Dead fish are popping up all along the Hudson River

Dead fish are turning up in large numbers all along the Hudson River from Manhattan to Yonkers, according to environmental organization Riverkeeper.

The group said finned fatalities are being reported from New York Harbor all the way north to Haverstraw Bay — and suffocation caused by climate change is the likely cause of death.

The unrelenting hot summer temperatures can overheat water, which decreases available oxygen for aquatic life to the point that fish can suffocate, Riverkeeper explained.

“The widespread deaths of Atlantic menhaden, and possibly other species, are most likely the result of prolonged heat and lack of rain, combined with other factors, which reduce levels of dissolved oxygen that the fish need to survive,” the group said.

Riverkeeper added that the general fragility of local waterways is also contributing to the phenomenon.

“It’s yet another warning about our need to restore the river to health and balance in the face of climate change,” the organization said.

Meanwhile, the gradual loss of oyster beds and reefs in local waterways has led to an overgrowth of algae.

“The destruction and loss of these beds killed off these filter feeders,” Riverkeeper said. “So the river starts from a compromised position, with over-nutrification from sewage and fertilizer.

“Later this summer, when we get a series of rainstorms or cloudy days, we’ll see lower water temperatures and less algae growth, and we’re likely to see a reduction of fish mortality as oxygen returns to adequate levels.”

“But we should consider this yet another warning that we need to restore the baseline health of the Hudson and New York Harbor in the face of climate change and ever-increasing global water temperatures,” the group added.