The location of the shark expeditions that I have participated in is the Island of Guadelupe.  This island is Mexican territory and is reached from San Diego by spending a day on the boat. Guadelupe Island is the site of an old Mexican prison and also the site of the home of the Guadelupe seal. Both the island and the seal are protected.

These expeditions take place in the late fall of the year and at this time the Pacific Ocean off the coast of the Baja is clear allowing for better photography. Furthermore, the tuna are in the vicinity of the Island and the Guadelupe seals are present as well, providing to prime food sources for the Great White Sharks.

The weather in the late fall is warm and calm.  However, this area is subject to hurricanes, which are somewhat rare and not very strong due to the lower water temperature.  The air temperature ranges from 65 to 75 degrees while the water temperature runs about 72 degrees.

The calm weather and the clear air lead to some excellent sunrise and sunset pictures.  There is nothing like getting up early in the misty morning, walking the deck with a cup of coffee and waiting for the first shout of “ sharks”. Then unlike the people in JAWS who ran from the water, we don our gear and prepare to jump in the water.

Due to the rarity of hurricanes, the calm weather and the proximity of Great White Sharks, this is obviously an ideal time for these expeditions.

SCHOOLS OF TUNA – FISHERMEN/SHARKS RELATIONSHIP – FOOD CHAIN 

The tuna run in large schools that often follow other schools of smaller fish called “bait balls”. The schools of tuna show up on the ships sonar when they get close.  The bait balls can be seen on the surface and look like a bubbling in the water.  When we see this bubbling, we grab our fishing poles and fish for tuna and yellow tail. 

Fishing for tuna is one of the techniques that we use to attract the sharks to the boat.  When sharks get in the vicinity of the boat the crew used chum (show picture of chum bucket) and frozen tuna to move the sharks into position for a photo op.  The chum that is used can be a combination of fish heads, minced tuna, whole fishes, tuna oil and beef.  The variety that was used on these expeditions was Chum Bucket.   One variety used in Australia consists of fish heads, minced blue fin and skipjack tuna, whole fishes and tuna oil, containers of both wet and dried blood and raw horsemeat, which is superior to beef in attracting the sharks.

After a day of diving and when dinner is over and our digital photography is edited, the equipment is cleaned and prepared for the next morning, we go out on the deck and use the lights of the boat to attract little fish that we catch on lures and store in a tank for the next day’s tuna fishing.  These are little sardines, which are used for bait when fishing for the tuna.

The Great White Sharks in the area have been tainted by man’s presence.  For years small fishing boats have come to this region to fish for tuna.  Over that time the sharks have learned that they don’t need to chase the tuna, instead they let the men catch the tuna on a fishing line and wait for them to exhaust themselves and the tuna. Finally the shark simply picks the tired tuna off the line for an easy meal and the man curses the shark.

I have never landed a tuna on these trips.  The sharks have always eaten mine.  We have actually had a couple of tuna landed where the shark has taken a chunk out of the fish.

The tuna that we do manage to land supplement our meals on the trip.  We cut up the best parts of the tuna and eat it raw with soy sauce (sashimi and sushi). The rest of it is grilled for tuna steaks.  Tuna is one fish that can be eaten raw without worrying about parasites. The FDA recommends that other fish be frozen before they are eaten in order to kill any harmful organisms.

You can see the progression of the food chain here.  The surrounding waters are filled with nutrients and food for various fish.  The food ranges from plankton to jellyfish to the seals, tuna and yellowtail that the great white sharks come to feast upon.  The sardines eat the plankton, the tuna eat the sardines and the Great White Sharks eat the tuna.  It’s a fish eat fish world out there.

BOAT – CREW – STAFF 

The boat that is used for the expedition is the Horizon, a 65 foot fishing vessel that can accommodate up to 30 divers/fishers plus crew but which only has 12 divers, four shark diving expedition and another four or five members of the boat crew. The crew functions 24 hours a day in order to support the expedition.  There are two cooks to prepare meals; a captain and support crew to keep all of the systems running.  The organization that sponsors the expeditions has a staff of four to lower and raise the cages, feed the sharks, keep the cages in position, move divers in and out of the cages and exchange camera equipment for the divers.

CAGES – DIVING GEAR – EFFECT OF COLD WATER ON DIVER

The cages are large enough to accommodate three to four divers with windows in the front and back to allow for pictures.  Note that these windows are large enough to let a shark poke its head in which happened last year when a large great white shark came in the back of the cage while we were all looking out the front.  The shark got stuck and since they don’t have reverse, it thrashed around until it got loose.  We had four divers in the cage at that time.  The two closest to the shark were crouched on the bottom of the cage as far away from the shark as possible.  The other two, including me, were taking pictures.  The fact that the shark came in the back of the cage while we were all watching another shark in the front of the cage is interesting and similar to something that has happened to me a few times while in the cages.  There have been times when while watching a shark in one position, another shark will come from a different direction and surprise you.  This one incident was from behind, another incident was from my left side while I was hanging partly out of the cage taking a shot of a shark on my right.  These animals are so silent that at times I don’t even notice them until they’re right in my face.  In another instance I was adjusting my camera when I looked up and found myself nose to nose with a Great White.  I just barely had time to take a shot and since it was so close I caught only part of its face.

The divers gear consist of cameras, thick wetsuits or drysuits and a lot of weight to keep the diver on the floor of the cage as it bounces around in the current.  We wear 40 pounds of weight around our waist to keep us in place.  For air we used what is called a hookah reg, which is an air hose that goes back to air tanks on the boat.

The divers are in the cages for one hour and out for one hour.  The hour in the cage can leave the diver cold and exhausted from bouncing around in the current.  During the diver’s hour out of the cage they barely have time to renew their camera equipment and grab a snack or a drink before being called to return to the cage.

The boat crew uses poles to keep the cages at a safe distance from the boats.  They also maintain the frozen tuna that is used for bait and chum the waters.  When a shark shows up they pull the bait away from the shark and attempt to move the shark in front of the cage so that the divers can get pictures.  When a diver runs out of film and wants another camera (you can’t change film underwater) the diver can pop up out of the cage and shout a prearranged camera number and location to the crew to get a replacement (I can get a video outtake of this).

My day in the cage is, at times, strenuous.  The water is cold, and strong currents most of the time rock the cage. When the jellyfish come floating through I have to dodge them to avoid getting stung.  Many jellyfish have protective poisons that can irritate the skin causing rashes and at times can cause severe and painful reactions.  To deal with the currents I hang on to the cage like a monkey and sway with the ocean to avoid being banged against the bars of the cage.  The shifts in the cage are for an hour at a time and nobody knows when the sharks are going to go for the bait.  When they approach my adrenaline starts flowing and I don’t notice the discomforts of my underwater home. However, when the sharks are playing hard to get, an hour seems like a very long time.

The day was not over when the sun went down.  After dinner, which may have included some of the day’s catch of tuna that the shark didn’t eat, I spend my evening editing digital video on my computer and downloading and editing still digital photos.

CAMERA EQUIPMENT – UNDER WATER OPTICS

One of the most popular cameras for underwater photographers is the Nikonos, made by Nikon.  I use a Nikonos V with a strobe, read that as giant flash, and a Sea & Sea 15 mm wide-angle lens to catch all of these large animals.  I also shoot a Canon digital camera in a protective underwater housing and a Sony digital video camera also in an underwater housing, both with wide-angle lenses. Taking pictures underwater is different, as I am sure you can imagine, from taking pictures on land.  I have the salt water to contend with and I have destroyed two cameras in the past when seawater leaked into the housing.  One of these instances occurred when I was hurrying to get back on a boat to avoid an interested blue shark.  I also have to take into account the different optics of underwater photography.  Seawater absorbs parts of the yellow spectrum of light giving pictures a blue tint, which gets stronger as you go deeper.  Seawater also magnifies objects for the human eye causing objects to appear to be larger than they actually are.  This can cause the photographer to misjudge the location of his subject.

ANATOMY -

The Great White Shark, Carcharodon Carcharias, is the largest carnivorous fish in the sea and most feared of all sharks.  The pups (baby sharks) are 3 to 5 feet long, and can grow to an adult size of 20 feet. The typical size of the sharks that have been sighted has been between 12 and 16 feet, which is consistent with the sharks that I have photographed.  The largest that I have seen is the big smiling one that attacked the large red float, which can be seen in some of my video (www.sealifepix.com).  The weight of a large sharks is estimated to run around one ton but it is thought that they could possibly weigh more than two tons.

The shark has no organ that can be used to produce sound. Other fish can make primitive sounds using their swim bladders but the shark has none. These animals do not roar or bellow or bark. In addition, the scales along the bodies of many sharks are hydrodynamically designed to reduce the sound of the animal swimming. They are very sneaky and extremely quiet swimmers.

As you can see from the pictures and video, most of the Great White Sharks have scars and wounds, especially around the snout and head. Some have large gashes on the side.  Some of these marks may have resulted from struggles with prey or mating partners, but many appeared to be the result of the shark’s habit of investigating objects using their snouts and mouths.  Note that my favorite subject, the smiling shark that attacked the red ball, has no marks.

Tiny black dots that are visible along the shark’s snout are pores with nerve connections to the brain. Called the ampullae of Lorenzini, they enable sharks to detect weak electric fields, such as those produced by electrochemical ‘reactions and muscle activity in other animals. Some researchers ‘believe that they enable sharks not only to locate prey hidden beneath the sand but also to navigate using the earth’s magnetic field.  It is also thought that the cages that divers like me use to observe and photograph these animals produce a weak electric current which may attract the curious shark or possibly irritate it.  One of the methods that I have used to ward off an interested shark when I am at the cage window is to wiggle my camera with the electrically charged strobe at the sharks face.  So far this has worked.

Great whites cannot stop swimming for long periods without suffocating. Nor can they live in captivity.  Repeated attempts to maintain a Great White in captivity have ended in the death of the shark within a matter of days.  They extract the oxygen that they need through their gills. Gill slits that can be seen in front of the pectoral fin are an obvious difference between sharks and other fishes.  Other fish have one gill slit on each side, sharks have between five and seven.   In addition, they have no reverse, which was evidenced when one swam into the camera window in the back of the cage on one of my dives.  The shark was not happy about getting stuck in the window and was able to get out only by thrashing around much to the dismay of the diver on that end of the cage.

The Great White Shark has knifelike teeth that are stored in two or three rows along both jaws of its mouth, 26 teeth in each row on the top and 24 on the bottom. Whenever teeth are lost during feeding or fighting, they are quickly replaced by pop up teeth.  The shark’s teeth are large, triangular and serrated enabling the shark to bite and cut away the meat from its prey.  These teeth are not set firmly in the jaw as our teeth, instead they are set in a membrane inside the jaw and as new teeth grow they force out the old teeth.  These new teeth are slightly larger than the teeth that they replace allowing for the growth in the size of the shark.  These teeth can replace themselves as often as every nine days depending on the age of the shark and the temperature of the surrounding water.  Fossilized shark teeth comparable to those of today’s Great White Sharks have been found in fossils that are as much as 30 million years old.  These sharks and their ancestors have always lived in the oceans unlike bony fish which are thought to have originated in fresh water and migrated to the seas.

The most noticeable feature of the Great White Shark is, of course, the large first dorsal fin.  The purpose of this fin is to stabilize the shark in the water.  The shark can change the shape of this fin thereby changing is hydrodynamics.  In addition to the first dorsal fin, the shark has a second dorsal fin.  Sharks, like humans, share a body design that features paired forelimbs, fins in shark language, and hind limbs.  The shark has two pectoral fins and two pelvic fins.  Toward the tail end of the shark you can find an anal fin and the caudal fin, which we might call a tail fin.  This last fin is the source of the shark’s propulsion and rapid bursts of acceleration.  Great White Sharks usually swim at a leisurely speed of 1 to 2 miles per hour but can achieve bursts of up to 35 miles per hour, about 10 times faster than I can swim.

The Great White Shark is the warmest of all sharks.  When the sharks capture a meal they possess a biological ability enabling them quickly to digest the food. Unlike most fish, Great White Sharks along with some of their relatives, maintain a body temperature higher than the surrounding water.  This difference allows them to maintain a body temperature as much as 25 degrees above the surrounding water temperature.  This is accomplished by a modified circulatory system and allows the shark to be more efficient than us mammals and is made possible by tiny arteries and veins that return the heat generated by the shark’s movements to the swimming muscles and the stomach. This principle of conserving warmth is similar to a device we call a counter-current heat exchanger. In most fish such heat is lost through the gills.  This higher temperature also allows the shark to function in deeper, colder waters. 

Great White Sharks are curious and will often inspect the divers and cages when they first approach our site.  The sharks are known to inspect floating objects due to their interest in eating pinipeds (including seals), which must go to the surface to breathe.  This behavior can be seen in one of my video clips that show a great white shark going for our foam rubber seal cutout.  The shark’s method of attack is to come from underneath the prey and to catch it on the surface.  This decoy is cut to look like a seal on the surface and has been painted brown.  You can speculate what the Great White Shark sees when it is swimming underneath a surfer with their arms and legs hanging off the sides of the surfboard.  If a diver is unlucky enough or unwise enough to be outside of the cage (see video of diver with large yellow video camera hanging out of cage as shark goes in for a bite), the shark may used its sensitive teeth and gums to determine whether the diver is edible.  By the time the shark has decided that the diver is not food, the diver has already lost an arm or a leg or has a major artery severed.  This is said to have been the fate of at least two divers in the Guadalupe Island area.  Researchers in California have observed large Great White Sharks attack sea lions, seals and elephant seals along the surface near the Farallon Islands.   Note that they have also seen Orcas attack and destroy Great White Sharks in this vicinity.  The observers noted that the sharks swam to the bottom, trying to conceal themselves, and then attacked in a near vertical rush to surprise the prey. The pinnipeds are usually bitten from below and behind. Note the video of the shark attacking the fake seal.  Then the Great White Sharks would then move off, either to allow the victims to bleed to death or lapse into shock, returning minutes later to consume the helpless prey.

Great White Sharks typically swim in opposite orbits, trying to avoid one another while taking turns at the bait we have set out. When a new shark arrives, it naturally investigates the source of the overwhelming scent that had guided it for perhaps a couple of miles. With the arrival of the new shark, those already on the scene, apparently bored by the lack of a good meal, might again express some interest in the frozen tuna  and chum. Along with the newcomer, they will make more approaches at the bait. Following this period of territory marking activity, the largest sharks present spend the most time near our baits. Smaller shark defer to larger sharks, but there are no set rules. Social order is maintained but requires constant adjustments to accommodate changing conditions. No fighting was ever observed on any of my dives.  I also found the sharks to be very patient animals as they would hover under the boat waiting for one of the people that were fishing to catch a tuna and wear it out so that the shark could have a real meal after having been teased by the frozen tuna bait.

The feeding preference of the shark changes with age and size. The most common item in the larger of the analyzed sharks – from six to fourteen feet long – was dolphin remains, followed by squid, bony fish, smaller sharks, crustacea, pinnipeds and sea birds.

Smaller whites seem to prefer fish, followed by some crustaceans and smaller sharks.

Researchers explain the difference in food preference as follows: smaller great whites are more agile and their teeth are narrower, giving them the ability to pursue and grasp small, bony fishes. Larger whites, more ungainly but equipped with broader, better cutting teeth seem more adept at surprising larger mammalian prey and biting into their muscular bodies.  Smaller sharks also stay in deeper waters limiting themselves to the animals that live there, while larger sharks range closer to the surface preying on seals, and other animals that rely on air to breathe.

Sound may be the most important shark sense for hunting.  They hear low-frequency vibrations at distances greater than a mile.  The shark sense of smell is also keen. They have the ability to scent food over great distances in the water and they can detect blood.  They have taste buds in their mouth, but we do not know much about their sense of taste.

ENDANGERED SHARKS

Sharks are very high in the food chain.  Their primary predator is man who has hunted them to near extinction out of fear or for their fins – shark fin soup – and their teeth.  However, man is not their only predator.  Orcas are another predator of Great White Sharks.

Some of the sharks that I have seen near Guadalupe have little tags hanging from the back of their dorsal fin.  Great White Sharks are a protected species in some areas including the state of California, South Africa, and a few other regions.  To monitor and protect the existing animals, one organization, Pfleger Institute of Environmental Research (PIER) has tagged about 35 of the sharks.  Some of these tagged sharks have shown up in the video that I shot off of Guadalupe, which was later provided to PIER.  The research of PIER indicates that the sharks leave the Guadalupe area in early winter and head to deep, as deep as 1500 feet, cold waters.  Some have later turned up near Hawaii, as shown by the satellite monitoring of their tags.   Then they show up again the following fall near Guadalupe to feed on the tuna, yellow tail and, yes, even the Guadalupe Seals.

Great White Sharks can also be seen along the coast of California north of the Guadalupe island site.  They are also seen in the Pacific Ocean off the coasts of Australia, New Zealand and Japan.  In the Atlantic and Indian Oceans they have been found off the coast of Brazil and South Africa.  There are some variations in the appearance of the sharks in these different regions.  The sharks from Australia tend to have longer snouts than those seen in Guadalupe and the ones found off the coast of South Africa are more of an olive color compared to the darker Guadalupe sharks.

Man is finally beginning to understand and respect this much maligned fish.  It’s not the mindless savage that we once thought. Sharks are essential to the balance of the oceans’ ecosystems but their future is dim.  We are killing them for food and parts in large numbers.  A greater appreciation of the purpose and the beauty of these animals will insure their existence for generations to come.