The Bronx River was considered an “open sewer” for years, due in large part to the large amounts of industrial waste dumped into the New York City waterway in the 19th and 20th centuries. Dolphins were among the many species hit by pollution — but last week, for the first time in years, they returned.
“That’s right — dolphins have been sighted in the Bronx River this week,” the New York City Department of Parks and Recreation said chirp Thursday with a video of at least two dolphins swimming in the water. “This is great news – it shows that decades-long efforts to restore the river as a healthy habitat are working well.”
the Bronx River Coalition He said dolphins were seen in Starlight Park, an area of the Bronx that had never used developed land before and has since been restored with plants, picnic areas, playgrounds and more. According to the parks department, this is the first time dolphins have made their way to the Bronx since 2017, although dolphins were sighted as recently as last year in the East River, which connects to the Bronx River.
Two dolphins were also spotted in the tributaries of Whale Creek last week next to Green Point, Brooklyn’s Newtown Creek sewage treatment plant.
The parks department said the dolphins may have “naturally found” their way back into the waterway in search of fish that frequent the tributaries. In 2018, the department released 400 adult herring, a type of herring, into the river as part of its efforts to help improve the water’s environment. In a video released then, management explained that the river is the only freshwater river in New York City, and that the hope is that newly released fish will use the area to lay eggs and that their offspring will do the same.
“The dolphins will not swim across the river but will remain in the estuary, where fresh water and marine water mix,” the parks department told CBS News. “This is why marine species like the dolphin are expected to be upstream, but we don’t expect them to be swimming in the freshwater parts of the Bronx, which get progressively fresher (less salty) as you go downstream.”
The river became highly polluted in the 19th and 20th centuries, according to the American Museum of Natural History, when it was used to dump industrial waste, including fertilizer and oil. This pollution has led to the loss of many plants and animals.
But the groups have been working for decades to restore the waterway. The Bronx Zoo stopped dumping more than 200,000 gallons of animal waste into the river in 2001 and the New York Botanical Garden stopped dumping thousands of gallons of pollutants into the water in 2002, according to the Bronx River Coalition.
According to the Parks Department, the latest sighting is “a sign of a healthy ecosystem.”
“Dolphins help provide ecological balance by preventing prey species from becoming overpopulated,” the department said, adding that they provide a “significant social benefit” as well.
“Seeing dolphins and knowing they live in your neighborhood park can inspire you with awe, wonder, curiosity, and pride, helping to foster a deeper sense of stewardship over the local environment and spur action to protect, care for, and restore important local habitats like the Bronx River.”
Although not often seen in the Bronx River, marine mammals are frequent visitors to the waters around the Big Apple. From spring to fall each year, bottlenose dolphins visit local waterways to feed.
With marine animals making their presence known in the area, the state’s Department of Environmental Conservation recently warned that people should avoid close contact. The Marine Mammal Protection Act requires that people avoid touching, feeding, disturbing or harassing marine mammals, and says those who do are subject to fines and imprisonment.