5,000 dead fish wash up on Rhode Island beaches. Experts blame something unexpected

Thousands of dead fish found on beaches in Rhode Island were victims of a New England heat wave, according to the Rhode Island Department of Environmental Management.

It happened Friday and more than 5,000 fish were found scattered along Bullock’s Cove and Allen’s Cove, south of Providence, reported WJAR.

“While the cause of the fish kills is still being investigated ... D.E.M. believes the die-offs were linked to low levels of dissolved oxygen in Narragansett Bay caused by high water temperatures from the recent heat wave,” the department posted Tuesday on Facebook.

Water temperatures along the shore were measured at 85 degrees that day, officials said.

The fish killed happened during a week when temperatures hit 90 degrees or above on four days, according to AccuWeather. The lingering heat has been such that temperatures hit 100 degrees one day in late July, the site reports.

The U.S. Geological Survey says fish kills often occur in the summer, because warm water holds less dissolved oxygen.

“Other organisms use oxygen, too, including the algae that grow in the summer,” the USGS said in a report.

“During the day, the algae produce oxygen through photosynthesis, but at night, when photosynthesis stops, they and other organisms keep respiring, using up oxygen. So on warm summer nights during algal blooms, the dissolved-oxygen concentration sometimes drops too low for the fish,” the USGS reports.