17.1 Introduction
The European Food Safety Authority reported a variety of drivers and potential issues associated with new trends in food production, and aquaponics was identified as a new food production process/practice (Afonso et al. 2017). As a new food production process, aquaponics can be defined as ’the combination of animal aquaculture and plant culture, through a microbial link and in a symbiotic relationship’. In aquaponics, the basic approach is to get benefit from the complementary functions of the organisms and nutrient recovery. The aquaculture part of the system applies principles that are similar to recirculating aquaculture systems (RAS). Aquaponics has gained momentum due to its superior features compared to traditional production systems. Thus, aquaponics seems capable of maintaining ecosystems and strengthening capacity for adaptation to climate change, extreme weather, drought, flooding and other disasters. These attributes are within reach, but as in other agri-/aquacultural production, aquaponics is not free of risks. Given the complexity of aquaponics as an environment for co-production of aquatic animals with plants, the hazards and risks may be more complicated.
The focus in this chapter is on categories of risk (i.e. animal health/disease) rather than specific risks (e.g. flectobacillosis disease). In traditional aquaculture, some of the more common types of production risks are diseases resulting from pathogens, unsuitable water quality and system failure. Snieszko (1974) reported that infectious diseases of fish occur when susceptible fish are exposed to virulent pathogens under certain environmental conditions. Thus, the interaction of pathogens, water quality and fish resistance is linked to occurrence of disease. Previous research using risk methods has studied the routes of introduction of aquatic animal pathogens in order to secure safe trade (e.g. import risk analyses) and support biosecurity (Peeler and Taylor 2011). Considering the similarity of aquaponics to RAS, it is expected that the health problems of aquatic animals in aquaponics may be identical to aquatic animals in RAS. Specifically, fluctuations in water quality may increase susceptibility of fish to pathogens (i.e. disease-causing organisms such as virus, bacteria, parasite, fungi) in RAS and cause disease outbreaks. Microorganisms in closed systems such as RAS or aquaponics are of significance in terms of maintaining fish health. Thus, Xue et al. (2017) reported the potential correlation between fish diseases and environmental bacterial populations in RAS. High pathogen density and limited medication possibilities make the system prone to disease problems. Disease or impaired health can cause catastrophic losses with decreased survival or poor feed conversion ratios. Regardless of which potential risk becomes problematic, each has the same impact: an overall decline in the production of a marketable quality product that then results in financial loss (McIntosh 2008). Diseases can be prevented only when the risks are recognized and managed before disease occurs (Nowak 2004). The severity of risks differs and will likely change depending on when each is encountered during the production cycle.