A sign of improving water quality in the New York City's Bronx River, an industrial waste dump for decades, is the spotting of common dolphins (Delphinus delphis) cruising the river on Monday, The short river rises north of the City and connects to the East River that separates the Bronx and Manhattan from Queens and Brooklyn. Sightings of wildlife previously absent have increased in the waters surrounding New York as water quality has slowly improved. Park officials think the dolphins found their way into the urban river hunting for fish. City authorities have stocked the river with fish, hoping to lure the predators.
The Bronx River, like many urban waterways, became a go-to dumping ground for industries along the banks, but as those industries declined and municipalities refrained from dump raw sewage, the marine habitat has recovered somewhat. The improvement took decades of effort, so the dolphin sign is hugely encouraging. Dolphins were seen in March 2021 in the East River. Whales regularly are spotted in the harbor. The New York Department of Environment has found that the urban waters around New York are the cleanest they have been since the Civil War. That is not surprising since raw sewage was dumped directly into the waters before sanitation practices came into being. The City has spent about $45 million over 40 years to improve water quality, not a huge amount, but enough to attract dolphins. [photo credit: Alamy