The sudden summer weather over the weekend is likely to blame for the death of millions of fish in the Shark River recently.

Fish kill in Belmar
Fish kill in Belmar (S.A.N.D.)

"The hot weather cooked the nutrients" in the water according to Larry Ragonese of the New Jersey Department of Environmental Protection, forming an algae that "loves oxygen." He explains that menhaden, a kind of bait fish, "are very susceptible to depletion of oxygen" which leads to a natural fish kill.

In a tweet, Belmar Mayor Matt Doherty called the fish kill "very concerning" and later added that the DEP was cleaning up the water. Doherty told CBS New York the fish were washing onto the docks and beaches.

Ilya Hemlin contributed to this report.