The question of whether sharks inhabit the deep, clear waters of Lake George is common for visitors to this major freshwater body in New York State. The definitive answer is simple: no, there are no sharks in Lake George. This landlocked Adirondack lake is geographically isolated and its freshwater composition makes it biologically incompatible with the vast majority of shark species.
The Definitive Answer: A Question of Salt and Biology
The overwhelming majority of the approximately 500 known shark species are obligate marine organisms, meaning they must live in saltwater. Their survival depends upon osmoregulation, a process that allows them to maintain a stable internal environment despite the high salt concentration of the ocean. Marine sharks retain high levels of urea and trimethylamine oxide (TMAO) in their blood, making their internal fluids slightly saltier than the surrounding seawater.
This hyper-osmotic state prevents the shark’s body tissues from constantly losing water to the ocean through osmosis. Excess salt that diffuses into the body across the gills and through food is actively excreted by the rectal gland, a specialized organ found only in cartilaginous fish. This system is tuned for a hypertonic, or salt-rich, environment.
If a typical marine shark were to enter a hypotonic environment like Lake George’s freshwater, this specialized system would fail. The concentration gradient would reverse, causing water to flood into the shark’s body tissues and bloodstream, leading to cellular swelling and rupture. Simultaneously, the shark would rapidly lose its stored salts and urea to the surrounding water.
The marine shark’s rectal gland would cease to function efficiently. Its kidneys, designed to conserve water, would be unable to excrete the massive influx of freshwater quickly enough. This biological challenge results in a fatal electrolyte imbalance and cellular damage, making long-term survival in freshwater like Lake George biologically impossible for nearly every species of shark.
The One Exception: Why Bull Sharks Aren’t in Lake George
The one species that often sparks speculation is the Bull Shark (Carcharhinus leucas), which is euryhaline, meaning it can tolerate a wide range of water salinities, including pure freshwater. This shark possesses physiological adaptations that allow it to reverse its osmoregulatory strategy when transitioning from salt to freshwater.
When in freshwater, the Bull Shark drastically reduces the production and retention of urea and TMAO, minimizing the osmotic gradient that causes water influx. The kidneys increase their output of extremely dilute urine by up to twenty times the marine rate, efficiently flushing out excess water. Its gills actively absorb sodium and chloride ions from the dilute water, using specialized ion transporters like Na+/K+-ATPase (NKA) and Na+/H+ exchanger 3 (NHE3) to compensate for salt loss.
Despite this biological capability, the Bull Shark is geographically unable to reach Lake George, which is an inland, landlocked lake. Lake George drains northward into Lake Champlain via the La Chute River. The La Chute River is a short, 3.5-mile stretch that features a total elevation drop of 226 feet, including several natural waterfalls and multiple man-made dams.
These natural and artificial obstructions, such as the Lake George Outlet Dam at Ticonderoga, create an impassable barrier for any aquatic life attempting to migrate upstream from Lake Champlain and the St. Lawrence River system. The sheer distance from the nearest marine environment, coupled with these barriers, means that even the adaptable Bull Shark cannot reach the waters of Lake George.
What Really Lives in Lake George’s Waters
While sharks are entirely absent, Lake George is home to a diverse population of native freshwater fish that can grow to impressive sizes. The lake’s clean, cold, and deep waters provide an ideal habitat for several large predatory species.
The Lake Trout (Salvelinus namaycush) is the lake’s largest native species, commonly reaching lengths of 15 to 34 inches and weights of up to 30 pounds. Northern Pike (Esox lucius), another top predator, inhabits the shallower, weedy bays and can grow to three or four feet in length.
The lake supports populations of both Smallmouth Bass and Largemouth Bass, which are popular with anglers and can reach lengths that make them formidable freshwater fighters. Other indigenous fish include Landlocked Salmon, Yellow Perch, and various sunfish species, all of which contribute to the lake’s healthy ecosystem.