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 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 117 116 117 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.