Sharks
Sharks (superorder Selachimorpha) are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago, before the time of the dinosaurs.
Since that time, sharks have diversified into 440 species, ranging in size from the small dwarf lanternshark, Etmopterus perryi, a deep sea species of only 17 centimetres (7 in) in length, to the whale shark, Rhincodon typus, the largest fish, which reaches approximately 12 metres (39 ft) and which feeds only on plankton, squid, and small fish through filter feeding. Sharks are found in all seas and are common down to depths of 2,000 metres (6,600 ft). They generally do not live in freshwater, with a few exceptions such as the bull shark and the river shark which can live both in seawater and freshwater.They respire with the use of five to seven gill slits. Sharks have a covering of dermal denticles that protect their skin from damage and parasites and improve fluid dynamics so the shark can move faster. They have several sets of replaceable teeth.
Well-known species such as the great white and the hammerhead are apex predators at the top of the underwater food chain. Their extraordinary skills as predators fascinate and frighten humans, even as their survival is under serious threat from fishing and other human activities.
Avoiding Shark Attacks
While there is no way to completely eliminate the possibility of a shark attack when one is in the water, one may take precautions such as:
- avoiding the water at dawn, dusk, or night, when sharks tend to feed;
- avoiding areas where sharks generally locate themselves, such as murky waters and steep drop-offs
- avoiding swimming alone, always being near a group of people, and if possible, avoiding being at the edge of the group;
- refraining from excess splashing or movement;
- preventing pets from entering the water;
- avoiding shiny jewelry, tan lines and bright clothing, all of which can attract sharks;
- avoiding areas where prey animals of sharks live, for instance seals;
- avoiding areas where the remains of fish have been discarded into the water, such as near fishermen cleaning their catch.
- sharks attack at 2-3 feet of water, so remember to stay closer than that in shark-infested waters.
Number of Shark Attacks from 2000 to 2011 Worldwide
| YEAR | Total Attacks | Fatal | Non-fatal |
|---|---|---|---|
| 2007 | 70 | 1 | 69 |
| 2002 | 65 | 3 | 62 |
| 2008 | 52 | 4 | 48 |
| 2003 | 55 | 4 | 51 |
| 2006 | 58 | 4 | 54 |
| 2005 | 58 | 4 | 54 |
| 2001 | 75 | 4 | 71 |
| 2009 | 64 | 6 | 58 |
| 2010 | 81 | 6 | 75 |
| 2004 | 65 | 7 | 58 |
| 2000 | 89 | 11 | 78 |
| 2011 | 75 | 12 | 63 |