The Open Access Israeli Journal of Aquaculture – Bamidgeh As from January 2010 The Israeli Journal of Aquaculture - Bamidgeh (IJA) will be published exclusively as an on-line Open Access (OA) quarterly accessible by all AquacultureHub (http://www.aquaculturehub.org) members and registered individuals and institutions. Please visit our website (http://siamb.org.il) for free registration form, further information and instructions. This transformation from a subscription printed version to an on-line OA journal, aims at supporting the concept that scientific peer-reviewed publications should be made available to all, including those with limited resources. The OA IJA does not enforce author or subscription fees and will endeavor to obtain alternative sources of income to support this policy for as long as possible. Editor-in-Chief Published under auspices of Dan Mires The Society of Israeli Aquaculture and Marine Biotechnology (SIAMB), Editorial Board University of Hawaii at Manoa Library Sheenan Harpaz Agricultural Research Organization and Beit Dagan, Israel University of Hawaii Aquaculture Zvi Yaron Dept. of Zoology Program in association with Tel Aviv University AquacultureHub Tel Aviv, Israel http://www.aquaculturehub.org Angelo Colorni National Center for Mariculture, IOLR Eilat, Israel Rina Chakrabarti Aqua Research Lab Dept. of Zoology University of Delhi Ingrid Lupatsch Swansea University Singleton Park, Swansea, UK Jaap van Rijn The Hebrew University Faculty of Agriculture Israel Spencer Malecha Dept. of Human Nutrition, Food and Animal Sciences University of Hawaii Daniel Golani The Hebrew University of Jerusalem Jerusalem, Israel Emilio Tibaldi Udine University Udine, Italy ISSN 0792 - 156X Israeli Journal of Aquaculture - BAMIGDEH. Copy Editor Ellen Rosenberg PUBLISHER: Israeli Journal of Aquaculture - BAMIGDEH - Kibbutz Ein Hamifratz, Mobile Post 25210, ISRAEL Phone: + 972 52 3965809 http://siamb.org.il The Israeli Journal of Aquaculture – Bamidgeh 58(1), 2006, 3-28. 3 EXOTIC SPECIES IN GLOBAL AQUACULTURE - A REVIEW William L. Shelton1* and Shmuel Rothbard2 1 Zoology Department, University of Oklahoma, Norman, Oklahoma 73019, USA 2 YAFIT Laboratory, Fish Breeding Center, Gan Shmuel 38810, Israel (Received 31.12.05, Accepted 10.1.06) Key words: aquaculture, exotic species, worldwide Abstract The culture of exotic fishes contributes about 17% to global food aquaculture production. Transplanted native species add substantially to the aquatic harvest of food and sport fishes in many countries. Some countries are very dependent on the cultivation of non-native species; yields of exotics exceed 25% of the total harvest in China, 60% of the freshwater harvest in the Philippines, and 50% of the production in Brazil. Aquatic food production in Israel is predomi- nately from introduced fishes. In the USA, transplanted species are economically important as food and sport fish and exotics are used in resource management as well as a major food source. Countries of origin for globally important fishes include China (endemic carps), USA (Atlantic salmon and rainbow trout), Europe (common carp), and Africa (tilapias). The aquacul- ture production of food fish will become increasingly vital as oceanic capture fisheries continue to stagnate. Exotic and transplanted fishes that are widespread today will represent a greater proportion of future aquaculture production because technology for their culture is already well known and can readily be applied, and because these species are more easily domesticated and genetically improved. Introduction Plants and animals have been moved from panion plants and animals have been greatly one area to another for centuries. Food crops modified from their native ancestral types and domesticated animals have been devel- through passive selection and active breeding oped and dispersed worldwide in association programs. Non-native domesticated and culti- with man’s resettlement. Humans have been vated terrestrial organisms are generally not integral in translocations of food crops to new perceived as exotic but, rather, as part of the areas outside their natural range. Such com- natural landscape. However, this does not * Corresponding author. E-mail: [email protected] 4 Shelton and Rothbard usually apply to aquatic species. Non-indige- ticularly because of the developing shortfall in nous fishes are commonly considered aliens capture fisheries. or invaders. Aquaculture is the farming of aquatic The concept of exotic organisms should organisms for food, sport, conservation, or be more precisely defined, especially within ornamental purposes. Artificial propagation is the context of aquaculture. The following ter- a vital component of contemporary aquacul- minology is based on Shafland and Lewis ture since it ensures a supply of seed stock for (1984). A species is considered ‘native’ or grow-out, enables selective breeding for stock ‘indigenous’ with reference to its historically improvement, and facilitates transfer and natural range. A fish that has been intention- maintenance of species outside their native ally or accidentally moved outside its natural range. While the culture of non-native species range is defined as ‘introduced’. Introduced has multiple benefits, it may also have com- fishes can be either ‘transplanted’ by man plications. between watersheds within the area of origin Aquaculture has been practiced for over (Lachner et al., 1970) or ‘exotic’ if the transfer 3,000 years, but improvements through the is between areas. Introduction generally application of scientific principles are relative- implies release or escape of an exotic or ly recent (Wohlfarth and Hulata, 1989; Billard, transplanted species into a natural ecosys- 1995). Most adaptive practices for economi- tem. Confinement in a commercial or cally important species have been incorporat- research facility can also be considered intro- ed within the past four to five decades, during duction, because escape is probable (Shelton the same period that sensitivity to environ- and Smitherman, 1984). Other somewhat mental issues has grown, particularly in indus- synonymous terms include alien, non-native, trialized countries. Thus, aquaculture was and invader (Lever, 1996). If reproduction and compelled to develop under a burden of ethi- recruitment occur, fish are considered ‘natu- cal and environmental constraints that did not ralized’ or ‘established’. The purpose of this restrict the formative period of agriculture. paper is not to defend the use of exotic fishes Restricting fish farming to the culture of native nor discuss potential impacts from introduc- fishes within their historic ranges represents a tions, but to focus on their importance in aqua- serious constraint to aquatic food production. culture. Many fish species have been moved out- All agricultural crops are exotic cultivars side their native range but relatively few have and all domesticated animals are products of been widely dispersed. The earliest species to a long history of selection. Grains originated in be relocated were the common carp, goldfish, the Middle East and many vegetables have and, somewhat later, rainbow trout. The com- derived from South American plants. mon carp was transplanted at the beginning of Agricultural practices evolved over centuries the sixth century from its native range in the and have been adapted to various climates lower Danube River, westward into Europe, and economies so that, now, non-native eastward into China, and southward into Italy organisms are fully accepted. Animal hus- (Wohlfarth, 1984; Balon, 1995). Several culti- bandry is based on a handful of exotics; four vated breeds of common carp are now recog- omnivorous mammals and four herbivorous nized. They have characteristics that are qual- birds form the basis of modern animal culture. itatively and quantitatively different from On the other hand, about 131 finfish species ancestral stocks, but are considered only mar- are commonly cultured, and few have been ginally domesticated (Hulata, 1995). The selected to any degree. Non-native fishes rep- development and transfer of the many vari- resent differing degrees of aquaculture pro- eties of goldfish date from the late 1100s to the duction in different countries, although not to mid-1600s. Rainbow trout transfers did not the extent that exotic cultivars and breeds are begin until 1874 (Gall and Crandell, 1992), but used in agriculture and animal husbandry. contemporary dispersal is nearly as far-flung Their importance is increasing, however, par- as that of common carp (Brannon, 1991). Exotic species in global aquaculture 5 Global introductions of aquatic species Table 1. Major fish introductions during the have increased throughout the twentieth cen- twentieth century. tury (Bartley and Casal, 1998). A total of 1,354 introductions of 237 species into 140 coun- Species No. introductions tries have been recorded. However, relatively few species are widely distributed and only Common carp 124 10-13 species were introduced into more than Rainbow trout 99 ten countries. Ninety-eight exotic species have been introduced for aquaculture and 78 Mozambique tilapia 92 for sport fishing, not including widespread Nile tilapia 80 transplanting within countries for culture or Silver carp 79 sport fishing. A total of 321 introductions (24%) resulted in established populations, but over 298 (22%) of the introductions did not become naturalized. Only 89 (7%) had suffi- generally static at around 95 million tons cient impact to