The duck pond at Anderson Park currently contains high levels of algae, which is not uncommon for this time of year. Unfortunately, the pond has developed a bacteria which poses some threat to water birds and pets who come into contact with the affected water.
Why algae forms
Algae grows when conditions are right, especially during warmer months, building up on the water’s surface or along the edges. It’s likely to form when:
- Water is warm
- Water is slow-moving or stagnant, like in drains, lakes or ponds during low flows
- Extra nutrients like nitrogen and phosphorus enter the water from runoff after rain, organic matter (such as animal waste or vegetation/grass clippings) or disturbed sediments
- People feed bread to the ducks in the pond, as it can rot in the water and promote bacteria growth.
How algae can cause avian botulism
When algae and other organic material die and decompose, it can reduce oxygen levels in waterways and sediment. This creates the ideal environment for botulism-producing bacteria to grow.
These bacteria produce a powerful toxin that causes avian botulism, a serious disease that makes birds weak or paralysed and often die. They can also carry the toxin to other waterways, affecting other areas where water birds live.
Birds can be affected when they:
- Feed in contaminated water
- Eat insects or plant material that have absorbed the toxin
Pets, especially dogs, are also at risk of getting sick if they enter or drink from contaminated water.
What is Council doing?
We are working with partners Hawke’s Bay Regional Council, the Department of Conservation, SPCA, Fish and Game and HB Bird and Wildlife Rescue to manage the algae bloom at Anderson Park pond and increased threat of avian botulism spreading. This includes:
- Keeping a close eye on bird health
- Monitoring environmental impacts
- Improving water conditions by removing algae through the use of chemical treatments and a weed boat
- Notifying community on the risks and affects of the algae bloom.
