Fresh raw fish and/or food fish trimmings is cooked, pressed, dried and milled to produce highly nutritious fishmeal. Fish oil is normally a clear brown/yellow liquid pressed form the cooked fish and normally refined. Fish used for the production of fishmeal and oil may be divided into three categories:
- Small bony whole fish used for the production of fishmeal and fish oil
- By-products such as fish offcuts and offal from the human consumption industry
- By-catches from another fishery that cannot be used for human consumption
Raw material from whole capture fish caught for fishmeal production are mainly small bony, oily short-lived, fast-growing fish where there is little or no demand for human consumption. The by-products such as fish trimmings from the processing sector is increasingly used as a valueble source for the production of fishmeal and fish oil. Many of the criticisms of the management of stocks are unfounded as the source fisheries are amongst the best managed globally, and these are naturally renewable resources that support global protein production. This is a function of the fast growth, high productivity and high levels of recruitment often seen in these fish populations, where, often the biggest influence on stock variability is environmental conditions (rather than fishing pressure). Often there are no direct human consumption markets for these species, and they support production of protein for which there is a very real demand, as well as fish oil which is used directly to achieve benefits for human and animal health.The fishing for capture species are generally well monitored and regulated to ensure a sustainable fishery that will continue to flourish. Fish are caught using fishing nets with government specified mesh sizes. The area where they are caught and the time of catching will be determined by government controls to ensure quotas are upheld. Many vessels carry trackers which allow satellite tracking. This assists government authorities to check fishing is done within the agreed areas and times. Additionally, boats are often checked on landing. Their catch is monitored for type of fish caught, size, where they are caught and time of catching.
Maintaining optimal quality of the raw material is fundamental to ensure good quality fishmeal and fish oil that will provide optimum nutritional value and obtain premium prices. Usually refrigerated seawater is used to chill the fish and keep them fresh, avoiding damage.