By Carol Tannenhauser
In the last week, large numbers of dead fish have been seen floating in the Hudson River alongside the Upper West Side.
On Wednesday, Amanda A. wrote, “While walking through Riverside Park, I noticed over 100 dead fish floating in the water.”
“This morning on my walk I experienced the horror of hundreds of dead fish floating in the Hudson,” Lynne Thurmond wrote on Thursday. “Some looked like they had exploded.”
No, we are not being visited by another natural disaster. According to the New York State Department of Environmental Conservation (DEC), the fish apparently died as a result of “a natural phenomenon,“ related to the warming of the water in the summer. A spokesperson explained:
“DEC received reports of several dozen dead Atlantic menhaden, also known as bunker, between 79th St. and the George Washington Bridge. The exact cause has not yet been determined but during the summer months as water temperatures warm, water is less able to hold dissolved oxygen than cool water. Fish such as bunker that swim in large schools are particularly vulnerable to low dissolved oxygen content. Low dissolved oxygen, or hypoxia, can often be fatal to these large schools while other fishes and marine organisms are stressed but will ultimately survive. Hypoxia can be triggered by large numbers of fish in confined bodies of water, excessive algal growth, and warm water temperatures. This is a natural phenomenon, and fish kills of this type can be expected during the warm months of the year and generally have little impact on region-wide fish population numbers.”