A new study shows that fish stocks in coral reefs along the coast of East Africa have been fished to worryingly low levels, with 70% below sustainable levels.The findings are a best-case scenario; computer models suggest stocks could be much lower.The study’s author calls for more careful regulation of fisheries in East Africa to allow stocks to recover — contrary to the current push for expansion of the fisheries sector. Fish populations in coral reefs off Kenya, Tanzania and Mozambique are being harvested at unsustainable rates, new research has found. In the study published in the journal Marine Ecology Progress Series, researchers found that at 38% of the coral reefs they surveyed in the region had fish stocks below sustainable levels. When sampling bias was accounted for, they estimate that 70% of the region’s coral reefs have been fished to below sustainable levels. Author Tim McClanahan, senior conservation zoologist at the Wildlife Conservation Society, surveyed fish populations at 238 sites along the East African coastline over 12 years. At each site, McClanahan counted fish, identified their species, and estimated their size in order to calculate their total biomass — a skill he has been refining for more than 30 years. “To count coral reefs is not the easiest thing,” McClanahan said. “Coral reefs are fairly chaotic and it gets more chaotic the more fish there are.” This is the first study of its kind and scale to be conducted in East Africa’s coral reefs and provides a worrying insight into the region’s fish stocks. “The findings are grounded on sound data sets collected in many sites along the coast,” said Edward Kimani, Research Scientist at Kenya’s Marine and Fisheries Institute, who was not involved with the study. East Africa’s fisheries are monitored by scientists at national fisheries departments, but their analyses are based predominantly on yield data reported by fishers. Their work is further complicated by the absence of reefs unaffected by fishing, which would provide baseline figures for comparison. “There are essentially no stock assessments in East Africa, which is a problem because you don’t know what the status of the sustainability is without these,” McClanahan said.