Shagreen--Conservation DistList Date : Tuesday, April 17, 2001 Mark Vine <100436.3447 [at] compuserve__com> writes >This enquiry is placed on behalf of a conservator without access to >the list. He has been given two 20 x 30 inch panels which the >custodian tells him are covered with shagreen (my understanding is >that this is the skin from the underside of a shark). The first time I saw shagreen it covered the surface of a tea caddy case. It was labeled "imitation leather" and had me stumped. Once it is known, however, shagreen has a very recognizable surface pattern that is unmistakable under magnification. Shagreen is the term for a coarse-surfaced hide; the original use for the name stems from the seed-impregnated donkey, horse or camel hide found on Persian riding boots and weapons from the 1600's. Generally, though, shagreen is assumed to be the untanned skin of sharks or rays. Shagreen has a long history of use.

Early protective wear and sand-paper applications aside, shagreen inlays for luxury items were made by Jacques Galuchat for Louis XIV in the 1750's; Herman Melville mentioned it 1851, in Moby Dick ("...Hosea Hussey had his account books bound in superior old shark-skin"); and the 1920's saw inspired designs by avant-garde furniture makers. The shagreen look has been imitated with paper; more recently, new low-friction swim suits which recreate the surface of sharkskin were used at the Sydney Olympics. The best illustrations of artifacts with shagreen components I know are in the catalogue of a retrospective exhibit held in Paris in 1994. The book (Caunes, Lison de et Perfettini, Jean. Galuchat. Les editions de l'amateur, Paris, France, 1994) is out of print but can still be found through French book dealers. Here are some identification notes: Sharkskin has a rough outer surface due to deeply embedded dermal denticles called "placoid scales".

The placoid scales of sharks and their close relatives, rays and skates, are composed of calcium carbonate, calcium phosphate, dentine and enamel like teeth, while the scales of all other fishes are composed of calcium salts and collagen fibres, like bone. Placoid scales are unique to sharks, rays and skates. They can range in size from microscopic and closely spaced (over half of shark species are less than one meter long) to prominent spikes. Depending on the species, age and location on the body, placoid scales have different shaped crowns with variable numbers of ridges, cusps, blades or keels and furrows. On the body of the shark, the common arrangement of denticles has the pointed cusp facing the tail. This head-tail direction feels smooth to the touch, while in the opposite direction it is sharp. On shagreen, the same directional difference between smooth and rough can be expected to some degree. Shagreen is prepared by scraping, stretching and drying. It is not a true leather but a rawhide. It is processed into a useable material by grinding, filing and polishing the surface denticles in order to flatten their sharp points.

The skin may also have been dyed, or have pearly white denticles interspaced with black varnish. (A chemical process to decalcify and soften placoid scales for producing commercially tanned leather did not exist prior to the 1920's). Black filler in-between closely spaced denticles is common, as are natural, light-coloured skins with ground-down spikes, e.g., from the stingray. Copper salts and other dyes were used for contrasting denticles and skin tones in shades of green, red, brown and yellow. The dermis of sharkskin is composed of a tight network of unusually long connective fibres that may be seen along exposed edges due to, for example, a distorted substrate or shrinkage. If necessary, a fibre can be tested with a protein stain. Using the microscope is advisable for this test since the shagreen (or its imitations) may have been originally adhered to a substrate with hot hide glue. It is also for this reason that I prefer an acrylic emulsion such as Rhoplex N-560 for conservation treatment. Finally, shagreen is susceptible to damage during RH fluctuations.

Under low RH, dermal denticles crack like teeth; the skin reacts by tearing, distortion or lifting off its substrate. For the conservation record, it is useful to describe the number of shagreen sections that were applied over an object, and include a close-up photograph to document the condition as well as the shape of it's placoid scales. Margot Brunn Conservator Provincial Museum of Alberta *** Conservation DistList Instance 14:55 Distributed: Thursday, April 19, 2001 Message Id: cdl-14-55-009 *** Received on 6.4 NON-FOOD USES 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) 2.9% The traditional uses of shark liver oil have been: As a lubricant in the tanning and textile industries. Crude liver oil containing squalene was used as a lubricant because it has a melting point of -75oC and a boiling point of 330oC. In cosmetics and skin healing products. In health products and traditional foods. To coat the hulls of wooden boats as a preservative against marine fouling. As fuel for street lamps.

To promote the healing of wounds, irritations of the respiratory and gastrointestinal tracts and general debility by fishermen in Scandinavia in ancient times. By the early 19th century its use there had ended except for a few isolated fishing communities. To produce Vitamin A during World War II, particularly in the USA and Australia. This led to an extensive fishery for tope shark and picked dogfish. The market in shark livers collapsed when synthetic imitations became available. 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] . Sharks are maintained live in public aquaria. Small sharks not suitable for trade are often used as bait. Processing wastes of chondrichthyans are used in the production of fishmeal for animal feed or fertilizer or to yield fish oils for industrial uses. Shark is used as ingredient in tanning lotions.

Shark livers are sometimes mixed with other food and used by shrimp farmers in aquaculture. [112] Shark cartilage is also used for the production of fishmeal. Whole small sharks and rays or parts of their bodies may be preserved for sale as curios. Glue is made from certain sharks and fish, which may in turn be used in the manufacture of lacquerware. [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. Shagreen | Define Shagreen at Dictionary.com shagreen noun 1. an untanned leather with a granular surface, prepared from the hide of a horse, shark, seal, etc. 2. the rough skin of certain sharks, used as an abrasive. adjective Also, shagreened. resembling, covered with, or made of shagreen. Origin of shagreen Shagreen: The Skin of Rays & Sharks — Retrospect | Apartment Therapy Email A closeup of a shagreen tabletop, from an Art Deco-era design by Jean-Michel Frank Shagreen has been a luxurious decorative material for many centuries, though it is perhaps most closely associated with the Art Deco era. Signifying luxury and exoticism, this often controversial material is once more in vogue. Shagreen typically refers to the skin of rays, sharks or dogfish, all of which are cartilaginous fish with a smoothly pebbled texture. It has been used for centuries as a mild abrasive, like sandpaper, in smoothing wood and metal.

Supposedly, ray skin has been prized since the time of the pharaohs, and during the Chinese Han Dynasty (202 BC - AD 220). It has been better documented and preserved since it began appearing on the sword hilts and armor of Japanese samurai during the Middle Ages, in part because its texture provided a reliable grip. Europe began importing shagreen-covered objects during the 17th and 18th centuries, and in the mid-1700s, a tanner in Paris became the first European shagreen expert (his name, Galluchat, has been transformed into galuchat, the French word for shagreen.) Louis XV 's most famous mistress, Madame de Pompadour, was the dominant patron of Monsieur Galluchat, and it was said that a week didn't go by when she didn't buy some new object, often in shagreen. Shagreen was often imitated in more accessible materials. Craftsmen would insert seeds into untanned leather, and then pressing the seeds into the leather before discarding them. They would then typically dye the reverse side green to approximate the authentic skin.

The word "shagreen" supposedly comes from the Turkish word "sagri," which refers to the rump or haunches of a mammal, presumably used in approximating the distinctive texture of sting rays. Shagreen became a popular material again in Europe during the Art Deco era, when designers sought to fuse the French tradition of luxury with exotic and precious materials. Designers like Clément Rousseau and Jean-Michael Frank used shagreen to create their most sumptuous furniture (images 4 & 6). There is some controversy about whether shagreen is an environmentally correct material. While some sources claim the use of the material may threaten the species, designers who use the material insist that their practice does no harm . At least two prominent companies that use shagreen, Ironies and R&Y Augousti, claim that they use only sustainably-sourced remnants from the fishing industry (images 9 & 10). Most extant antiques with shagreen are smaller objects, like glasses cases and sword hilts (images 2 & 3), but you can really see how durable the material is, through centuries of both use and neglect.

Today, you can find all sorts of objects in both real and faux shagreen, including tables, decorative boxes and picture frames.

Images: 1 Detail of a tableto by Jean-Michel Frank, via Paris Originals ; 2 Qing sword from the Qianlong period, sold at Sotheby's in 2002 for about $74,000; 3 Etui made in China circa 1900, via Ruby Lane Antiques ; 4 and 5 Small 1912 shagreen commode by Iribe and a 1921 chair by Clement Rousseau, both at the Musée des Arts Décoratifs in Paris, via Michael Hampton's blog ; 6 Shagreen lipstick case by Cartier, circa 1930, sold by Sotheby's in 2006 for about $750; 7 Jean-Michel Frank cabinet from the early 1930s, sold by Christie's in 2000 for about $746,000; 8 Karl Springer table from the 1970s, available from Craig Van Den Brulle on 1st Dibs; 9 Shagreen nesting tables from Ironies ; 10 R&Y Augousti Metal Circle Desk, available from L

ille for $5,300.

Sources: There is a beautiful French book on shagreen by Jean Perfettini called Le galuchat , published a few years ago. But I like this online history from The Leather Connection . R&Y Augousti items are available through Lille and at Barney's . Ironies is available to the trade at Jerry Pair . Shagreen | Definition of Shagreen by Merriam-Webster See words that rhyme with shagreen Britannica.com: Encyclopedia article about shagreen Seen and Heard What made you want to look up shagreen? Please tell us where you read or heard it (including the quote, if possible). APPENDIX III: NON-FOOD USES OF SHARKS by HOOI KOK KUANG APPENDIX III: NON-FOOD USES OF SHARKS by HOOI KOK KUANG 1 INTRODUCTION The writer's contract was to update information on the FAO publication entitled Shark Utilization and Marketing by Kreuzer & Ahmed (1978), concentrating on the uses of shark hides, liver oil and teeth, in particular on products which are not used as human food.

The report would include pharmaceutical products produced from sharks, but would not reproduce material found in the above-mentioned FAO report. Over the past 20 years, the recording of catches of sharks has improved only slightly so there is still a great deal of uncertainty about this fishery. The uses to which sharks have been put have changed, and the claims about their health benefits have increased. However, our understanding of these health claims has yet to be fully described. 2 SHARK LIVER OIL PRODUCTS Kreuzer & Ahmed (1978) reported that the development of synthetic vitamins (particularly vitamin A) led to the virtual collapse of the markets for shark liver oil; it relieved temporarily the fishing pressure on sharks. Shark liver oils have also been used in the textile and tanning industries, as lubricants, in cosmetics and skin healing products, in health products and in traditional foods. Over the past 20 years, the processing methods for shark liver oils have not changed very much, but quality control techniques have improved the product (Wong, 1998, pers comm) in tandem with related developments, such as refrigeration at sea.

However, Summers, Wong & Eyres (undated) also suggested that livers can be ensilaged and stored at ambient temperature instead of more costly refrigeration at sea. They argued that ensiling would not only prevent protein putrefaction and retard oxidation but also aid in the release and recovery of the oil. They considered this was most suited for fisheries located in remote areas. In one of their experiments they found that the highest amount of oil was extracted from samples of liver treated with formic and phosphoric acids and a permitted (food) antioxidant, and the least amount was extracted from a sample left to deteriorate. Rose (1996) observed that in the Maldives, which may possibly be considered as a remote area, the livers are simply left in the sun for hours or days before they are boiled and the oil extracted. Shark livers have been used traditionally as foods. This ranged from being eaten fresh after its harvesting and cooking, to being preserved by salting and, much later, cooked before eating. Other uses included the use of crude liver oils to coat the hulls of wooden boats as a preservative against marine fouling, and as fuel for street lamps.

Crude liver oils containing squalene were used as lubricants since its melting point is -75oC and its boiling point is 330oC. There are variations in detail, but the description by Tanikawa (1985) probably covers most of the principles involved in processing the liver for the crude oil. The livers or blubber are chopped or minced before cooking in steam or water. The mixture of oil and water is allowed to cool and settle. The residue may be used in fishmeal production (as in India), or as feed for pigs and poultry. The crude oil is then sent to separating tanks and may be centrifuged (Miwa, 1972). Tanikawa (loc cit) said that after the oil has separated the residue, called "cooked skin of whale", is eaten as a delicacy in the Osaka district of Japan. Summers, Wong & Eyres (undated) reviewed work on shark liver oils; part of this report appeared in Summers & Wong (1992).

They found that squalene, a triterpenoid hydrocarbon and precursor of sterols, was used to manufacture lubricants, pharmaceuticals and bactericides, and as a surface active agent in cosmetics. They reported claims that squalene prevented the formation of nitrosamines in topical products that contain an amine and a nitrosating agent. It was also said to increase skin permeability to topical ointment bases because of its miscibility with human sebum, where it also occurs naturally. Squalene has been used for centuries in many countries in skin creams to soften skin, reduce small facial wrinkles, speed up wound healing, as a moisturiser and as a bactericide (a feature it has in common with other members of the terpenes family). It is often hydrogenated to various extents and used as squalane, which is more stable. Summers et al investigated seven species of Squalidae that are common to the deep waters of the continental slope surrounding New Zealand; approximately 20% of the body weight was liver. It is believed that the large livers provide buoyancy for these deep- water sharks and contain energy sources adapted to their low oxygen environment.

They found that all the livers they investigated contained a large proportion of lipid but the composition of the lipid varied from species to species. These lipids typically consisted of a mixture of hydrocarbons (mainly squalene, and some pristane), diacyl and mono glyceryl ethers (compounds of fatty alcohols and glycerol by ether linkage) and triglycerides (esters of fatty acids and glycerol). They used a thin layer evaporator to obtain almost pure squalene with minor levels of lipid oxidation at an operational temperature of 136oC. The purified squalene contained trace amounts of pristane, which is considered a skin irritant. However, when the degummed, bleached, deodorised and partly hydrogenated product was used by laboratory staff for over 6 months, they did not report any skin irritations. In fact they commented that, when used as a base for sunscreen lotion, it had excellent penetration qualities (penetrates the skin at about 2mm/sec), was not greasy (the most desirable feature) and did not develop off-odours. Current interest in shark oils has focused on their purported effect on health.

Anecdotal statements have fuelled the market. Components of shark oils were said to cure certain diseases, relieve pain and improve health generally. Traditional uses in folk medicines have been cited from Japan, China, Spain and the Scandinavian countries to support these claims. The sharks named have included the Greenland shark (Somniosus microcephalus) and Gulper sharks (Centrophorus spp.) from Scandinavian waters, from around Papua New Guinea (their liver oil is exported to Japan for the manufacture of skin creams) and from the cold waters of the Western Pacific where they are known as Aizame sharks (a Japanese name (Liu, 1998) - one label described the Aizame sharks as scarce). The names of other sharks are shown in Table 1. However, none of these claims have been conclusively tested. The writer was unable to determine the volume of such products in the market. Yet, as peoples around the world grow older and potentially have more health problems, it is likely that the demand for health products will increase. Mention is made in the popular and technical literature of various components in the oils, especially oils from deepsea sharks.

(The possibility of using cheaper methods for preserving livers of sharks, as suggested by Summers et al, namely, using ensiling instead of refrigeration, may be extended to sharks captured from warmer and shallower waters and could lead to reducing the fishing pressure on deepsea sharks for their liver oils.) The function of these compounds in contributing to health remains incompletely understood. Squalene, for example, is a biosynthetic precursor of cholesterol yet it is claimed that it helps to normalise the blood cholesterol levels in people who eat a lot of fatty foods. Table 1 Sharks whose livers are harvested Tope Shark (Galeorhinus galeus) Snaggletooth Shark (Hemipristis elongata) Plunkets Dogfish (Centroscymnus plunketi) One advertiser on the Internet claimed that squalene is helpful to people with heart disease, diabetes, hepatitis and allergies, among others. No mention of the specific varieties of these diseases was given. The same advertiser also said that it would generally enhance the quality of life, result in better skin and people who worked hard would feel less tired.

Another substance found in shark liver oils in the early nineties, squalamine, was said to be a bactericide and later also believed to assist in curing infections involving yeasts, fungi and viruses and to strengthen the functions of the immune system. Common fatty alcohols found in shark liver oil are chimylalcohol, batylalcohol, and selachylalcohol (also known as alkylglycerols or glycerol ether lipids, often shortened to G-E- lipids in popular publications and on the Internet). These have been cited as the compounds which support healthy immune system function when consumed in natural products such as shark liver oil. Since the fatty alcohols are more concentrated in lymph nodes, liver, spleen and bone marrow, and since these glands are in turn associated with the body's immune functions, the claims have also been extended to the immune functions of these organs. However, they have to be in their natural form to be most beneficial, a condition which is unlikely to attract funds for research. As a result, thorough testing has not yet been carried out.

Shark liver oil is packaged in capsules for oral consumption, and sold either in its purified form, or mixed with various other health enhancing substances for synergistic effects (also not yet rigorously proven). Labelling has become quite sophisticated, with quantitative details of ingredients, including amounts of squalene, omega-3 polyunsaturated fatty acids, alkylglycerols, vitamins, etc, and daily requirements may also be shown on the labels. Prices of capsules in Hong Kong were lower in September 1997 than the prices reported by Parry-Jones in 1996. He reported that bottles of between 40 and 180 capsules cost between HK$238 and HK$595 a bottle. However, in September 1997, the Australian, Canadian and American products were priced between HK$100 and HK$440 for a bottle of between 60 and 100 capsules, while a bottle of 80 capsules made in China cost HK$200. Conservationists say that shark liver health products do not have any beneficial effects, and that they just result in the killing of more sharks.

One estimated that a tonne of shark liver oil was produced from between 2,500 and 3,000 sharks (cited in Rose, 1996). Republic of Korea imported 364 tonnes of shark liver oil in 1994; about a million shark livers, probably from deep waters, were harvested for their oils. 3 SHARK CARTILAGE PRODUCTS The cartilage of sharks contains chondromucoids, collagen, chondroalbumins (Suzuki, 1972) and other substances. One proximate analysis gave the following: 41% ash (with large amounts of calcium and phosphorus), 39% protein, 12% carbohydrate, 7% water, about 1% fibre and about 0.3% fat. Shark cartilage, not just shark fin, has been used traditionally as food by the Chinese and Japanese. For example, Tanikawa (1985) described the processing of boiled-dried cartilage ("meikotsu") made from pieces of jaw, fin and head parts. These are soaked in hot water, the meat is removed and then the cartilage is boiled and sun-dried.

The product was also exported to China and possibly eaten as a health supplement as well. In Hong Kong dried shark cartilage is sold as vertebral columns or as a by-product of shark fin processing. The former are mostly imported into Hong Kong from north and south America. They are cooked and eaten as food or boiled in soups or with herbs to improve health. The vertebral columns are sold as cylindrical rods as most of the vertebral processes have been trimmed off to simplify cleaning. The rods are of various diameters and about a metre in length. Most of the meat has also been removed and where it remains the rod is discoloured. Some rods are bleached white. In September 1997 these were retailed at HK$68 a kati (1 kati = 0.6 kg). Fin cartilage is produced as a by-product of shark fin processing. The skin of the fin is peeled off, followed by the removal of the fin needles which are used in shark fin soup. The remaining fan-shaped fin cartilage is dried and sold. In September 1997 the price was HK$38 a kati.

However, most of the fin cartilage is exported to Japan, believed to be the largest producer of shark cartilage products. Traders in Hong Kong understand that the blue shark cartilage is preferred in Japan because this contains the most gelatinous material. Recent interest in shark cartilage is concentrated almost entirely on its use in health supplements and as an alternative cure for certain diseases. Manufacturers of shark cartilage products claim that individuals have been cured of dreaded diseases and that sufficient observations have already been recorded for health authorities to justify clinical trials. They have also suggested that, until more definite results are available, sufferers should be encouraged to try it under proper medical supervision. A Dr Lane has been credited as raising the profile of shark cartilage. Although he believes that certain forms of cancer can be cured by shark cartilage, he has adopted the view that it "is not a miracle elixir" and "should not be viewed as a substitute for conventional therapy" (Lane, 1996). As with shark liver oil, it is also claimed that all chemical components in shark cartilage should be present in their natural proportions to enhance their synergistic effects. However, references are made to chondroitin as one of the active ingredients.

Over 25 years ago, Suzuki (1972) described the extraction of chondroitin sulphate (also simply called chondroitin) by hydrolysing the chondromucoids in shark cartilage. She also reported then that it was believed to be a remedy for arthritis and a method of ageing retardation in Japan. As people live longer, arthritis and ageing retardation will attract more and more attention. In fact, the use of shark cartilage products in health products and cosmetics overlaps that of shark liver oil, including its claims as a cure for various cancers. It is also used in the treatment of rheumatism, haemorrhoids, shingles, psoriasis and diabetic retinopathy. One advertiser additionally listed shark cartilage as effective against eczema, colitis, enteritis, poison ivy/oak, acne, varicose ulcers, phlebitis and cold sores. The number of references to shark cartilage on the Internet far exceeded those to shark liver oils. On one day in February 1998, there were 123 184 references to cartilage, compared to 1 230 for shark liver oil on the same website.

Yet, in the FAO publication in 1974 entitled Fishery Products edited by R Kreuzer, there was no mention of shark cartilage in contrast with the numerous references to shark liver oils. In Kreuzer & Ahmed (1978), there was equally scant reference to cartilage in comparison with shark liver oils although there was a reference to the use of chondroitin in eye drops, to which we will return. Trade figures are not available for shark cartilage tablets or powder, nor for shark liver oil capsules. They are likely to remain poorly reported until the products are more clearly defined and regulatory procedures are in place. A comprehensive report by TRAFFIC outlined the trade practices in the preparation and sale of shark cartilage. Rose (1996) observed that the processing of shark cartilage was labour intensive, as was the processing of shark fin, and was carried out in many parts of the world. Production was carried out when orders were received and there was a certain amount of specialisation; primary producers prepared the raw material, for example, but did not necessarily produce the tablets.

Marketing of the tablets was also carried out by agents; for example, shark cartilage tablets sold in Singapore were purchased through agencies rather than directly from manufacturers. This was probably because of the small quantities sold in individual retail outlets. Rose (loc cit) also concluded that shark cartilage production was probably not a threat to shark survival. An example she gave of financial returns to a United States-based harvester of a 23 kg shark was: cartilage US$2, fins US$25 and meat US$12.50. She mentioned that dried shark cartilage cost about US$1 per pound (0.45 kg) in the United States and Mexico, but Fahmeeda Hanfee (1996) reported that in India they fetched US$15-20 per kg, although it was unclear if it had been a more highly processed material. Although there is much emphasis on quality control to preserve the shark cartilage in its natural form, there is very little reported on its preservation after the shark is landed in fishing boats. Producers claim that to produce high quality cartilage products it is essential to remove meat and gristle by hand, without using strong or corrosive chemicals which may result in its denaturation.

Natural food enzymes may be used for the final cleaning, after which the cartilage is sun dried (as with shark fin) and air dried if necessary. The cartilage chips are milled into a fine powder and then sterilized. During the above processes the cartilage is kept cool and the use of strong or corrosive chemicals and radiation are avoided. Cartilage tablets or powder may be sold on their own or fortified with various health enhancers. Prices of shark cartilage tablets have recently fallen in Hong Kong with the appearance of more brands and perhaps a healthy scepticism among consumers. Parry-Jones (1996) found that bottles of between 45 and 100 tablets cost between HK$310 and HK$868 a bottle, whereas in September 1997 a bottle of 30 tablets produced in Australia cost HK$60 and a bottle of 90 tablets produced in the USA cost HK$480. In Singapore in February 1998 a 30-tablet bottle cost S$15. Labelling is sophisticated and shows the quantity of shark cartilage present.

Other natural products believed to promote health may also be included to widen the functions of the product, and quantitative details and daily requirements may also be shown on the labels. Unlike shark liver oil, which tends to glamorize deepsea sharks, shark cartilage is made from both deepsea and tropical sharks and the tablets manufactured from both types of sharks are sold in similar strengths. This may be one of the reasons why the species of sharks used for making cartilage tablets and powders have not been named (Rose, 1996). Unlike oils produced for internal use, which are taken only orally, shark cartilage is taken internally either orally or rectally, preferably rectally to avoid its digestion and the side-effects some people experience. The label on one package stated that "the most common side effects can include abdominal pain, constipation, diarrhoea, stomach upset, nausea and skin rash" and may also have "serious side effects, including stomach ulcers and intestinal bleeding". Better understanding of the product has also prompted warnings against taking the cartilage under certain conditions, including pregnancy, breast feeding, recent surgery and heart or circulatory problems.

Lane (1996) supported oral use, citing studies which showed that little digestion of shark cartilage took place in the stomach before it was absorbed into the blood. Chondroitin has been mentioned earlier. It has established its pharmaceutical use (Martindale, 1996). This standard text describes it as an acid mucopolysaccharide which is present in most mammalian cartilaginous tissues. It has been given to patients with ischaemic heart disease, for the treatment of osteoporosis and related disorders and hyperlipidaemia. A medium containing chondroitin sulphate A has been used to preserve corneas for transplantation and preparations containing it or its sodium salt have also been used as adjuncts to ocular surgery. It is interesting to note that Indian traders referred to its connection with heart diseases when reporting their sales of shark cartilage to Europe (Fahmeeda Hanfee, 1996), a point hardly emphasised by traders and manufacturers of cartilage products in other countries. Much attention is focused on the use of shark cartilage and shark liver oil for treatment of diseases.

The layman is, however, much confused by conflicting information; terminally ill people looking for cures need guidance but may be unsettled by answers from their health professionals. It would be helpful if a committee could be formed to review the literature regularly to provide this guidance in a more organized fashion, possibly also lending impetus to better management and conservation of sharks. The origin of some of these claims is probably to be found in studies where the growth of tumours in animals was slowed. This has been strengthened by observations that it limits the growth of cancer, especially cancerous tumours, by inhibiting the development of blood vessels in these tumours. Other diseases linked with this are arthritis, eczema, acne, ulcers, haemorrhoids and cold sores. It has been claimed as "a major cancer breakthrough" by one advertiser on the Internet. But a study presented to a meeting of the American Society of Clinical Oncology in Denver in May, 1997 said that shark cartilage was inactive in patients with advanced stages of breast, colon, lung and prostate cancer (Shark News, 1997).

An Internet release from the University of Florida (1998) stated that no convincing clinical trials were found to support the claim that it cured cancer. Nevertheless, we can expect a continued demand for shark cartilage because people desperate for a cure for terminal cancer will try any alternative treatment that offers a glimmer of hope. 4 SHARK SKIN PRODUCTS Shark skin is eaten as food in some countries. In some islands in the South Pacific, it is considered excellent (Matthew, 1996). In Taiwan Province of China the caudal skin of the White-spotted Guitarfish, Rhynchobatus djiddensis (Chen et al, 1996) is valued above all other shark skin. In countries where it is eaten, the skin is usually dried or smoked before it is finally cooked, and may have some meat attached as well. However, only a small amount of skin is eaten around the world. The Chondrichthyes have rough and hard placoid scales (Marshall, 1962), which are usually minute, but vary greatly in shape; they can also develop in certain parts of the body into prominent tubercles or spines.

When set closely together, these small scales give the skin surface the character of fine emery paper or cloth, which has resulted in its being used for sanding wooden and ceramic objects. Untanned skins are called shagreen, a term which includes the untanned leather from horses and seals (Tanikawa, 1985). Shagreen was formerly used for various polishing purposes in the arts, for armour, sword-hilts, and as a striking surface for lucifer matches. Since each placoid scale body has the same basic structure as a tooth and differs in superficial structure and arrangement in different groups, they are used for identification (Marshall, 1962). The stingray carries a sting, which is a highly specialized and dangerous integumentary structure that is characteristic of the dasyatid sting rays (Family Dasyatidae). Most of the skin which is used is made into leather. Kreuzer & Ahmed (1978) describe the cutting and skinning of sharks, and the grading of skins, which are usually salted before storage and transportation to the tannery. Shark skin is tanned in much the same way as the skins of land animals.

Tanikawa (1985) describes the process in detail and distinguishes between that in Japan, where hydrochloric acid was used, and the United States' use of sulphuric acid. He also describes the processes used in the tanning of fish skin. In Japan the hides of whale and shark were used to produce leather until the 1940s (Tanikawa, loc cit). This industry was threatened when considerable quantities of land animal hides were imported and never regained prominence. An entry in the Encyclopaedia Britannica (1972) states that by the early 1960s about 97% of the world's supply of hides and skins derived from the production of meat or wool was tanned into leather. It is no surprise then that shark and fish skins moved into niche-leather markets in Japan, providing textural and beautifully speckled colours for purses, hand-bags, Japanese sandals, watch straps, etc. This is probably an extension of the niche established by the elegant and expensive Boroso leather, which is made from the hides of small Morocco sharks; the denticles are not removed but instead polished to a high gloss.

Although a market for shark leather developed in the USA, Rose (1996) found that it was difficult to sustain. Among the various reasons she cited, its use in protecting the attached meat against physical, chemical/biochemical and bacteriological deterioration may have been the most important. Moreover, shark is not necessarily the poor man's meat now that its handling is much better understood. The production of good quality meat requires that the shark landed on board fishing boats be gutted, washed in fresh water, stored in ice or refrigerated, which results in the loss of hides of good quality. The usual shark fishery also found it difficult to supply the necessary numbers of hides consistently to sustain an industry. It is in those countries where dried/salted meat of the larger sharks (preferably a meter and a half in length or larger) is produced that the shark skin industry has been able to survive. One such country is Mexico where there are a number of tanneries. It is also next door to the United States where a relatively ready market for shark skin products exists.

Products made from shark skin, either with or without denticles, as advertised on the Internet include shoes, cowboy boots and sandals, wallets/purses, coin/key fobs, belts, key cases, lighter cases, cigar cases, watch bands, gun holsters and knife holders. Some advertisers on the Internet also offer to make items according to their customers' designs, including choice of colours, and presumably leather specifications; the terms and conditions have to be negotiated of course. In India, besides the above items, shark skin is also made into grips for scooter/bicycle handle covers. Rose (1996) provides a comprehensive summary of TRAFFIC's survey of the world's markets and trade in shark leather. The demand for shark leather is not believed to threaten the existence of sharks. A list of the species of sharks used for leather is listed in Table 2. Table 2 Sharks whose hides are used as leather Tiger Shark (Galeocerdo cuvier) Sawback Angelshark (Squatina aculeata) 5 SHARK TEETH AND JAW PRODUCTS Sharks have powerful jaws. Some sharks have sharp and pointed teeth with rough cutting edges adapted for predation on other fishes.

Others have flattened teeth adapted for crushing the shells of the crabs and molluscs on which they feed. According to Kreuzer & Ahmed (1978) small shark teeth are little used by humans. 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. The uses of teeth and jaws of sharks have been surveyed by TRAFFIC and summarised in Rose (1996). These include their use in traditional art works in certain islands in the South Pacific. The Gilbertese lash the teeth of sharks to the cutting edges and the spike of stingrays to the points of their traditional fighting swords. Shark teeth are used for cutting in Hawaii, and have also been fitted as knives, war clubs and other weapons. The other more recent use of shark teeth is more selective. Compared to meat, liver and other easily denatured products, teeth are certainly easier to harvest and preserve. Rose (1996) cited earlier sources indicating the Mako, Great White and Tiger sharks as the species preferred for their teeth, because of their large size.

Advertisements have appeared on the Internet offering teeth from precisely these sharks for sale. The teeth may be set in precious metals or encased in other materials, e.g. leather of various colours, and worn as necklaces. A company in Australia also enhance their setting with opals. The largest tooth (at 2 inches) the company offered from the Mako shark, set in either silver or gold, was priced at US$129.95. The smallest mako tooth advertised was 1 inch, set in the same way and offered at a price of US$39.95. The jaws of sharks are also stuffed and offered for sale on the Internet. The jaws of certain sharks have been eaten as traditional food. The display of teeth and jaws for sale is usually confined to tourist areas in Asia, America, Europe and Africa. The volume of teeth and jaws is not clearly known, but obviously they are by-products of shark fishing. Since they do not need preservation they may even be collected by traders only when their inventory is low. 6 OTHER USES The following is a compilation of items which have been observed by various writers from around the world and recorded in some detail by Rose (1996).

Small sharks are often used as bait, at times to catch other larger sharks or used in fish traps. Sharks may be preserved for sale as curios. These include whole small sharks and rays or parts of their bodies. The rostra of the sawfish are also dried for sale to tourists. Glue is made from certain sharks and fish, which may in turn be used in the manufacture of lacquerware. Small sharks are often made into fishmeal and fertilizer. There is a quite widespread use of dogfishes as specimens for dissection in schools and universities. More recently, fairly large marine sharks have been exhibited in public aquaria. Small specimens of freshwater sharks and rays are also kept in private tanks. Organizing dives among sharks is becoming popular in several countries, attracting mainly conservationists, and may be gaining attention and support from businesses and governments for different reasons. 7 REFERENCES Chen, G C T, K M Liu, S J Joung and M J Phipps. 1996. Shark fisheries and trade in Taiwan. TRAFFIC East Asia. 48 pages. Encyclopaedia Britannica. (1972) Fahmeeda Hanfee. 1996.

The trade in sharks and shark products in India: a preliminary survey. TRAFFIC International. 28 pages. INTERNET Websites. January - March, 1998. Kreuzer, R (Ed.) 1974. Fishery products. FAO and Fishing News (Books) Ltd. 462 pages. Kreuzer, R and R Ahmed. 1978. Shark utilization and marketing. FAO, Rome. 180 pages. Lane, I W and L Comac. 1996. Sharks still don't get cancer. Avery Publishing Group. 246 pages. Liu, K W. 1998. National Taiwan Ocean University. (Personal communication) Marshall, A J. 1962. 7th Edition of Parker & Haswell: A text-book of zoology. Macmillan & Co. Ltd. Martindale - The Extra Pharmacopoeia. 1996. 31st Edition. The Royal Pharmaceutical Society of Great Britain. Matthew, P. (1996) The Oceania region's harvest, trade and management of sharks and other cartilaginous fish: Solomon Islands, Western Province Overview.

TRAFFIC International. Miwa, K. 1972. Fish oil and fish liver oils. In: Utilization of marine products. Overseas Technical Co-operation Agency (OTCA), Government of Japan. 7 pages. Parry-Jones, R. 1996. TRAFFIC report on shark fisheries and trade in Hong Kong. 57 pages. Rose, D A. 1996. An overview of world trade in shark and other cartilaginous fishes. TRAFFIC International. 106 pages. Shark News. June 1997. Newsletter of the IUCN Shark Specialist Group. Summers, G and R Wong. 1992. Cosmetic products from semi-refined shark liver oil. INFOFISH International, 2/92. pp. 55-58. Summers, G, R Wong and L Eyres. Undated. Handling and processing shark livers for the recovery of squalene and diacyl glyceryl ethers. DSIR Crop Research Seafood Report No. 1, New Zealand. 34 pages. Suzuki, T. 1972. Pharmaceutical marine products. In: Utilization of marine products.

OTCA. 3 pages. Tanikawa, E. 1985. Marine products in Japan. Koseisha Koseikaku Co. Ltd., Tokyo. 506 pages.

Question: What name is given to the untanned skins of sharks and rays?
Answer: SHAGREEN