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6.4 NON-FOOD USES


In the following paragraphs a brief analysis of non-food uses of sharks is reported. More information on this subject can be found in the Appendix II of this report, written by Hooi K.K..

6.4.1 Shark liver oil products

Sharks have no swim bladder and their large livers saturated with oil maintain their buoyancy in water. Deep sea sharks such as gulper shark (Centrophorus granulosus), smallfin gulper shark (Centrophorus scalpratus), basking shark and tope shark are the major species targeted for this purpose, as they contain a higher yield of oil. Kreuzer and Ahmed[97] report that the size and weight of a shark’s liver varies by species and season. The weight of the liver of some shark species constitutes almost one fifth of its weight. Weight tends to increase with size as the larger the shark, the greater the relative weight of the liver. The ratio of liver weight to total body weight of some species is as follows:

Kitefin (Dalatias licha)

19.2%

Tiger (Galeocerdo cuvieri)

17.5%

Salmon (Lamna ditropis)

12.0%

Thresher (Alopias pelagicus)

10.0%

Soupfin (Galeorhinus japonicus)

2.9%

The traditional uses of shark liver oil have been:

Nowadays, demand is mainly for squalene oil, which is used in cosmetics, health food, and as high-grade machine oil. Squalene is a highly unsaturated aliphatic hydrocarbon, present in certain shark liver oils, mainly of the family Squalidae, and in cod liver oil, olive oil, wheat germ oil, rice bran oil and other vegetable oils. Although its occurrence was first reported by Tsujimoto in 1906, it was isolated only in 1926 by Heilborn et al. Shark liver oil is a natural source for this hydrocarbon and squalene is isolated from fish oil by high vacuum distillation. It can easily produce oxygen by combining with water and many studies have been related to its role of oxygen carrier. Some sharks have as much as 90% squalene in the liver and, because of its low specific gravity, thus maintain their buoyancy in water. Squalene is used as a bactericide, an intermediate in the manufacture of pharmaceuticals, organic colouring matter, rubber, chemicals, aromatics, in finishing natural and artificial silk and surface active agents. Nowadays it is extensively used as an additive in pharmaceutical preparations, cosmetics and health foods. It is prepared by adding proteins and carbohydrates.

A related compound of squalene is squalane, a saturated hydrocarbon obtained by hydrogenation of squalene. Squalane is also used in skin care products, as it is a natural emollient. It is less easily oxidised than squalene. Other chemical compounds found in shark liver oils are diacyl glyceryl ethers, which are considered to be efficient in healing wounds and in preventing the multiplication of bacteria.

According to FAO statistics, world production of shark liver oil has decreased from nearly 500 tonnes in 1976 to only 4 tonnes in 1997, 2 tonnes from Maldives and 2 tonnes from Republic of Korea. In 1976 Taiwan Province of China was the major producer with 213 tonnes, followed by Japan with 211 tonnes. The peak of production was recorded in 1977 at 720 tonnes, with 420 tonnes from Japan. Japan has not recorded its production of shark liver oil since1980 but has included it with other fish oil in Japanese statistics. Taiwan Province of China has decreased its production of shark liver oil substantially to only 2 tonnes in 1994. Exports of shark liver oil have never been very significant, only amounting to 5 tonnes worth US$3 000 in 1976, peaking at 992 tonnes worth US$5 million in 1985 (with Portugal as the main exporter with 936 tonnes) and were at nearly 140 tonnes, worth US$1.2 million in 1997. In 1997 Norway was by far the main exporter with 130 tonnes, valued at US$1.2 million, followed by Republic of Korea, Maldives and the Philippines. Reported imports of shark liver oil have been more consistent in the late 1980s/early 1990s, with a peak of 821 tonnes, valued US$9.3 million, in 1991. In 1997 they were 190 tonnes, worth US$726 000, with Norway as major importer (154 tonnes, US$358 000) in terms of volume and Republic of Korea in terms of value (38 tonnes, US$368 000).

Figure 56 World production of shark liver oil by country in tonnes

Source: FAO - FIDI.

Japan used to be one of the world’s major producers and exporters of shark liver oil. Between 1926 and 1940 Japan produced more than 3 800 tonnes annually on average. This declined in the following decades to average 220 tonnes per annum between 1973 and 1980. Production statistics have not been available since 1980. During the Second World War shark oil was used as a lubricant in combat aircraft and there was a substantial increase in demand. Statistics on Japanese exports and imports of shark liver oil are also unavailable, as it is included in the general category of fish oil. Nowadays it is an important component of cosmetics and health products and is also used in sanitary wipes used for cleaning toilets[98]

In the USA from 1930-50 shark liver oil was used in the production of vitamin A, with tope as the preferred species, but this manufacture ended when vitamin A was synthesised in the 1950s. Nowadays, there is a limited production of shark liver oil capsules, which is directed more at external markets than the domestic one. Yet, shark liver oil is now being promoted and sold as a cure for cancer in the same way as cartilage, albeit on a slightly smaller scale, and also as a cure for arthritis, psoriasis and many other ailments. One of the uses of liver oil is as an ingredient in Preparation H, an over-the-counter haemorrhoid ointment produced in the USA and distributed internationally[99]. Shark liver oil has been used for the tanning and curing of leather. Squalene is used in pharmaceuticals and cosmetic products such as skin creams.

In the Republic of Korea locally processed shark liver oil was previously used for paint and cosmetics, although nowadays it is used mainly as animal feed[100]. Crude shark liver oil (most probably squalene rich oil) is imported into Republic of Korea where it is packed locally and sold for human consumption in tablet and capsule form. Nowadays, Republic of Korea is considered to be one of the world’s major consumers of shark liver oil.

In China shark liver is used in the production of medicines and cosmetics. In India shark crude oil (the liver oil which is not suitable for pharmaceutical use) is used for painting boats as a local preservative. The use of shark liver oil for medical purposes is limited[101].

In Europe demand for shark liver oil is not very high except for France and Germany. French companies use shark liver oil and squalene in the manufacture of cosmetic and pharmaceutical products. It is used in the production of perfumery and cosmetics such as milk, lotions, creams and oil for the skin and hair. In Germany demand for shark liver oil was high in the past, particularly in the textile and leather business, for paints and varnishes and for cosmetics. Nowadays, it is also used in pharmaceutical products such as ointments and capsules.

In Africa shark liver oil is traded domestically within Eritrea, Somalia, Kenya and Madagascar for use in the maintenance of traditional fishing vessels[102]. Madagascar and Maldive export limited volumes of shark liver oil.

6.4.2 Shark cartilage

Sharks have a skeletal structure of cartilage instead of bone. There is a growing interest in the use of their cartilage in health supplements and as an alternative cure for certain diseases. Health supplements are also produced for pets and horses. Many claims, not scientifically proven, attribute to shark cartilage the role of being beneficial in cases of asthma, candidiasis, eczema, allergies, acne, phlebitis, peptic ulcers, haemorrhoids, arthritis, psoriasis, diabetic retinopathy, neovascular glaucoma, rheumatism, AIDS and above all cancer. Shark cartilage is considered beneficial in inhibiting the growth of tumours by impeding the vascularization of malignant tissues (angiogenesis).

Production and trade of shark cartilage is not documented. The markets for shark cartilage have substantially increased in the last few years, and prices are quite high. Major producing and consuming countries are the USA, Japan, Australia and India. Products with shark cartilage are sold also in Europe, Hong Kong, Taiwan Province of China, Singapore and many other countries. Products are produced in powder, capsule, and tablet form.

Unlike shark liver oil, which tends to glamorize deep-sea sharks, shark cartilage is made from both deep-sea and tropical sharks and the tablets manufactured from both types of sharks are sold in similar strengths[103]. Cartilage from blue shark is considered to be the best quality, as it is believed richer in chondroitin than those of other species. Chondroitin is an acid mucopolysaccharide, which is present in most mammalian cartilaginous tissues and is used for various health problems.

The USA represents one of the major producing country of products such as powder, creams and capsules manufactured from the cartilage of sharks. These products are sold on the domestic market and pre-packaged cartilage products are marketed and exported to about 35 countries under a variety of brand names.

Japan produces shark cartilage powder and capsules. These products are marketed for domestic use but they are also exported to countries such as the USA and Mexico and imported from the USA, New Zealand and Australia. Shark cartilage is used in Japan as a treatment for eye fatigue and rheumatism, with that of blue shark particularly appreciated.

Taiwan Province of China exports processed and unprocessed cartilage to Australia, New Zealand, Japan and USA and imports shark cartilage powder from the USA and Japan.

In Europe there is a growing market for shark cartilage products, with the UK and Spain as major distributors to other European countries.

6.4.3 Shark skin

The Chondrichthyes have rough and hard placoid scales[104], which are usually minute, but vary greatly in shape. Untanned skins are called shagreen, a term which includes the untanned leather from horses and seals[105]. Shagreen was formerly used for various polishing purposes in the arts, for armour, sword-hilts, and as a striking surface for lucifer matches.

Shark skin is also eaten as food in some countries but most of the skin used is made into leather. Shark hides are tanned in much the same way as the skins of land animals. Shark leather is used in the production of luxury items such as handbags, shoes, cowboy boots and sandals, wallets/purses, coin/key fobs, belts, key cases, lighter cases, cigar cases, watch straps, gun holsters and knife holders. In the past the skins were primarily employed for rasping and polishing wooden articles, when the denticles are left embedded in the skin, and only rarely were they used to produce leather. Among shark species whose skin is considered more suitable for the production of leather are the tiger, lemon, dusky, nurse, sandbar, porbeagle, shortfin mako, scalloped hammerhead and bull.

No statistics are available on the world production and trade of shark leather, yet the market for this product is not as it was before. In the past major producers/processors of shark skin were the USA, Mexico, Venezuela, Germany, UK and Japan.

A remarkable market for shark skin leather existed in the USA and the company “Ocean Leather Corporation” monopolised world production of shark leather for decades from 1925, handling around 50 000 shark skins annually in the mid-1980s. Now it no longer exists and only one tannery uses shark skins, along with other skins, for the production of exotic leathers. Shark leather was mainly used for cowboy boots in Texas and also for small leather goods like watchstraps and belts. The manufacture of these boots is now marginal due to a decline in popularity. With the increase in popularity of shark meat in the USA, the use of shark skin for the production of leather has become less profitable and interesting. Shark carcasses are usually sold with the skin intact in order to protect the meat and avoid oxidation. Furthermore, sharks have to be immediately bled, dressed and iced after they are caught to prevent urea from contaminating the meat, but exposure to fresh water or to ice damages shark skins. Shark skins are more often imported, with Mexico as the major supplier. Unfortunately shark skin has not been identified with its own commodity code in US statistics since 1989, when US imports were the highest recorded at 36 800 skins, in large part from Mexico. Data on the effective actual volume of this trade is not available.

The greater part of Mexican production of shark hides is exported to the USA plus a limited volume to Europe. There is also a local production of boots and small leather goods. The exports to the USA were particularly significant during the 1980s.

Until a few years ago, the shark leather market was rather important in Germany. It was used for furniture, book bindings, shoes and handbags. Shark skin was imported as a raw material and tanned. Increasing restrictions on the German tanning industry have led to imports of tanned skins. Shark leather was imported as whole skins. Nowadays, imports and production of shark leather are fairly limited. In France shark leather is used in the production of luxury items such as handbags, wallets and jewellery. Spain imports and exports shark skin and leather according to the statistics recorded by the General Service of Statistics and Planning. These products do not seem to have a great market in Spain; they are probably imported processed or semi-processed and then re-exported[106].

In Japan the hides of whale and shark were used to produce leather until the 1940s[107], since then shark and fish skins moved into niche-leather markets, providing textural and beautifully speckled colours for purses, hand-bags, Japanese sandals, watch straps, etc..

6.4.4 Shark teeth

Shark’s teeth and jaws have been used in various civilizations as functional and ceremonial objects[108]. Nowadays their use is chiefly confined to sale as tourist curious. Demand is mainly limited to tourist areas in the USA, Mexico, UK, Africa and Asia. The biggest shark species are preferred. According to Kreuzer and Ahmed[109], a fully grown shark yields around 150 teeth of saleable size. Small teeth have no great value so species such as mako and white are chosen. Shark teeth are valuable if they measure at least one-half inch across the base of the root to the tip. The larger ones have been used in traditional weapons and incorporated into ceremonial items or they are made into trinkets, curios or jewellery, especially as souvenirs for tourists. Jaws are also dried and sold as curios.

6.4.5 Other uses of shark

· Many other parts of the shark have been used for pharmaceutical purposes, such as ovaries, brain, skin and stomach (as in Uruguay[110]). The use of shark parts for health benefits has a long history, especially in Chinese traditional medicine. The first citation of the use of shark in medicine comes from the Tang dynasty (618-907 AD) with the skin and bile applied in compound recipes[111].


[97] KREUZER, AHMED R., idem.
[98] KIYONO H , idem.
[99 ]ROSE D.A., “Shark fisheries and trade in the USA” in ROSE D.A. “Shark fisheries and trade in the Americas”. TRAFFIC, USA, 1998.
[100] PARRY-JONES, “TRAFFIC report on shark fisheries and trade in the Republic of Korea”, in TRAFFIC report on shark fisheries and trade in the East Asian region”, in “The world trade in sharks: a compendium of TRAFFIC’s regional studies”, vol. I, TRAFFIC, 1996.
[101] HANFEE F., idem.
[102] BARNETT R., idem.
[103] HOOI K.K., idem, Appendix II.
[104] MARSHALL A J., 7th Edition of Parker & Haswell: “A text-book of zoology”, Macmillan & Co. Ltd, 1962.
[105] TANIKAWA E., idem.
[106] FLEMING E.H., PAPAGEORGIOU P.A, idem.
[107] TANIKAWA E., idem.
[108] ROSE, idem, 1996.
[109] KREUZER, AHMED R., idem.
[110] VILLALBA-MACIÁS J., “Shark fisheries and trade in Uruguay” in ROSE D.A., “Shark fisheries and trade in the Americas” TRAFFIC USA, 1996.
[111] CAI J.F., 1995, reported by PHIPPS M.J., “TRAFFIC report on shark fisheries and trade in the East Asian Region”, in ”The world trade in sharks: a compendium of TRAFFIC’s regional studies”, volume I, 1996.
[112] CHEN H.K., “Shark fisheries and the trade in sharks and shark products in Southeast Asia”, in ”The world trade in sharks: a compendium of TRAFFIC’s regional studies”, volume II, 1996.

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