You have full access to this article via your institution.Small-scale fishers, including this one fishing along the Oubangui River in Central African Republic, support hundreds of millions of people around the world.Credit: Florent Vergnes/AFP/GettyHow many of the world’s eight billion people fish to feed their families? How much does small-scale fishing contribute to economies? And what are the nutritional and environmental benefits from dropping a line in a drainage ditch, casting a net from the shore or diving into a lake?Small-scale fisheriesThese are important questions because their answers affect the welfare of the nearly half a billion people whose livelihoods depend, at least partially, on small-scale fisheries. They are also hard questions because data on this huge, relatively invisible group are scattered and patchy. That is now changing, thanks to a research project called Illuminating Hidden Harvests, which has been running since 2017, collecting data on small-scale fisheries from 58 countries. This week, Nature is launching a website dedicated to synthesizing and disseminating the studies emerging from the initiative. This digital resource includes research already published, and we plan to add future findings to it.Small-scale fisheries are practices in which, typically, the fishers are individuals, families or small groups of people without access to much capital who catch fish for their own food, or to sell. Their health is key to several of the United Nations Sustainable Development Goals (SDGs). And yet, relevant data are often missing, especially from economic statistics and from the models used to make policy decisions. Unless that changes, the marginalization of already-vulnerable people will only worsen, according to the project’s researchers.How I’m bringing the voices of local fishers into ocean policiesIlluminating Hidden Harvests is the work of an 800-strong team, including environmental, economic, social, nutritional and governance specialists. The overall project is led jointly by the UN Food and Agriculture Organization in Rome; the research institute WorldFish in Batu Maung, Malaysia; Duke University in Durham, North Carolina; and Stanford University in California. The researchers estimate that catches from small-scale fisheries represent some 44% of the economic value of all fish at the time of capture globally. Among those involved in the fisheries, some 53 million people go out to fish, mostly to put food on the table for their families, feeding hundreds of millions of people (X. Basurto et al. Nature 637, 875–884; 2025).The monetary value of small-scale catches is difficult to calculate. The Illuminating Hidden Harvests team estimates that the catch value from small-scale fisheries alone contributes US$77 billion annually to the world economy. That’s 50% more than previously thought, although that’s probably still an undercount. It’s not known how much these outputs are factored into relevant economic-policy choices. That is, in part, because economic models draw on the research literature, the most accessible of which is dominated by studies on bigger, more industrialized activities. A similar bias is prevalent in agricultural sciences. What we know is that at least 60 million people do paid work in small-scale fisheries, but there are many others, often women, who contribute unpaid labour to the process, such as mending nets. This also doesn’t include some 53 million subsistence fishers.How researchers are shining a light on the ‘invisible’ contributions of small-scale fishersThe overall effect of this undercounting is detrimental to small-scale fishers and their families. Say, for example, that a government is planning to expand coastal tourism, or considering licensing a big fishing fleet. Policymakers will use models to estimate how much these activities contribute to economies. But any risks or possible damage to the catches, livelihoods or well-being of small-scale fishers and their families tend to not be factored into the models, leaving the fishers and their families yet more vulnerable.Even before Illuminating Hidden Harvests, qualitative and quantitative social-science research has been carried out. Painstaking case studies have examined how these communities operate, including the gender split of the workload; how much of fishers’ overall activity is fishing; how rights to fisheries are determined; cultural practices; catch processing; and how fish are taken to market. But you won’t find this information in the models. This is something that the authors of the project rightly want to change. Now that they are starting to reveal numbers, policymakers must invest the extra effort to support this crucial sector.The work of Illuminating Hidden Harvests is not yet done. Illuminating the true size and impact of small-scale fishing cannot be a one-off activity. The world needs periodic data and follow-up studies, which, in turn, need funding and other kinds of support. Many small-scale fishers report that overfishing by large-scale outfits is depleting their catches, but there hasn’t been enough research or published data to capture what they are seeing. This, in turn, has impeded any meaningful action.Why we should protect the high seas from all extraction, foreverThe researchers have also discovered many untapped repositories of country-level data that could give insights into fisheries. At the same time, lots of countries have yet to disaggregate their general fisheries data into industrial and small-scale, or by the gender of the fishers. If this were done, the benefits could be big. For example, gender- and region-specific small-scale fisheries data could be matched to remote-sensing data on temperature and rainfall to understand how climate change is affecting the different genders.Another much-needed step is for research institutes in countries that depend on small-scale fisheries to educate and equip their fishery students to study this neglected endeavour. Currently, many such courses focus exclusively on large-scale fisheries.The UN will hold an international conference this month in Nice, France. The meeting aims to catalyse urgent action to conserve and sustainably use the ocean, seas and marine resources, specifically supporting the implementation of SDG14, which is called ‘life below water’. The work of the Illuminating Hidden Harvests’ team should help to propel small-scale fishing into the international policy arena. There’s now no excuse for governments or their economic advisers to not consider this industry in their decision-making.