Cape May, N.J. -- The thousands of dead menhaden that have washed up along Delaware Bay in South Jersey may have been victims of this summer's heat, biologists say.
Robert Van Fossen, in charge of emergency management for the New Jersey Department of Environmental Protection, said tests showed dissolved oxygen levels were low after the fish kill, The Press of Atlantic City reported. He said oxygen levels drop as water gets warmer.
The dead fish were found Wednesday along an 8-mile stretch of bay shore in Cape May County.
The fish probably died at night, Van Fossen said. During the hours of darkness, plants in the water are not carrying on photosynthesis and releasing oxygen, causing levels to fall.