II. RESULTS

1. Aquarium market in Japan

Japan has a 140 billion yen market for freshwater aquarium pets on a retail price basis (Toyoshima, 1995). This includes 95 billion yen for equipment and 45 billion yen for pets (including 26, 15, and 4 billion yen for tropical fishes, gold fish and carps, and aquatic plants, respectively). However, no reliable information is available on marine aquarium pets. It is generally said that the market scale for marine aquarium pets is 10 to 20 % of that for freshwater aquarium pets. It values approximately 5 to 10 billion yen.

According to a survey conducted in 1992 (Toyoshima, 1995), the percentage of households keeping aquarium pets in Japan (2.9 %) was much lower than those in USA (5.0 %) and Germany (5.5 %). It could therefore be presumed that the aquarium market in Japan might double in future. During the 10 year-period from 1987, the aquarium pet imports expanded 5.3 times in value (Ministry of Finance, 1987 to 1996).

The reasons for this remarkable increase in the Japanese aquarium market are as follows: (1) rapid economic development between 1986 and 1991, (2) an increase in leisure time due to introduction of two-day-off a week system, (3) prohibition of keeping large pet animals in multi-storied apartment buildings, and (4) introduction of a variety of aquarium equipments. Since 1993, however, aquarium business has been badly affected by the economic recession in Japan, particularly from the latter half of 1996.

In Japan, the distribution system for tropical freshwater aquarium pets basically consists of importers (or primary wholesalers), wholesalers (or secondary wholesalers), retailers, and consumers. There are 16 major importers for aquarium pets in Japan. Most of them are located in large cities, such as Tokyo and Osaka. Wholesalers buy imported aquarium pets from the importers, and sell them to retailers. There are about 200 wholesalers and 3,000 retailers in Japan. Consumers usually buy aquarium pets from retailers and their number is estimated to be 1.2 million (Toyoshima, 1995).

In addition to this regular route, there are many cases in which wholesalers and retailers directly import freshwater aquarium pets on irregular basis. A certain amount of intra-trading is also conducted among the wholesalers. Thus, the distribution system is very complicated.

2. Imports of aquarium pets in Japan

The finer details regarding the import of aquarium fishes excluding carps and gold fish, between 1987 and 1996, are presented in Tables 1 and 2 and Figure 1. In these statistics, there is no distinction between freshwater and marine aquarium fishes.

Table 1. Annual quantity (kg) of imported aquarium fishes (excluding carp and goldfish) in Japan. Country-wise break-up for the period 1987 to 1996.

(Source : Ministry of Finance, Japan)

Table 2. Annual value (x 1,000 yen) of imported aquarium fishes (excluding carp and goldfish) in Japan. Country-wise break-up for the period 1987 to 1996.

(Source : Ministry of Finance, Japan)

During the decade, the import increased 6.6 times (from 78 to 518 tons) in quantity and 5.3 times (from 1.5 to 8.0 billion yen) in value. Figure 2 shows the country-wise share of aquarium fish exports to Japan in 1996. Both in terms of quantity and value, the top five countries account for about 70 % of the total exports to Japan. During this period, all the countries mentioned above have increased their share of marine aquarium pets exported to Japan (Figure 3). Particularly, the imports from Indonesia and Singapore have shown a remarkable increase since 1992. Aquarium fish imports from the Pacific island countries increased from nil in 1988 to 1,542 kg in 1993 (Table 1). After that, however, it has been dropping and reached 490 kg (0.1 % of the total imports) in 1996.

Figure 1. Annual quantity and value of aquarium fishes imported into Japan.

Figure 2. Quantity (a) and value (b) of Japanese import of aquarium fishes, share by country of origin (1996).

Figure 3. Annual quantity of Japanese import of aquarium fishes from five major countries.

The present survey has revealed that the major exporters of marine aquarium pets to Japan are Indonesia, the Philippines, Singapore, and USA. In addition to these countries, Sri Lanka, Kenya, Egypt, Mauritius, Australia, and Vietnam export marine aquarium pets to Japan. Among marine aquarium pets, stony corals, which are listed in Appendix II of CITES, are imported only from Indonesia.

The information available on aquarium giant clam imports is fragmentary and none of these could be confirmed. At present, no aquarium giant clams are imported except for the specimens exhibited in public aquariums. All aquarium giant clams distributed in Japan are from Okinawa (mainly Ishigaki Island) and Amami-ohshima.

3. Giant clam supply from Okinawa

3-1. Catch and value

Giant clams commonly found in Okinawa are Tridacna crocea, T. squamosa, T. maxima, and Hippopus hippopus. T. crocea accounts for more than 90 % of the total giant clam landings.

Annual giant clam catches and average prices in Okinawa for the period to 1975 and 1995 are presented in Table 3 and Figure 4. The annual catch suddenly dropped from 578 tons in 1975 to 227 tons in 1976. Thereafter, it gradually decreased to 28 tons in 1995. Assuming the average weight of one piece of T. crocea, as 130 g, an annual catch of 28 tons is equivalent to 215,000 pieces in number. However, actual catches may be much higher than those in the statistical reports, because quite a number of giant clams are traded outside public markets through traditional routes.

Table 3. Annual quantity, value and average price of giant clams caught in Okinawa, over two decades from 1975.

(Source : Okinawa Prefecture)

Figure 4. Annual quantity and average price of giant clams caught in Okinawa.

Most of the giant clams are consumed as food in Okinawa, while only very few are distributed as aquarium pets. Giant clams are traditionally consumed as sashimi, sushi, and vinegared dishes at home. Currently, they are being served in restaurants as high-class foods because of their high price-tags. In order to meet the increased demand, giant clams cultured in the Philippines are also imported as frozen products in recent years to Okinawa (Kuronuma and Tamashiro, 1997). These are sold mainly in the common market as substitute to the local giant clams, and part of it is processed as canned foods.

In Okinawa the average price of giant clams used to be 400 to 600 yen/kg until 1985 (Figure 4). By 1992 it had increased to about 1,400 yen/kg. At the time of the present survey, T. crocea were being sold between 2,000 and 2,500 yen/kg (between 200 and 300 yen per piece) at fishermen's cooperatives and public markets. In the pet trade, special care has to be taken during catching, transporting, and stocking. This escalates the price of pet clams when compared to that of food giant clams. The present survey estimated the cost of T. crocea as pet to be around 500 yen per piece.

3-2. Seed production and culture

As mentioned above, the catch of giant clams has decreased, due probably to depletion of their stock. For the purpose of stock enhancement, Okinawa Prefectural Fisheries Experimental Station undertook a study on seed production of giant clams in 1972. In 1987, the Experimental Station succeeded in mass production of giant clam seeds, and started distributing them at a low price to fishermen's cooperatives in Okinawa for culture and release into the sea (Table 4).

The main species is T. crocea, and annually 44,000 to 459,000 seeds are distributed to the fishermen's cooperatives. In addition 18,000 to 218,000 seeds of T. squamosa are produced and distributed. Seeds of T. maxima and T. derasa are produced occasionally and distributed.

Table 4. Number of giant clam seeds released into Okinawa waters during the period 1987 to 1995.

(Source : Okinawa Prefectural Fisheries Experimental Center)

Okinawa Kuruma-ebi Co., Ltd., a private shrimp culture company, imported T. derasa seeds for experimental culture from Palau. The number of seeds imported was 2,400 (6 to 8 cm in shell length, SL) in 1989, and 1,000 (about 5 cm SL) and 10,000 (about 1 cm SL) in 1990. In 1992, for the purpose of establishing a commercial giant clam culture farm, the Okinawa Kuruma-ebi Co., Ltd. established Tarama Fisheries Co., Ltd. This company has been annually buying about 10,000 T. crocea and T. squamosa seeds from the Okinawa Fisheries Experimental Station for culture. The company has also tried to produce T. crocea seeds using their own facilities. In 1995, they succeeded in producing 300,000 seeds (2.7 cm SL). Though this company has not made any profits till date, they are eager to develop the giant clam culture industry.

3-3. Supply of aquarium giant clams

Members of fishermen's cooperatives can catch giant clams without any license. A fishery regulation set by the local government prohibits giant clam fishing during the spawning season between June and August. It also prohibits capture of T. crocea smaller than 8 cm SL and T. squamosa smaller than 20 cm SL. In addition to the regulation, some fishermen's cooperatives have set their own rules to protect the giant clam stock, such as: (1) prohibiting fishing with diving equipment, (2) setting areas closed to fishing, and (3) limiting daily number at 50 pieces per person.

According to a sales manager of Onna-son Fishermen's Cooperative, Okinawa, they have tried shipping aquarium fishes to the Japanese main islands, but discontinued it due to difficulties in handling marine aquarium organisms. In recent years, they have been selling aquarium fishes only to two local resort hotels, 100 to 200 fishes each, every 2 to 3 months. All giant clams landed at the cooperative unit, about 2,000 kg per year, are sold as food in markets.

In Onna-son Fishermen's Cooperative, two fishermen have been engaged in catching aquarium organisms as a side business, since 1995. They catch mainly invertebrates, such as giant clams and soft corals. In 1996, they sold about 2,000 giant clams to a wholesaler in Kanto area through a local broker. At the time of the present survey, about 200 pieces of T. crocea (8 to 10 cm SL) and 10 pieces of T. squamosa (15 to 20 cm SL) were being stocked in a land based tank.

Okinawa Aquarium Fish Center established in 1983 is being operated by fishermen. During the aquarium boom, the Center regularly shipped marine aquarium organisms to a wholesaler in Kanto area and retailers in Tokyo, Nagoya, Osaka, and Hiroshima. In terms of value, fishes accounted for more than 90 % of total marine aquarium organisms shipped by the Center. During the boom, 300 to 500 giant clams were sold yearly. In recent years, however, this center does not ship many aquarium organisms due to business depression and poor catch of aquarium fishes.

In Naha city, Okinawa, there are three retailers for aquarium pets. One of them was keeping 10 pieces of T. crocea (8 to 10 cm SL) which were being sold at 1,600 to 2,000 yen per piece at the time of the this survey. The retailer sold 1,000 to 2,000 T. crocea a year during the aquarium boom period, but of late it has dwindled to about 200 pieces.

In Okinawa, aquarium pet fishing is carried on in Okinawa Island and Ishigaki Island. In Okinawa Island, out of the 10 fishermen make a living on aquarium pet fishing, only 2 or 3 of them are very active. In Ishigaki Island, there are about 20 fishermen catching aquarium pets. The number of aquarium pet fishermen in Amami-ohshima is almost same as that in Okinawa Island.

Assuming that a fisherman is capable of catching a maximum of 1,000 aquarium giant clams in a year. Annual aquarium giant clam potential supply from Okinawa Island, Ishigaki Island and Amami-ohshima is estimated at 10,000, 20,000 and 10,000 pieces, respectively. Therefore, about 40,000 pieces of aquarium giant clams were supplied during the aquarium boom. The recent figures are estimated at 20,000 to 30,000 pieces.