Use of Edible Alien Crayfish for Human Consumption

CRUSTACEAN RESEARCH, SPECIAL NUMBER 7: 115–124, 2012

Use of edible alien crayfish for human consumption

Toshifumi Nonaka

Abstract.—In Japan alien crayfish (the 2011; Kawai, 2007). In addition, they signal crayfish Pacifastacus leniusculus and were initially introduced as a food item for the red swamp crayfish Procambarus clarkii) Japanese people. Therefore, the use as a food have increased. Alien crayfishes have a major is a potential method of reducing the number impact on Japanese freshwater ecosystems, and of alien crayfish. new methods for protection and conservation In this present paper, I will present some are needed. I give the Information as a kind of examples to show how to prepare the alien conservation by using on culinary use of edible. crayfish of P. leniusculus and P. clarkii. Alien crayfish in Japan INTRODUCTION In Japan, there are three species Pacifastacus leniusculus (Invasive Alien of crayfish. One is a native species, Species)(Photo. 1) Cambaroides japonicus, and two are Pacifastacus leniusculus (hereafter: signal alien species, Procambarus clarkii and crayfish) was originally introduced into Japan Pacifastacus leniusculus. P. clarkii are in the early period of Showa (1927–1930) as widely distributed in Japan, and are a food item for cultivation. damaging aquatic ecosystems in Japan. P. Although cultivation of this species was leniusculus are rapidly expanding distribution attempted in national fisheries experimental in Hokkaido and this species is damaging stations, the attempt was only successful ecosystems in Japan. It has been designated in Lake Tankaitameike in northern Shiga as an Invasive Alien Species (Ministry of the Prefecture and in Lake Mashu in Hokkaido. Environment Government of Japan:http:// The habitat of signal crayfish has www.env.go.jp/en/nature/as.html). To gradually extended so that their increasing prevent damage to ecosystems by these population is concerned to have had a marked two alien species, measures must be taken soon. One important measure is to reduce the number of adult crayfish. Australia and New Zealand have implemented eradication and control programs in various ways. See additional notes as (Gherardi & Angiolini, 2004). Although various attempts to remove alien crayfish in Japan have been carried out, there has not been a reduction in the number and distribution of alien crayfish. Also, the disposal of captured alien crayfish is problematic. Therefore, effective measures need to be taken. P. leniusculus has been used as a food item in Europe (e.g. Finland, Sweden, United Kingdom and so on), (National Geographic, Photo.-1 Signal crayfish(Pacifastacus leniusculus) CONSUMPTION OF ALIEN CRAyFISH 117 116 116

T. NoNTableaka -1 Sales procedure for signal crayfish

Photo.-3 The swamp crayfish (Procambarus clarkii) Photo.-4Temporary holding tank for signal crayfish

T. NoNTableaka -1 Sales procedure for signal crayfish

Photo.-3 The swamp crayfish (Procambarus clarkii) Photo.-4Temporary holding tank for signal crayfish

crayfish) was imported by Kamakura– shi, Kanagawa Prefecture as a food for the American bullfrog (Rana catesbeiana) in 1927 and the distribution was restricted to Photo.-5 Boiled signal crayfish Photo.-6 Live signal crayfish near Kamakura at the beginning. However the area of distribution quickly expanded, and habitation is now throughout much of the country until it reaches Hokkaido, Shikoku Photo.-2 News paper in Hokkaido (2010, December, 20th) over 100,000 number of signal crayfish and Kyushu. Alien crayfish as food Crayfish is a commonly used and negative influence on the native species and expensive food item in Europe. However, in the biodiversity, especially in Hokkaido, Japan, they are not commonly eaten because Fukushima (Lake Onogawa, Lake Hinohara), of the abundance and availability of seafood and Chiba (Tone River). in typical grocery stores. According to the fishery report of Signal crayfish Hokkaido in 2007, the total number of After the enforcement of the Invasive Photo.-8 Snack of signal crayfish captured signal crayfish in Lake Toya, Lake Alien Species Act on February 1, 2006, Shikotus, and Lake Shikaribetsu and others there are a very limited number of handling Photo.-7 Soup of signal crayfish was 19,412. In addition, in 2012, over contractors of signal crayfish; only two 100,000 individuals were captured in Lake fishery organizations, the Akan Lake Fishery Toya (Photo. 2). Collaboration Association (ALCA) and www.akan–gyokyo.com/index.html) of crayfish is permitted to ALCA only in the Procambarus clarkii (designated as Invasive the Toro Lake Fishermen’s Cooperative ALCA provides information for sales Akan Lake. The sales of signal crayfish started in September, 1993. The average Alien Species) (Photo. 3) Association, which are permitted to handle of signal crayfish, which targets general annual capture volume is from 2.5 t to 3 t. Procambarus clarkii (hereafter: swamp the species. The internet web site (http:// consumers. According to the Law, catching signal –Capture is allowed from May to CONSUMPTION OF ALIEN CRAyFISH 119 118 118 November T. NoN(Photo.aka 8) –The capture method is the so–called “pull–up method” using a basket trap The snack with powder of signal crayfish –The captured signal crayfish are kept Cooking in a holding tank for several days before There are several restaurants that serve dispatch as a requirement of the Invasive signal crayfish; however, most restaurants Alien Species Act. dealing with signal crayfish provide this In addition, the sales procedure (Table–1) food only for a limited period or season in in accordance with the Law needs to be the year. Typical menus of signal crayfish displayed when selling the signal crayfish. provided in restaurants are as follows: Sale Appetizer with signal crayfish (Photo. 9) Boiled signal crayfish served with Signal crayfish for personal consumption Photo.-9 Appetizer with signal crayfish Photo.-10 Fried signal crayfish (tempra) –Boiled signal crayfish (complete) (not seasonal vegetables with sauce americaine* cultured) 1,785 yen (Photo. 5) *Sauce americaine: Broth is made from –Boiled signal crayfish (incomplete: sauted and well boiled heads and husks of various sizes) (not cultured) 1,785 yen signal crayfish with various vegetables. Size: 20–33/ 1kg Whipped cream is put in to complete the Fishing season: mid May to end of sauce November Fried signal crayfish (tempra) (Photo. 10) Shipment unit: from 1kg Dispatch: Japanese style fried signal crayfish, fried Frozen with tempura powder. No limit on sale Signal crayfish for restaurants Boiled signal crayfish (Photos. 11 & 12) –Live signal crayfish (complete) (not Signal crayfish parboiled with salt. Lemon cultured) 1,630 yen (Photo. 6) may be added depending on preference. Also, –Live signal crayfish (incomplete, various Uchiko (ovary), or nursery powder, may be sizes) (not cultured) 1,470 yen added. Not only the tail meat but also the Photo.-11 Boiled signal crayfish (before eating) Photo.-12 Boiled signal crayfish (after eating) Size: 20–33/ 1kg internal organs are delicious. Fishing season: mid May to end of Grilled signal crayfish with herbs (Photo. 13) November Grilled signal crayfish, cut in half Shipment unit: from 1kg Dispatch: Not lengthwise, and sprinkling with various herbs frozen and salt, makes this dish more fragrant. *prices stated above for October, 2009 –Limited sale for restaurants by the Pasta of signal crayfish (Photos. 14 & 15) Invasive Alien Species Act Pasta dish with signal crayfish, finished using americaine sauce. Various Processed food arrangements, i.e., gnocchi, can be enjoyed. –Soup of lake lobster 500 yen per tin (Photo. 7) Japanese soup noodle with signal crayfish This is sold in the Akan fishery (ramen) (Photo. 16) collaboration association, and it also sells in Signal crayfish arranged in a Japanese souvenir shops, such as at the station and at soup noodle, ramen. the airport in Hokkaido. The swamp crayfish Photo.-13 Grilled signal crayfish with herbs Photo.-14 Pasta of signal crayfish The soup of the tomato flavoring The swamp crayfish has been sold in containing a can, and the present state–even Japanese food markets. However, there when–delicious, when and it is suggested to is very limited information on the market river fish such as eels, loach, and snapping in China, and is sold in grocery stores and add whipped cream for serving and it carries circulation of the swamp crayfish, when turtles, mainly handle the swamp crayfish. used in various Chinese recipes. Dealers of out It can be eaten in the style of potage or it compared with that of the signal crayfish. (Photo. 17) foreign foods in Japan, for example, in the uses can be used for the a sauce of pasta, etc., In Tokyo Metropolitan Central Wholesale The swamp crayfish is not a popular food Ameyoko Shopping Center Joint Association although arranged . Market, or Tsukiji Shijjo, (hereafter as Tsukiji item in Japan, although it is commonly eaten in Tokyo, so–called “Ueno Ameyoko”, –Snack of signal crayfish 500 yen per box market), the fish contractors selling various CONSUMPTION OF ALIEN CRAyFISH 119 118 119 November T. NoN(Photo.aka 8) –The capture method is the so–called “pull–up method” using a basket trap The snack with powder of signal crayfish –The captured signal crayfish are kept Cooking in a holding tank for several days before There are several restaurants that serve dispatch as a requirement of the Invasive signal crayfish; however, most restaurants Alien Species Act. dealing with signal crayfish provide this In addition, the sales procedure (Table–1) food only for a limited period or season in in accordance with the Law needs to be the year. Typical menus of signal crayfish displayed when selling the signal crayfish. provided in restaurants are as follows: Sale Appetizer with signal crayfish (Photo. 9) Boiled signal crayfish served with Signal crayfish for personal consumption Photo.-9 Appetizer with signal crayfish Photo.-10 Fried signal crayfish (tempra) –Boiled signal crayfish (complete) (not seasonal vegetables with sauce americaine* cultured) 1,785 yen (Photo. 5) *Sauce americaine: Broth is made from –Boiled signal crayfish (incomplete: sauted and well boiled heads and husks of various sizes) (not cultured) 1,785 yen signal crayfish with various vegetables. Size: 20–33/ 1kg Whipped cream is put in to complete the Fishing season: mid May to end of sauce November Fried signal crayfish (tempra) (Photo. 10) Shipment unit: from 1kg Dispatch: Japanese style fried signal crayfish, fried Frozen with tempura powder. No limit on sale Signal crayfish for restaurants Boiled signal crayfish (Photos. 11 & 12) –Live signal crayfish (complete) (not Signal crayfish parboiled with salt. Lemon cultured) 1,630 yen (Photo. 6) may be added depending on preference. Also, –Live signal crayfish (incomplete, various Uchiko (ovary), or nursery powder, may be sizes) (not cultured) 1,470 yen added. Not only the tail meat but also the Photo.-11 Boiled signal crayfish (before eating) Photo.-12 Boiled signal crayfish (after eating) Size: 20–33/ 1kg internal organs are delicious. Fishing season: mid May to end of Grilled signal crayfish with herbs (Photo. 13) November Grilled signal crayfish, cut in half Shipment unit: from 1kg Dispatch: Not lengthwise, and sprinkling with various herbs frozen and salt, makes this dish more fragrant. *prices stated above for October, 2009 –Limited sale for restaurants by the Pasta of signal crayfish (Photos. 14 & 15) Invasive Alien Species Act Pasta dish with signal crayfish, finished using americaine sauce. Various Processed food arrangements, i.e., gnocchi, can be enjoyed. –Soup of lake lobster 500 yen per tin (Photo. 7) Japanese soup noodle with signal crayfish This is sold in the Akan fishery (ramen) (Photo. 16) collaboration association, and it also sells in Signal crayfish arranged in a Japanese souvenir shops, such as at the station and at soup noodle, ramen. the airport in Hokkaido. The swamp crayfish Photo.-13 Grilled signal crayfish with herbs Photo.-14 Pasta of signal crayfish The soup of the tomato flavoring The swamp crayfish has been sold in containing a can, and the present state–even Japanese food markets. However, there when–delicious, when and it is suggested to is very limited information on the market river fish such as eels, loach, and snapping in China, and is sold in grocery stores and add whipped cream for serving and it carries circulation of the swamp crayfish, when turtles, mainly handle the swamp crayfish. used in various Chinese recipes. Dealers of out It can be eaten in the style of potage or it compared with that of the signal crayfish. (Photo. 17) foreign foods in Japan, for example, in the uses can be used for the a sauce of pasta, etc., In Tokyo Metropolitan Central Wholesale The swamp crayfish is not a popular food Ameyoko Shopping Center Joint Association although arranged . Market, or Tsukiji Shijjo, (hereafter as Tsukiji item in Japan, although it is commonly eaten in Tokyo, so–called “Ueno Ameyoko”, –Snack of signal crayfish 500 yen per box market), the fish contractors selling various CONSUMPTION OF ALIEN CRAyFISH 121 120 120 T. NoNaka

Photo.-21 Chinese hot stir-fried dishes of swamp Photo.-22 Chinese stir-fried dishes of swamp crayfish Photo.-15 Pasta of signal crayfish (gnocchi) Photo.-16 Ramen noodle of signal crayfish crayfish

Photo.-17 Swamp crayfish for sale in Tsukiji market Photo.-18 Swamp crayfish for sale in Ueno Ameyoko Photo.-23 Crayfish sold in a supermarket (July in Photo.-24 Crayfish served in a restaurant (July) Finland)

Photo.-25 Introduce Explanation of the concept of Photo.-19 Temporary holding pen for swamp crayfish Photo.-20 Boiled signal crayfish (left 3) and swamp Crayfish parties and associated product Photo.-26 Crayfish sold for the party crayfish (right 2) CONSUMPTION OF ALIEN CRAyFISH 121 120 121 T. NoNaka

Photo.-21 Chinese hot stir-fried dishes of swamp Photo.-22 Chinese stir-fried dishes of swamp crayfish Photo.-15 Pasta of signal crayfish (gnocchi) Photo.-16 Ramen noodle of signal crayfish crayfish

T. NoNakaeven in Tsukiji market, the purchase orders In Finland, crayfish fishing begins on Reduction of population sizes of alien for swamp crayfish tend to be periodical and July 21 crayfishes is one of the urgent issues for orders are typically made by foreign people. In Sweden, crayfish parties are held in the conservation/preservation of native In America, you can view images of various places in August to celebrate the ecosystems in Japan. Utilization of those boiled swamp crawfish or jambalaya. In summer. alien crayfishes as a food source can be one China, there is available information such In recent years, crayfish parties (Photo. of the possible measures to control their as restaurants which are popular for their 25) have been introduced to Japan; and as a populations, and at the same time achieving crayfish dishes. result, some grocery stores have started to the effective use of the natural resource. In Japan, individuals have HPs introduces sell imported crayfish (Photo. 26) from China The main problem associated with alien how to eat crayfish. However, in restaurants (Photo. 27) for crayfish parties. crayfish as foods is its image that they are able to tolerate low water quality, when these dishes are most regularly eaten. Proposal to reduce alien crayfishes Recently, across the country, which is to be compared with marine crabs, since they The annual retail volume of alien crayfish live in the mud of rivers and lakes where done as well as removal of crayfish in native in Japan is assumed to be approximately 5t. ecosystem conservation activities. Some the water quality is low. Also, the abundant For signal crayfish, the annual retail supply of fresh sea foods in the market leads people have to eat and let eat accordingly. volume is 2.5 to 3t according to the data But generally they are not considered as to a reduction of the attractiveness of alien Photo.-27 Sold crayfish (product from China) from Akan Lake in Hokkaido. For swamp crayfish. good food. Also, people who have played crayfish, it is estimated that the annual retail during their childhood with crayfish, majority Therefore, in order to promote the demand volume may be between 1 and 1.5t when for and acceptance of alien crayfishes as a of people do not consider swamp crayfish as the number of river fish wholesalers and the suitable as a food. food source, it is necessary to change the handle the swamp crayfish (Photo. 18). average volume (1) of the crayfish sold in image or remove the negative image of alien –The quantity which is traded of the For cooking methods of swamp crayfish, one wholesaler in Japan are considered. it seems that the cooking recipes for signal crayfish and increase the chance to be seen in swamp crayfish in the Tsukiji market during (1) The average volume of swamp local supermarkets gradually by improving May to October and 1 time is 5 kg to about crayfish are applicable to swamp crayfish. crayfish sold by one wholesaler is assumed to However, because the size of swamp crayfish the volume of market circulation. The 10 kg be 200kg following activities may be effective for the –Sell by laying in stock for two to three is much smaller than signal crayfish there are This volume of sales, the annual retail some limitations (Photo. 20). above goals: orders in one month volume of alien crayfish in Japan, can be –Promotions to explain the nutritional –Lay in stock and sell to orders from regarded as relatively small when compared benefits of alien crayfish as a food by French restaurants etc. Chinese hot stir–fried dishes of the swamp with the figure of imported freshwater developing cooking recipes that are The fisherman of Chiba Prefecture as Chinese mitten crab (Eriocheir sinensis), crayfish (Photo. 21) inexpensive and delicious, similar to those well as Ibaraki Prefecture, where fishing which is also a designated species in the The swamp crayfish was stir–fried for Shanghainese mitten crab. for swamp crayfish occurs in Kasumigaura Invasive Alien Species Act. The smallest together with prickly ash or red pepper is –Deregulation, or simplification, of Lake, and the catch is shipped to the Tsukiji imported volume in the recent years was 88t a popular Chinese dish. Although it has the legal procedures of the Invasive Alien market. in 2009 of Chinese mitten crab, and thus, a very hot seasoning, it is an appropriate Species Act and other relevant laws for –Several contractors capture the swamp the annual retail volume of alien crayfish in accompaniment to consume with alcohol, capturing and market circulation. crayfish, and all contractors start crayfish Japan is only 1/45 of the imported volume of such as beer, is suited well –Establishment of incentives for not only fishing in May, when the crayfish become Chinese mitten crab. capturing alien crayfish but also purchasing active. Chinese stir–fried dishes of the swamp cray- Stock estimation using more than them to handling contractors and buyers; i.e., –All crayfish shipped to Tsukiji market fish (Photo. 22) 100,000 individuals of signal crayfish was Crayfish Incentive Point). are captured from the wild and are not The swamp crayfish is stir–fried with implemented at Lake Toya in 2010. However, These institutional structures will improve cultured. seasoning in Chinese style. The back of there was still no clear sign showing the the attitude toward the use of alien crayfish –Capture is by using a basket trap. the main body of the swamp crayfish is cut population reduction of signal crayfish. among the general public and enhance the –According to the order amount to ship. prior to being cooked. The internal organs Estimations of the population sizes of the public consumption of these unwanted –Captured swamp crayfish will be kept promotes the taste of the swamp crayfish swamp crayfish and signal crayfish in Japan species as a food source while their between three and four days before shipping appropriately. are very difficult. population sizes in natural environments can (Photo. 19). However, the large number of individuals Crayfish party be controlled and reduced, resulting in less of swamp crayfish and signal crayfish in negative effects on aquatic ecosystems. Cooking In Finland and Sweden, there is a Hokkaido and Honshu, is of no doubt. There are a very few chances for the cultural custom to eat crayfish during the Use of alien species, the law for Invasive Because you they have been continuously Alien Species. Its original purpose was to general public to see dishes of cooked swamp summertime. In this time, crayfish are sold in active recorded in many parts of Japan as crayfish even though most Japanese people most supermarkets (Photo. 23). People enjoy remove the alien species. Therefore, careful well as programs to removal them in of efforts are required. have experience of playing with, or fishing eating crayfish in restaurants, or in their own Hokkaido. for swamp crayfish in their childhood. In fact, houses (Photo. 24). We are required to reduce the number of CONSUMPTION OF ALIEN CRAyFISH 123 122 123

habitats and habitats of alien crayfish in Tthe. No Nsupport.aka country and for their use as a business that Use of crayfish in elementary and secondary classes in holds alien crayfish food items. However, Japanese schools, with special reference to breeding and because of the continued use of the Alien LITERATURE CITED environmental education crayfish, there could be a need requirement Gherardi F., & C. Angiolini, 2004, for farming, would likely which may, if Eradication and control of invasive improperly regulated, increase the Alien species, in Encyclopedia of Life Support Systems (EOLSS), Developed under the crayfish in the future. Therefore, we are Taichiro Goto and Tadashi Kawai assuming a situation may arise, it is necessary Auspices of UNESCO, Eolss Publishers, to consider guidelines for the handling of Oxford, UK,[http://www.eolss.net] foods and the Law regarding Invasive Alien Kawai T., 2007, Natural history and conservation of freshwater crayfish in A b s t r a c t . — The red swamp crayfish hence this species must be treated with great Species responses to reduced populations of Procambarus clarkii was imported into Japan care and an environmental education using such Japan. 131 pp, Tokai University Press, alien crayfish. from New Orleans, Louisiana, USA, in 1927, a crayfish is important in Japan. We describe Tokyo. (in Japanese) and is now distributed across the Japanese how we have applied P. clarkii crayfish to an National Geographic. 2011, Food journeys Achnowledgements.—I wish to thank the Archipelago. This crayfish has been commonly elementary science education in Japan. Akan Lake Fishery Collaboration Association of lifetime, National Geographic Society, used as a teaching material with a specific (ALCA:Akan–cho) for giving information 82:1–319. (in Japanese) academic purpose in elementary schools. P. clarkii on sales of signal crayfish, and Wine Bar has body color variants, including an albino INTRODUCTION Jose (Chuo–ku, Sapporo) for their help in the form with a relatively transparent body that is Addresses: C. T. I Engineering Co., LTD Three species of crayfishes, signal various ways of cooking crayfish. My thanks particularly suitable for examining the internal Environment Division, 1–14–6 Kamikizaki, crayfish (Pacifastacus leniusculus), Japanese are also due to Dr. Tadashi Kawai (Wakkanai structures, such as digestive organs, beating heart Urawa–ku Saitama–shi, Saitama, Japan; crayfish (Cambaroides japonicus), and red Fisheries Institute, Wakkanai) for giving me and ovaries in female, without need for dissection. swamp crayfish (Procambarus clarkii), are the opportunity to publish and for various Email: [email protected] P. clarkii, as a non–native species, has potential found in Japan. Of these, signal crayfish and negative effects on the native aquatic eco–system: A B C

Fig. 1. Color variants of Procambarus clarkii. A, Albino; B, Wild red; C, Blue color.