Biendi Maganga-Moussavou had a problem.

As Gabon’s minister of fisheries, agriculture and food security, he helps oversee the African country’s marine protected areas, some of the most extensive in Africa. Covering 27% of Gabon’s Exclusive Economic Zone, these waters are supervised using monitoring technology that tracks larger vessels, which are required to report their catch. But many of Gabon’s fishers run smaller operations that don’t have such systems, or even automated identification.

"Thousands of boats were going out and we didn’t know where they were going or for how long,” Magana-Moussavou said in an interview. And since whatever they caught and where they caught it wasn’t registered, scientists couldn’t tell whether fishing restrictions were being respected or whether fish stocks in protected areas were increasing or declining. Gabon’s problem is the world’s problem. More than 30 million fishers worldwide — around 90% of the total, according to the United Nations Food and Agriculture Organization (FAO) — are considered small-scale. Together, they bring in about half of the world’s catch. With human populations rising and developing nations getting wealthier, the demand for seafood is escalating. An accurate assessment of the shrinking global fish supply is thus crucial to planetary food security. Right now though, that’s impossible.