American Fisheries Society Symposium 46:179–208, 2005 © 2005 by the American Fisheries Society Sea Urchin Aquaculture SUSAN C. MCBRIDE1 University of California Sea Grant Extension Program, 2 Commercial Street, Suite 4, Eureka, California 95501, USA Introduction and History South America. The correct color, texture, size, and taste are factors essential for successful sea The demand for fish and other aquatic prod- urchin aquaculture. There are many reasons to ucts has increased worldwide. In many cases, develop sea urchin aquaculture. Primary natural fisheries are overexploited and unable among these is broadening the base of aquac- to satisfy the expanding market. Considerable ulture, supplying new products to growing efforts to develop marine aquaculture, particu- markets, and providing employment opportu- larly for high value products, are encouraged nities. Development of sea urchin aquaculture and supported by many countries. Sea urchins, has been characterized by enhancement of wild found throughout all oceans and latitudes, are populations followed by research on their such a group. After World War II, the value of growth, nutrition, reproduction, and suitable sea urchin products increased in Japan. When culture systems. Japan’s sea urchin supply did not meet domes- Sea urchin aquaculture first began in Ja- tic needs, fisheries developed in North America, pan in 1968 and continues to be an important where sea urchins had previously been eradi- part of an integrated national program to de- cated to protect large kelp beds and lobster fish- velop food resources from the sea (Mottet 1980; eries (Kato and Schroeter 1985; Hart and Takagi 1986; Saito 1992b). Democratic, institu- Sheibling 1988). As North American fishery tionalized, and exclusive control over fishing stocks were reduced, sea urchin fisheries ex- grounds, including some aquaculture rights, panded in South America (Vasquez 1992). In favor and support fishery enhancement and Europe, fishery stocks have also been depleted aquaculture activities to increase production and aquaculture systems have been developed. in Japan’s coastal waters. An extensive program Sea urchins have been important since the 19th of research, education, and extension services century for developmental research, and large- support the national program, as Japanese con- scale laboratory systems for maintenance of sumption of seafood is the highest per capita broodstock are found in many universities (Leahy in the world. et al. 1978, 1981). Many species of sea urchins Sea urchin aquaculture began with manage- are currently fished or cultured (Table 1). ment of fishery resources where adult animals Sea urchins are an unusual candidate for were transplanted to more favorable habitats. aquaculture as they are harvested for their go- This fishery management tool led to sea urchin nads. Both male and female sea urchin gonads aquaculture research. These activities occurred are consumed, usually uncooked, but some are mainly in Kyushu, Tohoku, and Hokkaido, the salted, pickled, or made into paste. Processed regions with sea urchin fisheries. The objective sea urchin gonads remain one of the most valu- was to increase gonad production and supply able seafood products valued over US$100/kg high value products to a human population on wholesale markets (www.nmfs.gov/ows- where the standard of living was continuing to trade). Whole, live sea urchins, or processed improve. Sea urchin fisheries in Japan began gonads are sold in Asia, Europe, and North and showing signs of depletion in 1967 and efforts to culture sea urchins to supplement natural populations began in the early 1960s (Saito 1 E-mail: [email protected] 1992a, 1992b). To meet the demand for sea ur- 179 180 MCBRIDE Table 1.—Species, range, and countries where the species is cultured or where research projects are cur- rently in process. Species Family Range Country Anthocidaris crassipina Echinometridae mid-Honshu to Kyushu, South Japan Japan Heterocentrotus pulcherrimus Strongylocentrotidae North Honshu to Kyushu, South Japan Japan Pseudocentrotus depressus Toxopneustidae Tokoyo Bay to Kyushu, South Japan Japan Strongylocentrotus intermedius Strongylocentrotidae Tohoku to Hokkaido, North Japan, Korea, China, Russia (Kamchatka) Japan S. nudus Strongylocentrotidae Sagami Bay to Hokkaido, North Japan, Korea, China, Russia (Kamchatka) Japan Lytechinus variegatus Toxopneustidae Subtropical–Tropical Americas USA Loxechinus albus Echinidae South Peru, Chile Chile S. droebachiensis Strongylocentrotidae Circumpolar and south to Washington, New Hampshire, and Norway USA, Canada S. franciscanus Strongylocentrotidae Alaska to Baja California, East Pacific USA, Canada S. purpuratus Strongylocentrotidae Alaska to Baja California, East Pacific USA Heliocidaris erythrogramma Echinometridae Australia Australia Evechinus chloroticus Echinometridae New Zealand New Zealand Tripneustes gratilla Toxopneustidae Indo-Pacific Japan, Taiwan, and Philippines T. ventricosus Toxopneustidae Atlantic South America to Gulf of Mexico USA Paracentrotus lividus Echinidae North Atlantic–Mediterranean France, Belgium, Italy, Ireland, and Israel Psammechinus miliaris Echinidae North Atlantic–Mediterranean (Norway and Iceland to Morocco) Scotland chin roe products, the Japanese government sup- most cultured sea urchins are released as ju- ported basic and applied research on the feed- veniles (Table 2). ing habits, reproductive cycle, and environmen- Japanese demand for sea urchin products tal requirements. Initial research led to additional increased dramatically during the 1980s and and ongoing studies of nutrition, environmen- domestic production was able to supply about tal control, culture systems, and control of the one-half the consumer demand. This led to reproductive system (Imai 1978; Agatsuma rapid development and expansion of sea urchin 1998). fisheries in North and South America. Early Since 1970, approximately 55 prefectural warnings from fishermen and resource manag- hatcheries have produced small sea urchins for ers warned of fishery declines. Aquaculture re- cooperative units, which have collective rights search was rapidly initiated in many countries. over local aquatic resources. The production Sea urchin aquaculture in countries with fish- laboratories are responsible for supplying sea eries followed the same pattern as that seen in urchins to cooperative associations. The coop- Japan during the 1960s. Fishermen and scien- erative associations manage the land-based tists initially worked with sea urchins from the nursery units and restocking programs in suit- fishery populations and developed methods able coastal habitats. The coastal areas are man- and diets to enhance gonad production. These aged by predator removal, addition of algae, studies included holding sea urchins in sus- and sometimes habitat improvements, until pended cages or on the sea floor and transplant- harvest, usually 2 to 5 years later. More recently, ing urchins to habitats with more natural algal some cultured sea urchins are reared in cage food. Today, sea urchin aquaculture research systems at high density and fed cultured sea- often utilizes sea urchins collected from the weed until they are large enough for market- ocean in laboratory studies. ing (Mottet 1976, 1980; Doumenge 1990; T. In Europe, there is also a long history of Horii, National Research Institute of Fisheries sea urchins used as food. Sea urchins are eaten Science, Nagai, Japan, personal communica- whole and fresh in southern Europe, in contrast tion). Large-scale aquaculture of sea urchins to the processed roe products popular in Japan. to harvest size is not popular in Japan, and Sea urchins are sold through the fisheries sec- SEA URCHIN AQUACULTURE 181 Table 2.—Production of sea urchin seed for release and aquaculture in Japan for fiscal year April 1999 to March 2000 (data from T. Horii, National Research Institute of Fisheries Science, Nagai, Japan,). The number of product organizations that cultured or cooperative fishery associations that released each species and areas where species were released are also shown. The number of seeds produced is the total for the year and the number released is the actual amount released during this fiscal year. (org. = organizations, n.a. = not applicable) Seed Seed produced released Production size (mm) # of # of seed size (mm) # seed # of # of Species type mean range org. produced mean range released org. areas Tripneustes gratilla release 11 1–25 3 136,000 14 3–50 99,000 3 20 aquaculture n.a. Pseudocentrotus depressus release 16 3–29 11 9,460,000 12 3–30 3,739,000 79 25 aquaculture 8 3–17 2 152,000 n.a. Heterocentrotus pulcherrimus release 9 3–15 3 590,000 11 3–27 489,000 10 47 aquaculture 10 8–12 1 10,000 n.a. Strongylocentrotus intermedius release 11 2–49 28 64,985,000 12 2–106 57,895,000 94 486 aquaculture 8 3–22 2 6,696,000 n.a. S. nudus release 18 6–46 10 6,718,000 18 7–50 7,120,000 11 302 aquaculture 11 6–31 3 366,000 n.a. tor network by auction. Cultured sea urchins ment of wild populations with supplemental could be sold at a fixed price, which would re- feeding, transplanting of sea urchins to favor- quire management of harvesting, production, able habitat, and research scale hatcheries indi- and shipping. Much of the European sea urchin cate aquaculture production of sea urchins is supply is not eaten locally and the diversity of biologically possible, but the economics are regional preferences must be considered for unclear. Providing a consistent supply