible fisheries. Asian Fisheries Science,22: 285-296.Philips, E. S., J. S. Cobb and R. W. George. 1980. GeneralBiology. In: J. S. Cobb and E. S. Philips (Eds.) The Biologyand Management of Lobster, New York. 1: 1-82.Srikrishnadhas, B., V. Sunderraj and M. D. K. Kuthalingam.1983. Cage culture of spiny lobster Panulirus homarus.Proceedings of the National Seminar on Cage and PenCulture, Fisheries College and Research Institute, Tuticorin,India. p. 103-106.Syda Rao, G., Rani Mary George, M. K. Anil, K. N. Saleela,  S.Jasmine H. Jose Kingsly and G. H. Rao. 2010. Cage cultureof the spiny lobster Panulirus homarus (Linnaeus) atVizhinjam, Trivandrum along the south-west coast of India.Indian J. Fish., 57(1): 23-29.Tuan, L. A., N. T. Nho and J. Humbrey. 2000. Status of cagemariculture in Vietnam. In: I. C. Liao and C. K. Lin (Eds.),Cage aquaculture in Asia, Proceedings of the FirstInternational Symposium on Cage Aquaculture in Asia. AsianFisheries Society, Manila and World Aquaculture Society –South-east Asian Chapter, Bangkok. p. 111-123.Van Olst, J. C., J. M. Carlberg and J. T. Hughes. 1980. Aquaculture.In: J. S. Cobb and E.S. Philips (Eds.) The biology andManagement of Lobster, New York. 11: 333-384.Vijayakumaran, M., R.Venkatesan, T. Senthil Murugan, T. S.Kumar, D. K. Jha, M. C. Remany,  J. M.  Leema Thilakam,S. Syed Jahan, G. Dharani, S. Kathiroli and K. Selvan. 2009.Farming of spiny lobsters in sea cages in India. N. Z. J. Mar.Freshwat. Res., 43: 623-634. Received : 05/01/2010Accepted : 30/09/2010

Aquaculture of spiny lobsters in sea cages in Gujarat, India

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Aquaculture of spiny lobsters in sea cages in Gujarat, India

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