Fish farm sediment issues can be a major headache for people engaged in aquaculture. The accumulation of silt and sediment, a process referred to as siltation or siltification, over time can reduce the volume of a fish pond to the point where fish farming is no longer viable. There are also other negative potential impacts depending on what’s in the sediment that accumulates. If the silt is high in toxic elements such as hydrogen sulfides and nitrites, the release of those toxins into the water can significantly reduce fish yields. If there are high levels of organic matter in the sediment, the increased demand for oxygen from that material can deplete oxygen levels in the water, thereby reducing fish yields even further. One way to control and maintain not only fish pond volume but also water quality most conducive to fish farming is to remove excess sediment from fish ponds. Silt and sediment removal using dredging equipment such as the Weedoo SiltSucker is becoming an increasingly attractive option, especially as fish farmers become more aware of how it works and doesn’t create the additional negative impacts many have assumed would result.
Potential Negative Impacts of Fish Farm Sediment Removal
One of the first concerns people start raising when presented with the possibility of fish farm sediment removal is the potential negative impact on the aquatic environment. The assumption is that sediment at the bottom of a pond is an essential feature of the aquatic ecosystem. While this is true, it should be noted that what’s at issue here is the challenge of too much sediment. In other words, the remediation involved isn’t the removal of all sediment, just excess sediment. It should also be noted that one recent study has shown that while the initial impact of sediment removal from a fish pond does include a significant reduction of invertebrate organisms such as various insects, bugs, leeches, snails and so on, these populations gradually rebounded each year until reaching their pre-sediment-removal levels in just five years (source).
The Benefits of Fish Farm Sediment Removal
If a fish pond’s viability is threatened because siltation is reducing the pond’s volume to an unworkable level, the clearly there is a benefit to removing excess sediment to restore the water body to a more optimal volume. But it’s also important to recognize that depending on what’s in the sediment, additional benefits from silt removal may be realized that boost fish yields. In addition to improving overall water quality, fish farm sediment removal has been shown to reduce the amount of phosphorus released and a decline in chlorophyll-a and blooms of cyanobacteria.
Fish farm sediment removal is an immediate technique to gain the benefits it grants, but fish farmers would do well to consider coming up with longer-term solutions to sediment issues. This involves figuring out where the sediment is coming from in the first place and proactively stopping it at its source. If the source of excess sediment is coming from accelerated soil erosion in the surrounding landscapes, those issues need to be addressed and resolved. If the source of excess sediment cannot be corrected, then regular fish farm sediment removal will need to take place.
Then there is the issue of what to do with the sediment once it has been removed. The good news is that fish farm sediment can be a rich source of nutrients applied to agricultural operations. Savvy fish farmers can establish relationships with surrounding land farmers and recycle the nutrients by delivering them to farms for agricultural applications. This has become a relatively common practice at fish farms in Bangladesh, China, India, Indonesia, Malaysia, Thailand and Vietnam (source).
Tackling Fish Farm Sediment Removal with the Weedoo SiltSucker
The Weedoo SiltSucker is a quick-change snorkel attachment for our compact workboats and includes a three-inch gas-powered diaphragm pump ideally suited for silt and sediment removal. The snorkel is easily maneuvered to precisely target sediment build-up areas. The discharge hose can pump slurry up to 250 feet with a flow of up to 5200 gallons per hour. Ready to tackle your fish farm sediment removal project? Contact Weedoo today!