Don’t throw away that fish waste!

Composted fish waste can be an added resource for your garden.

Mixing fish waste into wood chips to produce a compost pile. Photo credit: Michigan Sea Grant

Mixing fish waste into wood chips to produce a compost pile. Photo credit: Michigan Sea Grant

The disposal or reuse of fish processing waste has long been a challenge for Michigan’s fish processing industry. Approximately 5 million pounds of waste from commercially processed lake whitefish, lake trout, and salmon are generated, annually. Several years ago and in an effort to help the Michigan fish processing industry find better solutions to handle fish processing waste materials, Michigan State University Extension, Michigan Sea Grant and Northern Initiatives conducted a project that determined the viability of composting fish waste. The objectives of the project were to develop a compost marketing strategy, produce compost that met identified market specifications, and document the levels of mercury and halogenated hydrocarbons along the composting process to allay concerns in using composted fish waste. Recreational fishers must also decide on how to dispose of their fish waste and fish waste composting should be an alternative to explore instead of disposing it into a landfill.

In this project, Michigan State University Extension, Michigan Sea Grant, and Northern Initiatives worked with the Great Lakes commercial fishing industry to secure fish waste for composting. Trial composting sites for this project were established in both the Upper and Lower Peninsula of Michigan. The composting techniques that were used in this project were developed by Wisconsin Sea Grant scientists, who explored the feasibility and reliability of composting fish waste with other readily available organic materials, such as wood chips and bark. The process developed by Wisconsin Sea Grant was designed to accommodate varying amounts of fish waste, from less than a bucket to a large truckload a day, making it equally suitable for backyard garden composting, as well as large scale commercial fishing operations. When properly followed, these techniques should result in no or very minimal odor.

Findings from this project showed that fish waste compost could be a component of a growing mix that meets a more demanding specification and for which the consumer is accustomed to paying a higher price. Based on the trials in this study, growing mixes containing 20-25% compost in a professional peat based growing media are optimum. There is nothing in compost made from fish waste that would prohibit it from being used in an organic cropping system.

More details of these fish waste composting projects can be found in the publications that can help you to start your own fish waste composting. To obtain an electronic copy of the Michigan Sea Grant/MSU publication “Composting Commercial Fish Processing Waste from Fish Caught in the Michigan Waters of the Great Lakes” connect to the web link: The Wisconsin Sea Grant publication “The Compost Solution to Dockside Fish Waste” can be found at

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