UPDATE: Channel 3 has learned that there's no expected cleanup planned for the massive fish kill discovered Thursday along a creek off Memphis Drive.

Chattanooga Public Works' Justin Holland says that since the kill is considered to be "natural," they will let nature takes its course and allow predators take care of the cleanup.

 PREVIOUS STORY: A Tennessee Wildlife Resources Agency biologist says a local fish kill may be due to natural causes.

Thousands of fish were found lying along a creek off Memphis Drive near DuPont Parkway, which spills into the Tennessee River.

Mime Barnes of the TWRA tells Channel 3 that sometimes this can be natural or due to other issues. The fish are part of the shad family, and range in size from 2 to 4 inches in length.

A TWRA biologist has been at the site since early Thursday morning, and is working to determine the cause. 

Justin Holland of Chattanooga Public Works says that crews from the Tennessee Department of Transportation discovered the dead fish Wednesday and contacted the Tennessee Department of Environment, which in turn contacted Waterwater Treatment staff.

Holland released the following statement:

"The Tennessee Wildlife Resources Agency (TWRA) is presently investigating the cause of the large numbers of dead fish seen in a wet weather conveyance that runs into the Tennessee River. At this point, officials believe that the cause is related to weather occurrences earlier this week, including recent increases in the water temperature and rainfall levels that are higher than normal.

Threadfin shad is a breed that is very sensitive to fluctuations in temperature, and recent warming trends may have depleted their oxygen levels beyond the point where they could survive. There are large numbers of dead threadfin shad throughout the region and we consider this to be a natural event outside of our control.

The City of Chattanooga will continue to remain in touch with our partners at TWRA and the Tennessee Department of Environment & Conservation (TDEC) about this occurrence. We will provide additional information about what happened if it becomes available."

Water samples were taken to determine if sewage played a role.

Stay with WRCBtv.com for updates to this story.