The city of South Portland is warning residents about an algae bloom in ponds at Hinckley Park that could prove deadly to dogs.

Finnegan leads the way while hiking the trails at Hinckley Park in South Portland in May 2021. ShawnPatrick Ouellette/Staff Photographer

The city’s Parks, Recreation and Waterfront staff said in a release Monday that it has identified cyanobacteria in the ponds. The bacteria is toxic and potentially fatal to dogs if ingested, and can caused stomach illness and rashes in humans.

The city is urging people to stay out of the water and to keep their pets from drinking or swimming in the ponds at Hinckley Park.

Anyone who comes into contact with the water is advised to wash their hands. If dogs come into contact with the water, owners may want to consult a veterinarian.

Once temperatures cool down, the algae will die, but the city doesn’t expect the ponds to be safe again until sometime this fall. Warning notices have been installed at park entrances and spots along the ponds.

This is not the first time that cyanobacteria has been identified in the two ponds. In July 2020, the city detected another outbreak at Hinckley Pond and Old Ice Pond of the blue-green algae.

The city said it is working on measures to hinder the growth of cyanobacteria, including the placement of native plants to stabilize soils that have been eroding along the lower pond’s eastern shoreline. The community can help by picking up pet waste, staying on designated walking trails and avoiding areas with bare and eroding soils.

Located off Highland Avenue, Hinckley Park is managed by the South Portland Land Trust. The park consists of 40 acres, two scenic ponds and fresh water fishing. A walking trail goes around both ponds.