For most divers, no other marine animal elicits more excitement than an encounter with a shark. Furthermore, this excitement is such that many divers spend a great deal of time, effort and money to intentionally seek out such encounters. Sharks are beautiful creatures and well worth the meeting. A few tips will help you maximize your interaction, be it a chance encounter or intentional.
Interactions vary considerably with each particular species. In this article I will address species that you’re likely to encounter in California, either by chance or by purposeful intent.
This first part of a two part article will deal with open ocean sharks. We will, however, not deal with the great white shark as encounters with these predators are extremely rare.
These are by far the most beautiful of the sharks you’ll encounter in California waters. A blue shark dive is a must for every serious California diver. They are sleek and graceful with outstanding coloration. The top half of the shark is an electric blue-gray while the bottom is a sleek silver. This dual coloring makes the shark nearly invisible when viewed from above or directly below. Blue sharks average three to five feet in length, with six feet being a large specimen. They are generally non-aggressive scavengers, seeking to eat only dead and dying fish or small bait fish and squid.
But common as they are and though frequently seen by divers, you still have to head out on a trip specifically designed to view these creatures. Blue sharks are open ocean animals and will usually be found only in deep waters. The rare exceptions are when a blue is seen at an offshore pinnacle, oil rig, on the outer fringes of a kelp forest that drops off to deep water or when they come to feed on mating squid.
Blue shark dive trips put divers hanging in cages far offshore in water several hundreds, if not thousands, feet deep. But first a “slick” of blood and ground up dead fish, known as chum, is put into the water. The bait is usually oily fish such as bonita, tuna, anchovies, sardines, etc. The scent trails behind the boat for miles drawing in sharks to its source. Sometimes attracting blue sharks takes minutes, sometimes hours. Some spots “in the middle of the ocean” are better than others. The pros that lead shark trips know best.
In addition to the slick, a bait “cage” is used of solid dead fish, often frozen in a block. The cage holds the bait together so that a scent trail forms but large chunks do not break or bitten off.
While keeping a scent in the water is important to attracting sharks. The bait cage keeps them around but limits the amount of debris in the water. In addition, the bait cage limits the food available to the sharks. If large chunks of food are available to the shark, the sharks feed, become satiated, and leave. Or worse, large chunks break off, sink and the sharks head to deep water to feed rather than staying near the boat around the divers. Once the sharks have arrived and divers are in the water, the chumming is stopped. Excessive chumming clouds the water for shark viewing and photography and sometimes over-stimulates the sharks, making diving more dangerous.
While most operators use a cage for divers, some will allow experienced divers out of the cage for more intimate encounters. To survive an out-of-the-cage experience with blue sharks requires nerve for two reasons. First, you will be hanging over thousands of feet of water. Second, you have nothing to cover your back and sharks come in from all directions. This is especially nerve-racking when there are a lot of sharks in the water. Stay out of the bait scent trail if you choose to go out of the cage. Going out of the cage also requires excellent buoyancy skills as you will being hanging mid-water over a very deep bottom. It also requires a strong swimming ability. Since boats are not at anchor, they drift in the wind and divers drift with the current. Divers and boats can become separated very quickly.
Blue sharks have some oddities about their behavior of which you should be aware. While they feed in a slow, methodical fashion, they are attracted to bright colors, especially orange, flashy metals and electronic devices such as strobes. They will move in on such items and bite. You will know they are getting ready to move in for a bite by an “arched back” posture. They are also very sensitive to touch—they don’t like it. Even just a gentle nudge will send them fleeing.
Mako sharks, on the other hand, are not slow methodic feeders. Like the blue, the are also an open water species. On dives for blue sharks a mako is the next most likely to show up. They are much more muscular, nervous and erratic in movement, and flash a mouthful of sharp teeth (blues have sharp teeth also, to be sure, but just not as obvious). For every 20 blues you encounter you might see a mako. And they don’t stick around long. Be quick with your camera and try to get an upward angle. They have similar coloration to the blue but blend into their background even more effectively. To maintain the interest of a mako, a large solid piece of fish, such as a head, can be tied off to the boat or cage. It gives them something to chew on and hold still for at least a short time.
In part two of this article we’ll look at how to properly interact with nearshore sharks like the leopard shark, soupfin, horn shark, and swell shark.