Corrected: Maryland's 2 million dead fish caused by cold water

(corrects to make clear 2,900 number of kills is for all species and not just large kills)

WASHINGTON (Reuters) - The death of two million fish that washed up on the shores of the Chesapeake Bay in Maryland appears to have been caused by a sudden drop in temperature, the state's Environment Department told Reuters on Thursday.

The mass kill is the latest in a string of bird and fish deaths around the world. Around 5,000 birds fell out of the Arkansas sky over the New Year's weekend and many dead fish were also found in a different part of the state.

Since then, reports of smaller-scale die-offs have been reported in Europe, Brazil, and Asia, causing many to speculate about the cause of the kills.

There is a perfectly reasonable explanation for the Chesapeake deaths, the Maryland Department of Environment said.

"The cause of this appears to be the rapid temperature drop combined with the large population of the juvenile spot fish," spokesman Jay Apperson told Reuters on Thursday.

The coldest December in 25 years caused cold water stress to the already overpopulated species, the department said in a statement.

There have been many such incidents in the past with 2,900 kills afflicting all fish species between 1984 and 2009 according to the department. The largest ever die-off was around 15 million in January, 1976.

The Chesapeake Bay is the largest estuary in North America.

(Reporting by Wendell Marsh, Editing by Greg McCune)

(wendell.marsh@thomsonreuters.com)