1/5: Don't dismiss the 'ducks in the pond statement' of Biplab Deb before reading this: While swimming ducks can increase surface aeration, there is no comparison of a mechanical aerator that mixes oxygen in the deeper layers of the water.
2/5: A study showed statistically significant differences in fish growth (& pH, dissolved oxygen (DO), etc) in a natural pond with ducks vs. a natural pond without ducks. Link here. So ducks were great for these ponds. lrrd.org/lrrd22/9/sasm2…
3/5: However, the size & health of the pond was not considered. There are many factors that can influence pond health & natural ponds are not replicas. The depth of ponds, growth of plants, duck/turtle/fish excreta, algae & sea weed are all responsible for depleting oxygen.
4/5: With considerable variables, e.g, deeper ponds, introducing ducks/ geese or even feeding fish will add more waste to the pond > increase fertiliser in the pond > increase in algal & plant growth depletion of oxygen in the pond.
5/5: In summers, this growth increases > produces a larger divide in distribution of oxygen between surface: deeper waters > leads to stratification (sun heating surface water while deeper water to remain cool) > can potentially lead to a "turnover" that rapidly kills fishes.
A reference: clemson.edu/cafls/about/in…
I don't think people are reading the entire thread before coming to conclusions. There is merit in the keeping ducks, according to research, in some natural ponds. But it won't work for every pond. To the contrary, in summer, having ducks can decrease aeration in deeper ponds.
