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Encounter with a Great White Shark


Sometimes, a once in a lifetime opportunity comes along. This may well be one, that is to say, for me. On March 4 2000, I joined the grey whale watching cruise by the Oceanic Society in San Francisco. We saw plenty of whales, but we were lucky that day. We found a great white shark feasting on an elephant seal off the coast of Point Reyes, a peninsula which is a good 50 km northwest of San Francisco. No baiting was used. This shark was doing its own thing in its natural environment, and did not seem to be interested in the boat at all. Therefore, you should not expect to find the shark in its famous pose: in close-up with its mouth wide open above the water.

At some point, the shark passed the boat at some depth below the surface. Its awsome shadow was clearly visible and showed us the true size of the beast. It seemed at least 3 meter (10 ft) long, maybe more, but it was certainly not a record breaker. I estimated its length by guessing how large a human would appear lying in the water. A more precise estimate would involve stretching my arm in the direction of the shark, which didn't seem to be a smart idea at the time. The largest great white sharks are up to 6 meter (20 ft) long.

The field naturalist who accompanied this trip identified the carcass as a female elephant seal (by itself up to 3 meter or 10 ft long). There was no distinct evidence of blood in the water, which indicates that the kill happened some time before we arrived. There is some blood in the water in Figure 8, but that must have leaked leaked when the shark took its bite.

About the images

The images are scanned versions of pictures I took during the time that we floated near the carcass. The pictures were taken with a 400mm F/6.3 telephoto lens. The pictures do not give a good impression of the amplitude of the larger waves, which shook the boat excessively. About a third of the passengers became sick at some point; some people were lying in the cabin for most of the trip. In these circumstances a tripod is useless. The only way to keep the carcass in the field of view is to keep the camera in hand and compensate for the shaking of the boat. A very short exposure time is required to freeze this movement. The shortest exposure time I have is 1/1000. An ISO 400 film is then required at, say, F/8 under a cloudly sky. This combination proved successful, although I would recommend an even shorter exposure time if you have it. An autofocus would be nice, I had to refocus manually, and some pictures are out of focus (not shown here). Most of the images do not display the entire picture.

In order to keep download time of this page to a minimum, low-resolution images are shown below.

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The head of the shark

Figure 1: Front of the shark's head, with its white snout and dorsal fin befind it. The black dots are NOT the eyes, but black spots on its nose. The eyes of the shark are completely in the upper grey part of its body (see Figure 2).

Figure 2: Shark's head seen from the side. The right eye is clearly visible in this picture. HIGH RESOLUTION GIF and HIGH RESOLUTION JPG

Figure 3: Back of the shark's head. Note its size, and compare this with the bite-marks in Figure 10.

The dorsal fin.

It might be possible to identify this shark as an individual by means of its dorsal fin. Note the carvings on the back side of the fin and its colour pattern.

Figure 4: Dorsal fin of the shark with the fron to the right. At this time, the shark apparently turned away from the carcass. To the right of the dorsal fin, is probably the tail fin.

Figure 5: Dorsal fin seen from the right side of the shark. Note the tail of the shark curved to its left side (away from the camera) and moving to its right side (towards the camera). The movement of the tail evident from the splashing water. HIGH RESOLUTION GIF and HIGH RESOLUTION JPG (C)JMS

Figure 6: High-resolution scan of the dorsal fin in Figure 5. Note the carvings on the back of the fin (also visible in Figures 1 and 4), and the colour pattern. A light-grey patch is visible on the lower front side (lower right in the picture). A similar colour pattern - front side of the fin lighter than back side - can be seen in pictures of other great white sharks. It is not a shadow effect, because it can be seen in other pictures of the dorsal fin. The original shows a lot more low-contrast details in the colour, which barely show up in this high-resolution scan.

Behaviour of the shark

Perhaps the most striking observation were the breaks between the bites. It was eating its lunch at its leisure. It is actually a well established that great white sharks can eat for hours on a single kill. I saw a scene like this in a TV documentary a long time ago, but don't take my word for it: see the article about great white sharks in the April 2000 issue of National Geographic magazine (what a coincidence! Somehow NG never ceases to amaze me). The shark must have wandered significant distances away from the carcass at times, because it passed just under the boat at some point. The distance from the carcass can be estimated assuming its length is 3 meter (for a mature female elephant seal). The typical length of the carcass on the pictures is about half the long side of the photo (i.e. one half times 35 mm on the photographic film). For a 400 mm focus, this means that the apparent size (angle) of the carcass was 0.5*35/400= 0.044 radians. For a true length of the carcass of 3 meter, this translates into a distance of 70 meter. If the actual size of the carcass was only 2 meter, the distance would still be 46 meter. To the eye it seemed much closer, but this is deceptive because the height of the observer above the water changes the perspective. Since we were adrift, the distance changed continuously, and at some point we were maybe at half this distance, but 70 meter seems a good average. From this one incident that we saw the shark near the boat, it would seem that the shark wandered more than 50 meters away from its kill between bites. Its feeding pattern looked more like a careful nibble once in a while than an instant violent devouring of its prey.

When it was at the carcass, the shark splashed violently with its tail (Figures 5 and 7). This is just what you expect from a shark taking a good bite from its prey. It was still eating when we left it.
Figure 7: Water splashing with the tail. From the apparent shape and location of the dorsal fin and the tail fin, the shark is either moving towards the camara or away from it.

Figure 8: The shark is not visible in this picture, but it is probably to the right of the carcass, where the turmoil in the water is. The water is coloured by blood on this side as well. Note the wave around the carcass, which shows it was pushed to the left by the shark taking a bite off it.

Figure 9: A gull was flying above the carcass, looking for small pieces left by the shark. It never landed, but our naturalist guide explained it was following the shark. After careful inspection of the original, I do not believe that the dark patch below the gull is its reflection on the water. The white material on the water was there when we found the shark. I do not know what it is. (C)JMS

The carcass

The carcass itself is interesting because the size of bite marks may help estimate the size of the shark. Figure 10 shows a close-up of the carcass. Note the the marks left by the teeth. Again assuming that the total length of the seal was 3 meter, the three bite marks covering the right half suggest a size of 50cm. At this point, I cannot say what this implies for the size of the shark.
Figure 10: The carcass of the elephant seal with three distinct bite marks in the right half. (C)JMS

Story of a Great White Shark being eaten by a killerwhale. This was not far from the place where the pictures on this page were taken.