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Remember: shark attacks on humans are rare, so simply seeing a shark does not necessarily mean that it has targeted you. Chance meetings with sharks that are on the hunt for other food or simply swimming from point A to point B are perfectly possible. Don't react tensely or frantically to the sight of a shark unless you have to — as mentioned above, making wild movements and large splashes can attract its attention and make it think that you are a wounded animal.  Instead, stay calm and focus on your immediate goal: getting out of the water quickly, quietly, and smoothly. Resist your natural instinct to make a mad dash to safety unless the shark is aggressively following you. If you are fishing in a small boat when you notice a shark, let any fish on the line go and move away. If you are diving at significant depths, surfacing quickly can be dangerous and should be used as a last resort. Instead, release any fish or bait you have with you and move laterally away from the shark. Exit the water at a reasonable pace once you are away from it. As you make your exit from the water, try to keep an eye on the shark if possible. Watch its body language — aggressive sharks tend to act noticeably different from non-aggressive ones. If you see the following signs, move more quickly as you try to get out of the water and get ready to defend yourself if necessary. Movements that indicate a shark might be ready to attack include:  Making quick, sharp turns while swimming. "Hunching" or arching the back. Circling, especially if the circles get tighter Charging Lowering the dorsal fin (the one on the back) Rubbing the belly against the sea floor Showing other sudden or erratic movements. In the very unlikely event that you are attacked by a shark, you will almost always fare better if the shark is not able to take you by surprise. If you see the signs of aggression listed above, keep your eyes on the shark and make an effort to use even, steady movements as you continue making an exit from the water. If you have anything you can use to defend yourself, grab hold of it. If you can, put your back to a reef, wall or another object to limit the shark's angles of attack. Most importantly, get ready to fight back. If you are near other people, it's also crucial to call out to them for several reasons. Not only will this notify them of the danger and give them a chance to themselves — it can also help you. Statistically, there are few cases of rescuers being attacked when helping someone else get away from a shark. It's thought that suddenly encountering a second person in the water can spook a shark enough to make it run away. Playing dead once a shark makes a decision to attack will do you no favors. This can make the shark think that you're defeated, which is what it wants, and may encourage more bites. On the other hand, if you make yourself appear strong and dangerous, the shark may go off to find easier prey. Remember: sharks aren't usually used to prey that puts up a serious fight — the majority would be much happier chasing an easy fish than a human who's willing to punch, kick, and gouge.  Try to strike the shark's eyes and gills with whatever you have. These areas are the most vulnerable, pain-sensitive parts of a shark. Punch and claw at them repeatedly until the shark lets you go. Contrary to popular myth, the nose is not as good of target as the eyes and gills. It's less sensitive to pain and is also right next to the mouth, which is the last thing you want to stick your hand into. If you're diving, use any tools you have, like a diving knife or even a spare tank to hit the shark.  Don’t stop fighting. The goal is to convince the shark that attacking you is more trouble than it is worth. Giving up will just make the shark's job easier. As soon as you can after a shark attack, get out of the water and stay out, even if you don't think you have any injuries. The adrenaline pumping through your body may make it difficult to judge how hurt you are at first. Getting out of the water (and staying out) doesn't just keep you out of the shark's reach, but also gives you a chance to determine what to do next with a reasonably level head.  Get medical attention for any injuries immediately, even if they don't seem serious. This is extra important if you are bleeding — since it is more difficult for your body to stop bleeding underwater, you may already have lost a significant amount of blood.  Don't get back in the water even if the shark seems to have left and you have no injuries. The only reason to get back in the water (provided you are uninjured) is to save them from a shark attack — as mentioned above, some sharks may flee when dealing with a group of people, rather than just one. This advice should go without saying. Almost any animal that is taunted, harassed, or chased will eventually defend itself. Sharks are no exception, though their deadly predatory capabilities make the consequences for mistakes much higher than with most animals. If you do see a shark, exit the water and leave it alone. Never do anything to provoke a shark, even if you think you are in a safe location, like on a boat. Accidents can still happen.

Summary:
Stay calm. Look for telltale warning signs of aggression. If an attack seems likely, adopt a defensive position. If attacked, fight! Get out of the water and assess your situation. Don’t ever bother or harass sharks.