Pearl culture in Japan is carried out mostly by small cooperatives or family enterprises, while only a few large-scale operations exist. In the peak period of production (1966), there were 4,710 co-operatives half of which were operating 1–14 rafts, one fifth operating 15–29 rafts, 12.0 %, 30–49 rafts and the rest more than 50 rafts. The total number of co-operatives came down to about 2,500 in 1973. This shows that small-scale operations are the mainstay in pearl culture. The Japanese pearl culturist has the advantage of being able to buy the mother oysters for his farm from those who are solely engaged in seed collection and mother oyster culture. In India also such small-scale operations at family level is possible if the production of oyster seed is done by hatcheries and supplied to the pearl culturist.
The activities, major inventory and manpower of a pearl culture establishment is summarised briefly to provide an overview for an easy understanding of the nature of this industry. Major work is in the sea involving pearl oyster collection and farming. Manpower needs and inventory items vary according to the scale of the operation.
A) Raw material: Pearl oyster (Pinctada fucata)
Oysters from natural beds
Activity: Seasonal survey of beds and collection by diving.
Inventory: Boats; self-contained underwater breathing apparatus (SCUBA) and diving accessories such as fins, masks, snorkel, depth-gauge, knife, belt; compressed air units (main and portable compressors); collection kit and oyster bins.
Manpower: Boat crew, navigator, divers, diving assistants.
Oysters cultured from wild spat
Activity: Collection of pearl oyster spat by suspending spat collectors from rafts at suitable sites.
Inventory: Rafts, lighted buoys, anchors, chain and spat collectors.
Manpower: Same as above and farm labour.
Oysters cultured from hatchery spat
Activity: Induced spawning, larval rearing, culture of larval food, spat production, transplantation.
Inventory: Hatchery building, A/C larval food production room, glass carbuoys, FRP tanks 50 l and 1 ton capacity, chemicals, U.V. sterilizing unit, seawater flow-through system, glassware, plasticware.
Manpower: Biologist, laboratory technicians, technical assistants.
B) Pearl oyster farm
Activity: Juvenile rearing, mother oyster culture, post-operation care, farm maintenance and farm stock maintenance.
Inventory: Log rafts, long lines, lighted buoys, floats, anchors, chain rope, juvenile rearing cages, cages, frame nets, dinghy, out-board motor, floating sheds and miscellaneous tools.
Manpower: Farm superintendent, technical assistants, farm labour.
C) On-shore establishment
Activity: Pearl oyster surgery and convalescence.
Inventory: Surgical tools and accessories, furniture, shell bead nuclei of different sizes, chemicals, glassware, plasticware, ultraviolet lamps and raceway.
Manpower: Chief technician and technicians.
Activity: Shore support for maintenance of farm and farm stock.
Inventory: Oyster cleaning tools, farm structure maintenance requirements (repairs and maintenance of raft, long line, floats, anchors, chain, cages, etc.) and oyster tanks.
Manpower: Same as for pearl oyster farm and on-shore establishment.
D) Pearl collection centre
Activity: Collection of cultured pearls and incidental natural pearls.
Inventory: Plasticware, chemicals, oyster knife, vats.
Manpower: Technical assistant
E) Pearl processing centre
Activity: Cleaning, sorting and grading of pearls; treatment of pearls for removal of minor blemishes; bleaching, dyeing, and colour improvements.
Inventory: Sorting trays, miscellaneous tools, chemicals and glassware.
Manpower: Pearl processing expert and technical assistant.
F) General services
Activity: Supply of quality filtered seawater to pearl oyster hatchery and surgery, raceway, flow-through system and other tanks, sterilized water for larval food production and larval rearing.
Inventory: Pump house, filter bed, sump, over-head tank, supply channel with regulators.
Manpower: Electrical supervisor and assistant.
Activity: To supply oil-free air to hatchery, larval food production laboratory, and pearl oyster surgical room.
Inventory: Air blowers with air supply tubes and regulators.
Manpower: Same as above.
Power and fresh water supply
Activity: Monitoring of oyster health and condition; maturity, seawater analysis, bacterial analysis of seawater; advice to farm superintendent and chief technician; feed-back to research system.
Inventory: General biological laboratory equipment and analytical equipment for seawater analysis.
Manpower: Biologist, chemist, laboratory technicians.
H) By-product unit
Activity: Conversion of by-products of pearl culture to value-added items.
Inventory: If the unit is self-contained, all items required for utilization of shell and meat; otherwise, collection, preservation and storage of materials, unit sale to outside agencies.
Manpower: Specific manpower to handle by-products processing work, if self-contained, otherwise linked to other items.
I) Management and administration
Activity: Planning, execution and administration of project.
Manpower: General manager, administration, accountants and stores staff.