A nearly 12-foot (3.65-metre) shortfin mako shark discovered off the coast of Montauk, New York, has sparked speculation over whether decades-old nuclear waste dumped nearby may have caused genetic mutations. However, scientists say there is currently no evidence of radioactive contamination.
The massive female shark, nicknamed “Sharkzilla”, was featured in the Discovery Channel’s Shark Week programme Sharkzilla Takes New York after researchers investigated a series of attacks on large marine animals in the area.
Marine scientist Craig O’Connell and his team began tracking the predator after several humpback whales, grey seals and even 400-pound (181kg) tuna were found with unusually large bite marks. One humpback whale had a bite measuring about 2 feet (61cm) across, while a grey seal suffered a wound stretching 22 inches (56cm).
The investigation eventually led researchers to the enormous female shortfin mako, which was tagged for tracking and sampled for laboratory testing.
The shark’s exceptional size prompted scientists to consider whether it could have been affected by radioactive waste dumped in the nearby Hudson Canyon. Between 1946 and 1970, the US government disposed of thousands of sealed barrels containing low-level radioactive waste in the area, with an estimated 15,000 barrels discarded during the late 1960s alone.
Some of the containers were later found to be leaking, raising concerns that radioactive materials may have entered the marine food chain and affected wildlife.
Despite the speculation, laboratory analysis found no traces of radioactive contamination in the shark’s tissue samples, ruling out claims that it had become a “mutant shark” due to nuclear waste.
Researchers instead believe the shark is likely pregnant, explaining its unusually large appetite and attacks on sizeable prey to support both itself and its developing offspring.
O’Connell said the discovery could be a positive sign that shortfin mako sharks are returning to waters off New York after years of population decline caused by overfishing. The area may once again be serving as an important breeding ground for the species.
Although fears of a radiation-induced “super shark” have been dismissed, experts say the return of large apex predators reflects changing marine ecosystems and have urged fishermen and water users to remain cautious and avoid approaching or disturbing wild sharks.
