Harnessing farm waste for fish feed

Signal of change / Harnessing farm waste for fish feed

By Helen Hughes / 08 Apr 2016

A three-year trial to convert waste from dairy farms into feed for fish has begun in New Zealand.  The project aims to use dairy shed effluent to farm algae and has been constructed as a complete system. The algae are cultured in purpose-built ponds and then transported to separate ponds to feed zooplankton: an excellent source of nutrition for fish. The zooplankton ponds are linked to the Aongatete River by a fish-friendly passage.

This project is funded by local and national government bodies and has been designed by the National Institute of Water and Atmospheric Research together with Raglan EELS.

So what?

Aquaculture’s demand for fishmeal is increasing rapidly, and is a major threat to our oceans. Not only does intense fishing make species populations unstable and threaten aquatic food chains, the use of fishmeal reduces the proportion of caught fish available to feed humans. This trial increases the nutrition available to wild fish, but could also be used on fish farms as a direct replacement for fishmeal.

The use of dairy shed effluent provides a consistent supply of nutrients that would previously have been disposed of. Capturing these wasted nutrients is a crucial step in securing food supply and also diverts waste away from drainage systems, improving water quality.

The innovation has potential to drive economic benefits for local farmers, including new opportunities for commercial fishing. Diversification has historically been a crucial option for farmers in hard times.

How replicable is the viability of this initiative in global farming systems of different shapes and species? Are there other innovative connections between different farming systems that could offer important feed solutions? Are knowledge-sharing or financial mechanisms more effective in encouraging development and uptake of agricultural innovations? What organisations are best placed to act?

Image credit: Bay of Plenty Regional Council


Bay of Plenty Regional Council (2016) ‘Dairy Effluent Conversion Project

Cornall, Jim (March 4, 2016) ‘Cow shed effluent converted to fish food’ 

What might the implications of this be? What related signals of change have you seen?

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