Plain Language Summary: Micronutrients in fishes differ between nature and nets on global reefs.

By Conor Waldock and Eva Maire.

Read the full paper here.

Shallow-water reefs are exceptionally diverse ecosystems. This biodiversity provides an affordable food source in the form of fish that benefits the health of millions of people living in their vicinity. Fish not only provide calories and protein but are also rich in micronutrients such as vitamins and minerals, often surpassing other locally available food sources. Yet, considering all the fishes in an ecosystem, are the most nutritious fishes caught?

Our study explored the micronutrients in more than 1000 reef fishes across 87 countries and we uncovered a disconnection between micronutrients in ecosystems and those reported as caught in small-scale fisheries. Fish species with the most micronutrients in ecosystems are seldom caught selectively. Furthermore, our research highlights that different ecosystems have varying compositions of natural and captured nutrients. So, even if small-scale fisheries excel in capturing one micronutrient, they can often miss out on another. These results indicate the challenges in implementing small-scale fisheries policies that attempt to increase micronutrient consumption from shifting to new species. However, some small-scale fisheries were already selective towards the mass of micronutrients stored in species with highly abundant local populations. This indicates policies which improved access and distribution of caught fish in food supply systems could leverage this existing resource to benefit people’s health.

The United Nations’ Food and Agricultural Organisation is promoting small-scale fisheries – and the health benefits of local fish consumption – as an accelerator of sustainable development. This is crucial because one in three people are still without adequate access to nutritious food, heightening the risk of poor health. Acknowledging the knowledge deficits revealed in our work could help nutritional-focused policies better reconcile social, economic, and biodiversity goals for a sustainable healthy planet and people.