Approximately 1,000 dead fish have been found floating in a pond at the National Mall, the National Park Service has confirmed.

Park Service employees spent Thursday scooping up the dead bluegills out of the Constitution Gardens pond into trash bags.

However, the number is not unusual for that pond, officials said, due to the construction and design of the area.

"This time of year with temperature changes in the water, it's not unusual," John Emminizer with the D.C. Department of the Environment said. "Algae blooms, the oxygen level changes in the water... It's a little unusual in a pond, but there's nothing to be concerned about."

Park Service officials have said they have long stressed the importance of redesigning the pond to maintain a better ecological balance.

The pond is at the top of the list for construction upgrades. It could take several days to determine the cause of the incident, however one of the pond's two air bubblers was off Thursday -- however, it's not clear whether that played a role.

Constitution Gardens is located in West Potomac Park, near Constitution Avenue and 17th Street NW. In addition to the pond, it also includes a memorial to the 56 signers of the Declaration of Independence, and several walkways and benches.

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