Warm Water Discharges Are Confusing Manatees

Warm water discharges from power plants and factories, which can change the temperature of waterways, appear to be confusing manatees, an endangered migratory mammal that requires certain temperatures to survive.

For municipal wastewater plants and industrial wastewater facilities, discharge temperatures are a key consideration. Some regions place limits on the allowable temperature increase caused by wastewater discharges. Washington state, for instance, provides a guide for municipal wastewater plants on how to reduce thermal impacts to surface water. EPA offers guidance on this issue, as well.

Discharge temperatures can have a major impact on wildlife, including manatees in South Carolina who found themselves in grave danger last month as a result of temperature changes.

WCBD reported last month: “As water temperatures in the lowcountry [of South Carolina] decrease, manatees typically migrate to warmer places, but officials say they began hearing reports [in November] about a few that didn’t get the memo. As many as 5 manatees were seen hanging out in the Cooper River outside of the Kapstone plant in North Charleston, SC.”

It appears that “warm water discharge from the KapStone Paper and Packaging mill in North Charleston” signaled to the manatees that they did not have to migrate, ultimately putting their lives in danger, according to The Post and Courier.

On the Cooper River, the manatees were met with an elaborate rescue effort last month, according to WCBD, which noted that the so-called “sea cows” weigh in at around 1,300 pounds. Officials attempted to move some of them to Florida in hopes that they would survive.

Water temperature changes in Florida are also affecting the manatees’ migratory patterns. Environmentalists are pressuring industry to play a role in supporting these animals.

“In Florida, wildlife agencies have negotiated agreements to protect the species while they mass at power plants. Those agreements include the utilities agreeing not to shut down the discharge while manatees are massing,” The Post and Courier reported.

Manatees who fail to migrate face serious risks.

“Manatees that don’t move out of the area in time are particularly vulnerable to cold stress syndrome, becoming torpid, incapable of swimming, unable to digest food and develop lesions on their skin. Manatees in this condition will die if they aren’t rescued and given proper treatment,” Public Radio East reported.