Fish is an important part of a healthy diet. Fish and seafood products are recommended to take a prominent position in the human diet thanks to their beneficial effect on the prevention of chronic degenerative diseases. The consumption of fish may be protective against cancers and cardiovascular diseases. Therefore, health authorities and the food industry have a joint interest in stimulating fish consumption.

by Dr. Nuray Erkan and Dr. Ferhat Cagiltay

The importance of fish in nutrition
Processed or unprocessed fish should reach the consumer as a high quality product. Fish is easily digestible as well as a high value food. The fish content is important for a healthy diet. Fish is known to be a source of protein rich in essential amino acids, micro- and macro elements (selenium, fluorine, iodine, calcium, phosphorus), fats that are valuable sources of energy, fat-soluble vitamins and unsaturated fatty acids. Lysine, methionine, threonine, tryptophan, isoleucine, leucine, phenylalanine and valine are generally regarded as essential amino acids for humans.

Amino acids are implicated in the central nervous system, and the process of learning: they are used in the treatment of depression and prevent the formation of fat in arteries, allergies, and are effective in the treatment of osteoporosis. Scientific studies indicate that the consumption of 100 g per day of raw or processed fish products (smoked, marinated, salted and canned), meets the daily requirement for essential amino acids. The significance of long chain polyunsaturated fatty acids (PUFA) has gained attention because of their role in the prevention of human coronary artery disease, in retina and brain development and in reducing the incidence of a number of conditions including breast cancer, rheumatoid arthritis, multiple scelerosis, psoriasis and inflammation.

Fish lipids are particularly rich in polyunsaturated fatty acids [especially the n-3 PUFA family of linolenic acid (C18:3 n-3) and its derivatives eicosapentaenoic acid (EPA or C20:5 n-3), docosapentaenoic acid (DPA or C22:5 n-3) and docosahexaenoic acid (DHA or C22:6 n-3)] that are only synthesised in humans at low rates. Mozaffarian et al. [1] reported that consumption of broiled or baked fish, but not fried fish, is associated with lower incidence of congestive heart failure (CHF). General recommendations for daily dietary intakes of DHA/EPA are 0.5 g for infants and an average of 1 g/day for adults and coronary heart disease patients. According to these scientific results, when 100 g of fish (meat) is consumed (about 1 portion), 100% of the daily DHA/EPA requirements for a person will be met.

Fish consumption in the world and factors influencing the consumption of fish
Usually fish is consumed as fresh fish and processed fish (smoked salted, marinated, dried and canned fish). Fresh fish is preferred as raw (such as sushi), fried, grilled, steamed or boiled. According to research by Erkan et al. consumption of grilled, steamed and boiled fish is more beneficial to health than consumption of fried fish.

Consumed fish is obtained from capture and aquaculture. Fish consumption per capita in the world is approximately 16 kg/person [table 1]. This value is increasing every year. There are many factors that affect the consumption of fish and other seafood. These factors are historical, ecological conditions (fish population in the region, environmental factors, geographic area, capture or fisheries), economic relations (the economy of the region, economic revenue from fisheries), and social factors (tradition, religion, living standards and availability of substitutes, the level of consumer education, the consciousness of consumer).

Geographical area is a major factor in fish consumption. Fish consumption varies according to countries and regions. In fish consumption analysis the proportion of the population living in coastal areas has a significant effect on fish consumption. For example, Iceland is the world’s largest fish producing and consuming country. The economy of Iceland is based on fishing. Japan is an island country too and the Japanese consume fish and seafood at an average of 15 million tons per year. Malaysia is also among the countries with the highest fish consumption in the world. Average fish consumption has increased from 49 kg per capita in 2000 to 53 kg per capita in 2005. This figure is expected to increase to 56 kg in 2010. Population growth,  increasing income, health consciousness, and an expanding downstream processing industry is also expected to spur the demand for fish in Malaysia. On the African continent, fish consumption is highest in Gabon and Senegal. In these countries, canned fish production is common. In Turkey the average fish consumption rate is about 8 kg/per year whereas on the coastal zones this rate is about 25 kg/per year. The low consumption of fish and fish products in Poland, Czech Republic and Ukraine as compared to that in other European countries is due, amongst other reasons, to inadequate promotion and a lack of sufficient information regarding their nutritional qualities [table 2].

Fish consumption in most countries has been growing with economic development and improvement in fish availability. China is a good example of this phenomenon. Rich countries consume more fish than poor countries, for example the Western nations have a tendency to consume more fish than other nations, particularly as their economies develop. In Asian nations economic development does not result in high fish consumption to nearly the same degree as in Western nations. However, Asian nations do have a greater tendency to consume fish at higher rates than other nations as their economies develop, indicating cultural predilections for certain types of animal foods. Similarly, the effect of urbanisation on fish consumption also suggests a cultural explanation, since urbanisation may lead to greater exposure to the culture of affluent, particularly Western, nations and therefore contribute to increased fish consumption. Research has also shown that the the consumption of fish rises in direct proportion to the education level of people.

The influence of religion
Religious prescriptions also affect the consumption of fish and seafood. For example India, although a coastal nation,  has a low seafood consumption becausemajor paths of Hinduism forbid killing and eating any animal including fish and seafood. Kosher rules restrict the consumption of fish to scaled and finned species, ie anchovy, mackerel, bluefish, tuna, sardine, cod haddock, trout, herring and tilapia, whereas shark, eel, dolphin and shellfish are forbidden. According to Islam every kind of seafood may be consumed, but some Islamic nations never eat certain types of seafood like turtle, crab, mussel, shrimp, crocodile etc. It has been suggested that in the Christian religion predominantly Catholic nations consume more fish and less meat than predominantly Protestant nations. Orthodox Christian holy books recommend a total of 180–200 days of fasting per year. The faithful are advised to avoid olive oil, meat, fish, milk and dairy products every Wednesday and Friday throughout the year. Seafood such as shrimps, squid, cuttlefish, octopus, lobsters and crabs as well as snails are allowed on all fasting days throughout the year.

The importance of aquaculture in fish consumption
Food consumption patterns, particularly fish consumption, have serious consequences for environmental sustainability. Excessive catching and the decline of specific species is an important consideration when analysing fish consumption.

As the worldwide consumption of fish and derived fish products has greatly increased during recent decades, the increase in demand has led to an expansion of the fishing fleet. Together with the higher efficiency of fish capture, this has contributed to overfishing and the risk of depletion of some natural fish stocks. There is as an urgent need to adopt more sustainable fisheries management to restore marine biodiversity and safeguard the contribution of fisheries to food security. In response to the overfishing of wild fish stocks and the increasing consumer demand for fish, consumers are now offered farmed fish as a valuable alternative [table 3].

Most mature aquaculture industries (e.g. milkfish in the Philippines, catfish in the USA, salmon and trout worldwide, eel in Japan and oysters, sea bass and sea bream in Europe) experienced initial phases of very rapid growth.

Milkfish is important seafood in Southeast Asia and some Pacific Islands. As milkfish is notorious for being much bonier than other food fish, deboned milkfish or “boneless bangus,” has become popular in stores and markets. Milkfish processing takes two forms: traditional ways include smoking, drying and fermenting, and bottling, canning and freezing are of recent origin.

Catfish have been widely caught and farmed for food for hundreds of years in Africa, Asia, Europe and North America. Judgments as to the quality and flavour vary, with some food critics considering catfish as being excellent food when others dismiss them as watery and lacking in flavour. In Central Europe catfish has often been viewed as a delicacy to be enjoyed on feast days and holidays. Catfish is eaten in a variety of ways; in Europe it is often cooked in similar ways to carp, but in the United States it is typically crumbed with cornmeal and fried. In Indonesia catfish are usually served grilled from street stalls and eaten with vegetables and soy sauce. It can also be eaten minced with chili sambal. In Malaysia catfish is fried with spices or grilled and eaten with tamarind and Thai chilli sauce and is also often consumed with steamed rice. In the Indian states of West Bengal, Assam and Bangladesh catfish is eaten as a favoured delicacy during the monsoons.

Salmon are intensively produced in aquaculture in many parts of the world. Salmon farming is very big in Chile, Norway, Scotland, Canada and the Faroe Islands, and is the source of most salmon consumed in America and Europe. Atlantic salmon are also, in very small volumes, farmed in Russia and the Island of Tasmania, Australia. Salmon flesh is generally orange to red. Salmon is consumed as fresh, salted (gravad), cold and smoked. Salmon and salmon roe have only recently come into use in making sashimi and sushi.

Rainbow trout (Onchorynchus mykiss) is farmed mainly in the river waters, and sold as either whole fresh fish in retail markets, or in fillet form in supermarkets and chain stores. Additionally, trout fillets in the form of smoked and vacuum packaged products are exported to various northern European countries and consumed with no further heating.

Eels are usually processed before retailing. Process techniques include smoking, jellying, pickling and kabayaki for the Japanese market. Over the last decade several species of marine fish including sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax) have been farmed in Greece, Turkey and in other Mediterranean counties in order to meet the increasing demand for fresh rather than frozen fish.

Conclusion
Ecological conditions in a nation have a positive influence on fish consumption. Fish consumption patterns may change over time as a result of globalisation and increasing trade. Aquaculture will be effective in meeting the increasing fish consumption. Historical, cultural, social and economic factors should be evaluated together when analysing fish consumption.

Further reading
- Erkan N, Özden Ö, Selçuk A. Effect of Frying, Grilling, and Steaming on Amino Acid Composition of Marine Fishes. Journal of Medicinal Food 2010; 13(6):1524-1531.-
- Huss HH, Ababouch L, Gram L. Assessment and management of seafood safety and quality. FAO Fisheries Technical Paper 2003; No. 444. Rome, FAO: 230p.
- Kurien J. Responsible fish trade and food security. FAO Fisheries Technical Paper 2005; No. 456. Rome, FAO: 102p
- Mozaffarian D, Katan MB, Ascherio A, Stampher MJ, Willet WC. Medical progress: Trans Fatty Acids and Cardiovascular Disease. The New England Journal of Medicine 2006; 354:1601-1613.
- Pieniak Z, Verbeke W, Scholderer J, Brunsø K, Olsen SO. European consumer’s use of and trust in information sources about fish. Food Quality and Preference 2007; 18:1050-1063.
- Ye Y. Historical consumption and future demand for fish and fishery products: exploratory calculations for the years 2015/2030. FAO Fisheries Circular 1999; No. 946. Rome, FAO: 31p.
- York R, Gossard MH. Cross-national meat and fish consumption: exploring the effects of modernization and ecological context. Ecological Economics 2004; 48: 293-302.

The authors
Nuray ERKAN¹* and Ferhat CAGILTAY²

¹ Department of the Seafood Processing and Quality Control. Faculty of Fisheries, Istanbul University, Turkey
² Department of Aquaculture, Faculty of Fisheries, Istanbul University, Turkey

*Corresponding author:
Nuray Erkan
Ordu Cad. No: 200 34470
Laleli/Istanbul, Turkey.
Tel. +90 212 455 57 00/16415