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Fish In, Fish Out: Perception of Sustainability and Contribution to Public Health

02 March 2015

This article, by Oleksandr A. Byelashov & Mark E. Griffin (Omega Protein Inc.), contributes to the ongoing debate regarding the sustainability of fishmeal and fish oil in aquaculture diets. It demonstrates why the “Fish In, Fish Out” metric, which is frequently used to show how many units of wild fish is needed to produce one unit of farmed fish, is not a valid tool for measuring the sustainability or efficiency of aquaculture production.

Additionally, the metric diverts attention away from the human health implications of how we raise fish.

It substitutes the mass of seafood for the arguably more important value-added dimension – the long chain omega-3 content per unit mass, which is low in fish raised on diets low in marine ingredients.

Fishmeal and fish oil produced by sustainable fisheries remain some of the most ecologically efficient ingredients that contribute to the overall gain of seafood biomass. Because many aspects of our health and wellbeing depend on wild fisheries, we must insist on well-managed fish harvest for the health of the world's population.


Cardiovascular diseases continue to be the most prevalent cause of death in the United States (Lichtenstein et al. 2006). Concurrently, farm-raised seafood is becoming less heart-healthy (Seierstad et al. 2005).

Why? At least partially because demand for seafood and aquaculture production continues to increase, and the supply of omega-3-rich, marine aquafeed ingredients remains flat. As a result, these ingredients are being displaced by land-based ingredients (Torrissen et al. 2011).

Not surprisingly, the long-term availability of marine resources became one of the most important and complex issues affecting environmental well-being and public health. But unfortunately, the “Fish In, Fish Out” concept, which intended to help make fish production more sustainable and is used as a guide for the environmentally conscious consumer (Tacon and Metian 2008), is fundamentally flawed.

Those who popularise it may mislead the consumer.

March 2015

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