The waste load from aquaculture operations can be traced back to fish feed1. It was found that the waste load sourced from fish feed was 10 to 20% and was found in the form of feces and organic wastes. Furthermore, this waste load was excreted into the culture system as nitrogen (N) and (P) phosphorus 1. The N and P load entering a water body depends on the diet composition, pelleted and extruded feed, feed quality, overstocking and stocking of premature fish, fish species, chewing feeding behavior, feed conversion ratio and water quality, which includes variables such as nitrite and dissolved oxygen2.
Commercial feed types, such as floating and drowned feed, have been used for C. carpio (common carp) aquaculture operations in Lake Maninjau, Indonesia recently. Intensive aquaculture operations can increase the loading of N and P into water bodies3. As a result, a rigorous assessment of the potential impacts of cage wastes on the receiving ecosystem is required for cage aquaculture to be accepted socially, environmentally and economically.
This motivated the researchers to perform a new study with to quantify the N and P loads released from the two types of feed (i.e. floating and drowned) used in the cultured C. carpio floating net cages in Lake Maninjau, Indonesia4.
The current research found clear evidence supporting that different feed types used for C. carpio (common carp) in floating net cages can release different amounts of total N and P into Lake Maninjau. Cyprinus carpio fed with drowned feed showing a better of growth rate and Feed Conversion Efficiency (FCE) compared than floating feed. The estimated N and P loads from the production of 1 ton of fish were significantly lower in drowned feed rather than floating feed.
Additionally, the estimated load of N and P from 1 ton of feed consumption was significantly lower in drowned feed compared to floating feed. The loading of N and P can be reduced by adjusting the amount of drowned feed used, managing the feeding regimes and timing of fish aquaculture. These techniques will help reduce the negative effects on the lake and have a positive effect to water quality.
Aquaculture, floating net-cages, feed types, mass balance, environmental factors, techniques, floating feed, drowned feed, feeding regimes, Conversion Efficiency.
- Kawasaki, N., M.R.M. Kushairi, N. Nagao, F. Yusoff, A. Imai and A. Kohzu, 2016. Release of nitrogen and phosphorus from aquaculture farms to Selangor River, Malaysia. J. Environ. Sci. Dev., 7: 113-116.
- Sun, M., S.G. Hassan and D. Li, 2016. Models for estimating feed intake in aquaculture: A review. Electron. Agric., 127: 425-438.
- Syandri, H., Azrita, Junaidi and A. Mardiah, 2017. Levels of available nitrogen-phosphorus before and after fish mass mortality in Maninjau Lake of Indonesia. Fish. Aquat. Sci., 12: 191-196.
- Syandri, H., Azrita and Mardiah, A., 2018. Effect of Feed Types and Estimation of Nitrogen-Phosphorus Loading Caused by Common Carp (Cyprinus carpio) in Lake Maninjau, Indonesia. J. Nutr., 17: 454-461.