Every ton of consumed fish generates about 30–70% fish waste (FW). FW contains nutrients which can be recycled as inputs in organic farming systems. FWs for production of dry and liquid fertilizers, fish-compost, and digestates. Establish FW-based fertilizer products in Europe, similar to OMRI listings. Regulations and possibilities to produce FW-based fertilizers in Norway.

Fish processing waste/wastewater/sludge has high protein and lipid contents. The choice of technology depends on the raw material and desired end-product. Salinity and microplastics are potential critical parameters. Fish sludge has a great potential but should be treated/refined before application. Fishery waste-based fertilisers perform equally to commercial synthetic fertilisers.

The commercial fertilizers, particularly fish based, are being utilized in crops of agriculture and horticulture and a number of fertilizers can be produced by fish waste. Fish waste composting is a fantastic approach to reduce waste volume, and compost supplemented with fish waste could be a useful organic fertilizer.