In the last few months we have experienced several fish kills in the storm water ponds in our community. The Dunes has discussed this with our Ecological Consultant and found the following:
First and foremost we are not the only community in Florida experiencing these fish kills, they are happening all over the State. The Indian River Lagoon has been experiencing one of the worst fish kills in years. See the link for a more in depth explanation of the fish kills in general: http://plants.ifas.ufl.edu/manage/overview-of-florida-waters/fish-and-wildlife/fish-kills/
The Fish Kills in January were most likely due to one of the coldest January’s on record and the fish died due to the cold.
The Fish Kills in February are most likely the result of lowered dissolved oxygen in the ponds due to the decaying of microscopic algae. This is attributed to one of the warmest Februaries on record. The microscopic algae increased their growth rate with the warm weather until they ran out of food and started to die off. This dead algae absorbs oxygen as it decays lowering the dissolved oxygen in the pond to levels where the fish cannot live and they die.
The question has been raised as to why only the Ocean Hammock ponds have had fish kills. The likely answers to this are the Ocean Hammock ponds are in general much shallower than the Hammock Dunes ponds. Deeper ponds offer more cold weather protection for the fish and more stable overall pond temperatures to reduce stress on the fish. Additionally there was more salt water intrusion in the Ocean Hammock ponds from the recent hurricanes which raised the salinity levels in the ponds and stress the fish. Adding fountains to the ponds are possible and they may help the fish kills but they cannot be installed quickly. We will continue to monitor the Dissolved Oxygen, salinity and nitrates in the ponds.
A pelican death was reported to the Florida Fish and Wildlife Conservation Commission. They were unable to send an officer to investigate due to work load but they did ask the Flagler County Sheriff’s Department to investigate the death. The Flagler County Sheriff Deputy did confirm the statements above with regard to the cold weather fish kills and the decay of the algae causing the fish kills as well. The death of the pelican was most likely a natural cause.