1001 USES OF A SHARK
ECOLOGY AND THE FISHING INDUSTRY
Recent statistics compiled by the United Nations Food and Agriculture Organization (F AO) reveal that the shark represents about 1% of the current market in fish, an enormous total amount. Having only in the last ten years or so become a regular part of the diet of countries such as the USA, the development of deep-freezing and preservation techniques, as well as the methods of culinary preparation, point to a major increase in shark consumption in the future.
On a more general level, and irrespective of the possible taste certain nations have for shark flesh, it is hard to see how the animal could escape the, often dramatically, increasing pressure of hyper intensive fishing, which is rendered unavoidable by a demand for protein proportional to a human population that has grown by 500% in 90 years. It is here in fact that the real world ecological problem lies, in this uncontrolled human overpopulation. If we had to find a single point in common between sharks and man, it might be that they have no true natural predators other than themselves.
The days are gone when man could believe that the planet's resources were limitless. Hardly has he discovered that all the sharks constitute major sources of protein when, ten years later, some species of shark are already on the road to extinction in certain regions of the world. Continental man passed from tl1e Bronze Age to that of farming and stock-rearing several thousand years ago. Tragically, while he is already moving into the post-industrial age, man is still in the Bronze Age with regard to the oceans, continuing to draw on them limitlessly, with no real international legislation, and above all with no concern for breeding and rearing. Under the pretext no doubt that the marine element is not his own, he has not yet looked seriously overboard to realize the huge capacity for breeding and rearing that lies hidden beneath the surface of the marine biotope.
In the 1900s, the skate was very abundant throughout the Irish Sea. Among other fish species, this relative of the rays and sharks began to be fished there by various methods, and in particular by trawling. This unselective method of fishing has carried on right up to the present day, but skates are no longer brought up in the nets. None have been caught in the Irish Sea for over ten years. The disappearance of the common skate went virtually unnoticed and with no comment in the scientific literature. According to Brander, from calculations based on our knowledge of reproduction and feeding habits, we have for several years been capable of determining the threshold below which the reservoir of any given species will disappear. Again according to Brander, this threshold was crossed for the common skate only a few years ago. This skate is still present, in small numbers, in the waters bordering the Irish Sea to the north and south. It is, however, too late for it to return to this sea, unless all forms of fishing for all species of fish are suspended there for an indeterminate period. As this solution is currently unfeasible, the common skate represents for Brander the first indisputable example of the extermination of a species through uncontrolled industrial fishing. If the minimum non-restricting measures had been taken ten or so years ago in accordance with our increased knowledge as regards the management of fish populations, there is no doubt that the forecast would have been much better .
Compagno for his part cites the case of the School Shark or Tope (Galeorhinus galeus) of south of Australia. This species has been fished for since 1927, but under permanent monitoring. Whenever an alarming reduction was noted in catches of the shark, an investigation was set up and appropriate measures imposed. After sixty years of intelligent exploitation, the School Shark population shows no sign of becoming extinct.
As for those species thought to be dangerous, some might think industrial fishing would be the ideal definitive means of protection against them? Apart from the fact that this style of fishing could not be selective between dangerous species and others, we ought also to determine whether or not the permanent eradication of species, such as the Great White Shark, would lead to a serious imbalance in the animal world. Studies were made on the island of An Nuevo, 225 kilometers west of Baja California, by Le Boeuf and Ainley between 1980 and 1985, on the ecological relationships between pinnipeds, seals and sea elephants, on the one hand, which are very abundant on the island, and on the other the Great White Sharks, which are very numerous in the surrounding waters. As early as 1885, Townsend had noticed that 25% of female sea elephants bore deep scars from shark teeth. Few young, on the other hand, displayed such after-effects, leading him to think that they do not survive bites owing to their small size. Again on the same island, Le Boeuf established that, out of nine wounded females, only one was able to rear its young successfully. It is conceivable that, the moment the seal or porpoise population becomes very abundant, the Great White Sharks change over a few years from a mainly piscivorous diet to a diet centered on these mammals. They then become geographically tied to this region, and the food they take allows them both to select out the weakest elements among their new prey and at the same time to control its overpopulation. If the Great Whites in this region did not exist, or did not change their feeding habits at the right time, there would be overpopulation among the seals, and a considerable reduction in the numbers of fish. Here, then, there is a classic ecological balance in which man does not playa part since the An Nuevo islands are uninhabited. The time when this balance may be questioned is when seal colonies, moving closer to urban sites, may be deemed responsible for an increasing presence of Great Whites, and potentially a greater number of attacks. This problem was a topical one in 1990 in some parts of the globe, and in California in particular .
This correlation between dangerous sharks, the weight of commercial fishing and ecology can be illustrated again in an interesting fashion by the current situation of two well-known sharks in Lake Nicaragua. These are the Bull, Zambezi or Nicaragua Shark or Carcharhinus leucas and the Nicaraguan sawshark (another elasmobranch). Only the first is a real danger to man, the second has
Map of Lake Nicaragua, kingdom of the Bull Shark.
never been known to attack. The two fish habitually enter shallow fresh waters, and in particular have established themselves in the huge Lake Nicaragua in Central America. This lake flows into the Caribbean Sea via the San Juan river, regularly followed in both directions by the two fish in accordance with their breeding cycles. We have already discussed the impact that the Bull Shark has always had on the populations of American Indians around the lake (see Devil sharks and god sharks) on account of its very old habit of attacking man.
Thomas B. Thorson (University of Nebraska) made a very long study of these two fish from 1960 to 1982, as part of an official programe which set out to tag as many fish as possible so as to see what their migratory cycles, their growth rates, etc. were. In all 3500 Bull Sharks and 377 sawsharks were tagged. It was through this operation that it was possible to confirm that regular and rapid migrations took place between the lake and the Caribbean Sea. The Bull Shark has its greatest population density in the lower part of the river and at its mouth, and breeds in the adjoining brackish waters, but not in the lake. The higher upriver one goes, the lower the number of sharks. By contrast, the sawshark is very abundant in the lake, where it breeds, and its concentration diminishes as one moves downriver. In the case of the Bull Shark, the population in the lake is maintained at a constant level by recruitment from the coastal population, while for the sawshark recruitment is achieved almost entirely through new individuals being born in the lake.
Studies in 1960 found the Bull Shark population to have been in slight decline for a few decades, although not in any significant way, and Thorson had no difficulty in finding sharks to tag, not only at San Carlos in Nicaragua but also at the point where the lake flows into the San Juan, and at the Rio Colorado in Costa Rica, where the main arm of the Rio empties into the Caribbean Sea. However, the decline became more distinct in the 1970s when three or four entrepreneurs from Rio Colorado started buying sharks right through the year for their flesh, fins and sometimes their skins.
Several thousand sharks were caught every year, and this could not fail to have repercussions on the population at the river mouth. In 1982, Thorson calculated that only 10-20% of the sharks entering the mouth got as far as the lake. Therefore, the population in the lake could only decrease in parallel with that at the mouth. His tagging figures at San Carlos confirmed his fears: in 1965, a few hours fishing in the lake brought in several sharks; in 1975, the new government made a decision to do something about the decreasing numbers by banning fishing for profit for two years; but good intentions were not followed by good actions, and political developments in the country have prevented further measures. I visited Barra del Colorado myself in 1984 to fish for tarpon. While I was there, I asked a Costa Rican to tell me a good place for shark-baiting; he told me to stick to tarpons as there were many more of them, so I let it go.
Lake Nicaragua was indisputably the best place in the entire world for sawsharks up to 1970, for no commercial fishing had ever been organized there. In that year, Thorson caught and tagged 252 sawsharks off San Carlos in 43 days. The record was 23 in a single day. But then commercial fishing started. At first it was just a small business in the northwest of the lake, at Granada, for catching and freezing the fish. However, within a few years there was organized fishing with nets over the whole lake. In 1974, Thorson caught only one fish in five days, 30 times fewer than four years earlier. In 1976-1977, he had a team of three men at Barra del Colorado, and three at San Carlos. During the whole of that year, these men caught 11 sawsharks, or one per month. Thorson conveyed his alarm to Managua, but nothing was done -perhaps because the owner of the largest sawshark-fishing company was none other than a government minister who couldn't care less about the extinction of the species. A case, no doubt unique, of a single man being capable of exterminating a species of fish within a few years. In 1980, the new government decided that the catch would be limited to 113 tonnes per year, and fishing banned during the four breeding months; it later instituted a two-year moratorium banning all fishing for sawsharks and other sharks. According to Thorson, at such a rate it would still take ten to twenty years for the population to recover to an acceptable level.
These few examples show not only how the noble line of the lords of the sea is not safe from the risk of extinction, but also the speed with which excessive fishing pressure can bring about this extinction. This is due to a number of factors:
the relatively slow growth of these sharks, and the long period necessary to reach reproductive age;
the fact that they have relatively few offspring;
their long gestation period (one of the longest in the animal kingdom).
We now have sufficient scientific knowledge to be able to provide effective advice to fisheries administrators in order for them to find a balance between real needs, profit margins, ecology , and also, for the relevant regions, the "shark danger".
We should never again have to see a repeat of what happened in November 1986 on the Californian coast. The Thresher or Fox Shark (Alopias vulpinus) was very widespread up to this time off Los Angeles, and was always regularly fished here as indeed it was in other parts of the globe, especially Europe (see the map at the end of the book). This species moves north in summer, and heads back towards the south of the west coast of the United States in autumn. In that November, some fishermen who had been using a purse net were traveling in a spotter plane, when they saw an enormous shoal of Thresher Sharks heading southwards following the coastline. Ten or so fishing boats immediately converged on the area, and spent two whole weeks catching hundreds of the poor shark, exterminating the entire shoal. In the aftermath of this veritable "genocide" , the authorities were very late in asking themselves whether the species could ever be restored in this region of the globe.
Beulah Davis told me a story of how an American senator, having heard that some male sharks lived in the north of the Pacific while the females lived right down in the south, decided to put them all together to create a profitable shark fishing industry .This only goes to prove that an American can be a senator and at the same time ridiculously ignorant of the most elementary rules of nature.
THE SHARK AS A GAME FISH
The technical advice in this section is taken largely from Rob Hughes, the great Florida fisherman who has more than 8,000 sharks to his name, including 2,000 caught with rod and line.
I have mentioned elsewhere the importance of industrial fishing (300,000 tones in 1984), and the danger it represents for a species which reproduces very slowly. I have also detailed the different techniques of net fishing carried out near coasts for the prevention of attacks, and emphasized the remarkable effectiveness of this method both in Australia and in South Africa. Sport-fishing of the shark is relatively recent so far as its approval by the very responsible International Game Fish Association is concerned. Only six sharks are recognized as truly sport fish: the Great White, the Tiger, the Mako, the Porbeagle, the Blue and the Thresher. These fish can be caught at any time of day or night from a bridge, a pier or a boat, near the shore, offshore or at open sea.
If in a boat, you must make certain that it is big enough to be stable in high seas, it should be at least 5 meters long, and that its freeboards are high enough so that it does not become flooded at the slightest listing, and that it has a wide enough beam so as not to capsize with the first big catch. Furthermore, the hull should be solid
Complete trace for shark-fishing. Pieces of fish or mammals, or even a live fish, can be attached to the hooks.
enough not to split at the least blow from a discontented shark's snout (see Attacks on boats).
The length of your fishing rod depends on the method of fishing you have chosen. From a pier, the rod must be shorter (approximately 2.7 metres) and stronger so as to give better control. From a boat, it can be longer and more flexible, w4ich will allow the sharp tugs by the shark to be absorbed. Not being limited by space, one can follow the shark that flees merely by starting the engine. The best rod is made of solid fibreglass (hollow ones can break) and measures 2.7 to 3.3 metres. The guides should be on rollers, as this is the only way not to scratch them and risk breaking the line.
The choice of reel again depends on your method of fishing. From the shore, a greater length of line is needed, and you should opt for a 124/0 to 16/0 with 800 to 1,000 metres of line tested to 130 Ibs (a British measure, used throughout the world). From a boat, a 10/0 reel with 600 metres of 80 Ib line is required. Do not forget to secure the wing of the reel to the boat, this will avoid the risk of seeing the line go overboard. The reel can be attached to your body harness to make it easier to negotiate the shark's fleeing movements and sudden turns. Do not skimp on the "padding" between the harness and the butt of the rod: you will understand why when you have to put up with this butt pressing into the pit of your stomach for three hours.
The rod handle must be covered with a material that is non-slip, even when soaked with water or coated with fish mucus. Cork or rubber generally suffice, especially if the diameter has been adapted to the size of your hand. Some fishermen make themselves a handle based on resin molded on their hand, which is all very well as long as the rod does not turn.
The line is the third determinant item in the success of a shark-fishing trip. You must never go below 80 Ibs, and, if you are really going for very big fish, you will have to opt for 130 Ibs; you may perhaps cause your neighbors to smile at your optimism, but the smiles will disappear if you hook a 1,000 lb Tiger Shark.
For the line trace you have a choice between steel monofilament or plaited wire. Each has its advantages. Monofilament will pass between the shark's teeth and cannot be cut in two, but it can get twisted or break with pulling. Plaited wire is too big to pass between the teeth and runs the risk of being cut, but in return it will not twist and will not break.
The choice of line trace also involves its length as well as its strength. We know that the shark's skin is extremely rasping, and no l1on~metallic line can stand up to it for long when the shark winds it around its body as its struggles; the projecting edges of the fins very quickly achieve the same result. It is therefore essential to choose a sufficiently long metal wire: 3 meters (for boat fishing) to 7 metres (for fishing from shore, with risk of rocks). A good size is the 1/16 stainless steel (it is in fact twisted and not plaited).
The hook must be made from a single piece of steel, and not turned over on itself and welded, in order to avoid it opening up when pulled on. Its size can vary but the 120 is a good intermediate size. These eye hooks will get rusty in the area of the "eye" if they are not cleaned, but they have much better resistance than ordinary hooks, even welded ones. The line trace should be mounted as per the drawing above with bushes press~fitted.
Before casting the line, there is still the choice of bait to be made. Shark bait has to be both oily and bloody. These two cardinal qualities ensure a good diffusion in the water and detection at long distance. In Florida, for example, the gray mullet, the bonito, the stingray and the bullhead are considered good baits, with the mullet and the bonito topping the list. You must cut the bait into pieces of between half and one kilo. Some fishermen think that "the bigger the
bait, the bigger the catch will be". However, a small bait can be rapidly swallowed, while a large bait may simply be held in the mouth while the shark does a half- turn, and thus be torn off when the line tightens, before the hook has even had a chance to embed itself.
Many fishermen use the assembly shown below with a live fish, which has the advantage of acting as a lure corresponding to the shark's usual prey and of emitting vibrations, which we know the shark to be very susceptible to.
Sometimes the mounted hook is not enough, and baiting is the only method of attracting sharks to the boat. In that case you need to put whole fish into a meat minceJ;' and hurl handfuls of this mixture over the stern. This method is not always considered sporting, especially in some parts of the world where there are lots of sharks. Some fishermen compare it to shooting a deer that comes to eat corn which has been spread on the ground by the hunter beforehand. What you must never do under any circumstances is lure with bait from the shore, for this would not only attract the ingenuous sharks you are seeking, but also the big predators, which are not averse to taking fishermen (a number have been seized in this way in less than a metre of water).
Bob Hughes recommends using a "clip rope" in order to avoid losing the shark that you have managed to bring in up to the side of the boat -loss at this stage is a common problem. I recommend the
The "clip rope" I a safety measure
To line trace
use of a nylon rope of 3/8 to 1/2, a few meters in length (according to the design of the boat) and comprising two loops at each end. One of the loops is attached to the steel trace by means of the fast-grip clip, and the other to any cleat or sturdy mooring point of the boat. It is then possible to get rid of the rod, or even to cut the line, so that the only thing you have to deal with is hauling the animal aboard. It must be noted that even an apparently tired and listless fish always keeps a spectacular reserve of energy for struggling as soon as it is taken out of its element. All those who have lost one or more fingers, sliced off by a 130 lb line when a shark returned to the deep, are well aware of the problem. This nylon rope can itself be attached to a "shock rope", which is in fact made of stout India rubber and allows shocks to be absorbed.
Once the shark is out of the water, it must still be gaffed if it is to be hauled aboard. It may be gaffed anywhere, but it is best to aim as near to the the gills as possible. The ordinary gaffing spear is dangerous and a number of fishermen have been knocked senseless and died while they were trying to finish off their catch. The "flying spear" , especially one with four spikes, is much safer. If you fish from shore, the ideal grappling iron is the one used for scaling walls, with three or four barbed spikes.
For finishing off the animal, the "bangstick" , which was described in the section on preventative means, is ideal, since it fires a no.12 cartridge into the head of the shark at point-blank range. The baseball bat is more "sporting" and very effective if you know how to use it, or even a sledgehammer will do, provided you do not smash the boat's hull.
Once all this equipment has been prepared, all that remains is to catch the shark of your dreams, and to try to guess what species it is while it is still out of reach. You will already know what type of shark you can or cannot catch according to your location (see the maps for each species at end of the book).
Lemon Sharks and Sand Tiger Sharks are often fished near beaches, Nurse Sharks near corals and reefs, while Tigers are met with in deeper waters and hammerheads out at sea. If it is the tarpon season, the hammerheads approach coasts to seek out this select prey. I had the chance to see this for myself a few years ago in Costa Rica when I was fishing for tarpon from a flat-bottomed boat 200 meters from a village by the name of Tortuguero on the Caribbean coast. A friend had caught one of these magnificent tarpon, but I was less fortunate and beginning to feel thoroughly fed up with this static and futile fishing. Suddenly I caught sight of a spectacular wake from something heading towards my walnut hull, the gunnel of which was just 20 centimeters above the water, and there below us was a magnificent hammerhead shark. The local fisherman who was with me told me that there was no point in carrying on fishing for tarpon with a monster like that in the waters, and I did not argue.
How the shark behaves on the hook will also help you to work out what it is. The Nurse Shark puts up a fierce struggle and twists and turns when it is close to the boat; the Lemon Shark fights only for 150 meters; the hammerhead pulls hard and does not give up easily; the Mako leaps out of the water and fights on for a long time.
The time of year is also a guiding factor according to the fishing area. For example, in Florida, the winter period from October to April is associated with the presence of Brown, Dusky, Bull and Tiger Sharks, whereas the summer from May to September brings Lemon, Nurse and hammerhead sharks, and again Bull and Tiger Sharks. Finally, do not forget that the only safe way to remove a hook from a shark's mouth, is to wait until the next day.
A love of game fishing, allied to a frenzied fascination for sharks, can lead to somewhat bizarre excesses. A few years ago, a very youthful retired gentleman from the Caux region on the north coast of France undertook to implement his lifelong dream: to fish for sharks in the English Channel.
On his very first trip out from the little port of Saint-Valery-en-Caux, near Dieppe, our man captured a 50 kilo Porbeagle. This was all that was needed for him to be overcome with euphoria, and as a result he founded an organization, unique in France: the "Saint- V alery Shark Club" .
The club was set up in the old customs office, which had a weighing machine just in the right place, right on the quay where future catches would be unloaded. A superb coat of arms soon crowned the entrance ta the building, and the only thing left was to organize a competition to give the new club its aristocratic pedigree.
The first competition drew fishermen from the whole of Europe, and on a fine morning in September all the teams took to sea for six hours of adventure. A number of sponsors had offered five or six cups for the event; the Altea Hot~l accommodated the biggest champions; the regional newspaper, the Paris-Normandie, ran the front-page headline "Jaws at Saint-Valery-en-Caux"; the customs scales had been checked -in short everything was absolutely ready for an international competition worthy of those which regularly take place in the tropics. The only restriction laid down by the adjudicating committee of the event was a total ban on baiting with coagulated blood, in order to avoid excessive catches.
When the time for the prize-giving came, at the end of a very full day, a certain perplexity could be seen on all faces. The first prize was in fact rewarded for the only catch of the competition: a dogfish weighing 2.5 kilos, not even ratifiable by the international authorities since its weight was below 5 kilos. Lots were therefore drawn among the friendly participants for the other cups, and they parted empty-handed but happy all the same. In Maupassant country (Normandy), cider and calvados always make up for the greatest disappointments.
I have not yet dared talk about gastronomy in connection with the shark for I am French and the French are always fastidious on this subject, but it should be known that the shark is a highly sought-after food in Asia, where at least twenty-five classic ways of preparing it exist in Japan alone. In the Yucatan, fillet of young shark is one of the dishes most in demand by the descendants of the Aztecs, and dried salted shark is sold everywhere in Mexico. In the USA, the frozen fillets of white fish that are found in supermarkets under the name of "cod" or "swordfish" are very often actually shark. Nearer home, the popular British fish and chips very often consist of shark rather than true bony fish, and in particular of Porbeagle, which is very abundant, especially in the Irish Sea.
So it is not necessary to be in a life-and-death situation to feed on shark, and you may perhaps be happy to know a few basic preparation methods for the day when you wish to justify your catching a lovely shark to your ecologist admirers.
First of all you should know that not all sharks taste the same, and that the following six species are considered to be the tastiest: the Great White Shark, the Mako, the Porbeagle, the two kinds of thresher and the dogfish; after this come the Small Dusky and the hammerhead sharks. The flesh of the huge Basking Shark for instance is too flabby to be eaten. No shark is poisonous, however their livers are to be avoided, often being much too rich in vitamin A, although unlike those of the swordfish, they do not contain high concentrations of mercury.
Another elementary principle is to know that shark's flesh very quickly takes on an ammoniacal taste, and so it must be prepared and chilled as soon as possible after the animal is captured. It must be cleaned and gutted like any fish, the skin removed along with the dark flesh that is found just beneath it, and the fillets not cut too thick. The latter should be coated with flour and placed in the refrigerator for at least one night, again to avoid the taste of ammonia.
If you are on an island, an uninhabited coast, or an isolated boat, shark meat is ideal for smoking, but you will need to be patient: six to eight hours in a special oven at 115°C, 25 to 30 hours in the open, for fillets 3 centimetres thick which you will have salted and basted in margarine beforehand.
As for recipe details, I prefer to refer readers to the specialist works, although I will point out that this fish cannot be steamed or braised like many bony fish with a very delicate flavour. You should also be very generous with the green lemon, the onion, the garlic, the salt, the Cayenne pepper or chili powder, the paprika, the olive oil, etc.
The fins soaked in brine for two days and then dried are highly prized as raw material in oriental markets. When boiled, their cartilage releases a smooth gelatin which gives body and taste to soups. Note that for this preparation only the dorsal and pectoral fins are used.
And then, if you do not have the courage to prepare shark meat for yourself, you can always cut it into into big pieces with the skin still on, as it makes the best possible bait for crabs. You can also feed it to your cat or dog; it is one of the main food sources for domestic animals and livestock in many countries.
If dietetics will convince you, you will be happy to hear that shark meat contains 7% protein, very little cholesterol and is very nourishing.
THE SHARK MEMENTO
The tourist industry has considerably increased the demand for all those little objects and other knick-knacks in poor taste which some package-tour travellers like to deck themselves out in. The shark is a prime target for these modern-day Tatarians who are mad about shark teeth mounted on pendants, open jaws for their walls, bracelets made out of vertebrae, or in a word about all those trophies captured by others which make you look like a man when you get back home. Even the shark's eyes have found a place on the market. After having boiled them for an hour or so (preferably outside rather than indoors), you have only to cut them open to be able to remove that delightfully-shaped, little lens, now hardened, which is known as the crystalline lens. This lens can be dried, pierced, mounted and even renamed by a jeweller who will sell you a "shark pearl". These pearls are a real hit with American tourists. Another brainwave in the same style involves threading a few dozen cartilaginous vertebrae, which have been bleached beforehand in chlorinated water, on to a metal rod, interlocking the lot, fitting a metal knob and selling the object as... a walking stick! I would not advise you to rely on it as support for a broken a leg, but, if you ever run out of conversation, you will have a magnificent talking point. I must add here that, besides these slapdash pieces of trash for "suckers" , I have recently come across a 19th century walking cane with a finish, a sturdiness and a patina that are all magnificent. The friend who sports this object uses it to ease a painful back complaint, and the admiral who presented it to him as a gift on behalf of the "Royale" in this case chose, beyond any doubt, an object worthy of his rank.
The shark's hide is one of the main trophies of shark fishing, for it lasts an extremely long time if it is prepared correctly, namely if it is well flayed and then washed, cured, dried, etc. The dried skin is known as "shagreen" because of its similarity to the untanned granulate hide of the back and hindquarters of a horse (this leather also being known as shagreen) .
The most sought-after skin which fetches the highest price in the leather industry , is that of the Tiger Shark. Hammerhead skin is among the cheapest. The denticles are removed before the skin is tanned to make a handsome and durable leather which is used for quality shoes and cowboy trousers. It is even more elastic than cowhide or pigskin and much sturdier (150 times more resistant than, that of bovid leather).
The Ocean Hide and Leather Company of New Jersey was the first and the biggest producer of shark leather, but is now running into supply difficulties and having problems satisfying demand since the commercial shark fisheries are having problems. Not enough is known about the reproductive rates of sharks, but we do know that the replacement rate around the fishing areas is too low, equally in the United States, Mexico or Cuba as in Australia or England. It may seem that the solution lies in ocean fishing on the high seas, which is what the Japanese already do.
The Japanese are the world's leading shark-catchers and have a long tradition involving sharks. This is why samurai sabres have always had hilts covered with Angel Shark hide, the roughness of which prevents the sword from slipping in the hand.
This skin was also used for a very long time as sandpaper before it was manufactured by industrial methods. To prove this for yourself, you need only pass your hand over the skin of a shark in a tail-to-head direction, it is extremely abrasive while going from head to tail it is amazingly soft. In Sumatra, the skin of the Angel Shark is used to make drum skins. Up to the beginning of this century, it was fashionable to cover various personal items with polished shagreen: spectacle cases, jewelry boxes, book bindings, etc.
A final type of highly prized leather, the "Boroso leather" , comes from the processing of Moroccan sharks. The dermic denticles are not removed, but polished so as to give the leather a texture that is both aesthetically pleasing and very tough.
THE SHARK IN PHARMACY AND IN SURGERY
In the 1930s the liver of sharks was discovered to contain oils and vitamins in great amounts. A veritable explosion of shark fisheries followed, notably in California, where after a few years a steep decline in the population of the "Soup Fin Shark" was recorded.
When the benefits of vitamin A on the night vision of wartime fighter pilots were discovered, the numbers of sharks taken became uncontrolled and there was what was called the vitamin A "gray gold rush" .This rush abruptly ceased when a more economical means was discovered of manufacturing certain vitamins synthetically. The fisheries had to close, and the population of the Soup Fin Shark (Galeorhinus zyopterus) returned to normal in only two years.
The squalene contained in the liver of numerous sharks is a much sought-after oil in cosmetics, and is what lies behind the interest of some fishermen in the enormous Basking Shark, whose liver is in proportion to its size. Shark liver also provides basic materials for manufacturing lubricants and paint bases.
In the United States, corneas of elasmobranchs (fish with cartilaginous tissues), and more particularly those of sharks, have been successfully used for grafting onto the human eye. They have the advantage that they do not dilate when the salt content in the surrounding environment varies, unlike those of the bony fish (teleosts).
The cartilage of sharks is used in the treatment of serious burns, and some liver oils may be anticoagulants and may reduce cholesterol levels.
THE SHARK AND THE CINEMA
I have attempted to explain in another chapter the reasons for man's fascination for the shark, and it is significant that the greatest success story in the history of the cinema up to the 19805 was attributable to this terror of the seas. Steven Spielberg allowed no technical obstacle to stand in his way in making his Great White Shark true to life. Three robot models were perfected by Robert Mattey, former head of special effects at the Walt Disney studios. Made of plastic, they weighed 1,500 kilos, measured 8 meters in length, cost 150,000 dollars each, and were called Bruce. It has to be said that the bosses at Universal Studios in Los Angeles naively imagined that they could film real Great Whites on location in their natural element! All the powers of persuasion of an Australian man-and-wife team specializing in undersea filming (Ron and Valerie Taylor) were needed to get the go-ahead for the models to be made instead.
Is the film credible? I discussed this with Professor Compagno in 1989, when he was director of the Grahamstown Institute of Ichthyology in South Africa. He had been the film's technical adviser for the most spectacular sequences, and he confirmed that, taken individually, all the situations are plausible. From the size of the shark to the targets of its attack, from the size or the power of its jaws to its resistance to harpooning, from its method of attacking from below in deep water to the surface attack on the beaches, all the events depicted are possible and have already occurred on many an occasion at various places around the world. There is hardly anything that can be criticised apart from the rather excessive accumulation of attacks, and above all the animal's anthropomorphic determination to have the hide of its three pursuers by no matter what means. This film was followed by several others which claimed to be in the same vein, but in which the improbability of the situations vied with the absurdity of the scenarios. Professor Compagno was not consulted on these purely commercial productions.
Another feature film ought also be mentioned with regard to sharks and more particularly to Great Whites: this is Blue Water , White Death. Made earlier than Spielberg's film, it did not have the same international impact for it was much less commercial, but the heros were real sharks, not models.
THE SHARK VIRILITY TEST
The Blue Shark is a cosmopolitan fish and a dangerous one, capable of reaching 3.8 metres in length and credited with a number of attacks on people and boats.
One particular "sport" has developed in certain diving clubs in south California which involves swimming among Blue Sharks. To be certain of their presence, they are first of all lured with blood and pieces of fish thrown around the boat. To date, this "test of manhood" reserved for male divers has not yet claimed any lives, but the day a big Blue Shark or a Tiger Shark comes along to liven up the initiation ceremony, things may change.
In fact the Blue Shark is not very aggressive when mixing with divers under the water, but nor is it very timid either and it likes to come and see what is going on. before attacking it generally circles around its victim for a while, on the whole unlike the large predators such as the Tiger or the Great White, which suddenly appear from any direction and rush straight at their victim.
As you can see the Shark plays a much greater part in our daily life than we might think. Even if the newspaper headlines and sensational films are only an epiphenomenona with respect to a predator that does not haunt British coasts, the shark remains a unique animal, to be taken into consideration in fields of research as varied as ecology, adaptation, evolution, hydro dynamism, physiology in general, safety at sea, etc.