Algal blooms, fish kills occurring across the state

Published 8:46 am Tuesday, August 4, 2015

RALEIGH – State officials urge people to avoid contact with potentially harmful algal blooms that have shown up in prominent water bodies statewide in recent weeks due to North Carolina’s hot weather.

State officials from the Division of Water Resources are working with state public health officials to investigate algal blooms in the western part of the state and in and around the Albemarle Sound and the Chowan River in the state’s coastal plain.

Algal samples collected from the eastern portion of Waterville Lake in western North Carolina have been identified by DWR biologists as Microcystis aeruginosa, a colonial bluegreen alga. This alga is visible as green specks distributed throughout the water column but most noticeable when it collects on the surface forming thick films and swirls.

Blooms of these algae may be potentially harmful if the Microcystis is producing microcystin, a cyanotoxin that in sufficient concentrations can damage the liver. The presence of Microcystis does not mean the toxins are being produced; the triggers for the algae to produce the toxin are not well understood. As a precaution, samples of the algae are being analyzed at the state public health lab to determine if the cyanotoxin is present.

In the eastern part of the state, division staff has received numerous complaints of algal blooms described as being like “smelly, green pea soup” through the Albemarle Sound and Chowan River areas near Queen Anne’s Creek. The algae have been identified as Anabaena planctonica, a filamentous bluegreen alga.

Although whether this alga can produce the same form of toxin as the Microcystis is unclear, as a precaution, samples of the algae are being analyzed for microcystin at the state public health lab.

While it is safe to boat or fish in the affected areas, health officials routinely encourage the public to avoid contact with large accumulations of the algae and to take precautions to prevent children and pets from swimming or ingesting water in an algal bloom. North Carolina has had no reports of adverse health effects in humans associated with freshwater algal blooms.

A diverse population of algae is usually beneficial and provides a rich food source for aquatic animals. However, when hot temperatures and calm water combine with nutrient-rich waters, large algal blooms may form that can produce toxins that pose a human health hazard. The algal blooms also may reduce the oxygen available to fish and other aquatic animals, which can result in fish kills.

Fish kills have been reported in the lower Chowan River, and near the Blounts Bay and Pamlico River areas where lower dissolved oxygen levels have been recorded.

State health and water quality officials recommend the following steps to safeguard pets and children from any potentially harmful algal bloom:

Keep children and pets away from water that appears very green, discolored or scummy.

Do not handle or touch large mats of algae.

Avoid handling, cooking or eating dead fish that may be present.

If you come into contact with an algal bloom, wash thoroughly. Also, use clean water to rinse off pets that may have come into contact with an algal bloom.

If your child appears ill after being in waters containing an algal bloom, seek medical care immediately.

If your pet appears to stumble, stagger or collapse after being in a pond, lake or river, seek veterinary care immediately.

For more information on the potential health effects from algal blooms, visit the N.C. Division of Public Health’s website at: To learn more about algae, visit the N.C. Division of Water Resources’ website at: