Mostly unknown by visitors, tucked away almost 120 miles from the salty waters of the Caribbean Sea, fresh water sharks patrol Lake Nicaragua. Here, the fresh water provides no sanctuary for swimming animals; this shark’s comfort in fresh water is unusual among their kin.
The sharks inhabiting Lake Nicaragua are bull sharks (Charcharinus leucus). Bull sharks are medium to large sharks that can reach more than 11 feet in length. Bull sharks were named so because of similar characteristics to a bull on land; they possess stocky bodies and an often aggressive with an unpredictable nature.
While Lake Nicaragua is only 12 miles from the Pacific Ocean at some points, it does not connect to it. The only navigable route to salt water is via the San Juan River, which is passable for small boats with drafts of less than 3 feet. Covering almost 4,500 square miles, Lake Nicaragua is a relatively shallow body of water, with an average depth of about 40 feet.
For some time scientists thought the sharks inhabiting Lake Nicaragua were a separate species and tagged some sharks for research purposes. Later, scientists discovered these same sharks swimming in the Caribbean, effectively demonstrating that the sharks were able to travel the nearly 120-mile journey up the San Juan River. This proved that the sharks in Lake Nicaragua were not a unique species.
The habitat preferences of bull sharks vary with their age, and populations from different geographic regions adapt to their habitats differently. In general, young bull sharks are born in coastal waterways and estuaries. They spend their youths in these shallow and relatively predator-free environments before moving into the more open habitats that their parents frequent. As a species, bull sharks are remarkably adaptable, and are able to thrive in a variety of habitats.
Even though there are sharks in the water, Jicaro is not located near the areas sharks have been spotted. Due to the massive size of the lake, and the dwindling population of fresh water sharks, you are unlikely to see one even if you wanted to.