Aquaculture and Shrimp Culture

Aquaculture in general and shrimp culture in particular have recently been developing strategies of super-intensive cultures

without water exchange. This approach addresses environmental questions raised by both society and the scientific community regarding sustainable development concepts which demand a convergence of ecological prudence, economic efficiency and social equity in all human activities (Bailey, 1988; Brown, 1989; Pruder, 1992; Macintosh and Phillips, 1992; Kinkelin and Michel, 1992; Pe´ rez, 1993; Currie, 1994; Primavera, 1994; Rosenthal, 1994; Larsson et al., 1995; Kestemont, 1995).

Pioneer work such as Reid and Arnold (1992) and Williams et al. (1996) demonstrated that it is possible to produce shrimp at high density in raceway systems that use water recirculation. The recent progress made in the area of super-dense cultures, also known as ‘‘suspended-growth systems’’ (Hargreaves, 2006) and ‘‘active suspension ponds’’ (Avnimelech, 2006), reinforces the idea that it is possible to produce aquatic organisms in an intensive and especially bio-safe way. The absence of effluents, the reduction of utilized space, and the dramatic reduction of the introduction of infectious diseases, are the main criteria for justifying its development (McNeil, 2000; McAbee et al., 2003; Burford et al., 2003, 2004; Pruder, 2004; Sowers et al., 2005; Wasielesky et al., 2006; Azim and Little, 2008; De Schryver et al., 2008; Schveitzer et al., 2008).

Although this relatively new aquaculture technology is still developing (De Schryver et al., 2008), important research efforts

have been made with the objective of comprehending the physical, chemical and biological phenomena present in the water that dictate the dynamic of the cultures (Hopkins et al., 1993; Moss and Pruder, 1995; Sandifer and Hopkins, 1996; Davis and Arnold, 1998; Avnimelech, 1999; Browdy et al., 2001). Some studies suggest that shrimp culture in a closed system (without water exchange) can maintain water quality considered acceptable for these organisms (Thakur and Lin, 2003). Others suggest that the water quality, in spite of being ‘‘poor’’ due to the large quantity of nutrients that are accumulated over time, is sufficient to guarantee the growth and survival of the animals (Burford et al., 2003). Hargreaves (2006) criticizes the majority of studies regarding these so-called ‘‘suspended-growth systems’’, because they suggest that the role of the bacteria in reference to the maintenance and the improvement of the water quality is more important than the phytoplankton metabolism.

The importance that primary productivity has in the cultures (extensive, semi-intensive, polycultures, etc.) of different organisms is well-documented (Noriega-Curtis, 1979; Laws and Malecha, 1981; Chang and Ouyang, 1988; Yusoff and McNabb,