Fish Oils, Misconceptions and the Environment

Abstract

The recent article by Greene et al.1 concluded that because of inconclusive results and environmental concerns “clinicians should not recommend fish oil intake or fish consumption.” At the outset, let me state that this letter aims at addressing only the environmental considerations expressed by the authors. In line with the authors,1 there is consensus among conservation and fisheries scientists regarding the full-exploitation status of fish stocks, with any expansion deemed unsustainable.2 In actuality, wild capture fisheries production has largely been static since the 1980s (Figure 1).3,4 An important issue misconstrued by Greene et al.1 is that aquaculture is capable of covering any shortfall in the “not-increasing” availability of wild fish. In fact, since the 1960s, the expansion of aquaculture has doubled the per capita food fish supply, recording a growth rate that has outpaced the rate of increase in the world’s population.2,3 FIGURE 1— The global fishery and aquaculture production and the fishmeal and fish oil production. Nevertheless, the actual impact of aquaculture on seafood supply has been questioned on the grounds that wild fish are used (as fishmeal and fish oil) in feed for farmed fish.5 Accordingly, Greene et al.1 suggested that “because most fish farms raise carnivorous fish … fish farming likely exacerbates the problem.” Unfortunately, this is not entirely accurate. Firstly, the farming of carnivorous fish (such as salmon), though common in western societies, is a very small part of global aquaculture (∼six percent of total production).3 However, it must be reported that fishmeal and fish oil are also used for noncarnivorous species (such as shrimp and tilapia).6 Nevertheless, the volume of seafood cultured with the use of fishmeal and fish oil has been estimated to be 39% of total aquaculture production.3,6 The remaining 60% is composed of species that are low in the trophic chain (i.e., filtering feeding mollusks), farmed without the use of any wild fish-derived resource.3,6 Secondly, there are other major elements that are often forgotten: (1) aquaculture consumes 25% of global fisheries production but contributes 50% of global seafood availability,3 (2) the fisheries of species intended for fishmeal and fish oil production is well regulated and sustainably managed,7 and (3) the annual global production of fishmeal and fish oil has remained constant over the last five decades.3,4,6 The latter is clearly indicating that the expansion of aquaculture, and the consequent increasing demand for feed, has not impacted on global fishery pressure (Figure 1). In reality, the expansion of aquaculture has only been responsible for a shift in the use of fish meal and fish oil; from industrial or nonedible uses to fish nutrition. This way aquaculture is actually responsible for increased availability of the omega-3 fatty acids EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) for humans. In my opinion, when it comes to health, food recommendations, and benefit derived from fish and seafood, environmental considerations should not be a concern.