• TROCHUS AND TURBO FISHERY IN ANDAMANS K. K. APPUKUTTAN Vizhinjam Research Centre of Central Marine Fisheries Research Institute Introduction shell fisheries and Rao (1936, 1937, 1939) has The sea around Andaman and Nicobar dealt in detail the taxonomy, fishery, feeding Islands is a rich ground for a variety of com­ habits, behaviour. breeding behaviour and mercially important molluscs. Among the sea parasites of trochus from Andamans. PaniJiker shells, troehus or top shell and turbo or tur­ (1938) has briefly reviewed theTesearch works ban shells occupy a unique position for their done on the trochus from the Andaman utility and abundance. As early as in 1929, waters. Recently Menon (1976) and Chatterjee the trDehus -fishery was organised at Andaman (1976) have d'escribed the commercial import­ Islands and a consolidated scientific report ance and the possibilities of developing shell was published in 1938 on the shell fisheries of handicrafts in A ndaman Islands. these Islands during 1930-35 period dealing Description with the history of Andaman shell fisheries, Trochus niloticus is the common top shell fishing methods, the important beds of top and turban shells and the scientific work done of commercial importance (Fig. A), exploited on these shells. The local Government after in large quantities in and around Andaman realising the importance of this fishery, started and Nicobar Islands. The shell is conical or giving the fi shing grounds on lease to mer­ pagoda-like, white with many reddish brown chants for fishing and collected royalty from longitudinal bands. The mother-of-pearl them. underline the shell surface. The shell attains a size of 8 em to 12 em and the period of Previous work life is about 10 years. Sexual maturity is . Amirthalingam (1932) and Setna (1933) reached when the shell attains 6-7 em dia­ have reported the details of the Andaman meter. The brilliant lusture of mother of December, 1 &77 21 pearl is more in 8.5 - 10.0 cm sized shells. outer surface is dark and rnott1ed with brown The growth rate studies on this shell showed and white. Pearly layer is visible when the that the female shells grow faster, growth rate outer coating of the shell is removed. A large vary inversely with the size of shells and and solid operculum is present. Shells rang­ growth in diameter is closely related with ing from 8- \8 em are being exploited. This growth along the whorl of the shell. This is found in Andaman and Nicobar Islands species is a continuous breeder, spawns during and Japan. or immediately after warm season (Rao, 1936). This species is widely distributed from Ceylon, Fishing zone Mergui", Andaman and Nicobar Islands to Nine important fishing zones, their port Samoa, Queensland, Western Australia, New and latitude are given below: Caledonia, Philippines, Fiji to Japan. I. Cape Price to Mayabunder, between 11° 56.5' and 130 34.S'N. Port-Maya­ Turbo murmoratus is the turban shell bunder. exploited from these Islands (Fig. B). This is 2. Cape Price to Austen Straight, bet­ popularly known as 'green snail'. The shell ween Lat 12° 54' and 13° 34.5'N. is thick, massive with a wide aperture. The Port - Mayabunder. 22 Seafood Export Journal 3. Mayabunder to long Island, between Island know the rich shell beds in the coastal Lat 12° 24' and 12° 55 'N. area and collect the shell during low tide, Port - Long Island. especially from the mangroove area_ These shells are always seen underneath the rocks, 4. Long Island to Shoal Bay, between coral stones, in the crevices of rocks or burried Lat 12° 0.5' and 12° IS'N. ill the mud. Divers reach the shell beds by Port - Long Island. means of dinghy called Sampan or Bongo . 5. Shoal Bay to Chiriatapu, between dong; and they dive 'without any diving gears . Lat 11° 29' and 11 ° 56.4'N. In each Bongo dong; 10 adults will be engaged. Port - Port Blair. Such a unit will be able to collect about 100 shells a day. The main fishing season begins 6. Chiriatapu to Port Mouat, between by January and lasts till July. Most produc­ Lat 11 ' 29' and 1[0 38'N. tive area for trochus and turbo are zone five Port - Port Mouat. and six but the larger sized shells are being collected mainly fr om zone eight and nin~. 7. Ritchies Archipelago, Island and Islets, between Lat 10' 46.5' and and 12' 19'N. Port - Port Blair. Statistics 8. Nicobar Central group, between Lat A total of 400 tonnes of trochus and lOS 7' 52' and 8' 35' N. Port-Nancowrie. ton nes of turbo was lande d during 1976. A rough estimate of average shell landings of 9. Nicobar Southern group, between Lat the Island is between 400-600 tonnes for 6' 45 ' and 7' 31' N. Port-Nancowrie. trochus and 100-150 tonnes for turbo shells per year. The present market price of raw The A ndaman and Nicobar administrat­ shells of turbo is Rs. 10,000/- per tonne and tion have leased out all these nine zones for Rs. 4,000/- for trochus sheIl. A cleaned turbo fishing every year. There are seven licensed shell may cost between Rs. 20/- and 50/- and shell collectors in the Island and each is trochus shell between Rs, 5/- and 15/-. The permitted to raise up to 25 tonnes of shells finished product viz. necklace, carved out of a year. bits of turbo shell costs Rs. 35/- to 60/-; ear­ flngs Rs. 15/- to 25/-: finger rings Rs. 5/- to Method of fishing 10/-; wrist let Rs. 25 /- to 30/-; buttons Rs. Both the species are exploited from 7.50 per set; cufflinks Rs. 8/- to 15/- a pair; shallow and deeper waters. The turbo shell s table lamp Rs, 18/- to 55/- and lockets Rs. are collected from a depth ranging from 6- 13 5/- to 15/-. The estimated profit of the indus­ . fathom by skin diving. The divers in the try is around 25%. December, 1977 23 Utilisation-processing custume jewellery, buttons and a variety of The raw shells brought by the divers are curious articles. In Calcutta there are several collected and dumped in godowns by the handicrafts units and they manufacture num­ local shell merchants. The soft part of the ber of shell articles. ·The process of manu­ shell is taken out either by boiling or by pit factu re of shell articles include curing in boil­ curing. Once the soft body parts are removed ing water, the removal of the upper skin by completely, the shell is cleaned, graded, mechanical abrasion, bleaching, cutting, shap­ packed in gunny bags and marketed. It is ing, fitting, engraving, enamelling and final understood from the local merchants that finishing. there is 10-20% of tbe wormed shells in trochus and turbo collected from various Finished products fishing zones of the Island. The boring orga­ Pictures of saints, beautiful designs, nisms are mainly polychaetes and bivalves. names etc., can be embossed on these shells The percentage of damaged shells are more in by means of pootographic method. At Anda­ large sized shells. Fouling organisms like, mans there are few sh~ll handicrafts emporia, barnacles are also seen in trochus and turbo where engraving of shell pieces into beautiful shells. Encrustation of calcarious algae is a models, lockets, rings etc., are being done by common phenomenon. Damaged shells were expert artisans. The important articles made found more in the trochus landings than in out of these shells are table lamp, pen stand, turbo. necklaces, ashtrays, ear rings, chain lockets, Both these shells are most sought after but bowls, cufflinks, fork, spoon and buttons. for industrial purposes. Turbo shells are con­ sidered as costliest and is heavy and nearlv The final products are sold widely in rounded in shape. By cleaning and mechani­ almost all the cities and tourist centres all cal grinding of the shell, the internal pearly over India. Of late some shell merchants of lusture is revealed. After cleaning and pro­ Calcutta and South India are exporting the cessing, these shells are highly attractive and finished products to different countries viz. versatile. Trochus shells also have the internal France and U. S. A . The ornaments and mother of pearl layer and by cleaning and nova/til'S made out of these shells have good polishing the outer layer, the pearly luster is market in the U. S. A. In France, buttons revealed. made of shells are utilised for latest fashion Japan and the Western countries have designs. The market is fast improving and developed modern industria I techniques to the need for popularising the industry is much process the trochus and turbo shells into essential. 84 Seafood Export Journal Conclusion Marine Fisheries Research Institute, Cochin Apart from trochus and turbo shells. for the kind help and encouragements given Xancus are also being caught in good num­ for preparing this note and to Shri P. M. G. bers. Chank beds are located mainly near Menon, Director of Fi sheries, Andaman and Kalapadu, Vandur and Rose Island. About Nicohar Islands for kindly making available 5,000 good chanks were being landed during some of the data on trochus and tnrbo fishery. 1976 in the Port Blair area. They range in size from 115-175 mm. Other important REFERENCES shells collected along with chanks are Cassis Amirthalingam, C. (1932). Breeding of trochus and cornuata (Helmet shells), Lambi. lambis, L, preservation of the bed in the Andamans. chiragra (five finger chanks or Scorpion shells) Curl'. Sci .. 1 : 31. Murex sp., Nautilus sp., (pearly nalltilus), Chatterjee, S.