Commercial Jellyfish Fisheries in South East Asia

Information by Makoto Omori & Eiji Nakano
Tokyo University of Fisheries, Tokyo, Japan

Scientific Name: Rhizostomeae, Scyphozoa spp - undifferentiated
Australian Standard Fish Name:  Jellyfish
AQIS Code: JLY
Australian Species Code: 11 120000
Catch Method:  Wild caught

Exporters of Jelly Fish 
Importers of Jelly Fish 
Processors of Jelly Fish 
Wholesale Suppliers of Jelly Fish 
Seafood Agents for Jelly Fish

Jellyfish Fisheries in South East Asia
 

Abstract
A few large jellyfish species in the order Rhizostomeae constitute an important food in Chinese cooking. For more than 1700 years, they have been exploited along the coasts of China. Such jellyfish became an important fishery commodity of Southeast Asian countries in the 1970's with increasing demand from the Japanese market. Recently, Japan has imported 5400-10,000 tons of jellyfish products per year, valued at about 25.5 million US dollars, annually from the Philippines, Vietnam, Thailand, Malaysia, Indonesia, Singapore and Myanmar. Judging from the type names at market and the external appearance of the semi-dried products, the edible jellyfish harvest in Southeast Asia is composed of more than 8 species. They are caught by various kinds of fishing gear including set nets, drift nets, hand nets, scoop nets, beach seines and hooks. The fishery is characterized by large fluctuations of the annual catch and a short fishing season that is restricted from two to four months. The average annual catch of jellyfish between 1988 and 1999 in Southeast Asia is estimated to be about 169,000 metric tons in wet weight and the worldwide catch is approximately 321,000 metric tons. Needs for future study on the biology of rhizostome jellyfish are discussed as they relate to understanding population fluctuations.

Introduction
Some species of large jellyfish are considered to be delicacies for Chinese cooking. Their medicinal value has also been recognized for a long time (South China Sea Institute of Oceanology, 1978; Hsieh & Rudloe, 1994). For over a thousand years, jellyfish have been exploited along the coasts of China. The Chinese philosopher Zhang Hua (232-300 A.D.) described the use of jellyfish as food in the old literature "Natural History" during the Tsin Dynasty (Wu, 1955).  Today the Japanese are the leading consumers of jellyfish. Since the 1970's, with increasing demand from the Japanese market, jellyfish fishing has become popular in Southeast Asia. More recently, small-scale exploitation of jellyfish has also commenced in other countries such as Australia, India, Mexico, Turkey and the USA.

In Southeast Asia, jellyfish are fished in the Philippines, Vietnam, Malaysia, Thailand, Indonesia, Singapore and Myanmar.  One of the present authors (Eiji Nakano) has engaged in trade of jellyfish commodity for 27 years. He estimates that about wo thirds of the products are exported to Japan and the remainder are sold to South Korea, Taiwan, Singapore, Hong Kong and recently the USA.

In spite of its importance as a commodity, only a little is known about the biology and fishery of edible jellyfish.  This is particularly so in Southeast Asia where scientific studies cannot catch up with the rapid development of exploitation. The fishery is characterized by considerable fluctuation in the catch and the good season is restricted to a few months, which vary by locality. This circumstance causes instability of the fishery. The present review compiles available information on the fishery of edible jellyfish in Southeast Asia, in order to call some attention to the ecology of the animals and perhaps to stimulate further development of the jellyfish fishing industry in the region.

Species
Edible jellyfish all belong to the order Rhizostomeae, in the Scyphomedusae. The bodies of these jellyfish are large, and considerably tough and rigid, with a thick umbrella.  At least 11 species in 5 families, i.e. Cepheidae, Catostylidae, Lobonematidae, Rhizostomatidae and Stomolophidae, are known to be exploited worldwide. Taxonomic charachteristics and geographic distribution of each species can be found in Kramp (1961).

Cephea cephea is distributed widely in the Indo-West Pacific from the Red Sea to Touamotu Archipelago. Catostylus mosaicus, Crambione mastigophora and Crambionella orsini were added rather recently to the list of marketable species. Catostylus mosaicus is distributed in the Philippines, New Guinea and west coasts of Australia, and is exploited in New South Wales, Australia. Crambione mastigophora occurs in the Malay Archipelago, Java and Truk Island, whereas Crambionella orsini is found in the Red Sea, Iranian Gulf and Bengal Bay. Lobonema smithii and Lobonemoides gracilis are restricted to tropical waters in the Indo-West Pacific. Morphologically these two species are quite similar and Dr P. Cornelius (Pers. comm.) considers that all 'species' of Lobonema and Lobonemoides to be just one species Labonema smithii, Rhizostoma pulmo is distributed in the Mediterranean, Bay of Biscay, North Sea and Black Sea.  According to Dr A. Kideys (pers.comm.), a small amount of this species is commercially fished in Turkish coasts of the Sea of Marmara and Black Sea.  Rhopilema esculentum, the most expensive species at market, is distributed in the western part of Japan, Po Hai, Yellow Sea and the East and South China Sea (Hon et al., 1978).  On the other hand, Rhopilema hispidum occurs in warmer waters in the Indo-west Pacific, from the southern part of Japan, southern coasts of China, Philippines, Malaysia and Indonesia to the Indian Ocean and the Red Sea. Stomolophus meleagris has been recorded in the southeast Atlantic coast of the USA, Gulf of Mexico, off Baja California and off Panama.  On the other hand, Nemopilema nomurai is found in the marginal seas of the northwestern Pacific. This species was described by Kishinouye (1922) as a distinct species, but was mistakenly placed in the genus Stomolophus by Uchida (1954), and moreover, it was included under the species S. meleagris (Kramp, 1961). However they are not in the same species at all, and we propose to refer S. nomurai to its original genus (omori, Kitamura & Cornelius, unpublished).  It grows to an enormous size, being sometimes greater than 1 metre in diameter and as much as 150 kg. Heavy occurrence of the species along the Japanese coast of the Sea of Japan was reported in 1920, 1958 and 1995 (Kishinouye, 1922; Shimomura, 1959; Yasuda, 1995). In addition to these 11 species, Dr T. Heeger (pers. comm.) recently informed us that he saw fresh Cassiopea ndrosia at the market in Carmen, north of Cebu, Philippines, for local consumption.

Because of their large size and difficulties in preservation for taxonomic study, taxonomic specialists have not yet had opportunities to study many specimens of edible jellyfish. Therefore, some species from Southeast Asia have still not been properly identified. Variations in morphological features, size and coloration are considerable, and the taxonomy remains somewhat confused.

Jellyfish are processed with a mixture of salt and alum, and the semi-dried products are marketed as a commodity (Hon et al, 1978; Omori, 1981; Rumpet 1991; Hsieh & Rudloe, 1994; Hsieh et al., 2001). Judging from the shape of these commodities, the edible jellyfish harvest in Southeast Asia is composed of more than 8 species. Jellyfish Dealers and Merchants call the jellyfish at market simply by the following 8 types based on the color, form, texture and size of the semi-dried products.

1. 1.  Red type or China type. Slightly reddish with smooth exumbrella.  Umprella 300-600 mm in diameter.  Probably Rhopilema esculentum.
2. 2.  White Type.  Exumbrella whitish with numerous 1-3cm long, pointed papillae. Umbrella up to 500mm in diameter.  Most certainly Lobonema smithii.
3. 3.  Sand Type.  Exumbrella whitish with numerous small projections and brown spots.  Umbrella reaches over 500mm in diameter.  Probably Rhopilema hispidum.
4. 4.  River Type. Whitish or slightly brown, small; exumbrella not smooth. Diameter up to 200mm. This is often fished in estuaries and near the mouths of rivers.
5. 5.  Cilacap Type. Lilac colored when alive; diameter up to 250mm. There are fine peripheral radial ridges on the exumbrella. This type occurs mainly in Cilacap, East Java.
6. 6.  Prigi Type.  Reddish purple when alive; diameter up to 400mm. Peripheral radial ridges are not very clear. This type occurs abundantly in Prigi Bay and Muncar, East Java, and identified in Muncar as Crambione mastigophora by Dr M. Toyokawa (pers. comm.).
7. 7.  Semi-China Type. Light yellowish; exumbrella smooth. Diameter up to 150mm. This type is similar to the Red type but smaller.
8. 8.  Ball type.  Slightly brownish; umbrella thick and rigid. The wide marginal ridges and grooves of exumbrella are themselves distinctive.  Dr P. Cornelius (pers. comm.) identified as Crambionella orsini.

Fishery in Southeast Asia

History
Chinese immigrants probably first introduced the jellyfish fishery to a few places in Southeast Asia. But, the fishery remained at a small scale before 1970, as Japan imported most of its semi-dried jellyfish from China. Due to instability of production and a rapid rise of the price in China, however, Japanese merchants in Thailand, Malaysia and Indonesia emphasized jellyfish fishing and technical development of the processing in the 1970's. After that, the jellyfish fishery was expanded to sites in the Philippines, Vietnam and Myanmar.

Fishing methods and behavior of Jellyfish
The fishing gear used includes various set-nets, drift-nets, push-nets (scoop nets), hand nets, beach seines and weirs. A typical set-net with rectangular mouth is set at a depth of 2-10 metres across a tidal current. Drift nets are also used across the current flow with a system of floats and sinkers. Hand nets, long poles with two edged iron hooks on top and trawling nets are also commonly used for incidental catch. There is no distinctive difference in fishing methodology applied to different species or locality.

In general, the entire body of the Red and Semi-China types are brought back, but for the White and Sand types, fishermen often cut off the 'leg' portion (mouth, arms) while at sea and only umbrellas of the medusae are loaded into the boat.

Fishing is carried out during the daytime only, as fishermen search for jellyfish when they appear at the surface of the water. Naturally, weather conditions and tide affect such fishing operations, as jellyfish aggregate at the water surface only when the sea is calm.  They occur near the seashore at high tide, and are transported to offshore as the tide starts to recede.

The Tiver type is found mainly in brackish water near the mouth of rivers, whereas the White type occurs in more offshore waters. The Sand type is found in both environments.  According to fishermen, the distance of horizontal migration of the Red type is generally greater than other types.

Fishing grounds and Fishing Season

Figure 1. Main fishing grounds of jellyfish in Southeast Asia.  1.  San Miguel Bay, 2.  Carigara Bay,  3. Malampaya Sound, 4. Haiphon, 5. Tonking Bay, 6. Cam Ranh, 7. Phu Quoc Island, 8. Rayong, 9. Samut Sakhon, 10. Ranong, 11. Ulu Kuala Matu, 12. Kabong, 13. Kuchina, 14. Sematan, 15. Ipoh, 16. Kuala Lumpur, 17. Penang, 18. Pangkor, 19. Talok Anson, 20. Bacan Island, 21. Balikpepan, 22. Kotabalu, 23. Tuban, 24. Cirebon, 25. Muncar, 26. Prigi, 27. Cilacap, 28. Bangka Island, 29. Tanjung Balai, 30. Medan, 31. Sittwe

Figure 1 shows the main fishing grounds of jellyfish in Southeast Asia. Based on data collected mainly by the authors and some information from previous reports, the fishing seasof for various types of jellyfish in each location is indicated on Table 2. (see below)  In Thailand, fishing is seen along the Gulf of Thailand from Tayong to Songkla and around Ranong in the Andaman Sea (Soonthonvipat, 1976). In Malaysia, the fishing grounds are at Telok-Anson and neighbouring waters in the Strait of Malacca and around Kuching and Ulu Kuala Matu in Sarawak (Rumpet, 1991)

There is an inverse relationship between the fishing season and the monsoon. The main fishing season of jellyfish is between March and May and August and November. Fishermen stay at home during the dry season (December and February) when northeast or northwest winds and rough seas prevail.  The fishing is also intermittent in some areas during the southwest monsoon (rainy season)

In order to make the analysis simple, we have assumed the peak season of each fishing ground in Table 2 to be the first even-numbered month after fishing starts.  Then, 35% of the peaks were in August, 26% in April and 18% in October.  Figure 2 shows comparison between locations of fishing grounds with peak season and the general pattern of the offshore surface currents (Wyrtki 1961). Most of the fishing grounds are found where water currents have velocities of 12 or 15 cm s¯¹. In the fishing grounds located very near shore, the current velocity must be much lower.  The life history of jellyfish and other factors such as fishing method and size of fishing boat may be also responsible for setting the fishing season.  In some regions is carried out only during periods when the main offshore fishing for other fish is suspended by unfavourable weather conditions.

The places where great numbers of edible jellyfish occur are characterized by having a large tidal range, shallow depth, semi-enclosed water mass, freshwater inflow through river systems and development of mangrove swamps.  Such factors apparently create favourable conditions for settling of polyps and recruitment. In Thailand and Malaysia, fishermen say that the jellyfish catch has decreased after extensive coastal development and cutting of mangrove trees.

Table 2.  Main fishing grounds and fishing season of various types of jellyfish in Southeast Asia.

Production and Catches
According to records of the Tokyo Customs House, the amount of semi-dried jellyfish commodities imported annually from Southeast Asia to Japan varied from 5369 to 10,084 metric tons (average 7,874 tons per year) during the period from 1988 to 1999 (Table 3).  As the total amount imported from China during the same 12 year period averaged 2,933 tons, the figures show the current importance of jellyfish production in Southeast Asia.  A number of dealers and merchants estimate that the actual catch of jellyfish in Southeast Asia may be approximately 1.5 times larger than the amount exported to Japan.  In this connection, for example, the amount of semi-dried products exported from Sarawak varied from 358 to 1,510 tons annually during the period from 1980 to 1987 and of that 59-96% (average 83%) was for Japan (Rumpet, 1991). Water content of edible jellyfish is about 95% (measured on Rhopilema esculantum, Omori, unpublished) and production yield from fresh jellyfish to the marketed commodity is about 7% of the original weight (Omori, 1981). Thus we can estimate average annual catch of jellyfish in Southeast Asia to be approximately 169,000 tons in wet weight.  This estimate is larger than the statistics indicated by Food and Agriculture Organization of the United Nations (FAO) on their website (1999).  In the FAO statistics, the average annual jellyfish catch in Southeast Asia during the period from 1988 to 1997 was 85,697 tons wet weight.  Because of the difficulty of data collection ant the processing treatments in Southeast Asia, we are convinced that our catch statistics are more realistic than those of the FAO.

According to the FAO statistics, the jellyfish catch in other areas than Southeast Asia (almost all from China) is 152,382 tons in wet weight per year during the same period.  Adding up this figure with that in Southeast Asia, we estimate annual catch of jellyfish in the world to be about 321,000 tons in wet weight.

The commercial value of imported commodities from Southeast Asia to Japan varied annually from 1,479 to 4,113 million JPN yen (average 2,733 JPN yen which is equivalent to about 25.5 million US dollars) between 1988 and 1999 (Table 4). This figure is only slightly higher than the total value of jellyfish imported from China, because the Chinese commodity consisted mainly of the most favoured species, Rhopilema esculentum. In this connection, the price of the umbrella of R. esculentum is about 2,400 JPN yen kg., whereas that of wholesale Southeast Asian (mixed) species is only about 350 JPN yen kg. The price of the mouth-arms is generally less than half that of the umbrella portion.

Table 3 - Amount of jellyfish commodity imported to Japan from 1988 to 1999 (metric tons). Data from the Information Office, Tokyo Customs House. + means less than 0.1%

Table 4. Values of jellyfish commodity imported to Japan from 1988 to 1999 (x million JPN yen). Data from the Information Office, Tokyo Customs House

Needs for Further Biological Study
In spite of their importance as a fishery commodity, almost nothing is known about the biology and ecology of edible jellyfish in Southeast Asia. Many commercial jellyfish species in the region have no scientific name. At first, therefore, taxonomic study should be carried out with many specimens from various fishing grounds for proper identificatin of the species involved

Secondly, we emphasize the need for life history studies.  The jellyfish fishery is characterized by considerable fluctuations in catch and the fishing season is restricted to a few months of each year. Unprecedented mass occurrences of rhizostomes sometimes disturb net fishing, while on other occasions they suddenly disappear from fishing grounds. In addition to local weather conditions, certain biological factors such as life history, growth and migrations must be involved in these phenomena. Scyphomedusae that have a polyp stage are typically tied to coastal regions where a shallow bototm or floating material can be found, onto which the planulae can settle. Then, when strobilation is completed, ephyrae are liberated and developed into your medusae. We consider that the number of polyps reproduces asexually and the number of ephyral discs liberated from the polyps are crucial factors that determine the population size of the 'harvested' medusa stage.  Therefore, we particularly emphasize needs for future study on the life of the polp stage for prediction of the fishery resources and fluctuations.

Only a few studies exist on the growth and feeding of rhizostome jellyfish. According to Ding & Chen (1981), Rhopilema esculentum needs 2-3 months from ephyra of 1.5-3.0mm in diameter to maturity with umbrella 250-450mm in diameter in the Liaodong Bay, northeast China. In the Ariake Sea, Japan, the same species completes its metagenic life cycle within 1 year (s. Nakano, 1980, cited by Omori, 1981). The population increased in average diameter of umbrella from 17mm to 700mm (from 0.61g to 27kg in wet weight) between the middle of May and early September.  Thus, the growth exponent, k, is 0.09 or, expressed as a daily growth rate, 9% for a medusa of 17mm umbrella diameter, calculated using the relationship:  

where W is the wet weight and t is the duration at time t. This is the only information on growth of any edible jellyfish.

White kind of food supports such large growth efficiency of jellyfish? As rhizostome jellyfish have many suctorial mouths, each with a diameter smaller than 1mm, they appear to be plankton feeders. Hon et al (1978) reports that diatoms, ciliates and small planktonic crustaceans are digested extracellularly by Rhopilema esculentum. Larson (1991) reports that Stomolophus meleagris feed primarily on small zooplankton, with bivalve veligers constituting 63% of the gut contents, followed by tintinnids (9%), copepod nauplii (9%), gastropod veligers (8%) and small numbers of many other zooplankters. Additional research on growth and feeding is clearly needed to understand the biology and ecology of commercial jellyfish.

See Also

Exporters of Jelly Fish  |  Importers of Jelly Fish  |  Processors of Jelly Fish  |  Wholesale Suppliers of Jelly Fish  |  Seafood Agents for Jelly Fish