The Bull Sharks of Lake Nicaragua
The exquisitely beautiful Lake Nicaragua is the largest lake in Central America. This freshwater lake in Nicaragua covers an area of over 8,000 square kilometers and is often referred to by the local people as “the sweet sea”. This name is appropriate because, apart from the lack of salt, this lake is very much like the sea complete with waves, archipelagos of islands and sharks.
Despite being a freshwater lake, Lake Nicaragua contains sharks that have adapted to freshwater life. This originally led scientists to believe that, due to the lake’s proximity to the Pacific Ocean, the area that the lake currently occupies was previously a giant bay. The theory for the presence of these sharks was that over a period of time, the gap closed forming a lake and trapping the sharks which then adapted as the water as it gradually changed from saline to fresh. Recent studies, however, have shown that the sharks have more than likely traveled up the San Juan River which connects the lake to the Caribbean Sea, jumping upstream in much the same way as salmon do.
Although scientist initially thought that the Lake Nicaragua shark was a separate species, it has been discovered that they are in fact bull sharks, so named because of their broad flat snout, stocky shape and notoriously unpredictable, aggressive behavior. This shark, which is called the Nicaragua shark in Nicaragua, is also known as the Zambezi or Zambi shark in Africa and Sundarbans or Ganges shark in India as well as a variety of names in other parts of the world. Unlike most marine sharks, bull sharks can tolerate and adapt to fresh water, although they are not true freshwater sharks. Bull sharks prefer warm shallow waters and are found worldwide in rivers and along coastlines. Because bull sharks are unpredictable and often aggressive and because they favor shallow waters, they are considered to be one of the more dangerous species of shark from a human standpoint, and it is believed that they are responsible for the majority of shallow water attacks on humans.
As with any lake as well as the sea, humans must learn to treat the non-human inhabitants with respect and acknowledge their right to be there. Lake Nicaragua is no different, and although the Nicaragua shark is a creature to be wary of, it certainly does not detract from the beauty of this amazing lake in Nicaragua.