18 DECEMBER 2014 • WORLD AQUACULTURE • WWW.WAS.ORG Global rainbow trout Oncorhynchus mykiss aquaculture production reached 732,432 t in 2009, with a value of more than US$ 3.4 billion (FAO 2011b). The most important nations producing rainbow trout in 2008 were Chile (149,411 t), followed by Norway (75,316 t) and Iran (62,630 t). Rainbow trout was introduced into Lebanon in 1958 (FAO 2011a). Aquaculture in Lebanon started as subsistence food production in the 1930s (FAO 2011a). Commercial-scale aquaculture in Lebanon started in the 1990s, after the civil war. Development, technical expertise and a greater demand for seafood products were provided by investors and tourists who returned after armed conflicts ended (Lebbos and Saoud 2006). More than 90 percent of aquaculture production in Lebanon is rainbow trout. The remaining 10 percent includes small quantities of carp, catfish, penaeid shrimp and tilapia. Rainbow trout production in the country in 2002 was estimated by the Ministry of Agriculture to be 600 t or by trout farmers to be 1,000 t (Lebbos and Saoud 2006). A 2011 article published in the Lebanese daily newspaper, Al-Akhbar (Al-Akhbar. com), suggested that rainbow trout production may have reached 1,700 t yearly. There are reportedly 150 fish farms in Lebanon, most of them small, family-owned businesses (FAO 2011a). Most (70 percent) aquaculture in Lebanon takes place along the Assi (Orontes) River (Lebbos and Saoud 2006), near the northern border with Syria, in earthen and concrete raceways (Figs. 1 and 2). The Assi River is a perennial stream located in northern Lebanon, Environmental Impact of Trout Aquaculture on the Lebanon Portion of the Assi River Nadim Farajalla, Yara Daou, I.P. Saoud a few kilometers northeast of the Litani River source (Fig. 3). The Orontes River Valley region is arid, mainly because the mountain range on the west side of the Bekaa Valley deprives the valley of rainfall. Annual precipitation averages 250 mm (El Moussaoui and Yazigi 2005) and temperatures vary between an average of 5.5 C in January to 32 C in August (El Moussaoui 2001). The Lebanese portion of the Assi River, which flows north into Syria, is 46 km long. The annual flow rate of the Lebanese part of the Assi River is 480 million m3 (Ministry of Environment 2001). The Assi River has excellent water quality for trout aquaculture. It has the clear, cool, oxygenated, fast-flowing waters necessary to meet the water quality requirements of rainbow trout (Table 1). However, these water quality attributes also make the river desirable for municipal uses, traditional irrigation and recreational activities. It is imperative that aquaculture not pollute the water, making it unsuitable for other uses. Fish farmers along the Assi River near the town of Hermel use earthen or concrete raceways supplied with constantly-flowing water diverted from the river. This has environmental consequences that depend on farm size, number of surrounding farms, load of fish in each farm, intensity of feeding, flushing capacity of the aquatic environment, bacteriology and biodiversity of the milieu and land use around aquaculture farms TOP, FIGURE 1. A rainbow trout farm along the Lebanon portion of the Assi River. MIDDLE, FIGURE 2. Aerial view of trout ponds on the Assi River near the town of Hermel, Lebanon. BOTTOM, FIGURE 3. The Assi (Orontes) River and its watershed in northern Lebanon.
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