In the spring, a combination of disease and low oxygen stress causes many Louisiana ponds to experience partial fish die-offs.
“Overcrowding, over-feeding or over-fertilizing almost always compound these problems,” LSU AgCenter aquaculture specialist Greg Lutz says.
During the winter, low temperatures force fish into a state of slow motion. They eat very little, and their immune systems respond very slowly.
“When temperatures begin to rise in the spring, disease-causing organisms, already naturally present in a pond, can get the upper hand on fish that are in a weakened state,” he says.
Stress caused by abrupt temperature fluctuations (which many parts of the state experienced in the past several months) often aggravates fish health problems by further suppressing immune responses.
Fish also rely on algae to produce the majority of oxygen they need to survive in a pond. As single-celled plants suspended in the water, algae blooms absorb nutrients in the water and, during daylight hours, convert those compounds to oxygen.
As pond water warms during the springtime and the amount of sunlight increases, winter algal die back and are replaced by species better suited to summer conditions.
“When the winter bloom dies off abruptly, insufficient oxygen levels may persist for several days,” Lutz says. “This may kill some fish directly or cause sufficient stress to weaken their immune systems.”
Other springtime problems caused by algal blooms, especially in deeper ponds, involve turnovers. When cool rainwater or heavy wind “turns over” the pond’s surface and breaks down layering patterns, the resulting drop in oxygen levels can cause the fish to suffocate.
Mechanical aeration is required to raise oxygen levels once depletion has begun. Pumps can be used to pull water from a depth of 2 to 3 feet and spray it back into the pond.
“Water should not be drawn from greater depths because this will only intensify the turnover effect,” Lutz says. “Emergency aeration will be most effective in smaller ponds. But the success of any aeration practice will depend on the severity of the oxygen depletion.”
There is no guaranteed approach that eliminates springtime fish losses to disease or oxygen problems, but avoiding excessive fish densities and high levels of fertility throughout the year will help minimize the chances of a fish kill in the spring.
For tips on all aspects of pond management, visit LSUAgCenter.com and search for fish ponds.
If you prefer to spend your time with furry as opposed to finned friends, RescueMe has many adorable adoptable animals including:
Creature Feature
Cuba is a female terrier/Australian Shepherd/Min pin/eclectic mix. Her mom weighs about 25 pounds and her dad weighs 35, so she is expected to be a medium-sized dog. She gets along well with other dogs. Since she is young, she will probably adapt to children and cats easily.
Autumn is an adorable 2-month-old female tabby. Autumn and her siblings were born in a bush outside an elderly man’s home. Luckily, they were saved before any harm became them. They are now ready for a home to call their own forever.
Prince Duke (“Duke”) is a 2-year-old male shih tzu/poodle mix. When Duke’s owners could no longer keep him and his mother, Madde, they surrendered the dogs to a shelter. Ideally, the pair would like to be adopted together. Duke does well with kids, cats and other dogs.
Mercedes is a 3-year-old Russian blue mix. She was found in a warehouse trying to take care of herself and 5 babies. The kittens have all found homes. Now it’s mama’s turn. Mercedes is a little shy but very loving.
Stretch is a 3-year-old male Dachshund mix. He does well with other dogs and cats. He would probably do well with kids, too. Stretch came into rescued when his previous owner moved and left him behind. Stretch now wants a home where he won’t ever be left again. He loves to play with balls and is just missing someone to throw them for him.
Hugo is a 7-month-old male orange tabby. He gets along well with other cats and dogs. He was rescue from an uncertain fate in a feral colony. His days of wondering where his next meal is coming from are over. Now, all he wants is a home.
All these pets have been spayed/neutered, vaccinated and litterbox trained. Many other adoptable dogs, puppies, cats and kittens are available from Rescue Me Animal Welfare Society.
