Advice to consumers is to increase the amount of fish we eat, to guard against cardiovascular diseases. However, should consumers be concerned about the ethics of eating wild fish and is farmed fish a healthy choice?
Fishing on demand for health
Fish and seafood are known to provide a valuable source of protein, essential vitamins and minerals. In addition, dietary recommendations for most of the European population suggest eating one or two portions of oily fish (e.g. salmon or mackerel) weekly. The recommendations are based on the knowledge that oily fish are an excellent source of omega-3 fatty acids, which are beneficial to cardiovascular health and also to foetal development.1,2
How is your fish produced?
Globally, the consumption of fish has increased greatly over recent decades.3 In the European Union (EU), fish catches have declined but consumption has increased by at least 10% over the last decade, with the increase met by farmed fish. Currently, it is estimated that around two-thirds of the fish caught in the EU is caught from the wild.4 Examples of predominantly farmed fish include salmon, rainbow trout and carp, whilst wild-caught fish include herring, tuna, mackerel and pilchards. For wild fish, the nutritional content and contaminant levels are dependent on many factors, which are not easily controlled: species, season, diet, location, life stage and age. Fish higher up the food chain (e.g. salmon, tuna, swordfish) can accumulate contaminants. In fish that are raised using techniques of aquaculture – or farming methods – there can be tighter control over the diet the fish eat, and there are strict EU regulations concerning contaminants in farmed fish.
Nutritional value of farmed versus wild fish
Farmed fish are fed a controlled diet, usually based on fish oil and fish meal. This diet is not subject to the seasonal variations found in the diets of wild fish. Consequently, research has found that lipid levels in farmed fish are more constant than those of wild fish.3
Fishmeal to feed farmed predator fish (e.g. salmon) is mainly produced from fish not meant for human consumption, such as capelin or sprat. Vegetable sources of fishmeal are being used increasingly, however this could reduce the amount of omega-3 fatty acids in farmed fish. Feeding a fish-derived diet for the last few weeks can be employed to offset such an effect.
Sustainability of fish for consumers
It is estimated that if current fishing practices continue, fish stocks will be severely depleted within 40 years. In the EU marine area, just over 10% of fish stocks are sustainable. Clearly, farmed fish could provide a solution to meet the demand sustainably.
Despite studies showing that there are no sensory differences between farmed and wild fish, consumers perceive wild fish to be more healthy and tasty than farmed fish.5 However, there are advantages of farmed fish, namely:
- Regular supplies
- Consistent nutritional content
- Strict controls on production
- Cheaper, more stable prices
Research has shown that although consumers attach high value to the sustainability and ethics of fish production, this interest is not necessarily associated with attitudes and purchasing behaviour.5 Refusing to eat wild fish has been associated with ethical concerns, whereas refusing to eat farmed fish is linked to expected lower quality of the food. Aquaculture is not without negative environmental effects: overfishing to produce fish feed, change in habitats, effluents and the impact on biodiversity when fish escape from farms. In response, a number of EU projects have been funded to optimise aquaculture so that it can meet consumer demand in a responsible and sustainable fashion.
In addition, it is perceived that farmed fish are less healthy. However, due to the controlled environment, diseases can be contained in farmed fish, thus improving fish welfare.6 An important goal of aquaculture is to ensure an acceptable level of welfare such that farmed fish are comparable with ‘natural’ wild fish.
For the consumer, both farmed and wild fish are safe and nutritious to eat, with no major differences between them, provided that farmed fish are raised under appropriate conditions. In response to overfishing, farmed fish is a viable alternative to meet nutritional recommendations to eat more fish.
EU project RAFOA (Researching Alternatives to Fish Oils in Aquaculture) -
EU project AQUAMAX (Sustainable Aquafeeds to Maximise the Health Benefits of Farmed Fish for Consumers) - http://www.aquamaxip.eu/
EU project CONSENSUS (Towards Sustainable Aquaculture in Europe) -
- Mente A, de Koning L, Shannon HS, Anand SS (2009). A systematic review of the evidence supporting a causal link between dietary factors and coronary heart disease. Archives of Internal Medicine 169(7):659-69.
- Innis SM (2007). Dietary (n-3) fatty acids and brain development. Journal of Nutrition 137(4):855-9.
- Cahu C et al (2004). Farmed and wild fish in the prevention of cardiovascular diseases: Assessing possible differences in lipid nutritional values. Nutrition, Metabolism and Cardiovascular Diseases 14:34-41.
- European Food Safety Authority. Opinion of the Scientific Panel on contaminants in the food chain [CONTAM] related to the safety assessment of wild and farmed fish. Available at: http://www.efsa.europa.eu/en/efsajournal/pub/236
- Verbeke W et al (2007). Perceived importance of sustainability and ethics related with fish: a consumer behaviour perspective. Journal of the Human Environment 36:580-5.
- Bergh O (2007). The dual myths of the healthy wild fish and the unhealthy farmed fish.Diseases of Aquatic Organisms 75:159-64.